U.S. patent application number 14/914625 was filed with the patent office on 2016-07-21 for production apparatus for carbon nanotubes, feed unit for being part of production apparatus, and production method for carbon nanotubes.
This patent application is currently assigned to NATIONAL UNIVERSITY CORPORATION SHIZUOKA UNIVERSITY. The applicant listed for this patent is JNC CORPORATION, NATIONAL UNIVERSITY CORPORATION SHIZUOKA UNIVERSITY. Invention is credited to Yoku INOUE, Tauto NAKANISHI, Takayuki NAKANO.
Application Number | 20160207772 14/914625 |
Document ID | / |
Family ID | 52586680 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160207772 |
Kind Code |
A1 |
INOUE; Yoku ; et
al. |
July 21, 2016 |
PRODUCTION APPARATUS FOR CARBON NANOTUBES, FEED UNIT FOR BEING PART
OF PRODUCTION APPARATUS, AND PRODUCTION METHOD FOR CARBON
NANOTUBES
Abstract
The invention shows a production apparatus for producing carbon
nanotubes by the gas-phase catalysis process, comprising: a first
chamber having a growth region that is a region in which carbon
nanotubes are formed; a first temperature adjustment device capable
of adjusting a temperature of the growth region in the first
chamber; a pressure adjustment device capable of adjusting a
pressure in the first chamber; a first feed device capable of
feeding a carbon source to the growth region in the first chamber;
a second temperature adjustment device capable of adjusting a
temperature of a solid-phase iron family element-containing
material disposed in the production apparatus; and a second feed
device capable of feeding a gas-phase halogen-containing substance
into the production apparatus so that the iron family
element-containing material of which the temperature is adjusted to
a predetermined temperature by the second temperature adjustment
device can react with the halogen-containing substance.
Inventors: |
INOUE; Yoku; (Shizuoka,
JP) ; NAKANO; Takayuki; (Shizuoka, JP) ;
NAKANISHI; Tauto; (Chiba, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL UNIVERSITY CORPORATION SHIZUOKA UNIVERSITY
JNC CORPORATION |
Shizuoka
Tokyo |
|
JP
JP |
|
|
Assignee: |
NATIONAL UNIVERSITY CORPORATION
SHIZUOKA UNIVERSITY
Shizuoka
JP
JNC CORPORATION
Tokyo
JP
|
Family ID: |
52586680 |
Appl. No.: |
14/914625 |
Filed: |
August 28, 2014 |
PCT Filed: |
August 28, 2014 |
PCT NO: |
PCT/JP2014/072623 |
371 Date: |
February 25, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 23/745 20130101;
C01B 32/162 20170801; C01B 32/16 20170801 |
International
Class: |
C01B 31/02 20060101
C01B031/02; C23C 16/26 20060101 C23C016/26 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 28, 2013 |
JP |
2013-177237 |
Claims
1. A production apparatus for producing carbon nanotubes by a
gas-phase catalysis process, comprising: a first chamber having a
growth region that is a region in which carbon nanotubes are
formed; a first temperature adjustment device capable of adjusting
a temperature of the growth region in the first chamber; a pressure
adjustment device capable of adjusting a pressure in the first
chamber; a first feed device capable of feeding a carbon source to
the growth region in the first chamber; a second temperature
adjustment device capable of adjusting a temperature of a
solid-phase iron family element-containing material disposed in the
production apparatus; and a second feed device capable of feeding a
gas-phase halogen-containing substance into the production
apparatus so that the iron family element-containing material of
which the temperature is adjusted to a predetermined temperature by
the second temperature adjustment device can react with the
halogen-containing substance.
2. The production apparatus according to claim 1, wherein a
substrate is disposed in the growth region to allow the carbon
nanotubes to be formed in an array-like form on a base surface of
the substrate.
3. The production apparatus according to claim 1, wherein the
carbon nanotubes can be formed by a gas-phase flow reaction in the
growth region.
4. The production apparatus according to claim 1, further
comprising a second chamber in which the iron family
element-containing material can be accommodated and of which inside
communicates with inside of the first chamber, wherein the second
feed device can feed the halogen-containing substance into the
second chamber.
5. The production apparatus according to claim 1, further
comprising: a second chamber capable of accommodating the iron
family element-containing material; and a third feed device capable
of feeding a gas-phase substance existing in the second chamber
into the first chamber, wherein the second feed device can feed the
halogen-containing substance into the second chamber.
6. The production apparatus according to claim 1, wherein the iron
family element-containing material is disposed in the first
chamber.
7. A feed unit for a gas-phase catalyst, the feed unit being to be
part of a production apparatus for producing carbon nanotubes by a
gas-phase catalysis process, the feed unit comprising: a feed unit
chamber capable of accommodating a solid-phase iron family
element-containing material; a feed unit temperature adjustment
device capable of adjusting a temperature of the iron family
element-containing material in the feed unit chamber; a
halogen-containing substance feed device capable of feeding a
halogen-containing substance into the feed unit chamber; and a
discharge device capable of discharging the gas-phase catalyst
existing in the feed unit chamber outside the feed unit
chamber.
8. A production method for carbon nanotubes, the production method
using the feed unit according to claim 7 to obtain the carbon
nanotubes formed in an array-like form on a base surface of a
substrate.
9. A production method for carbon nanotubes, the production method
using the feed unit according to claim 7 to obtain the carbon
nanotubes as a generated substance by a gas-phase flow
reaction.
10. A production method for carbon nanotubes, comprising: a first
step of feeding a gas-phase catalyst into a first chamber, the
gas-phase catalyst including a substance obtained by reacting a
solid-phase iron family element-containing material and a gas-phase
halogen-containing substance with each other; and a second step of
foaming the carbon nanotubes from a carbon source fed into the
first chamber using a catalyst generated based on the gas-phase
catalyst existing in the first chamber.
11. The production method according to claim 10, wherein: the first
step includes allowing a substrate disposed in the first chamber to
exist in an atmosphere including the gas-phase catalyst; and the
second step includes forming the carbon nanotubes in an array-like
form on a base surface of the substrate.
12. The production method according to claim 11, wherein the carbon
source is fed into the first chamber in a state in which the
gas-phase catalyst exists in the first chamber via the first
step.
13. The production method according to claim 11, wherein a
temperature of the substrate in the first step is lower than a
temperature of the substrate in the second step.
14. The production method according to claim 10, wherein the carbon
nanotubes are formed as a generated substance by a gas-phase flow
reaction.
15. The production method according to claim 10, wherein an iron
family element contained in the iron family element-containing
material includes iron.
16. The production method according to claim 10, wherein the first
step includes performing a reaction to obtain the gas-phase
catalyst outside the first chamber, and the gas-phase catalyst is
fed into the first chamber from outside of the first chamber.
Description
TECHNICAL FIELD
[0001] The present invention relates to a production apparatus for
carbon nanotubes, a feed unit for being a part of the production
apparatus, and a production method for carbon nanotubes.
[0002] As used herein, the "carbon nanotube array" (also referred
to as a "CNT array" herein) is a kind of a synthetic structure of a
plurality of carbon nanotubes (also referred to as "CNT" herein)
(hereinafter, the individual shape of CNT giving such a synthetic
structure will be referred to as a "primary structure" while the
above synthetic structure may also be referred to as a "secondary
structure"), and means an aggregate of CNT in which a plurality of
CNT grow so as to be oriented in a predetermined direction
(specific one example may be a direction substantially parallel to
one normal line of a plane of a substrate) with regard to at least
part of a major axis direction. The "growth height" as used herein
refers to a length (height) of a CNT array grown from a substrate
in the direction parallel to the normal line of the substrate in a
state in which the CNT array is attached on the substrate.
[0003] In the present description, a structure having a
configuration in which a plurality of CNT are entangled to each
other will be referred to as a "CNT entangled body," in which the
structure is formed by continuously drawing the plurality of CNT
from the CNT array by taking part of CNT of the CNT array to pull
the CNT so as to be separated from the CNT array (work therefor
herein will be also referred to as "spinning" after work for
producing threads from fibers as related to a conventional
art).
BACKGROUND ART
[0004] CNT have a specific configuration of having an outside
surface formed of graphene, and therefore application in various
fields is expected as a functional material and also as a
structural material. Specifically, CNT have excellent
characteristics, such as high mechanical strength, light weight,
satisfactory electrical conduction characteristics, satisfactory
heat characteristics such as heat resistance and heat conductivity,
high resistance to chemical corrosion, and satisfactory field
emission characteristics. Accordingly, the use of CNT conceivably
includes a lightweight and high strength wire, a probe of a
scanning probe microscope (SPM), a cold cathode of a field emission
display (FED), an electrically conductive resin, a high strength
resin, a corrosion-resistant resin, a wear-resistant resin, a
highly lubricating resin, electrodes of a secondary battery and
fuel cell, an interlayer wiring material for LSI, and a
biosensor.
[0005] As one of production methods for CNT, Patent Literature No.
1 discloses a method comprising: preliminarily forming a
solid-phase metal catalyst layer on a surface of a substrate by
means of sputtering and the like, such as by vapor-depositing a
thin film of a metallic material; disposing the substrate provided
with the solid-phase metal catalyst layer in a reactor; forming
catalyst particles from the metal catalyst layer to be growth
nuclei on the substrate; and feeding a hydrocarbon gas into the
reactor to form a CNT array on the substrate. Hereinafter, the
method comprising: forming the solid-phase catalyst particles as
the growth nuclei on the substrate as described above; and feeding
a hydrocarbon-based material into the reactor, in which the
substrate provided with the solid-phase catalyst particles is
disposed, to produce a CNT array will be referred to as a
solid-phase catalysis process.
[0006] As a method for highly efficiently producing a CNT array by
the solid-phase catalysis process, Patent Literature No. 2
discloses a method of feeding a material gas that contains carbon
and no oxygen, a catalyst activator that contains oxygen, and an
atmospheric gas, while meeting predetermined conditions so that
they are brought into contact with a solid-phase catalyst
layer.
[0007] Another method is also disclosed which produces a CNT array
in a different manner from that of the method described above. More
specifically, Patent Literature No. 3 discloses a method
comprising: sublimating iron chloride; using the sublimated iron
chloride as a precursor to form a catalyst to be growth nuclei on a
substrate; and using the catalyst to form a CNT array. This method
is substantially different from the arts as disclosed in Patent
Literature Nos. 1 and 2 in that a halogen-containing substance in
gas-phase is used as a catalyst precursor and this substance is
used to form a catalyst. In the present description, the production
method for a CNT array as disclosed in Patent Literature No. 3 will
also be referred to as a gas-phase catalysis process.
CITATION LIST
Patent Literature
[0008] Patent Literature No. 1: JP 2004-107196 A [0009] Patent
Literature No. 2: JP 4803687 B [0010] Patent Literature No. 3: JP
2009-196873 A
DISCLOSURE OF INVENTION
Technical Problem
[0011] In the production method for a CNT array by such a gas-phase
catalysis process, the action of the catalyst may be different, as
caused by difference in the forming process of the catalyst, from
the production method for a CNT array by the above solid-phase
catalysis process. Therefore, the solid-phase catalysis process and
the gas-phase catalysis process are considered to be substantially
different production methods for a CNT array. Accordingly, when
producing CNT having various primary structures and secondary
structures by the gas-phase catalysis process, a variety of
approaches can be provided to improve the productivity based on the
production method being the gas-phase catalysis process.
[0012] An object of the present invention is to provide a means
capable of improving the production controllability of CNT to be
produced by the above gas-phase catalysis process.
Solution to Problem
[0013] The present invention provided to attain the above object is
as described below.
(1) A production apparatus for producing carbon nanotubes by a
gas-phase catalysis process, comprising: a first chamber having a
growth region that is a region in which carbon nanotubes are
formed; a first temperature adjustment device capable of adjusting
a temperature of the growth region in the first chamber; a pressure
adjustment device capable of adjusting a pressure in the first
chamber; a first feed device capable of feeding a carbon source to
the growth region in the first chamber; a second temperature
adjustment device capable of adjusting a temperature of a
solid-phase iron family element-containing material disposed in the
production apparatus; and a second feed device capable of feeding a
gas-phase halogen-containing substance into the production
apparatus so that the iron family element-containing material of
which the temperature is adjusted to a predetermined temperature by
the second temperature adjustment device can react with the
halogen-containing substance. (2) The production apparatus
according to the above (1), wherein a substrate is disposed in the
growth region to allow the carbon nanotubes to be formed in an
array-like form on a base surface of the substrate. (3) The
production apparatus according to the above (1), wherein the carbon
nanotubes can be formed by a gas-phase flow reaction in the growth
region. (4) The production apparatus according to any one of the
above (1) to (3), further comprising a second chamber in which the
iron family element-containing material can be accommodated and of
which inside communicates with inside of the first chamber, wherein
the second feed device can feed the halogen-containing substance
into the second chamber. (5) The production apparatus according to
any one of the above (1) to (3), further comprising: a second
chamber capable of accommodating the iron family element-containing
material; and a third feed device capable of feeding a gas-phase
substance existing in the second chamber into the first chamber,
wherein the second feed device can feed the halogen-containing
substance into the second chamber. (6) The production apparatus
according to any one of the above (1) to (3), wherein the iron
family element-containing material is disposed in the first
chamber. (7) A feed unit for a gas-phase catalyst, the feed unit
being to be part of a production apparatus for producing carbon
nanotubes by a gas-phase catalysis process, the feed unit
comprising: a feed unit chamber capable of accommodating a
solid-phase iron family element-containing material; a feed unit
temperature adjustment device capable of adjusting a temperature of
the iron family element-containing material in the feed unit
chamber; a halogen-containing substance feed device capable of
feeding a halogen-containing substance into the feed unit chamber;
and a discharge device capable of discharging the gas-phase
catalyst existing in the feed unit chamber outside the feed unit
chamber. (8) A production method for carbon nanotubes, the
production method using the feed unit according to the above (7) to
obtain the carbon nanotubes formed in an array-like form on a base
surface of a substrate. (9) A production method for carbon
nanotubes, the production method using the feed unit according to
the above (7) to obtain the carbon nanotubes as a generated
substance by a gas-phase flow reaction. (10) A production method
for carbon nanotubes, comprising: a first step of feeding a
gas-phase catalyst into a first chamber, the gas-phase catalyst
including a substance obtained by reacting a solid-phase iron
family element-containing material and a gas-phase
halogen-containing substance with each other; and a second step of
forming the carbon nanotubes from a carbon source fed into the
first chamber using a catalyst generated based on the gas-phase
catalyst existing in the first chamber. (11) The production method
according to the above (10), wherein: the first step includes
allowing a substrate disposed in the first chamber to exist in an
atmosphere including the gas-phase catalyst; and the second step
includes forming the carbon nanotubes in an array-like form on a
base surface of the substrate. (12) The production method according
to the above (11), wherein the carbon source is fed into the first
chamber in a state in which the gas-phase catalyst exists in the
first chamber via the first step. (13) The production method
according to the above (11) or (12), wherein a temperature of the
substrate in the first step is lower than a temperature of the
substrate in the second step. (14) The production method according
to the above (10), wherein the carbon nanotubes are formed as a
generated substance by a gas-phase flow reaction. (15) The
production method according to any one of the above (10) to (14),
wherein an iron family element contained in the iron family
element-containing material includes iron. (16) The production
method according to any one of the above (10) to (15), wherein the
first step includes performing a reaction to obtain the gas-phase
catalyst outside the first chamber, and the gas-phase catalyst is
fed into the first chamber from outside of the first chamber.
Advantageous Effects of Invention
[0014] According to the production method for CNT of the present
invention, it becomes easy to feed the gas-phase catalyst into the
first chamber. Therefore, when the CNT are produced by the
gas-phase catalysis process, it is expected to make easy to control
the generation amount and the structural properties (both the
primary and secondary structures) of the CNT.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a drawing schematically showing a configuration of
a production apparatus for a CNT array according to a first
embodiment of the present invention.
[0016] FIG. 2 is a drawing schematically showing a configuration of
a gas-phase catalyst feed device of the production apparatus shown
in FIG. 1.
[0017] FIG. 3 is a drawing schematically showing a configuration of
an example of a production apparatus for a CNT array according to a
second embodiment of the present invention.
[0018] FIG. 4 is a drawing schematically showing a configuration of
another example of a production apparatus for a CNT array according
to the second embodiment of the present invention.
[0019] FIG. 5 is an image showing CNT that constitute a CNT
array.
[0020] FIG. 6 is a graph showing an outer diameter distribution of
CNT that constitute a CNT array.
[0021] FIG. 7 is an image showing a state in which a CNT entangled
body is produced by spinning a CNT array.
[0022] FIG. 8 is an enlarged image of part of a CNT entangled body
obtained from a CNT array.
[0023] FIG. 9 is an image when observing a CNT mesh produced by a
production method according to Example 1.
[0024] FIG. 10 is an image when observing a CNT mesh produced by a
production method according to Example 2.
[0025] FIG. 11 is an image when observing a fracture surface
including a direction parallel to the growth direction of a CNT
array produced by a production method according to Example 3.
[0026] FIG. 12 is an image when observing a fracture surface
including a direction parallel to the growth direction of a CNT
array produced by a production method according to Example 4.
[0027] FIG. 13 is an image when observing a fracture surface
including a direction parallel to the growth direction of a CNT
array produced by a production method according to Example 5.
[0028] FIG. 14 is an image when observing a CNT mesh produced by a
production method according to Example 6.
[0029] FIG. 15 is an image when observing a fracture surface
including a direction parallel to the growth direction of a CNT
array produced by a production method according to Example 16.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Embodiments of the present invention will be described
below.
1. Production Apparatus for CNT Array
[0031] A production apparatus for a CNT array according to a first
embodiment of the present invention will be described with
reference to the drawings.
[0032] FIG. 1 is a drawing schematically showing a configuration of
a production apparatus used for a production method for a CNT array
according to the first embodiment of the present invention.
[0033] As shown in FIG. 1, production apparatus 10 for a CNT array
is provided with electric furnace 12. Electric furnace 12 takes on
a substantially cylindrical shape that extends along predetermined
direction A (direction in which a material gas flows). Inside
electric furnace 12, reaction vessel pipe 14 as a first chamber
having a growth region that is a region in which CNT are formed is
passed through. Reaction vessel pipe 14 is a substantially
cylindrically-shaped member formed of a heat-resistant material
such as quartz, has an outside diameter smaller than an outside
diameter of electric furnace 12, and extends along predetermined
direction A. In FIG. 1, substrate 28 provided with a base surface
that is a surface on which a CNT array grows is disposed in the
growth region of reaction vessel pipe 14. That is, the growth
region in production apparatus 10 for a CNT array includes a region
in which substrate 28 in reaction vessel pipe 14 is disposed.
[0034] Electric furnace 12 is provided with heater 16 and
thermocouple 18. In production apparatus 10 for a CNT array, heater
16 and thermocouple 18 constitute a first temperature adjustment
device. Heater 16 is disposed so as to surround a predetermined
region (in other words, a predetermined region of substantially
cylindrically-shaped reaction vessel pipe 14 in an axial direction,
and hereinafter, also referred to as a "heating region") in
predetermined direction A of reaction vessel pipe 14 to generate
heat for raising a temperature of an atmosphere in the pipe in the
heating region of reaction vessel pipe 14. Thermocouple 18 is
disposed in the vicinity of the heating region of reaction vessel
pipe 14 inside electric furnace 12 to allow output of an electrical
signal that represents a temperature associated with a temperature
of the atmosphere in the pipe in the heating region of reaction
vessel pipe 14. Heater 16 and thermocouple 18 are electrically
connected to control device 20.
[0035] To the upstream side (in FIG. 1, to one end at the left
side) of reaction vessel pipe 14 in predetermined direction A, feed
device 22 is connected. Feed device 22 is provided with raw
material gas feed device 30, gas-phase catalyst feed device 31,
gas-phase co-catalyst feed device 32, and auxiliary gas feed device
33. Feed device 22 is electrically connected to control device 20,
and also electrically connected to each feed device of feed device
22.
[0036] Raw material gas feed device 30 (first feed device) can
feed, into the inside of reaction vessel pipe 14 (in particular, to
the growth region), a carbon compound (for example, hydrocarbon
such as acetylene) that serves as a raw material of CNT
constituting the CNT array, i.e. a raw material gas that contains a
carbon source. A flow rate of feeding the raw material gas from raw
material gas feed device 30 can be regulated using a publicly known
flow rate regulating instrument such as mass flow.
[0037] Gas-phase catalyst feed device 31 can feed a gas-phase
catalyst into the inside of reaction vessel pipe 14 (in particular,
to the growth region). As used herein, the "gas-phase catalyst" is
a collective term of a substance that is a halogen-containing
catalyst precursor and that can be in a gas-phase state in the
growth region of the reaction vessel pipe 14 and a suspended
substance that is formed based on the halogen-containing catalyst
precursor. At least part of substances that constitute the
gas-phase catalyst attaches on the base surface of the substrate
28, and at least part of catalysts that contribute to formation of
a CNT array is formed based on the attached substances.
[0038] As shown in FIG. 2, gas-phase catalyst feed device 31 has a
unit structure as will be described below. That is, gas-phase
catalyst feed device 31 is provided with feed unit chamber 31A that
can accommodate therein solid-phase iron family element-containing
material M and a feed unit temperature adjustment device that can
adjust the temperature of iron family element-containing material M
in feed unit chamber 31A. In production apparatus 10 for a CNT
array, the feed unit temperature adjustment device constitutes a
second temperature adjustment device. In FIG. 2, the feed unit
temperature adjustment device is composed of heater 31B and a
temperature measurement device such as a thermocouple not shown.
The feed unit temperature adjustment device can adjust the
temperature of iron family element-containing material M in feed
unit chamber 31A.
[0039] Gas-phase catalyst feed device 31 is provided with
halogen-containing substance feed device 31C (second feed device)
that can feed a halogen-containing substance into feed unit chamber
31A. Iron family element-containing material M, of which the
temperature is adjusted to a predetermined temperature by the feed
unit temperature adjustment device (including heater 31B and the
like) in feed unit chamber 31A, reacts with the halogen-containing
substance fed by halogen-containing substance feed device 31C
thereby to be capable of generating a kind of a gas-phase catalyst.
Gas-phase catalyst feed device 31 is provided with discharge device
31D that can discharge a gas-phase substance, which includes a
gas-phase catalyst formed by the above reaction and exists in the
feed unit chamber 31A, outside feed unit chamber 31A. In FIG. 1,
the destination of the gas-phase substance is inside of reaction
vessel pipe 14, and the gas-phase substance, which includes a
gas-phase catalyst, is fed into reaction vessel pipe 14 (in
particular, to the growth region) from gas-phase catalyst feed
device 31. Halogen-containing substance feed device 31C and
discharge device 31D may be provided with means for adjusting the
amount of a substance that passes therethrough.
[0040] A specific method of accommodating solid-phase iron family
element-containing material M in feed unit chamber 31A and a
specific form of iron family element-containing material M in feed
unit chamber 31A are not limited. When iron family
element-containing material M is an iron-based material, iron
family element-containing material M may be a block-like iron
member or may also be a flat plate-like iron member. In an
alternative embodiment, iron family element-containing material M
may have a steel wool-like form or a mesh-like form. In a further
embodiment, iron family element-containing material M may have a
powder form.
[0041] Gas-phase catalyst feed device 31 may have an exhaust system
(pressure adjustment device) that can regulate the pressure in feed
unit chamber 31A, and may also have a gas feed system (gas feed
device) that can adjust the atmosphere in feed unit chamber 31A
(specific examples include purging the inside with an inert gas or
hydrogen). Having such an exhaust system and/or gas feed system
allows the reaction of iron family element-containing material M
and halogen-containing substance to more stably occur.
[0042] Gas-phase co-catalyst feed device 32 can feed a gas-phase
co-catalyst into reaction vessel pipe 14 (in particular, to the
growth region). The gas-phase co-catalyst will be described later.
The flow rate of feeding the gas-phase co-catalyst from gas-phase
co-catalyst feed device 32 can be regulated using the publicly
known flow rate regulating instrument such as the mass flow.
[0043] Auxiliary gas feed device 33 allows feed of a gas other than
the above raw material gas, gas-phase catalyst and gas-phase
co-catalyst, for example, an inert gas such as argon (such a gas
herein is generically referred to as an "auxiliary gas") into
reaction vessel pipe 14 (in particular, to the growth region). The
flow rate of feeding the auxiliary gas from auxiliary gas feed
device 33 can be regulated using the publicly known flow rate
regulating instrument such as the mass flow.
[0044] To the other end at the downstream side (right side in FIG.
1) of reaction vessel pipe 14 in predetermined direction A,
pressure regulating valve 23 (part of the pressure adjustment
device) and exhaust device 24 (also part of the pressure adjustment
device) are connected. Pressure regulating valve 23 allows
regulation of the pressure in reaction vessel pipe 14 by varying a
degree of opening and closing of the valve. Exhaust device 24
performs vacuum exhaust of the inside of reaction vessel pipe 14.
Specific types of exhaust device 24 are not particularly limited,
and a rotary pump, oil diffusion pump, mechanical booster,
turbomolecular pump, cryopump or the like can be used alone or in
combination therewith. Pressure regulating valve 23 and exhaust
device 24 are electrically connected to control device 20. In
addition, reaction vessel pipe 14 is provided therein with pressure
gauge 13 for measuring the internal pressure thereof. Pressure
gauge 13 is electrically connected to control device 20 to allow
output of an electrical signal that represents the internal
pressure of reaction vessel pipe 14 to control device 20.
[0045] As described above, control device 20 is electrically
connected to heater 16, thermocouple 18, feed device 22, pressure
gauge 13, pressure regulating valve 23 and exhaust device 24 to be
input with the electrical signals output from the devices or the
like, and based on the input electrical signals, to control
operation of the devices or the like. Examples of specific
operation of control device 20 will be presented below.
[0046] Control device 20 allows input of the electrical signal
output from thermocouple 18 and related to the internal temperature
of reaction vessel pipe 14, and to heater 16, allows output of a
control signal related to operation of heater 16 as determined
based on the electrical signal. Heater 16 to which the control
signal from the control device is input allows operation for
increasing or decreasing an amount of produced heat to vary the
internal temperature in the heating region of reaction vessel pipe
14, based on the control signal.
[0047] Control device 20 allows input of an electrical signal
output from pressure gauge 13 and related to the internal pressure
in the heating region of reaction vessel pipe 14, and to pressure
regulating valve 23 and exhaust device 24, allows output of a
control signal as related to operation of pressure regulating valve
23 and exhaust device 24 as determined based on the electrical
signal. Pressure regulating valve 23 and exhaust device 24 to which
the control signal from control device 20 is input allow operation
of varying a degree of opening of pressure regulating valve 23,
and/or varying the exhausting capability of exhaust device 24, and
the like, based on the control signal.
[0048] According to a preset timetable, control device 20 allows,
to each device, output of a control signal for controlling
operation of each device or the like. For example, control device
20 allows, to feed device 22, output of a control signal for
determining start and stop of feeding a substance from each of raw
material gas feed device 30, gas-phase catalyst feed device 31,
gas-phase co-catalyst feed device 32 and auxiliary gas feed device
33 of gas feed device 22, and the flow rate of feed thereof. Gas
feed device 22 to which the control signal is input, according to
the control signal, allows operation of each feed device to start
or stop feed of each substance such as the raw material gas into
reaction vessel pipe 14.
[0049] Control device 20 can control operation of each part that
constitutes gas-phase catalyst feed device 31. More specifically,
based on the electrical signal from the temperature measurement
device such as a thermocouple of gas-phase catalyst feed device 31,
control device 20 can output a control signal as related to
operation of heater 31B. Heater 31B, to which the control signal is
input, varies the temperature of iron family element-containing
material M in feed unit chamber 31A in accordance with the control
signal. Control device 20 can output a control signal as related to
operation of halogen-containing substance feed device 31C.
Halogen-containing substance feed device 31C, to which the control
signal is input, varies the feed amount of the halogen-containing
substance into feed unit chamber 31A in accordance with the control
signal. This variation of feed amount can vary the degree of the
reaction of iron family element-containing material M and
halogen-containing substance thereby to adjust the generation
amount of gas-phase catalyst and the like. Control device 20 can
output a control signal as related to operation of discharge device
31D. Discharge device 31D, to which the control signal is input,
can adjust the timing and amount of discharging the gas-phase
catalyst generated by the reaction of iron family
element-containing material M and halogen-containing substance
outside feed unit chamber 31A, i.e. feeding the gas-phase catalyst
into reaction vessel pipe 14 in FIG. 1, in accordance with the
control signal. When gas-phase catalyst feed device 31 is provided
with additional exhaust system and/or gas feed system as described
above, control device 20 can output control signals as related to
operations thereof.
[0050] A production apparatus for a CNT array according to a second
embodiment of the present invention will be described with
reference to the drawings. FIG. 3 is a drawing schematically
showing a configuration of a production apparatus used for a
production method for a CNT array according to the second
embodiment of the present invention. As shown in FIG. 3, production
apparatus 50 for a CNT array according to the second embodiment of
the present invention has a common basic configuration with that of
production apparatus 10 for a CNT array according to the first
embodiment of the present invention as shown in FIG. 1 except that
feed device 22 is provided with halogen feed device 51 that can
feed a halogen-containing substance as substituted for gas-phase
catalyst feed device 31 and that iron family element-containing
material M can be disposed in reaction vessel pipe 14.
[0051] In such a configuration of production apparatus 50 for a CNT
array according to the second embodiment of the present invention,
the reaction of halogen-containing substance, which is fed from
halogen feed device 51 to the vicinity of iron family
element-containing material M, and iron family element-containing
material M is performed in reaction vessel pipe 14. Gas-phase
catalyst obtained by this reaction diffuses in reaction vessel pipe
14 to reach the growth region. In FIG. 3, heater 16 can adjust the
temperature of substrate 28 disposed in reaction vessel pipe 14 and
the temperature of iron family element-containing material M.
[0052] As in production apparatus 50 for a CNT array according to
the second embodiment of the present invention, when the reaction
of the halogen-containing substance and iron family
element-containing material M is performed in reaction vessel pipe
14, the atmosphere temperature in reaction vessel pipe 14 can be
controlled in a divided manner in reaction vessel pipe 14. For
example, production apparatus 60 for a CNT array shown in FIG. 4 is
provided with a plurality of thermocouples 18A and 18B, and heater
16 can control the temperature in a divided manner in the axial
direction of reaction vessel pipe 14 (upstream side and downstream
side) based on the electrical signals from respective
thermocouples.
[0053] Therefore, in the region at the upstream side (left side in
FIG. 4) of reaction vessel pipe 14, the upstream side (left side in
FIG. 4) of heater 16 can be operated based on the electrical signal
from thermocouple 18A thereby to adjust the temperature of iron
family element-containing material M disposed in a space at the
downstream side (right side in FIG. 4) of halogen feed device 51.
Production apparatus 60 for a CNT array shown in FIG. 4 is provided
with tubular member 61 at the downstream side of halogen feed
device 51, and the tubular member 61 has a downstream-side end with
an opening from which iron family element-containing material M is
disposed in a hollow portion of the tubular member. Employing such
a structure increases the possibility that the halogen-containing
substance fed from halogen feed device 51 and iron family
element-containing material M react with each other, which may be
preferred.
[0054] In the region at the downstream side (right side in FIG. 4)
of reaction vessel pipe 14, the downstream side (right side in FIG.
4) of heater 16 can be operated based on the electrical signal from
thermocouple 18B thereby to adjust the temperature of the growth
region in which substrate 28 is disposed. According to such a
structure, it is possible to generate the gas-phase catalyst at the
upstream side of reaction vessel pipe 14 while adjusting the
temperature of the reaction region at the downstream side of
reaction vessel pipe 14.
[0055] A production apparatus for a CNT array according to an
embodiment of the present invention may be provided with two or
more structural features of the above production apparatuses 10, 50
and 60 for a CNT array. In an embodiment, a CNT apparatus may be
provided with gas-phase catalyst feed device 31 so as to be capable
of feeding the gas-phase substance including the gas-phase catalyst
into reaction vessel pipe 14 and may further be provided with
halogen feed device 51 so that iron family element-containing
material M disposed in reaction vessel pipe 14 and the
halogen-containing substance fed from halogen feed device 51 can
react with each other in reaction vessel pipe 14.
2. Production Method for CNT Array
[0056] A production method for a CNT array according to an
embodiment of the present invention will be described. The
production method for a CNT array according to the present
embodiment includes a first step and a second step.
(1) First Step
[0057] The production method for a CNT array according to the
present embodiment includes a first step that feeds the gas-phase
catalyst, which includes a substance obtained by reacting
solid-phase iron family element-containing material M and gas-phase
halogen-containing substance, into the first chamber. This reaction
of solid-phase iron family element-containing material M and
gas-phase halogen-containing substance may be performed outside
reaction vessel pipe 14 as in the case of using production
apparatus 10 for a CNT array, or may also be performed inside
reaction vessel pipe 14 as in the case of using production
apparatus 50 or 60 for a CNT array. In this manner, substrate 28
disposed in reaction vessel pipe 14 is allowed to exist in an
atmosphere that includes the gas-phase catalyst.
[0058] Here, in the production method for a CNT array according to
the present embodiment, it is preferred that substrate 28 is
provided with a base surface that is a surface formed of a material
including an oxide of silicon, at least as part of the surface of
substrate 28.
[0059] The specific constitution of substrate 28 is not limited.
The shape thereof is arbitrary, and may be a simple shape such as a
flat plate or a cylinder, or may have a three-dimensional shape in
which complicated recesses and projections are provided. Moreover,
the entire surface of the substrate may be the base surface, or may
be in a so-called patterned state in which only part of the surface
of the substrate is the base surface, and other parts are not.
[0060] The base surface is a surface formed of a material that
contains an oxide of silicon, and the CNT array is formed on the
base surface in the second step. Detail of the material
constituting the base surface is not limited as long as the
material contains an oxide of silicon. Specific one example of the
material constituting the base surface may be quartz (SiO.sub.2).
Specific other examples of the material constituting the base
surface include SiO.sub.x (x.ltoreq.2) which can be obtained such
as by sputtering silicon in an oxygen-containing atmosphere.
Specific still another example may be silicon-containing composite
oxide. Specific examples of an element other than silicon and
oxygen that constitutes the composite oxide include Fe, Ni and Al.
Specific still another example may be a compound in which a
nonmetallic element such as nitrogen and boron is added to an oxide
of silicon.
[0061] The material constituting the base surface may be identical
with or different from a material constituting substrate 28. To
present specific examples, specific examples include a case where
the material constituting substrate 28 is formed of quartz and the
material constituting the base surface is also formed of quartz,
and a case where the material constituting substrate 28 is formed
of a silicon substrate based essentially on silicon, and the
material constituting the base surface is formed of an oxide film
thereof.
[0062] As described above, the first step includes: feeding the
gas-phase catalyst into reaction vessel pipe 14 using gas-phase
catalyst feed device 31 in production apparatus 10 or using halogen
feed device 51 and iron family element-containing material M
disposed in reaction vessel pipe 14 in production apparatus 50 or
60; and allowing substrate 28 provided with the above base surface
to exist in an atmosphere that includes the gas-phase catalyst. Any
of production apparatuses 10, 50 and 60 for a CNT array can be used
to feed various kinds of gas-phase catalysts into reaction vessel
pipe 14 by appropriately selecting the composition of iron family
element-containing material M and the kind of halogen-containing
substance.
[0063] Iron family element-containing material M is a material that
contains an iron family element (i.e. at least one kind of iron,
cobalt, and nickel), and the specific composition thereof is not
limited. Specific examples of iron family element-containing
material M include iron-based alloy (steel), cobalt base alloy, and
nickel base alloy, and examples of the alloy element include other
iron family elements, chromium, manganese, titanium, niobium,
vanadium, silicon, phosphorus, tungsten, and molybdenum. Iron
family element-containing material M may be constituted of one kind
of material, or may also be constituted of plural kinds of
materials. In view of easy availability, easy formation of CNT and
the like, it is preferred that the iron family elements contained
in iron family element-containing material M include iron.
[0064] The halogen-containing substance is a material that contains
halogen (i.e. at least one kind of fluorine, chlorine, bromine, and
iodine), and the specific composition thereof is not limited.
Specific examples of the halogen-containing substance include
hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide
(HBr), and hydrogen iodide (HI). The halogen-containing substance
may be constituted of one kind of substance, or may also be
constituted of plural kinds of substances.
[0065] The gas-phase catalyst according to the present embodiment
includes a reaction product of iron family element-containing
material M and halogen-containing substance, and specific examples
thereof include halide of an iron family element (also referred to
as "iron family element halide" herein). Specific further examples
of such iron family element halide include iron fluoride, cobalt
fluoride, nickel fluoride, iron chloride, cobalt chloride, nickel
chloride, iron bromide, cobalt bromide, nickel bromide, iron
iodide, cobalt iodide, and nickel iodide. In the iron family
element halide, different compounds may occasionally exist
according to valence of ion of the iron family element, such as
iron(II) chloride and iron(III) chloride. The gas-phase catalyst
may be constituted of one kind of substance or plural kinds of
substances.
[0066] In addition to any of the above feed methods, another means
may be used to feed the gas-phase catalyst into reaction vessel
pipe 14. To present a specific example in such a case, when
iron(II) chloride, anhydrous, as the catalyst source is disposed
inside the heating region of reaction vessel pipe 14 to sublimate
the iron(II) chloride, anhydrous, by heating the inside of the
heating region of reaction vessel pipe 14 and simultaneously
negatively pressurizing the inside, the gas-phase catalyst
including a vapor of the iron(II) chloride is allowed to exist in
reaction vessel pipe 14.
[0067] Pressure of the atmosphere in reaction vessel pipe 14 in the
first step, specifically, in the growth region in which substrate
28 is disposed is not particularly limited. The pressure may be the
atmospheric pressure (about 1.0.times.10.sup.5 Pa) or a negative or
positive pressure. When the inside of reaction vessel pipe 14 is
adjusted to a negative pressure atmosphere in the second step, the
atmosphere is preferably adjusted to the negative pressure also in
the first step to shorten transition time between the steps. In a
case where the inside of reaction vessel pipe 14 is adjusted to the
negative pressure atmosphere in the first step, the specific total
pressure in the atmosphere is not particularly limited. Specific
examples include adjustment to 10.sup.-2 Pa or more and 10.sup.4 Pa
or less.
[0068] When gas-phase catalyst feed device 31 is used to feed the
gas-phase catalyst, the temperature in the atmosphere in reaction
vessel pipe 14 in the first step is not particularly limited. The
temperature may be ordinary temperature (about 25.degree. C.), and
the atmosphere may be heated or cooled.
[0069] As will be described later, the growth region in reaction
vessel pipe 14 is preferably heated in the second step, and
therefore the growth region may preferably be heated also in the
first step to shorten the transition time between the steps.
[0070] When the temperature of the growth region in reaction vessel
pipe 14 is increased in the first step, the temperature of
substrate 28 disposed in the growth region also increases unless
cooling is performed. As a result, depending on the atmospheric
composition of the grow region, the temperature of substrate 28
increasing in the first step may possibly affect the formation of
catalyst on the base surface of substrate 28 and the like. Specific
examples of such an effect include a case in which, when the
gas-phase catalyst fed into reaction vessel pipe 14 from gas-phase
catalyst feed device 31 includes a halogen-containing substance,
e.g. hydrogen halide, this halogen-containing substance affects the
formation of catalyst formed on the base surface of substrate 28
and the like. If it is preferred to reduce such an effect, the
temperature of the growth region in reaction vessel pipe 14 should
not be unduly increased in the first step. More specifically, the
temperature of substrate 28 in the first step may preferably be
lower than the temperature of substrate 28 in the second step.
[0071] When halogen feed device 51 is used to feed the gas-phase
catalyst, the temperature of the atmosphere in reaction vessel pipe
14 may have to be increased to such an extent that a reaction
occurs in reaction vessel pipe 14 to generate a substance as one
kind of gas-phase catalyst from the halogen-containing substance
and iron family element-containing material M. This temperature may
be set in accordance with the kind of the halogen-containing
substance, the kind of iron family element-containing material M,
the pressure of the atmosphere in reaction vessel pipe 14, and the
like. Even in such a case, when the problem as described above is
concerned, it is preferred to employ a configuration as production
apparatus 60 for a CNT array so that the temperature of substrate
28 is not unduly increased.
[0072] When halogen-containing substances other than the gas-phase
catalyst can be fed into reaction vessel pipe 14 in the first step,
such halogen-containing substances may include those that function
as an etchant for the catalyst having been formed, owing to
carrying out the first step, on the base surface of substrate 28
and that have a possibility of affecting the formation of CNT
(specific examples of such halogen-containing substances include
hydrogen halide as described above). If it is preferred to reduce
this effect, the feed amount of such halogen-containing substances
other than the gas-phase catalyst into reaction vessel pipe 14 may
be restricted so that the concentration of the above
halogen-containing substances is not unduly increased in reaction
vessel pipe 14 (particularly in the growth region).
[0073] In addition to the above method, iron(II) chloride,
anhydrous, may be used as the feed source for the gas-phase
catalyst, this iron(II) chloride, anhydrous, may be heated to
sublimate the iron(II) chloride, and a generated vapor of the
iron(II) chloride may be introduced into reaction vessel pipe 14 in
which substrate 28 is disposed. The sublimation temperature of
iron(II) chloride is about 950 K in the atmospheric pressure (about
1.0.times.10.sup.5 Pa), but can be decreased by adjusting the
atmosphere inside the heating region of reaction vessel pipe 14 to
a negative pressure.
(2) Second Step
[0074] In the second step, the catalyst generated based on the
gas-phase catalyst existing in the first chamber is used to form
CNT from the carbon source contained in the raw material gas fed
into the first chamber. Specifically, the gas-phase catalyst, which
includes a reaction product of iron family element-containing
material M and halogen-containing substance, is used as a catalyst
precursor to generate a catalyst on substrate 28, and the catalyst
is used to form CNT from the carbon source.
[0075] Kinds of the raw material gas are not particularly limited,
but ordinarily, a hydrocarbon-based material is used and specific
examples include acetylene. The method for allowing the raw
material gas to exist in reaction vessel pipe 14 (particularly in
the growth region) is not particularly limited. As in production
apparatuses 10, 50 and 60 described above, the raw material gas may
be allowed to exist by feeding the raw material gas from raw
material gas feed device 30, or a material that can generate the
raw material gas may be allowed to previously exist inside reaction
vessel pipe 14 to generate the raw material gas from the material
and to diffuse the raw material gas in reaction vessel pipe 14, and
thus the second step may be started. When the raw material gas is
fed from raw material gas feed device 30, the flow rate of feeding
the raw material gas into reaction vessel pipe 14 is preferably
controlled using a flow rate adjusting instrument. The flow rate of
feed is ordinarily expressed in terms of a unit of sccm and 1 sccm
means a flow rate of 1 mL per minute for gas converted under an
environment of 273 K and 1.01.times.10.sup.5 Pa. In the case of the
production apparatuses 10, 50 and 60 having the configurations as
shown in FIGS. 1, 3 and 4, the flow rate of gas to be fed into
reaction vessel pipe 14 is set up based on an inside diameter of
reaction vessel pipe 14, pressure measured using pressure gauge 13,
and the like. Specific examples of a preferred flow rate of feeding
an acetylene-containing raw material gas when the pressure by
pressure gauge 13 is within 1.times.10.sup.2 Pa or more and
1.times.10.sup.3 Pa or less include 10 sccm or more and 1,000 sccm
or less, and in this case, the flow rate thereof is further
preferably adjusted to 20 sccm or more and 500 sccm or less, and
particularly preferably, to 50 sccm or more and 300 sccm or
less.
[0076] As used herein, the "gas-phase co-catalyst" means a
gas-phase component having a function (hereinafter, also referred
to as a "growth promotion function") for enhancing the growth rate
of a CNT array to be produced by the gas-phase catalysis process
described above, and in a preferred embodiment, a gas-phase
component having a function (hereinafter, also referred to as a
"function for improving spinning properties") for further improving
the spinning properties of the CNT array produced. Detail of the
growth promotion function is not particularly limited. Specific
components of the gas-phase co-catalyst are not particularly
limited as long as the components fulfill the growth promotion
function described above, and preferably, also the function for
improving spinning properties, and specific examples include
acetone.
[0077] The method for allowing the gas-phase co-catalyst to exist
in reaction vessel pipe 14 (particularly in the growth region) in
the second step is not particularly limited. As in production
apparatuses 10, 50 and 60 described above, the gas-phase
co-catalyst may be allowed to exist by feeding the gas-phase
co-catalyst from gas-phase co-catalyst feed device 32. When the
gas-phase co-catalyst is fed from gas-phase co-catalyst feed device
32, the flow rate of feeding the gas-phase co-catalyst into
reaction vessel pipe 14 is preferably controlled using the flow
rate adjusting instrument. In an alternative embodiment, a material
that can generate the gas-phase co-catalyst may be allowed to
previously exist inside reaction vessel pipe 14 to generate the
gas-phase co-catalyst from the material by means of heating,
pressure reduction or the like and to diffuse the gas-phase
co-catalyst in reaction vessel pipe 14.
[0078] The total pressure in the atmosphere inside reaction vessel
pipe 14 in the second step is not particularly limited. The total
pressure may be the atmospheric pressure (about 1.0.times.10.sup.5
Pa) or a negative or positive pressure. The total pressure may be
appropriately set up in consideration of a composition (partial
pressure ratio) of substances existing in reaction vessel pipe 14,
or the like. To show specific examples of a pressure range when the
atmosphere inside the heating region in reaction vessel pipe 14 is
adjusted to a negative pressure, the pressure range is adjusted to
1.times.10.sup.1 Pa or more and 1.times.10.sup.4 Pa or less,
preferably, 2.times.10.sup.1 Pa or more and 5.times.10.sup.3 Pa or
less, further preferably, 5.times.10.sup.1 Pa or more and
2.times.10.sup.3 Pa or less, and particularly preferably,
1.times.10.sup.2 Pa or more and 1.times.10.sup.3 Pa or less.
[0079] Temperature of the growth region in reaction vessel pipe 14
in the second step is not particularly limited as long as a CNT
array can be formed on the base surface of substrate 28 using the
raw material gas under the condition in which an appropriate amount
of the gas-phase catalyst and the gas-phase co-catalyst, which is
used as necessary, exists in the growth region. As described above,
setting a lowered temperature on the base surface of substrate 28
in the first step may contribute to the formation of the catalyst
on the base surface, in which case the temperature of the growth
region in reaction vessel pipe 14 in the second step may be changed
to be higher than that in the first step.
[0080] Temperature of the base surface in the second step may be
controlled by adjusting the temperature of the growth region in
reaction vessel pipe 14. Temperature of the base surface of
substrate 28 in the second step is preferably heated to
8.times.10.sup.2 K or higher. When the temperature of the base
surface of substrate 28 is 8.times.10.sup.2 K or higher,
interaction between the gas-phase catalyst and gas-phase
co-catalyst, which is used as necessary, and the raw material gas
is easily caused on the base surface to facilitate the growth of a
CNT array on the base surface of substrate 28. From a viewpoint of
easily causing this interaction, the temperature of the base
surface in the second step is preferably heated to 9.times.10.sup.2
K or higher, more preferably 1.0.times.10.sup.3 K or higher, and
particularly preferably 1.1.times.10.sup.3 K or higher. The upper
limit of the temperature of the base surface of substrate 28 in the
second step is not particularly limited, but when the temperature
is excessively high, the material constituting the base surface
and/or the material constituting the substrate (these materials may
be or may not be identical) may occasionally lack in stability as
solid, and therefore the upper limit is preferably set up in
consideration of the melting point and sublimation temperature of
these materials. When the load of the reaction vessel pipe is taken
into consideration, the upper limit of the temperature of substrate
28 is preferably adjusted to about 1.5.times.10.sup.3 K.
3. CNT Array
[0081] As one example of a CNT array produced by the production
method according to the present embodiment, as shown in FIG. 5, the
CNT array has a part having a configuration in which a plurality of
CNT are disposed so as to be oriented in a certain direction. When
diameters of the plurality of CNT in the part are measured to
determine a distribution thereof, as shown in FIG. 6, most of the
diameters of the CNT are within a range of 20 to 50 nanometers.
Diameters of CNT can be measured from an observed image obtained
when observing CNT that constitute a CNT array, such as using an
electron microscope.
[0082] The CNT array produced by the production method according to
the present embodiment can have the spinning properties.
Specifically, the CNT constituting the CNT array are taken and
drawn (spun) in a direction in which the CNT are separated from the
CNT array, and thus a structure (CNT entangled body) having the
plurality of CNT entangled to each other can be obtained. FIG. 7 is
an image showing a state in which the CNT entangled body is formed
from the CNT array, and FIG. 8 is an image in which part of the CNT
entangled body is enlarged. As shown in FIG. 7, the CNT
constituting the CNT array is continuously drawn, and thus the CNT
entangled body is formed. Moreover, as shown in FIG. 8, the CNT
constituting the CNT entangled body is entangled to each other
while being oriented in a direction (spinning direction) in which
the CNT is drawn from the CNT array to form a connected body. A
member having the CNT array and allowing formation of the CNT
entangled body herein is also referred to as a "spinning source
member."
4. CNT Entangled Body
[0083] The CNT entangled body obtained from the spinning source
member can have various shapes. Specific one example may be a
linear shape, and specific another example may be a web shape. The
linearly-shaped CNT entangled body can be handled in a manner
equivalent to that for fibers if twist is added when the spinning
source member is drawn to obtain the linearly-shaped CNT entangled
body, and used also as electrical wiring. On the other hand, the
web-shaped CNT entangled body can be directly handled in a manner
similar to that for a nonwoven fabric.
[0084] The length of the CNT entangled body in the spinning
direction is not particularly limited, and needs to be
appropriately set up according to an intended use. In general, the
spinning length of 2 millimeters or more allows application of the
CNT entangled body to a part level such as a contact part and an
electrode. Moreover, in the linearly-shaped CNT entangled body, the
degree of orientation of the CNT constituting the body can be
arbitrarily controlled by changing a spinning method from the
spinning source member (examples thereof include varying the degree
of twist). Accordingly, the CNT entangled body in which the
mechanical characteristics or the electrical characteristics are
different can be produced by changing the spinning method from the
spinning source member.
[0085] If the degree of entanglement is decreased, the CNT
entangled body becomes fine in the case of the linear shape, and
thin in the case of the web shape. If the degree progresses, the
CNT entangled body becomes difficult to visually observe, and the
CNT entangled body on the occasion can be used as transparent
fibers, transparent wiring, or a transparent web (transparent
sheet-shaped member).
[0086] The CNT entangled body may consist only of CNT or may also
be a composite structure with any other material. As described
above, the CNT entangled body has the configuration formed of the
plurality of CNT being entangled to each other, and therefore a
void exists among the plurality of entangled CNT in a manner
similar to that for a plurality of fibers constituting a nonwoven
fabric. The composite structure can be easily formed by introducing
powder (specific examples include metal fine particles, inorganic
particles such as particles of silica, and organic particles such
as particles of an ethylene-based polymer) into the void portion
thereof or impregnation with a liquid thereinto.
[0087] Moreover, the surface of the CNT constituting the CNT
entangled body may be modified. The outside surface of CNT is
constituted of graphene, and therefore the CNT entangled body is
hydrophobic as is, but hydrophilic treatment is applied to the
surface of the CNT constituting the CNT entangled body, and thus
the CNT entangled body can be made hydrophilic. Specific one
example of such a hydrophilization means may be plating treatment.
In the above case, the CNT entangled body obtained is formed into
the composite structure between the CNT and a plated metal.
5. Production Apparatus and Production Method for CNT Having Shape
Other than Array Shape
[0088] CNT having a shape other than an array shape can be produced
using any of production apparatuses 10, 50 and 60 for a CNT array
described above. For example, there can be formed an aggregate of
curved CNT without anisotropy, i.e. CNT having a secondary
structure that can function as a three-dimensional mesh as a
result, in a state in which ends of each of CNT are fixed on
substrate 28 (such an aggregate of CNT will be referred to as a
"CNT mesh" herein). The CNT mesh can be produced by adjusting
production conditions in a similar method to the production method
for a CNT array, i.e. a method of performing the first step (feed
of the gas-phase catalyst) and the second step (feed of the carbon
source) using any of production apparatuses 10, 50 and 60 for a CNT
array described above. The CNT mesh can be used as a member having
such a function as that of bump of flip chip.
[0089] CNT can also be produced as a generated substance by a
gas-phase flow reaction. Specifically, if the first step (feed of
the gas-phase catalyst) and the second step (feed of the carbon
source) are carried out in a state in which a substrate is not
disposed in the growth region where substrate 28 would be disposed
when producing a CNT array, chemical interaction can be caused
between the gas-phase catalyst existing in the growth region and
the raw material gas containing the carbon source to form CNT in
the growth region as a generated substance by a gas-phase flow
reaction. During this operation, it is not easy for CNT grown in
the growth region to grow to come close to one another to such an
extent that the CNT have an array shape, so that CNT having low
anisotropy in shape can be obtained.
[0090] In view of more stably obtaining CNT as a generated
substance by a gas-phase flow reaction, the raw material gas may be
fed prior to feeding the gas-phase catalyst. That is, if the raw
material gas containing the carbon source is fed into reaction
vessel pipe 14 to allow the carbon source to exist in reaction
vessel pipe 14, and in this state the gas-phase catalyst is fed
into reaction vessel pipe 14, the gas-phase catalyst fed into
reaction vessel pipe 14 can immediately interact with the carbon
source to form CNT. In this case, the entire region in which the
raw material gas exists in reaction vessel pipe 14 can be the
growth region. Moreover, the growth region can include a region to
which the gas-phase catalyst is fed in reaction vessel pipe 14. In
view of more stably obtaining CNT as a generated substance by a
gas-phase flow reaction, predetermined direction A of reaction
vessel pipe 14 may be the downward direction in the vertical
direction.
[0091] The embodiments described above are set forth in order to
facilitate understanding of the present invention, and not to limit
the present invention. Therefore, each of the elements disclosed in
the embodiments described above also includes all design
modifications and equivalents belonging to the technical scope of
the present invention.
EXAMPLES
[0092] The present invention will be further specifically described
by way of Examples and the like below, but the scope of the present
invention is not limited to the Examples and the like.
Example 1
[0093] A CNT array was produced using a production apparatus for a
CNT array having the configuration shown in FIG. 4. As the iron
family element-containing material, 8 g of iron powder (325 mesh,
average particle diameter: 45 to 50 .mu.m) was prepared, and the
iron powder was placed on the inside surface of a tubular member
disposed at the downstream side of the halogen feed device in the
first chamber.
[0094] As the substrate, a quartz plate (20 mm.times.5 mm.times.1
mm in thickness) was prepared. Accordingly, in the present Example,
all of the material constituting the base surface and the material
constituting the substrate were quartz. The quartz plate was
disposed in a portion located at the downstream side of the
reaction vessel pipe, in a state of being placed on a quartz
boat.
[0095] Inside of the reaction vessel pipe was evacuated to
1.times.10.sup.-1 Pa or less using an evacuating device.
Subsequently, the region at the upstream side of the reaction
vessel pipe was heated to 1.1.times.10.sup.3 K using a heater so
that the temperature of the tubular member of the halogen feed
device in the reaction vessel pipe and the temperature of the iron
plate placed therein would be about 1.1.times.10.sup.3 K. In
addition, the region at the downstream side of the reaction vessel
pipe was heated to 6.0.times.10.sup.2 K so that the temperature of
the quartz plate would be about 6.0.times.10.sup.2 K.
[0096] In this state, feed of HCl from the halogen feed device was
initiated with an amount to be a flow rate of 5 sccm, and this feed
of HCL was maintained for 20 minutes. During this period, the
region at the downstream side of the reaction vessel pipe was
heated to 8.0.times.10.sup.2 K, and the temperature of the quartz
plate came to about 8.0.times.10.sup.2 K after 20 minutes passed
from initiating the feed of HCl. The first step was thus
completed.
[0097] Next, the feed of HCL from the halogen feed device was
stopped, and in the state in which the feed of HCL was stopped, the
region at the downstream side of the reaction vessel pipe was
heated for 12 minutes to 1.1.times.10.sup.3 K so that the
temperature of the quartz plate would be about 1.1.times.10.sup.3
K.
[0098] Subsequently, in a state in which the temperature of the
entire region of the reaction vessel pipe was 1.1.times.10.sup.3 K,
the second step was carried out by feeding acetylene as the raw
material gas from the raw material gas feed device at an amount to
be a flow rate of 1,000 sccm, and acetone as the gas-phase
co-catalyst from the gas-phase co-catalyst feed device at an amount
to be a flow rate of 50 sccm, into the reaction vessel pipe for 10
minutes.
[0099] As a result, a CNT mesh was obtained on the quartz plate as
shown in FIG. 9.
[0100] Raman spectrum of the obtained CNT mesh was measured using a
Raman spectrometer ("NR-1800" available from JASCO Corporation),
and the G/D ratio was calculated as a value of 2.92.
Example 2
[0101] The first step and the second step were carried out by
performing the same operation as in Example 1 except that the feed
amount of HCl was set at an amount to be 10 sccm.
[0102] As a result, a CNT mesh was obtained on the quartz plate as
shown in FIG. 10. The G/D ratio of CNT constituting the obtained
CNT mesh was 2.49.
Example 3
[0103] The first step and the second step were carried out by
performing the same operation as in Example 1 except that the feed
amount of HCl was set at an amount to be 15 sccm.
[0104] As a result, a CNT array was obtained on the quartz plate as
shown in FIG. 11. The G/D ratio of CNT constituting the obtained
CNT array was 2.19.
Example 4
[0105] The first step and the second step were carried out by
performing the same operation as in Example 1 except that the feed
amount of HCl was set at an amount to be 20 sccm.
[0106] As a result, a CNT array was obtained on the quartz plate as
shown in FIG. 12. The G/D ratio of CNT constituting the obtained
CNT array was 2.53.
Example 5
[0107] The first step and the second step were carried out by
performing the same operation as in Example 1 except that the feed
amount of HCl was set at an amount to be 25 sccm.
[0108] As a result, a CNT array was obtained on the quartz plate as
shown in FIG. 13. The G/D ratio of CNT constituting the obtained
CNT array was 1.81.
Example 6
[0109] The first step and the second step were carried out by
performing the same operation as in Example 1 except that the feed
amount of HCl was set at an amount to be 30 sccm.
[0110] As a result, a CNT mesh was obtained on the quartz plate as
shown in FIG. 14. The G/D ratio of CNT constituting the obtained
CNT mesh was 2.58.
Examples 7 to 12
[0111] The same operation as in each of Examples 1 to 6 was
performed except that the substrate was changed from the quartz
plate to a silicon substrate having a thermally-oxidized film and
the base surface of quartz was changed to a base surface of a
silicon oxide film. Results and G/D ratios thereof are listed in
Table 1 together with the results of Examples 1 to 6.
TABLE-US-00001 TABLE 1 Feed Generated amount of substance G/D
Substrate HCl (sccm) (Secondary shape) ratio Example 1 Quartz 5
Mesh 2.92 Example 2 10 Mesh 2.49 Example 3 15 Array 2.19 Example 4
20 Array 2.53 Example 5 25 Array 1.81 Example 6 30 Mesh 2.58
Example 7 Silicon 5 Not generated -- Example 8 substrate 10 Not
generated -- Example 9 having 15 Array 2.22 Example 10 oxidized 20
Array 2.71 Example 11 film 25 Mesh 2.91 Example 12 30 Mesh 2.61
Examples 13 to 16
[0112] The same operation as in Example 1 was performed to carry
out the first step and the second step except that, as the iron
family element-containing material, 1.0 g of a red-brown iron oxide
(Fe.sub.2O.sub.3) powder (100 mesh, average particle diameter: 140
to 150 .mu.m) was used as substituted for the iron powder and the
feed amount of HCl from the halogen feed device was set at 2.5 sccm
(Example 13), 5 sccm (Example 14), 7.5 sccm (Example 15), and 10
sccm (Example 16). As a result, a CNT array was obtained in any of
the cases (see FIG. 15). In any of the cases, the iron family
element-containing material remaining on the inside surface of the
tubular member after the second step was black colored.
INDUSTRIAL APPLICABILITY
[0113] The CNT entangled body obtained from the CNT array produced
by the production method for CNT according to the present invention
is suitably used as electrical wiring, a heater, a strain sensor,
and a transparent electrode sheet, for example. The CNT mesh and
CNT without a specific secondary structure produced by the
production method for CNT according to the present invention are
suitably used as an electrode material for a secondary cell.
REFERENCE SIGNS LIST
[0114] 10, 50, 60 . . . Production apparatus for CNT array [0115]
12 . . . Electric furnace [0116] 13 . . . Pressure gauge [0117] 14
. . . Reaction vessel pipe (First chamber) [0118] 16 . . . Heater
(Part of first temperature adjustment device) [0119] 18 . . .
Thermocouple (Part of first temperature adjustment device) [0120]
20 . . . Control device [0121] 22 . . . Feed device [0122] 23 . . .
Pressure regulating valve (Part of pressure adjustment device)
[0123] 24 . . . Exhaust device (Part of pressure adjustment device)
[0124] 28 . . . Substrate [0125] 30 . . . Raw material gas feed
device (First feed device) [0126] 31 . . . Gas-phase catalyst feed
device [0127] 32 . . . Gas-phase co-catalyst feed device [0128] 33
. . . Auxiliary gas feed device [0129] 31A . . . Feed unit chamber
[0130] 31B . . . Heater (Part of second temperature adjustment
device) [0131] 31C . . . Halogen-containing substance feed device
(Second feed device) [0132] 31D . . . Discharge device [0133] 51 .
. . Halogen feed device [0134] 61 . . . Tubular member
* * * * *