JP2009102763A - Method for producing fine carbon fiber yarn, fine carbon fiber formation substrate used in this production method, and fine carbon fiber yarn produced by the production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a fine carbon fiber yarn that can eliminate non-uniformity of physical properties, a fine carbon fiber forming substrate used in the production method, and a fine carbon fiber yarn. <P>SOLUTION: The method for producing a fine carbon fiber yarn includes forming a catalyst layer on a substrate, growing a fine carbon fiber aggregate in a chemical-vapor phase on the substrate formed with the catalyst layer, continuously drawing out the fine carbon fiber from the fine carbon fiber aggregate to form a fine carbon fiber yarn. In order to define an area to draw out the fine carbon fiber from the fine carbon fiber aggregate in a predetermined pattern, a portion that can not draw out the fine carbon fiber is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a method for producing fine carbon fiber yarn by continuously drawing fine carbon fibers from an aggregate of fine carbon fibers obtained by chemical vapor deposition, a fine carbon fiber-forming substrate used in the production method, and The present invention relates to a fine carbon fiber yarn produced by the production method.

  Fine carbon fibers are excellent in electrical characteristics, mechanical characteristics, and the like, and are expected to be used and applied in various industries such as field emission displays and conductive fillers.

  In recent years, fine carbon fiber yarns composed of carbon nanotubes and carbon nanotube sheets using the same have been proposed (Patent Document 1 and Non-Patent Documents 1 and 2).

  Non-Patent Document 1 discloses a method of forming fine carbon fiber yarns from an aggregate of fine carbon fibers grown with high density and high orientation on a substrate by chemical vapor deposition.

  In Patent Document 1 and Non-Patent Document 2, a fine carbon fiber sheet or a fine carbon fiber rope can be formed from an aggregate of fine carbon fibers grown on a substrate with high density and high orientation by a chemical vapor deposition method. Is disclosed.

The above-mentioned fine carbon fiber yarn and sheet are expected to be used for new applications because of their non-existing forms, and are expected to be applied to various industries.
International Publication WO2005 / 102924 Pamphlet Chang et al., “Multifunctional carbon nanotube fibers by miniaturizing the prior art”, Science magazine, USA, published by the American Association for the Advancement of Science, November 19, 2004, 306, 1358-1361 (Zhang et al. ,, Science, AAAS, “Multifunctional Carbon Nanotube Yarns by Downsizing an Ancient Technology”, VOL 306, 1358-1361, 19 November 2004) Chang et al., “Tough and Transparent Multifunctional Carbon Nanotube Sheet”, Science Magazine, USA, American Society for the Advancement of Science, August 19, 2005, 309, 1215-1219 (Zhang et al., Science, AAAS , “Strong, Trasnsparent, Multifunctional, Carbon Nanotube sheets”, 309, 1215-1219, 19 August 2005)

  39 is a photomicrograph (140 ×) showing a state in which fine carbon fibers are continuously drawn from an aggregate of fine carbon fibers formed on a substrate to produce fine carbon fiber yarns, and FIG. It is a microscope picture (50 times) of the microscope picture which image | photographed the state after fine carbon fiber was pulled out from the board | substrate.

  As shown in FIG. 40, the fine carbon fibers are randomly drawn from the drawing start end (left end of the photograph) and are interrupted at the end portion (right end of the photograph). In the photograph of FIG. 40, the bright part is a part from which the fine carbon fibers are drawn, and the dark part is an aggregate of the remaining fine carbon fibers. As shown in FIG. 40, the fine carbon fiber yarn drawn out in a disorderly manner has a problem that the physical properties become non-uniform due to the non-uniform yarn diameter.

  Therefore, in order to solve the above problems, the present invention is produced by a method for producing fine carbon fiber yarns capable of eliminating the non-uniformity of physical properties, a fine carbon fiber-forming substrate used in the production method, and the production method. The main purpose is to provide fine carbon fiber yarns.

  In order to achieve the above object, a method for producing fine carbon fibers according to the present invention comprises forming a catalyst layer on a substrate, and subjecting the substrate on which the catalyst layer is formed to chemical vapor deposition of an aggregate of fine carbon fibers. A method for producing fine carbon fibers, wherein the fine carbon fibers are continuously drawn from the aggregate of fine carbon fibers to form fine carbon fiber yarns, wherein the fine carbon fibers are extracted from the aggregate of fine carbon fibers. The fine carbon fiber forms a non-drawable portion where the fine carbon fiber cannot be drawn so as to define a region for drawing out in a predetermined pattern.

  The undrawable portion is preferably formed such that the region from which the fine carbon fiber is drawn has a constant width.

  The undrawable part is a process of partially destroying the aggregate structure of the fine carbon fiber after the chemical vapor deposition of the aggregate of the fine carbon fiber, a process of partially removing the aggregate structure, And it can form by performing at least any one process of the process which changes in part the fine carbon fiber of the said aggregate.

  The process of partially destroying the aggregate structure of the fine carbon fibers may include a process of dropping fine droplets onto the aggregate of the fine carbon fibers.

  The process of partially destroying the aggregate structure of the fine carbon fibers includes a process of pressing a blade tool against the aggregate of the fine carbon fibers, and a process of scratching the aggregate of the fine carbon fibers with the blade tool. At least any processing may be included.

  The undrawable portion is formed by subjecting the aggregate of fine carbon fibers to chemical vapor deposition, and then subjecting the aggregate to at least one of laser processing, ion beam processing, electron beam processing, and plasma processing. You may form by giving.

  In the laser processing, a linear or belt-like undrawn portion is formed in the fine carbon fiber aggregate by sweeping the laser light on the fine carbon fiber aggregate at a controlled output and sweep speed. Is preferred.

  It is preferable to control the width of the whitening zone formed in the aggregate of fine carbon fibers by laser light irradiation by controlling the output and sweep speed of the laser light.

  The undrawable portion is formed by patterning the catalyst layer so that a region in which the fine carbon fibers are subjected to chemical vapor deposition has the predetermined pattern before chemical vapor deposition of the aggregate of the fine carbon fibers. May be formed.

  The undrawable portion may be formed by pressing at least one partition plate for partitioning a region from which the fine carbon fiber is drawn onto the aggregate of the fine carbon fibers.

  In order to achieve the above object, the fine carbon fiber-formed substrate according to the present invention is a fine carbon fiber formed by forming a catalyst layer on the substrate and chemical vapor deposition on the substrate on which the catalyst layer is formed. An assembly of carbon fibers, and a region where the fine carbon fibers are drawn from the aggregate of the fine carbon fibers so as to define a region in a predetermined pattern, and a non-drawable portion where the fine carbon fibers cannot be drawn. It is characterized by.

  In the fine carbon fiber-forming substrate, it is preferable that a region for drawing out the fine carbon fibers has a constant width.

  The undrawn portion of the fine carbon fiber-forming substrate is a portion where the fine carbon fiber aggregate structure is partially destroyed, a portion where the fine carbon fiber is partially removed from the fine carbon fiber aggregate, and It may include at least one of the portions where the fine carbon fibers of the aggregate are partially altered.

  The part of the fine carbon fiber forming substrate where the aggregate structure of the fine carbon fibers is partially broken may be formed by dropping fine droplets onto the aggregate of the fine carbon fibers.

  The undrawn portion of the fine carbon fiber-formed substrate may be formed by subjecting the aggregate of fine carbon fibers to at least one of laser processing, ion beam processing, electron beam processing, and plasma processing. good.

  In the fine carbon fiber-formed substrate, it is preferable that a whitening zone by laser light irradiation is formed in the aggregate of the fine carbon fibers.

  The undrawn portion of the fine carbon fiber-formed substrate may be formed by patterning the catalyst layer so that a region where the fine carbon fiber is grown by chemical vapor deposition has the predetermined pattern.

  In one embodiment, the undrawn portion of the fine carbon fiber-formed substrate is formed in a spiral shape.

  According to the present invention, in order to define the drawing area of the fine carbon fiber from the aggregate of fine carbon fibers as a predetermined pattern area, by forming the non-drawable portion of the fine carbon fiber, the disorder of the fine carbon fiber is formed. It is possible to limit the drawing and uniform physical properties of the fine carbon fiber twisted yarn.

  The best mode for carrying out the present invention will be described below with reference to FIGS. In addition, the same code | symbol was attached | subjected to the same component through all the drawings and all the embodiments.

  The present invention relates to a method and an apparatus for continuously producing fine carbon fiber yarns from an aggregate of fine carbon fibers grown on a substrate by chemical vapor deposition.

  The aggregate | assembly of the fine carbon fiber formed on a board | substrate is demonstrated in detail below.

  The substrate is not limited, and a known or commercially available substrate can be used. For example, a plastic substrate, a glass substrate, a silicon substrate, a metal such as iron or copper, or a metal substrate containing an alloy thereof can be used. A silicon dioxide film may be laminated on the surface of these substrates. In the present invention, it is particularly preferable to use a substrate in which a silicon dioxide film is formed on a silicon substrate by thermal oxidation or vapor deposition, and a catalyst layer is laminated on the silicon dioxide film. The catalyst layer can be preferably formed by evaporating or sputtering iron. Thereby, the aggregate | assembly with which the fine carbon fiber was formed with high density and high orientation can be manufactured.

  Fine carbon fibers to be chemically vapor-grown on a substrate are vapor-grown carbon fibers having a fibrous form such as single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanofibers.

  The form of these fine carbon fibers is not particularly limited, but for reasons such as easy formation of fine carbon fiber yarns, it is preferably an aggregate formed with high density and high orientation on the substrate. It is desirable to be.

The high density means that the bulk density of the carbon nanotubes on the substrate is 1-1000 mg / cm ³ , preferably 10-500 mg / cm ³ , more preferably 10-100 mg / cm ³ . If the bulk density is smaller than this range, the interaction between adjacent carbon nanotube molecules is weakened, and the pull-out property may be deteriorated. High orientation means that fine carbon fibers are adjacent to each other and stand perpendicular to the substrate plane.

  Such an assembly of fine carbon fibers that are vertically aligned at a high density by chemical vapor deposition is called a carbon nanotube forest or a vertically aligned structure of carbon nanotubes. The average length of the fine carbon fibers formed by chemical vapor deposition is preferably 0.02 mm or more, more preferably 0.03 mm or more, and still more preferably 0.05 mm or more. The average diameter of the fine carbon fiber material is not limited, and is usually 0.5 to 100 nm, preferably about 1 nm to 100 nm, and more preferably about 5 to 50 nm.

  The temperature during chemical vapor deposition may be any temperature, but it is particularly preferably high temperature, for example, about 600 to 1000 ° C. The pressure at the time of vapor phase growth is not limited, but usually it may be performed at atmospheric pressure. The gas used for vapor phase growth may contain carbon, but usually a hydrocarbon such as acetylene may be used. A rare gas such as helium may be used as the carrier gas. Although reaction time can be suitably set according to manufacturing conditions, what is necessary is just to be about 3 minutes-12 hours, for example.

  FIG. 1 shows a photomicrograph of the aggregate of carbon nanotubes, which are fine carbon fibers formed on the substrate as described above, taken from the side. FIG. 1 is an SEM photograph at a magnification of 500 times, and shows a state in which fine carbon fibers 2 are vertically oriented at a high density on a substrate 1.

  A part of an aggregate of carbon nanotubes grown with high density and high orientation on a substrate, that is, an aggregate of carbon nanotubes by holding multiple fine carbon fibers with tweezers or connecting them to the tip of a thin needle-like object When the carbon nanotubes are separated from the body, the carbon nanotubes are pulled out from the substrate as adjacent filaments are connected to each other in a chain to form continuous filaments. The mechanism by which such a phenomenon occurs is not necessarily clear, but preferably, the carbon nanotubes pulled out in this way and connected in a string form are pulled out while appropriately twisted. By applying the twist, thread breakage can be reduced.

  In the present invention, in the aggregate of fine carbon fibers, an undrawable portion where the fine carbon fibers cannot be drawn is formed so as to define a drawing area of the fine carbon fibers in a predetermined pattern.

  The undrawable portion can be formed by partially destroying the aggregate structure of fine carbon fibers.

  There are various methods for partially destroying the aggregate structure of fine carbon fibers. For example, a thin blade like a razor blade is pushed into an aggregate of fine carbon fibers formed on a substrate. The assembly can be broken by an operation or an operation of scratching the aggregate in a streak shape using the blade. The blade-like tool may be any one that can form a concave portion due to a streak-like indentation mark or scratching mark in an aggregate of fine carbon fibers, and a micro knife used for micromachining can be mentioned as a suitable example.

  Such microfabrication can be performed by controlling a microknife using a micromanipulator while magnifying and observing with a microscope. As the micromanipulator, a known one used for fine processing can be used. Specifically, the blade edge of the microknife is lowered from above the aggregate of fine carbon fibers and is slightly pushed into the aggregate, or the microknife is moved horizontally in parallel with the blade surface in the depressed state. To form a streak-like indentation mark or scratch mark.

  The micrograph which copied the upper surface and longitudinal cross-section of the fine carbon fiber aggregate | assembly which formed the multiple streak-like indentation mark or scratch mark as mentioned above is shown in FIG. 2, FIG. As can be seen from the photograph in FIG. 3, the indentation mark or scratch mark 3 does not have to reach the substrate, and it is sufficient that the vertical alignment structure in at least the vicinity of the surface layer of the fine carbon fiber aggregate 2 is destroyed. Further, as can be seen from the photograph in FIG. 3, the scratch marks 3 destroyed the vertical alignment structure by crushing the vertical alignment structure of the fine carbon fibers constituting the aggregate of the fine carbon fibers from above. It has a form. Since the aggregate of the fine carbon fibers is cramped by being slightly pressed from above with a microknife, the vertical alignment structure of the fine carbon fibers can be easily broken.

  Since the vertical alignment structure of the fine carbon fiber aggregate is broken in the plurality of streaky indentations or scratches formed in the fine carbon fiber aggregate in this way, the fine carbon fiber is pulled. Not issued. As a result, an undrawn portion for defining a region from which the fine carbon fiber is drawn is formed.

  A region defined by two adjacent parallel streak indents or scratches defines a region in which fine carbon fibers are drawn from the aggregate with a constant width. FIG. 4 shows a state in which the fine carbon fiber yarn 5 is produced by pulling out the fine carbon fiber from the aggregate of fine carbon fibers between the two streaky indentation marks or scratch marks while being twisted. It is a microscope picture shown. In FIG. 4, a plurality of fine carbon fibers drawn from the aggregate of fine carbon fibers are attached to a micro drill outside the photograph, and the micro drill is separated from the aggregate while rotating the micro drill. Thus, twisting is applied while being pulled out in a state where the fine carbon fibers are chain-connected. It is possible to attach a plurality of fine carbon fibers to the needle tip just by piercing the microdrill tip from the side surface into the aggregate of fine carbon fibers, but applying an adhesive or the like to the tip of the microdrill You can keep it.

  As another method for partially destroying the aggregate structure of fine carbon fibers, a method of dropping microdroplets onto the aggregate can be mentioned. For example, a microdroplet such as an ethanol aqueous solution is dropped by a microdispenser, and a desired region of the aggregate of fine carbon fibers is crushed by a drop impact of the droplet. The microdispenser is a dispenser capable of dispensing microliters or less, and a known microdispenser can be used. The liquid used for the fine droplets is not particularly limited as long as it is a liquid that can break the vertical alignment structure of the fine carbon fibers by being dropped onto the fine carbon fibers.

  FIG. 5 is a photomicrograph taken from above of a state in which fine droplets are dropped using a microdispenser on an aggregate of fine carbon fibers, and FIG. 6 is a photomicrograph taken of a longitudinal section. As can be seen from FIG. 5, the micro droplets are continuously dropped on a straight line so as to form the undrawable portion 6 of the line pattern in plan view. In order to drop micro droplets in a row in this way, for example, while moving an XY table on which a substrate on which fine carbon fiber aggregates are formed is moved in a constant direction at a constant speed, from a micro dispenser This can be done by dropping fine droplets at regular time intervals.

  As a method for dropping micro droplets, an ink jet nozzle used in an ink jet printer can be used instead of the micro dispenser. FIGS. 7 and 8 are a top view photograph and a cross-sectional photograph of a state in which fine droplets are dropped on an aggregate of fine carbon fibers by an inkjet nozzle. As can be seen from FIG. 7, the line-shaped undrawn portion 7 is formed by the fine droplets, but the fine droplets dropped in the line shape do not necessarily have to be connected, and adjacent droplets are The distance may be a certain distance (for example, less than or equal to the radius of the microdroplet).

  FIGS. 9A to 9E are photomicrographs taken of a state in which droplets ejected from the inkjet nozzles were dropped. As shown in FIG. 9A, the droplet does not reach the substrate 1. In the part of FIG. 9 (e), the aggregate structure of the fine carbon fibers is not broken, and the structure changes in the part of FIG. 9 (d). In the part of FIG. It can be seen that the vertical alignment structure of the body is completely destroyed.

  Further, the portion where the fine carbon fibers cannot be drawn can be formed by partially removing or altering the aggregate of the fine carbon fibers. In addition to the method using blades and microdroplets as described above, a method of partially destroying or removing the aggregate structure of fine carbon fibers by energy irradiation or a method of partially altering the aggregate. It can also be used. As a method by energy irradiation, a fine processing method by a known processing technique such as laser processing, ion beam processing, electron beam processing, or plasma processing can be used. By using these fine processing methods, a desired portion of the aggregate of fine carbon fibers can be destroyed, removed, or altered to form a non-drawable portion that defines a drawing region of the fine carbon fiber.

  10 and 11 are photomicrographs in which the undrawable portion 8 is formed using a carbon dioxide laser marker, FIG. 10 is a top view, and FIG. 11 is a cross section. FIGS. 12 and 13 are photomicrographs in which the energy output of the carbon dioxide laser is made lower than in FIGS.

  The laser marker is preferably capable of three-dimensional control of the laser spot. As such a laser marker, for example, a three-dimensional control laser marker sold by Keyence Corporation can be used. By using such a laser marker, by adjusting the energy output and / or sweep speed of the laser light, only the surface layer portion of the fine carbon fiber aggregate may be lost, and the undrawable portion may be formed. It may disappear until reaching the position to form an undrawn portion.

  By forming a plurality of linear or strip-like undrawable portions by laser processing at a desired pitch, a region from which fine carbon fibers are drawn can be formed with a constant width.

  When observed with an optical microscope, a portion (hereinafter referred to as a “whitening zone”) in which fine carbon fibers appear to be altered and formed white is formed at the edge along the length direction of the linear or belt-like laser mark. This whitening zone will be described later in the examples. The width of the whitening zone formed in the aggregate of fine carbon fibers by laser light irradiation by controlling the output and sweep speed of the laser light. This whitening zone plays an important role in defining the region from which the fine carbon fibers are drawn, as will be described later.

  In addition to laser processing, ion beam processing and electron beam processing can form a non-extractable portion as in laser processing. However, ion beam processing and electron beam processing are performed in a vacuum chamber. In addition, the portion that cannot be pulled out can also be formed by plasma processing. Plasma processing is larger in size than laser processing, but there is an advantage that a desired undrawable portion can be formed instantaneously by using a stencil (metal mask).

  Further, the undrawable portion that defines the drawing region of the fine carbon fiber can be formed by patterning the catalyst layer. For the patterning of the catalyst layer, a patterning technique used as a microfabrication technique for integrated circuits can be used.

  Lithography can be used for such patterning. For example, first, a positive type resist film is applied to the substrate before the catalyst layer is formed. Next, the resist film is exposed using a mask (reticle) having a mask pattern that matches a region (drawing region) from which fine carbon fibers are drawn, and the mask pattern is transferred to the resist film. Next, a resist pattern that matches the undrawn portion is left by development and rinsing. After the catalyst layer is deposited on the substrate on which the resist pattern is formed, the resist pattern is removed by a known method, so that a substrate in which only the portion matching the undrawable portion is not formed with the catalyst layer can be manufactured. . In the substrate including the catalyst layer patterned in this way, an aggregate of fine carbon fibers is chemically vapor-grown only in a predetermined pattern region (region where the catalyst layer is formed).

  As another method for patterning the catalyst layer, after forming the catalyst layer on the entire surface of the substrate, the catalyst layer is formed using a laser processing apparatus so that the region where the fine carbon fiber is chemically vapor-grown becomes a predetermined pattern. A method of etching can also be adopted. The method for etching the catalyst layer is not limited to laser etching, and other known dry etching or wet etching can be employed.

  As yet another method for patterning the catalyst layer, the extraction is performed by masking the catalyst layer on the catalyst layer of the catalyst layer laminated silicon substrate to form a region in which the fine carbon fibers are not subjected to chemical vapor deposition. Impossible sites can also be formed.

  The non-drawable part that defines the drawing area of the fine carbon fiber can have various shapes, such as a plurality of lines extending in parallel or in parallel, or comb-like lines that mesh with each other at equal intervals (FIG. 14). Or the vortex which winds a vortex at equal intervals can be made into the shape of a winding (FIG. 15), the shape of the meandering line in parallel, etc. In addition, the shape of the undrawn portion is not limited to a linear shape or a belt shape, but from the viewpoint of effective utilization of the fine carbon fiber, it is desirable that the area of the undrawable portion is small.

  Furthermore, as another method of forming the undrawable portion, it can be formed using a pressing tool 10 as shown in FIG. The pressing tool 10 for forming the undrawn portion includes at least one partition plate 11. By pressing the partition plate 11 against the aggregate 2 of fine carbon fibers, the region from which the fine carbon fibers are drawn out from the aggregate 2 can be partitioned by the partition plate 11 and defined in a predetermined pattern.

  FIG. 17 shows another embodiment of the pressing tool. In the pressing tool 10a shown in FIG. 17, the partition plate 11a is formed in a spiral plate shape for forming the spiral wire-shaped undrawable portion of FIG. The partition plate may have a flat shape as shown in FIG. 16 or a spiral shape as shown in FIG. 17, or a desired shape according to the required pattern of the extraction region.

  By using the method as described above, a region where the fine carbon fibers cannot be pulled out from the aggregate is formed, thereby defining a region where the fine carbon fibers are pulled out from the aggregate of the fine carbon fibers. Therefore, if the undrawable portion is appropriately controlled, it is possible to prevent the fine carbon fibers from being drawn out in a disorderly manner, thereby reducing the fine carbon fibers that cannot be used for the yarn and are wasted.

  The undrawable portion is preferably formed so that the drawing region in the aggregate of fine carbon fibers has a constant width. By setting the drawing area of the fine carbon fiber to a constant width, the yarn produced by being drawn only from the drawing area can be prevented from variation in the yarn diameter. However, the width of the drawing area of the fine carbon fiber is preferably 5 mm or less, more preferably 2 mm or less. This is because if the width of the drawing region exceeds 5 mm, variations in the yarn diameter are likely to occur.

  Hereinafter, the present invention will be described in detail using examples. In addition, this invention is not limited to the following Example.

Example A silicon substrate on which a catalyst layer made of an iron film having a thickness of 4 nm was laminated was produced by sputtering iron on a silicon substrate (commercial product, 1 cm ² ).

  This substrate was placed in a thermal CVD apparatus, and a carbon nanotube aggregate was formed on the substrate by performing a thermal CVD method. The gas supplied into the thermal CVD apparatus was a mixed gas of acetylene gas and helium gas (acetylene gas 5.77 vol%). The thermal CVD conditions were temperature: 700 ° C., pressure: atmospheric pressure, acetylene gas concentration increase rate in the initial stage: 0.10 vol% / second, and reaction time: 10 minutes.

The grown carbon nanotubes had an average length of 190 μm and a thickness of about 15.3 nm, and the aggregate of carbon nanotubes on the substrate was formed with a high density and high orientation with a bulk density of 40 mg / cm ² .

  Samples in which carbon nanotube aggregates obtained as described above were formed into a plurality of parallel linear portions of carbon nanotubes using laser processing, inkjet, microknives, and microdispensers (Examples 1 to 14) was prepared, and fine carbon fiber yarn was drawn out.

Example by Laser Processing A carbon dioxide laser marker was used for laser processing. The carbon dioxide laser marker used was a 3-Axis CO ₂ laser marker manufactured by Keyence Corporation, head: ML-Z9550C, controller: ML-Z9500C, wavelength: 10.6 μm, average output: 30 W, marking space: 50 × 50 × 4 mm Printing resolution: 1 μm, laser irradiation width: 40 μm.

The CO ₂ laser marker has, as laser irradiation parameters, an output (% with respect to 30 W) and a speed at which the laser spot is moved, that is, a sweep speed (mm / second), and the combination of these determines the irradiation intensity.

In determining the irradiation conditions for performing patterning by laser processing on the carbon nanotube aggregate, first, the influence on the carbon nanotubes by CO ₂ laser irradiation was examined. After irradiating the CO ₂ laser within an irradiation intensity range of 25 to 75% and a sweep rate of 100 to 1000 mm / second, the upper surface and cross section of the carbon nanotube substrate were magnified 100 to 250 times and an optical microscope (Inc. Photographs taken with a Nikon system stereo microscope SMZ-1500) are shown in FIGS.

10 and 11 show the results of processing the laser marker at an output of 75% and a sweep speed of 100 mm / sec. FIGS. 12 and 13 show the results of processing the laser marker at an output of 25% and a sweep speed of 1000 mm / sec. . Although there are differences in the width and depth of removal of the carbon nanotubes in the region irradiated with the CO ₂ laser due to the difference in irradiation intensity and sweep speed, the region from which the carbon nanotubes are drawn (drawing region) can be patterned with a uniform width. all right.

Therefore, the laser marker is set to an output of 25% and a sweep speed of 1000 mm / second, and the laser marker is controlled on the carbon nanotube aggregate along a line having a predetermined line pitch by using the laser marker control software. It was set to sweep. FIG. 18 shows the result of testing the relationship between the line pitch and the width (pattern width) of the drawn region of the carbon nanotube aggregate formed by the line pitch. Since the line pitch and the pattern width are in a very good correlation as shown in FIG. 18, the CO ₂ laser marker is fine with a desired uniform width in the region where the fine carbon fibers are drawn from the carbon nanotube aggregate. It became clear that this is a method that can define the pattern.

In addition, yarn production was attempted from the whitening zone generated along the edge of the irradiation mark (also the edge of the carbon nanotube extraction region) when the CO ₂ laser was irradiated. However, it was impossible to extract carbon nanotubes from the whitened zone. As shown in FIG. 10, the whitening band is generated widely when the irradiation intensity is high. This whitening zone is considered to be a site where the carbon nanotube has been altered and thickened by laser irradiation (see FIG. 31) and has lost the possibility of chain extraction.

On the other hand, we tried to produce yarn by pulling out carbon nanotubes from a carbon nanotube aggregate using a substrate in which the irradiation intensity was reduced and a non-extractable part was formed in a linear predetermined pattern under the condition that almost no whitening zone was generated. . As a result, a phenomenon was observed in which the carbon nanotubes were drawn out from the CO ₂ laser irradiated portion, and the drawing width was increased. That is, there was a portion where the laser irradiation portion did not function as a non-extractable portion.

  Considering the above events together, the whitening zone is a portion that cannot be pulled out, and is therefore a useless region in terms of yarn production efficiency. However, it has become clear that, in controlling the drawer width, it plays an extremely important role as a “separation zone” that suppresses the extension of the drawer width.

Therefore, the CO ₂ laser irradiation conditions were optimized so that this “separation zone” was generated with the minimum width and surely. As the irradiation intensity, CO ₂ laser was irradiated within the range of output of 10 to 30% and sweep speed of 500 to 1500 mm / second, and the result showing the relationship between the irradiation intensity and the width of the separation band is shown in the graph of FIG. The graph showing the relationship between the intensity and the maximum groove depth of the portion disappeared by laser irradiation is shown in the graph of FIG. From FIG. 19 and FIG. 20, in order to minimize the damage to the carbon nanotubes and form a separation zone that is an undrawable part, it is desirable to perform the treatment at an output of 20% or less and a sweep speed of 1000 mm / second or more. I understood it.

However, when the substrate irradiated with laser under the conditions of 20% output and 1500 mm / second sweep speed and 10% output and 1000 mm / second sweep speed was observed with an optical microscope, the edge of the extraction region was distorted and straightened. It was found that the control of the drawer width was insufficient (FIGS. 21 and 22). From the results of FIGS. 19 to 22, in the laser marker used in this example, it is preferable that an output of 20% and a sweep speed of 1000 mm / second are suitable as the irradiation conditions of the CO ₂ laser when forming the undrawable portion. I understood.

  Therefore, by appropriately controlling the laser beam output and the sweep speed, the separation band can be reliably and narrowly formed.

Next, a spinning experiment was conducted from the carbon nanotube aggregate in which the undrawable portion was formed by the CO ₂ laser marker. Since the pattern width is in the order of several hundreds of micrometers for the production of carbon nanotube aggregates, a micromanipulator equipped with a micro drill with a diameter of 30 μm (1-254 manufactured by Micro Tool Co., Ltd .: drill tip diameter 0.03 mm) is used. did. The production conditions were 40000 T / m (turns per meter).

  The tip of the micro drill is stabbed at a predetermined depth on the side surface of the carbon nanotube aggregate extraction region (see FIG. 23), the carbon nanotube is entangled at the tip of the pierced micro drill, and the micro drill is driven around the axis by motor drive The carbon nanotubes were pulled out in a chain and continuously, and the carbon nanotube yarn was produced by pulling out the carbon nanotubes while twisting them (see FIG. 24).

  FIGS. 25 and 26 show optical micrographs when carbon nanotube yarns are produced from a substrate having a line pitch width of 200 μm (carbon nanotube pattern width is 100 μm), and FIG. 27 shows SEM photographs (10,000 times) of the produced yarns.

  In addition, FIG. 28 shows an SEM photograph (800 ×) enlarging a part of FIG. Further, FIGS. 29 to 32 show SEM photographs in which the drawable area A, whitening bands (separation bands) B and C, and the laser irradiation part D in FIG. 28 are enlarged.

  As shown in FIG. 25, the region where the carbon nanotubes are drawn from the aggregate of carbon nanotubes was successfully formed into a pattern with a certain width by fine processing using a laser marker. The constant width of the region from which the carbon nanotubes are drawn leads to the homogenization of the carbon nanotube yarns. The produced yarn had a diameter of 1 μm or less (FIG. 27), and the production of ultrafine carbon nanotube yarn was successful.

Example using microknife Feather razor microsurgical blade K-715 was mounted as a microknife on a M401 micromanipulator manufactured by Suruga Seiki, and remotely controlled.

  While magnifying and observing the carbon nanotube aggregate with a microscope, the microknife is pushed into the carbon nanotube aggregate under the control of the micromanipulator, or horizontally moved by dragging the microknife. By repeating the operation of separating the microknife from the carbon nanotube aggregate, a plurality of parallel linear indentations or scratches were formed on the carbon nanotube aggregate.

  When the indentation mark or scratch mark was observed with a microscope, the vertically aligned structure of the carbon nanotube aggregate was partially broken and destroyed (see FIG. 3).

  With the linear indentation marks or scratch marks extending in parallel, the lead-out area of the fine carbon fiber is formed in a bowl shape, and the tip of the micro drill is stabbed to a predetermined depth on the side surface of the bowl-shaped carbon nanotube aggregate. The carbon nanotube is entangled with the pierced tip, the micro drill is rotated around the axis by a motor drive, and the carbon nanotubes are pulled out while twisting, and the carbon nanotubes are continuously pulled out to produce the carbon nanotube yarn. (See FIG. 4).

  From the scratch marks, it was confirmed that the carbon nanotubes were not pulled out and functioned as undrawn portions.

Example using a micro dispenser A micro droplet is dropped on an aggregate of carbon nanotubes by a micro dispenser so that traces of micro droplets form a line along a predetermined linear trajectory. Formed (see FIGS. 5 and 6).

  In addition, what mounted Muto Engineering Co., Ltd. non-contact jet dispenser JETMASTER2 in the high-speed processing and high precision desktop robot SHOTMASTER300 made by the company was used on condition of the following as a microdispenser.

Basic conditions: CONTINUE MODE (ON 3ms, OFF 3ms)
Pressurization condition: 10 kPa, nozzle: 32 gauge, 5 mm length, stroke: 0.03 mm
Head normal pressure: 500 kPa, work clearance: 10 mm
Head moving speed: 60 mm / sec Discharged liquid: ethanol 25% aqueous solution The streaky droplet traces extending in parallel formed a pull-out area of fine carbon fibers into a bowl-shaped carbon nanotube aggregate on the side surface. Carbon nanotubes are chained by piercing the tip of the microdrill to a predetermined depth, tying carbon nanotubes around the pierced tip, rotating the microdrill around the axis by a motor drive, and pulling out the carbon nanotubes while twisting them. The carbon nanotube yarn was produced by continuously drawing out.

  It was confirmed that the carbon nanotubes were not pulled out from the portion of the droplet mark and acted as a portion that could not be pulled out.

Example by inkjet printer A droplet is dropped on an aggregate of carbon nanotubes by an inkjet printer so that the minute droplet traces form a line along a predetermined linear trajectory. Then, a portion where fine carbon fibers cannot be drawn was formed (see FIGS. 7 and 8).

  As an inkjet printer, Keyence Corporation MK-9100 (nozzle diameter: 34 μm, theoretical ink droplet diameter: 80 μm, maximum printing speed: 1018 characters / second) was used.

  A microdrill is stabbed to the side of the carbon nanotube aggregate between rows of minute droplet marks, the carbon nanotube is entangled with the pierced microdrill, the microdrill is rotated by a motor drive, and the carbon nanotube is By pulling out while twisting, carbon nanotube yarns were produced by continuously pulling out carbon nanotubes in a chain.

  It was confirmed that the carbon nanotube was not pulled out from the portion of the minute droplet mark and acted as a non-drawable portion. Further, even if the liquid droplets arranged in one row were somewhat discontinuous and separated, the carbon nanotubes that were pulled out did not protrude out of the row of minute droplet marks. Therefore, the region from which the carbon nanotubes were pulled out could be defined by the rows of microdroplets.

Test Example By forming the undrawable portion according to the above example, a region where the carbon nanotubes are pulled out from the aggregate is formed with a constant width, and the diameter of the carbon nanotube yarn pulled out from the pulling region with the constant width, The relationship with the width of the extraction region was examined. The diameter of the carbon nanotube yarn was measured at 10 locations at 1 mm intervals in the length direction, and an average value was obtained and a standard deviation was calculated.

  In addition, the relationship between the diameter of the drawn carbon nanotube yarn and the tensile strength was examined.

  As a comparative example, a carbon nanotube thread drawn from a carbon nanotube aggregate in which a non-drawable portion was not formed was used.

  The test results are shown in Table 1.

Graphs created from the results in Table 1 are shown in FIGS.

  Referring to the standard deviation values in Table 1, it can be seen that the example in which the width of the lead-out region is constant has less variation in the diameter of the obtained carbon nanotube yarn than the comparative example.

  Moreover, it can be seen from the graph of FIG. 33 that the width of the drawn region and the diameter of the obtained carbon nanotube yarn are in a proportional relationship. Therefore, it was confirmed that the diameter of the carbon nanotube yarn can be controlled by controlling the width of the drawing region.

  Furthermore, it can be seen from the graph of FIG. 34 that the tensile strength increases as the diameter of the carbon nanotube yarn decreases. From this, it is understood that it is extremely important in the industry to produce carbon nanotube yarns that are as thin as possible without variation in diameter. As is apparent from the above description, according to the method of the present invention, it is possible to control the diameter of the carbon nanotube yarn and produce a carbon nanotube yarn that is uniform and has the required fineness.

Example by Etching Catalyst Layer A silicon substrate on which a catalyst layer made of an iron film was laminated was prepared, and the catalyst layer was etched before vapor growth of carbon nanotubes by thermal CVD. For the etching, a 3-Axis YVO4 laser marker (head controller: MD-V9900 (standard type), wavelength: 1064 nm, output: 13 W) manufactured by Keyence Corporation was used. The laser light irradiation conditions were an output of 60%, a sweep speed of 500 mm / second, and the irradiation intensity was adjusted by changing the Q switch frequency between 40 kHz and 80 kHz. The result of observing the upper surface of the silicon substrate irradiated with the YVO ₄ laser when the Q switch frequency is 40 kHz and 80 kHz with an optical microscope (100 times) is shown in FIGS. FIG. 35 shows the case of 40 kHz, and FIG. 36 shows the case of 80 kHz. As shown in FIG. 35, when the irradiation intensity is strong (Q switch frequency is small), the pattern (etching trace) of the catalyst layer by the YVO ₄ laser is easily observed, but when the irradiation intensity is small, the YVO ₄ laser It was difficult to confirm the irradiated part.

Next, FIG. 37 and FIG. 38 show the results of observing the upper surface of the aggregate of carbon nanotubes synthesized with a thermal CVD apparatus with an optical microscope after pattern etching of the catalyst layer with a YVO ₄ laser. FIG. 37 shows the case of 40 kHz, and FIG. 38 shows the case of 80 kHz. As shown in FIG. 37, in the sample with high irradiation intensity (Q switch frequency is small), the edge portion of the cocoon-like extraction region of the carbon nanotube aggregate was disordered, and it was not in a state that can be used for yarn production. On the other hand, as shown in FIG. 38, in the sample with low irradiation intensity, the pattern without the edge disturbance is formed in the extraction region of the synthesized carbon nanotube aggregate, although the pattern of the catalyst layer cannot be confirmed with an optical microscope. Thus, it has been clarified that an extraction region having a predetermined pattern can be produced.

It is the microscope picture which copied the side surface of the aggregate | assembly of the fine carbon fiber vapor-phase-grown on the board | substrate. It is the photograph for demonstrating the manufacturing method of the fine carbon fiber thread | yarn which concerns on this invention, Comprising: It is the microscope picture which image | photographed from the upper part the area | region which cannot be pulled out with a microknife. FIG. 3 is a photomicrograph showing a longitudinal section of the subject in FIG. 2. FIG. 3 is a photomicrograph showing a state in which carbon nanotube yarns are formed by pulling out carbon nanotubes from the undrawn portion shown in FIG. 2. It is the photograph for demonstrating the manufacturing method of the fine carbon fiber yarn which concerns on this invention, Comprising: It is the microscope picture which image | photographed the site | part which cannot be pulled out with a micro dispenser from the upper direction. 6 is a photomicrograph showing a longitudinal section of the subject in FIG. 5. It is the photograph for demonstrating the manufacturing method of the fine carbon fiber yarn which concerns on this invention, Comprising: It is the microscope picture which image | photographed the site | part which cannot be pulled out with an inkjet nozzle from the upper direction. It is the microscope picture which copied the longitudinal cross-section of the to-be-photographed object of FIG. It is a microscope picture which expands and shows the longitudinal cross-section of the to-be-photographed object of FIG. 8 partially. It is a photograph for demonstrating the manufacturing method of the fine carbon fiber yarn which concerns on this invention, Comprising: It is the microscope picture which image | photographed the example of the undrawable part by a laser from the upper direction. It is a microscope picture which shows the longitudinal cross-section of the to-be-photographed object of FIG. It is the photograph for demonstrating the manufacturing method of the fine carbon fiber thread | yarn which concerns on this invention, Comprising: It is the microscope picture image | photographed from the other example of the site | part which cannot be pulled out by a laser. It is a microscope picture which shows the longitudinal cross-section of the to-be-photographed object of FIG. It is a top view which shows an example of the undrawable site | part for demonstrating the manufacturing method of the fine carbon fiber yarn based on this invention. It is a top view which shows another example of the undrawable site | part for demonstrating the manufacturing method of the fine carbon fiber yarn which concerns on this invention. It is a perspective view which shows the use condition of the partition plate applied to the manufacturing method of the fine carbon fiber yarn based on this invention. It is a perspective view which shows the use condition of the partition plate of another form. It is a graph which shows the correlation with the line pitch of the laser beam by a laser marker, and the width | variety (pattern width) of the area | region where the fine carbon fiber defined by laser irradiation is pulled out. It is a graph which shows the relationship between the irradiation intensity | strength of a laser beam, and the width | variety of the whitening zone | band (separation zone). It is a graph which shows the relationship between the irradiation intensity | strength of a laser beam, and the maximum groove depth of an irradiation area | region. It is the optical micrograph which looked at the undrawable site | part which carried out the laser processing of the laser marker 20% of output, and sweeping speed 1500mm / sec from the upper direction. It is the optical micrograph which looked at the undrawable site | part which carried out the laser processing by the laser marker 10% of output, and sweeping speed 1000mm / sec from the upper direction. It is a microscope picture for demonstrating the state which pierces a micro drill in the aggregate | assembly of the fine carbon fiber of FIG. FIG. 24 is a photomicrograph showing a state in which a fine carbon fiber yarn is manufactured by rotating the micro drill while being separated from the state of FIG. 23. FIG. 25 is a photomicrograph showing a state in which a fine carbon fiber yarn is manufactured by rotating the micro drill while separating from the state of FIG. 24. It is an optical microscope photograph which expands and shows the state after a fine carbon fiber is pulled out in FIG. It is a SEM photograph which expands and shows the fine carbon fiber yarn shown by FIG. FIG. 27 is an SEM photograph at 800 times magnification showing an encircled portion in FIG. 26. 29 is an SEM photograph showing an enlargement of the drawable area A in FIG. 28, FIG. 29A is 5000 times the upper surface, FIG. 29B is 50000 times the upper surface, FIG. 29C is 5000 times the cross section, FIG. 29 (d) is 50000 times the cross section. It is the SEM photograph which expands and shows whitening zone B of Drawing 28, Drawing 30 (a) is 5000 times the upper surface, Drawing 30 (b) is 50000 times the upper surface, Drawing 30 (c) is 5000 times the section, FIG.30 (d) is 50000 times of a cross section. It is the SEM photograph which expands and shows whitening zone C of Drawing 28, Drawing 31 (a) is 5000 times the upper surface, Drawing 31 (b) is 50000 times the upper surface, Drawing 31 (c) is 5000 times the section, FIG.31 (d) is 50000 times of a cross section. It is the SEM photograph which expands and shows the laser irradiation part D of FIG. 28, FIG.32 (a) is 5000 times the upper surface, FIG.32 (b) is 50000 times the upper surface, FIG.32 (c) is 5000 times the cross section, FIG. 32D is 50000 times the cross section. In this invention Example, it is a graph which shows the relationship between the width | variety of the area | region where a fine carbon fiber is pulled out, and the average diameter of a fine carbon fiber yarn. In the Example of this invention, it is a graph which shows the relationship between the average diameter of fine carbon fiber yarn, and tensile strength. A silicon substrate formed by laminating a catalyst layer with iron deposition film is an optical micrograph showing the state of etching the catalyst layer by irradiating the Q-switching frequency 40KHzYVO ₄ laser. A silicon substrate formed by laminating a catalyst layer with iron deposition film is an optical micrograph showing the state of etching the catalyst layer is irradiated with YVO ₄ laser of Q switch frequency 80 kHz. FIG. 36 is an optical micrograph showing an aggregate of carbon nanotubes vapor-grown on the substrate of FIG. 35. FIG. FIG. 37 is an optical micrograph showing an aggregate of carbon nanotubes vapor-grown on the substrate of FIG. 36. It is a microscope picture which shows the state which draws out fine carbon fiber from the aggregate | assembly of fine carbon fiber, and produces the thread | yarn for demonstrating the conventional method. It is the microscope picture which image | photographed the state after fine carbon fiber was pulled out from the board | substrate on the conventional method.

Explanation of symbols

1 Substrate 2 Aggregate of fine carbon fibers 3, 6, 7, 8 Undrawable part

Claims (19)

A catalyst layer is formed on a substrate, and an aggregate of fine carbon fibers is grown by chemical vapor deposition on the substrate on which the catalyst layer is formed, and the fine carbon fibers are continuously drawn from the aggregate of fine carbon fibers. A method for producing fine carbon fibers, which forms fine carbon fiber yarns,
The fine carbon fiber yarn is characterized in that the fine carbon fiber forms a non-drawable portion where the fine carbon fiber cannot be drawn so as to define a region for drawing the fine carbon fiber from the aggregate of fine carbon fibers in a predetermined pattern. Production method. The manufacturing method according to claim 1, wherein the undrawable portion is formed such that a region from which the fine carbon fiber is drawn has a constant width. The undrawable part is a process of partially destroying the aggregate structure of the fine carbon fiber after the chemical vapor deposition of the aggregate of the fine carbon fiber, a process of partially removing the aggregate structure, The manufacturing method according to claim 1, wherein the method is formed by performing at least one of the processes of partially altering the fine carbon fibers of the aggregate. The manufacturing method according to claim 3, wherein the process of partially destroying the aggregate structure of the fine carbon fibers includes a process of dropping micro droplets onto the aggregate of the fine carbon fibers. The process of partially destroying the aggregate structure of the fine carbon fibers includes a process of pressing a blade tool against the aggregate of the fine carbon fibers, and a process of scratching the aggregate of the fine carbon fibers with the blade tool. The manufacturing method according to claim 3, comprising at least one of the processes. The undrawable portion is formed by subjecting the aggregate of fine carbon fibers to chemical vapor deposition, and then subjecting the aggregate to at least one of laser processing, ion beam processing, electron beam processing, and plasma processing. It forms by giving, The manufacturing method in any one of Claims 1-3 characterized by the above-mentioned. In the laser processing, a linear or belt-like undrawn portion is formed in the fine carbon fiber aggregate by sweeping the laser light on the fine carbon fiber aggregate at a controlled output and sweep speed. The manufacturing method according to claim 6. The manufacturing method according to claim 7, wherein the width of the whitening band formed in the aggregate of the fine carbon fibers by the irradiation of the laser light is controlled by controlling the output and sweep speed of the laser light. Method. The undrawable portion is formed by patterning the catalyst layer so that a region in which the fine carbon fibers are subjected to chemical vapor deposition has the predetermined pattern before chemical vapor deposition of the aggregate of the fine carbon fibers. The manufacturing method according to claim 1, wherein: 2. The undrawn portion is formed by pressing at least one partition plate for partitioning a region from which the fine carbon fibers are drawn against the aggregate of the fine carbon fibers. Manufacturing method. A substrate,
An aggregate of fine carbon fibers formed on the substrate by forming a catalyst layer and chemical vapor deposition on the substrate on which the catalyst layer is formed;
A region where the fine carbon fibers are drawn out from the aggregate of the fine carbon fibers is formed so as to define a region in a predetermined pattern, and the non-drawable portion where the fine carbon fibers cannot be drawn;
A fine carbon fiber-forming substrate comprising: 12. The fine carbon fiber-formed substrate according to claim 11, wherein a region for drawing out the fine carbon fibers has a constant width. The undrawable portion includes a portion where the aggregate structure of the fine carbon fibers is partially destroyed, a portion where the fine carbon fibers are partially removed from the aggregate of the fine carbon fibers, and the fine carbon fibers of the aggregate. The fine carbon fiber-formed substrate according to claim 11, comprising at least any one of the portions obtained by partially modifying the structure. The part of the aggregate structure of the fine carbon fibers partially broken is formed by dropping micro droplets on the aggregate of the fine carbon fibers. Fine carbon fiber forming substrate. 12. The undrawable portion is formed by subjecting the aggregate of fine carbon fibers to at least one of laser processing, ion beam processing, electron beam processing, and plasma processing. A fine carbon fiber-formed substrate as described in 1. 16. The fine carbon fiber-forming substrate according to claim 15, wherein a whitening zone by laser light irradiation is formed in the aggregate of fine carbon fibers. 11. The non-drawable portion is formed by patterning the catalyst layer so that a region in which the fine carbon fiber is subjected to chemical vapor deposition has the predetermined pattern. 11. Fine carbon fiber forming substrate.   The fine carbon fiber-forming substrate according to any one of claims 11 to 17, wherein the undrawable portion is formed in a spiral shape. The fine carbon fiber yarn manufactured by the manufacturing method in any one of Claims 1-10.