KR101917105B1

KR101917105B1 - Fiber complexes and methods of manufacturing the same

Info

Publication number: KR101917105B1
Application number: KR1020160115208A
Authority: KR
Inventors: 이상현; 노호균; 김승민; 김태욱; 배수강; 이동수; 이승기
Original assignee: 한국과학기술연구원
Priority date: 2016-09-07
Filing date: 2016-09-07
Publication date: 2018-11-09
Also published as: KR20180027934A

Abstract

A conductive fiber bundle comprising a plurality of conductive fiber strands; And a plurality of metal particles formed inside the conductive fiber bundle. Such fiber composites have excellent mechanical and electrical properties and can be widely used in fields where current capacity is required.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a fiber composite,

The present invention relates to a fiber composite comprising metal particles. More particularly, the present invention relates to a fiber composite having excellent current capacity and electrical conductivity and a method for producing the same.

Conductive fiber is a material that is in the form of fiber but has low resistance and can flow current. In general, the conductive fibers have a number of fine strands entangled with many pores therein, and the electrical and mechanical properties of the conductive fibers are deteriorated by these pores.

FIG. 1 shows a carbon fiber produced according to the prior art. The conductive carbon fiber as shown in FIG. 1 is a fiber produced by successively injecting and twisting a plurality of strands of carbon nanotubes. Therefore, there are many pores inside, and the pores inside and outside are connected to each other.

On the other hand, the carbon fiber can be produced through the carbonization process of a polymer to realize high strength and high conductivity, but requires a complicated manufacturing process. In addition, the production of continuous fibers using carbon nanotubes has a continuous carbon nanofiber shape because they connect or twist relatively short carbon nanotubes to form long fibers. However, there are many interfaces and voids between the nanotubes, so that the electrical and mechanical properties of the carbon nanofibers can not be maintained. Conductive fibers with different pores also have similar problems.

In order to improve the performance of the conductive fiber, research has been conducted to fabricate a fiber composite by performing a plating process of electrodepositing metal on the surface of the conductive fiber body by electrolysis of a metal salt solution. However, There is a problem that the current density is not constant since the surface area of the conductive fiber is very small and unstable at the time of two-roll plating, thereby lowering the reliability of the final product. In addition, the research to date has been limited to plating only on the surface of the fibers.

In order to solve this problem, there is a desperate need to develop new methods for maintaining or improving the electrical and / or mechanical properties of conductive fibers.

KR 10-2007-0061702 A KR 10-2011-0134062 A KR 10-2013-0159979 A

Embodiments of the present invention provide fiber composites having excellent electrical and mechanical properties.

Other embodiments of the present invention provide a method of making the fiber composite.

In one embodiment of the invention, a conductive fiber bundle comprising a plurality of conductive fiber strands; And a plurality of metal particles formed inside the conductive fiber bundle.

In an exemplary embodiment, the conductive fiber strand may be a carbon nanotube fiber strand.

In an exemplary embodiment, the metal particles can be formed in the pores of the conductive fiber strands or between the adjacent conductive fiber strands.

In an exemplary embodiment, the conductive fiber strands and the metal particles in the fiber composite may have a volume ratio of 1:30 to 10: 1.

In an exemplary embodiment, the conductive fiber strands may have an average diameter of 1 nm to 100 nm.

In an exemplary embodiment, the fiber composite may further comprise a metal layer formed on the conductive fiber bundle.

In an exemplary embodiment, the metal layer may have a thickness in the range of 10 nm to 1 cm.

In an exemplary embodiment, the fiber composite may exhibit a current capacity in the range of 1.0 x ¹⁰ ² A / cm ² to 1.0 x ^{10 10} A / cm ² .

In an exemplary embodiment, the fiber composite may exhibit a tensile strength in the range of 10 cN / tex to 10,000 cN / tex.

In an exemplary embodiment, the fiber composite may be used in at least one selected from the group consisting of a flexible electronic device electrode, a capacitor, an electromagnetic shielding heat dissipation material, and a heat dissipation material.

In another embodiment of the present invention, there is provided a method of making a conductive fiber bundle comprising: conducting a pretreatment process on a conductive fiber bundle comprising a plurality of conductive fiber strands; And performing a plating process on the pretreated conductive fiber bundle to form a plurality of metal particles in the conductive fiber bundle; Wherein the fiber composite material is a fiber composite material.

In an exemplary embodiment, the electroplating process may be performed for 1 second to 9 days.

In an exemplary embodiment, when the electrolytic plating process is performed, the electrolytic plating process may be performed through a plating bath including a dummy cathode.

In an exemplary embodiment, the dummy cathode may have an area ranging from 1 cm ² to 100 m ² .

In an exemplary embodiment, the current density in the plating bath can be kept uniform within a range of 0.001 A / dm ² to 60 A / dm ² .

In an exemplary embodiment, the method further comprises: performing an electroless plating process on the pretreated conductive fiber bundle for 60 seconds to 9 days to form a metal layer on the conductive fiber bundle .

According to the present invention, metal particles can be formed inside and outside of a conductive fiber bundle having a general porous structure, and a metal layer can be further formed on the outer surface of the conductive fiber bundle. These metal particles can organically connect between the conductive fiber strands constituting the conductive fiber bundle so as to have higher electrical and mechanical characteristics. In the case of the fiber composite prepared by the present invention, the current capacity and the electric conductivity can be increased by about 100 times as much as the conventional conductive fiber, and the tensile strength can be improved by about 4 to 6 times.

In addition, according to another embodiment of the present invention, since the fiber composite is manufactured by a roll-to-roll process in a plating bath including a dummy cathode, a constant current density can be ensured in the conductive fiber bundle, . Particularly, in the prior art, a very fine and stable current must be supplied in order to deposit a suitable metal particle in a material having a surface area of several tens of micro-microns. The equipment capable of applying such a fine and stable current is very expensive It is difficult to control the solution appropriately. However, when the plating bath including the dummy cathode is used, since the area of the dummy cathode is larger than the surface area of the fiber, the variation width of the current density is decreased, It is possible to produce the fiber composite material smoothly, and the efficiency of the process can be improved.

Accordingly, the fiber composite of the present invention can be utilized in fields requiring high current capacity and electrical conductivity, and can be widely used in functional new materials such as flexible electronic device electrodes, super capacitors, electromagnetic wave shielding, and heat radiation / heat generation materials.

1 is a cross-sectional view schematically showing the structure of a conductive fiber according to the prior art.
2 is a cross-sectional view schematically showing a structure of a fiber composite produced according to an embodiment of the present invention.
3 is a cross-sectional view schematically showing the structure of a fiber composite produced according to another embodiment of the present invention.
4 is a schematic diagram showing the construction of a plating bath for producing a fiber composite according to an embodiment of the present invention.
5A to 5C are SEM images showing the surface of the fiber composite prepared according to Example 1. Fig. 5B is an enlarged SEM image of one area of FIG. 5A, and FIG. 5C is an enlarged SEM image of one area of FIG. 5B.
6A to 6C are SEM images showing the surface and cross-section of the fiber composite prepared according to Example 2. Fig. 6B is an enlarged SEM image of one area of FIG. 6A, and FIG. 6C is an enlarged SEM image of one area of FIG. 6B.
7 is an SEM image showing a cross-section of the fiber composite prepared according to Examples 1 and 2. Fig.
FIG. 8 is a graph showing the results of measurement of the current capacity of the fiber composite prepared according to Examples 1 and 2 and the general conductive fiber prepared according to Comparative Example 1. FIG.
9 is a graph showing the results of measuring the tensile strength of the fiber composite prepared according to Examples 1 and 2 and the general conductive fiber prepared according to Comparative Example 1. Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention.

As used herein, the term " core-shell structure of a fiber composite " refers to a structure consisting of a metal film surrounding the outer surface of the conductive fiber.

As used herein, the term " fiber composite " refers to a concept including, for example, a conductive fiber bundle consisting of a plurality of conductive fiber strands and metal particles existing between the conductive fiber strands or existing in the pores of the conductive fibers.

As used herein, " conductive fiber strand " means a fiber strand having an average diameter in the range of 1 nm to 100 nm. The conductive fiber strands may have a porous structure.

In one embodiment of the invention, a conductive fiber bundle comprising a plurality of conductive fiber strands; And a plurality of metal particles formed inside the conductive fiber bundle. The metal particles may be connected to each other to form a conductive fiber bundle so as to have higher electrical and mechanical properties.

On the other hand, the fiber composite of the present invention is schematically shown in Fig. Referring to FIG. 2, in the conductive fiber bundle of the present invention, there may be a plurality of metal particles and may exist between adjacent conductive fiber strands or pores of the conductive fiber strands. In this case, the electrical and mechanical properties of the conductive fiber bundles (that is, the aggregate of the conductive fiber strands) can be improved, and finally, the electrical and mechanical properties of the fiber composite can be improved.

In an exemplary embodiment, the conductive fiber strands of the conductive fiber bundles may have an average diameter in the range of 1 nm to 100 nm. If the average diameter of the conductive fiber strands is less than 1 nm, the fiber characteristics may be difficult to realize, and if it exceeds 100 nm, the mechanical properties such as electrical and / or ductility may be deteriorated.

For example, the conductive fiber strand may be, for example, a carbon nanotube fiber strand composed of carbon nanotubes.

When the conductive fiber strand contained in the conductive fiber bundle is a carbon nanotube fiber strand (or carbon nanotube strand), the degree of the pore inside the conductive fiber bundle can be controlled by controlling the injection tension during the production of the fiber. Generally, when a high tensile force is applied, a low porosity is shown because the distance between the carbon nanotube fibers (or carbon nanotubes) inside the carbon nanotube fibers is narrowed. When the carbon nanotube fibers (or carbon nanotubes The distance between them is widened to show a high porosity. Therefore, it is possible to control the porosity through adjustment of the tension applied during fiber injection.

In the exemplary embodiment, the material that can be used as the metal particles is not limited to the metal particles, but may be lithium, magnesium, zinc, cadmium, titanium ), Copper (Cu), aluminum (Al), nickel (Ni), yttrium (Y), silver (An), manganese (Mn), vanadium (V), iron (Fe), lanthanum Ta, niobium (Nb), gallium (Ga), indium (In), cobalt (Co), chromium (Cr) and antimony (Sb).

The metal particles may further include non-metallic particles such as sulfur (S), selenium (Se), phosphorus (P), arsenic (As), boron (B), nitrogen .

In an exemplary embodiment, the volume ratio between the plurality of conductive fiber strands and the plurality of metal particles in the core portion of the conductive fiber bundle may range from 1:30 to 10: 1, more preferably from 1: 1 < / RTI > When the content of the metal particles is excessively low as compared with the conductive fiber strands, the characteristics of the conductive fibers are not different from those of the conventional conductive fibers because the metal particles can not completely connect the conductive fiber strands. On the other hand, if the content of the metal particles is excessively high, the thickness of the fiber composite becomes thick, and the connection between the metal particles is formed, resulting in a problem that flexibility of the fiber composite is reduced.

In addition, the metal particles may have an average diameter of 100 nm to 1 mm, and preferably an average diameter of 0.5 to 5 μm. If the average diameter is excessively small, the conductive fiber strands can not be properly connected. If the average particle diameter of the metal particles is excessively large, the flexibility of the fiber composite decreases.

Meanwhile, the fiber composite may further include a metal layer formed on the conductive fiber bundle as shown in FIG. In this case, the electrical and / or mechanical properties of the fiber composite can be further improved.

In one embodiment, the metal layer formed on the conductive fiber bundle may have a thickness of 1 to 100 times the average diameter of the conductive fiber strands within the conductive fiber bundles. If the metal layer is formed to be thinner than the average diameter of the conductive fiber strands in the bundle of conductive fibers, a sufficient improvement in conductivity can not be expected, and if the metal layer is excessively thick, problems may arise in terms of flexibility.

On the other hand, in the exemplary embodiment, the metal layer may have a thickness of 10 nm to 1 cm. Preferably in the range of 10 nm to 5 mm, and more preferably in the range of 1 탆 to 10 탆.

In an exemplary embodiment, the metal layer may be formed of, for example, lithium, magnesium, zinc, cadmium, titanium, copper, aluminum, (Ni), yttrium (Y), silver (An), manganese (Mn), vanadium (V), iron (Fe), lanthanum (La), tantalum (Ta), niobium (Nb) ), Indium (In), cobalt (Co), chromium (Cr), antimony (Sb) and the like.

The metal layer may further include non-metallic particles such as sulfur (S), selenium (Se), phosphorous (P), arsenic (As), boron (B), nitrogen (N)

As described above, the fiber composite of the present invention includes a conductive fiber bundle including a plurality of conductive fiber strands and metal particles formed therein, and the metal particles are used to organically bond the conductive fiber strands constituting the conductive fiber bundle So that they can have higher electrical and mechanical characteristics. Accordingly, the fiber composite can exhibit excellent current capacity and tensile strength. Because of this, the fiber composites can be used where flexibility and high electrical and mechanical properties are required. Flexible electronic device electrodes, super capacitors, electromagnetic wave shielding, heat dissipation / heat generation materials, and the like.

In an exemplary embodiment, the fiber composite according to the present invention may exhibit an increased current capacity value from 10 to 1 x 10 ⁴ times the conventional fiber. For example, the fiber composite may exhibit a current capacity in the range of 1.0 x 10 ² A / cm ² to 1.0 x 10 ⁶ A / cm ² .

In addition, when the fiber composite further includes a metal layer, the current capacity can be further improved and the current capacity in the range of 1.0 x ¹⁰ ² A / cm ² to 1.0 x ^{10 10} A / cm ² can be shown.

In an exemplary embodiment, the fiber composite may exhibit an increased tensile strength 4 to 10 times as much as conventional fibers. For example, the fiber composite may exhibit a tensile strength in the range of 10 cN / tex to 1,000 cN / tex.

In addition, when the fiber composite further comprises a metal layer, it may exhibit an improved tensile strength, for example, a tensile strength in the range of 20 cN / tex to 10,000 cN / tex.

The above-described fiber composite includes a step of performing a pretreatment process on a conductive fiber bundle including a plurality of conductive fiber strands; And performing an electroless plating process on the pretreated conductive fiber bundle to form a plurality of metal particles in the conductive fiber bundle; And the like.

In an exemplary embodiment, the electroless plating process may be performed for 1 second to 9 days under current density conditions ranging from 0.01 A / dm ² to 60 A / dm ² . When the process conditions of the electroless plating process are out of the range, a plurality of metal particles are not formed or excessively formed in the conductive fiber bundles, so that the flexibility of the fiber composite may be deteriorated.

In one embodiment, the electroless plating process may be performed for 1 second to 60 seconds. The electroless plating process may be performed at less than 1 second to less than 9 seconds. On the other hand, when the electroless plating process is performed, an electroless plating process may be performed through a plating bath including a dummy cathode. In this case, the dummy cathode in the plating bath prevents over concentration of ions in the solution The current density can be kept constant more easily. As a result, a constant current density can be ensured and the metal particles can be controlled to be plated in a certain amount on the conductive fiber bundles.

Also, since the surface area of the dummy negative electrode is very large as compared with the surface area of the fiber composite, it is possible to make a current density capable of smoothly forming metal particles in the inside even with a relatively precise current application equipment, So that the metal particles can be controlled to be plated in a predetermined amount on the conductive fiber bundles.

In an exemplary embodiment, the dummy cathode may have a surface area ranging from 1 cm ² to 100 m ² . Preferably, the dummy cathode may have a surface area of 10 cm ² to 100cm ² range. When the surface area of the dummy cathode is out of the above range, it may be difficult to secure a constant microcurrent density.

Meanwhile, the method for fabricating the fiber composite may further include performing an electroless plating process on the conductive fiber bundle for 60 seconds to 9 days at a current density of 0.001 A / dm ² to 60 A / dm ² , And forming a metal layer on the outer surface of the bundle. If the process conditions of the electroless plating process are out of the above range, the metal layer may not be formed or excessively formed and the flexibility of the finally formed fiber composite may be deteriorated.

In one embodiment, the electroless plating process may be manufactured through a roll-to-roll plating apparatus.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

Example

[Example 1]

The carbon nanotube fibers (several nanometers to several tens of nanometers in diameter) wound on the winding roll were wound and wound, and the ends of the twisted carbon nanotube fiber bundles were separated and connected to the roll of the pretreatment water tank shown in FIG. First, the substrate was immersed in a degreasing solution and a washing solution, and then subjected to a pretreatment. After passing through the roll connected to the plating bath, current density was 4.5 A / dm ² using a copper plating solution shown in the following table. Copper for a second time.

ingredient density Copper sulfate 220 g / l Sulfuric acid 60 g / l Chlorine ion 0.01% Organic polish 5ml / l

The sample from the plating bath was washed with water and dried to prepare a fiber composite in which metal grains were formed inside the carbon nanotube fiber bundles.

[Example 2]

The carbon nanotube fiber strands wound on the take-up roll were wound and wound, and the end of the twisted carbon nanotube fiber bundle was separated and connected to the roll of the pretreating water tank. First, the substrate was immersed in a degreasing solution and a washing solution to be subjected to a pretreatment. After passing through a roll connected to the plating bath, a copper plating solution as shown in Table 2 was used at a current density of 4.5 A / dm ² , air agitation, a cathode pile, And copper plating was performed for 60 seconds.

A core-shell type fiber in which metal grains are formed inside a bundle of carbon nanotube fibers through a process of washing and drying the sample from the plating bath through a roll, and a metal film is formed on the surface of the carbon nanotube fiber bundle Complex.

[Comparative Example 1]

The carbon nanotube fiber strands were wound and then twisted to produce a carbon nanotube fiber bundle, and the conductive fiber according to Comparative Example 1 was fabricated.

[Experimental Example 1]

The fiber composite prepared according to Example 1 and comprising metal particles was observed through a scanning electron microscope and is shown on the left side of Figs. 5A to 5C and Fig. 5A to 5C, the surface and the interior of the fiber composite can be confirmed. It can be seen that a plurality of copper particles are well formed inside and outside the carbon nanotube fiber bundles. 5A to 5C. As a result, it can be confirmed that a plurality of copper particles are uniformly distributed in the inside.

[Experimental Example 2]

The fiber composite prepared according to Example 2 was observed through a scanning electron microscope and is shown on the right side of Figs. 6A to 6C and Fig. 6A to 6C and FIG. 7, it can be seen that a metal layer is formed on the surface of the carbon nanotube fiber bundle including the metal particles, so that the fiber composite is formed into a core-shell structure. At this time, in the case of the core of the fiber composite, it can be seen that the metal particle and the bundle of carbon nanotube fibers having porosity form an organic structure, and in the case of the shell, a film form is observed.

[Experimental Example 3]

The current capacities of the fiber composite prepared according to Examples 1 and 2 and the conductive fiber according to Comparative Example 1 were measured, and the results are shown in FIG. FIG. 8 shows that the current capacity of the fiber composite prepared according to Example 1 and Example 2 is higher by about 100 times than that of the conductive fiber according to Comparative Example 1. FIG.

[Experimental Example 4]

The tensile strengths of the fiber composite prepared according to Examples 1 and 2 and the conductive fiber according to Comparative Example 1 were measured and shown in FIG. 9, the fiber composite prepared according to Example 1 showed a tensile strength improved by about 57% as compared with the conductive fiber according to Comparative Example 1, and the fiber composite prepared according to Example 2 had a tensile strength improved by about 590% .

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of protection of the present invention as long as it is obvious to those skilled in the art.

Claims

A conductive fiber bundle comprising a plurality of conductive fiber strands;
A plurality of metal particles formed in the conductive fiber bundle; And
And a metal layer formed on the conductive fiber bundle,
The metal particles having an average diameter of 100 nm to 1 mm,
The metal particles organically connecting the conductive fiber strands contained in the conductive fiber bundle,
Wherein the conductive fiber strands and the metal particles in the fiber composite have a volume ratio of 1:30 to 10: 1.

The method according to claim 1,
Wherein the conductive fiber strand is a carbon nanotube fiber strand.

The method according to claim 1,
Wherein the metal particles are formed between adjacent conductive fiber strands or in pores of the conductive fiber strands.

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The method according to claim 1,
Wherein the conductive fiber strands have an average diameter of 1 nm to 100 nm.

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The method according to claim 1,
Wherein the metal layer has a thickness in the range of 10 nm to 1 cm.

The method according to claim 1,
The fiber composite is 1.0 x10 ² A / cm ² to 1.0 x10 ¹⁰ fiber composite shown the current capability of the A / cm ² range.

The method according to claim 1,
Wherein the fiber composite has a tensile strength in the range of 10 cN / tex to 10,000 cN / tex.

The method according to claim 1,
Wherein the fiber composite is used in at least one selected from the group consisting of a flexible electronic device electrode, a capacitor, an electromagnetic shielding heat radiation material, and a heat generation material.

Performing a pretreatment process on a conductive fiber bundle including a plurality of conductive fiber strands;
Forming a plurality of metal particles in the conductive fiber bundle by performing an electrolytic plating process on the pretreated conductive fiber bundle; And
And further performing an electroless plating process on the pretreated conductive fiber bundle for 60 seconds to 9 days to form a metal layer on the conductive fiber bundle,
The metal particles having an average diameter of 100 nm to 1 mm,
The metal particles organically connecting the conductive fiber strands contained in the conductive fiber bundle,
Wherein the conductive fiber strands and the metal particles in the fiber composite have a volume ratio of 1:30 to 10: 1.

12. The method of claim 11,
Wherein the conductive fiber strand is a carbon nanotube fiber strand.

12. The method of claim 11,
Wherein the electroplating process is performed for 1 second to 9 days.

12. The method of claim 11,
Wherein the electroplating process is carried out through a plating bath including a dummy cathode when the electrolytic plating process is performed.

15. The method of claim 14,
The dummy cathode 1cm ² To 100 m < ^{2 &} gt ;.

15. The method of claim 14,
Wherein a current density in the plating bath is uniformly maintained within a range of 0.001 A / dm ² to 60 A / dm ² .

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