HK1177190A - Method for producing multilayer graphene coated substrate - Google Patents

Description

Method for producing multilayer graphene-coated substrate

Technical Field

The present invention relates to a multilayer graphene-coated substrate which can be used as a transparent conductive film or a conductive film for an electrode for a panel such as a liquid crystal display or a plasma display, an electrode for a display element such as a notebook personal computer, a mobile phone or a touch panel, an electrode and an electrode base material for a lithium ion battery, a lithium ion capacitor, a fuel cell, a thin film solar cell, another primary battery or a secondary battery, and a sheet or the like for effectively releasing heat generated inside various devices, and a novel method for producing the same.

Background

Conventionally, a transparent conductive film (transparent electrode) is formed by coating ITO (indium tin oxide) on a glass substrate, a PET (polyethylene terephthalate) resin film, or the like by sputtering, vacuum deposition, or the like. However, since indium constituting ITO is a rare earth element and there is a concern about the supply thereof, and there is a possibility that dust of ITO in the production field may cause health damage, research and development of alternative materials therefor are actively being carried out. Graphene is expected as a promising candidate, but has not yet been put to practical use because it cannot be industrially stably produced.

In lithium ion batteries, capacitors, lithium ion capacitors, fuel cells, and the like, film-like electrodes obtained by mixing fine powders of graphite, carbon black, and the like with polyvinylidene fluoride and a solvent, slurrying the mixture, coating the slurry on a current collector such as a copper foil, and drying the slurry have been put into practical use. For example, in a negative electrode of a lithium ion battery, a film-like electrode using artificial graphite, natural graphite as a main material and a copper foil has been put to practical use. Such a lithium ion battery is used as a driving battery for an electric vehicle, and is actively researched and developed because it is necessary to improve energy efficiency and to extend a cruising distance per charge.

Graphite is an active material that generates charge and discharge by intercalation of lithium ions, but is difficult to be formed into a sheet alone because it is a powder. Thus, the sheet is made by bonding the sheet to a copper foil or the like together with a binder such as polyvinylidene fluoride. Although there are graphite sheets obtained by forming graphite alone into sheets, they are not used for heat-resistant gaskets and the like in which compressive strength is important because they are extremely weak in the bending direction and the stretching direction.

The multilayer graphene is expected to be used as a negative electrode material for a lithium ion battery and an electrode for a lithium ion capacitor because it intercalates lithium ions in the same manner as graphite. For example, if graphene can be directly formed on a copper foil, the resistance which is a problem in the binder component can be reduced, and the thickness of the electrode layer can be reduced, thereby improving the charge/discharge capacity. Further, if graphene can be directly formed on a resin film or the like or can be formed into a composite with the resin film or the like, a battery can be formed without using a copper foil. In lithium ion batteries for electric vehicles, weight reduction is required, and the specific gravity of copper is as high as about 9g/cm³. On the other hand, if a PET resin formed or compounded with graphene can be produced, the specific gravity is less than 2g/cm³Therefore, a large reduction in weight can be achieved.

As a technique for producing graphene on a substrate, there are CVD method, SiC thermal decomposition method, graphene oxide reduction method, and the like, but each of them has a problem, and a method capable of more convenient and stable production is required.

For example, the CVD method is a method in which a film made of graphene is formed on one surface of a metal foil such as copper or nickel by Chemical Vapor Deposition (CVD), a resin film is attached to the film, the metal foil is removed by etching, and the film made of graphene is transferred from the surface from which the metal foil is removed onto a final substrate such as PET resin (non-patent documents 1 to 4). However, in this method, since the composite material is produced as a composite material strongly bonded to the graphene layer due to the catalytic action of the metal foil, it is necessary to remove all the metal foil with an acid in order to transfer the film temporarily formed on the metal foil to the substrate, which causes problems such as a complicated manufacturing process and the possibility of introducing defects into the film during the transfer.

The SiC thermal decomposition method is a method in which the SiC substrate is heated to about 1300 ℃ to cause Si on the surface to be scattered and the remaining C to be autonomously recombined into graphene (non-patent document 5), and has a problem that the SiC substrate used is expensive and transfer from the SiC substrate is difficult.

Further, the graphene oxide reduction method is a method in which graphite powder is oxidized and dissolved in a solution, and the obtained material is applied to a substrate and reduced (non-patent documents 6 and 7), and has a problem that a reduction process is required, and it is difficult to completely reduce the graphite powder, and thus it is difficult to secure sufficient conductivity and transparency.

Documents of the prior art

Non-patent document

Non-patent document 1 q.yu et al, appl.phys.lett.93(2008)113103

Non-patent document 2 x.li et al, Science 324(2009)1312

Non-patent document 3 X.Li et al, Nano Letters 9(2009)4268-4272

Non-patent document 4 s.bae et al, Nature Nanotech, 5(2010)574

Non-patent document 5 c.berger et al, j.phys.chem.b 108(2004)19912

Non-patent document 6 s. horiuchi et al, JJAP 42(2003) L1073

Non-patent document 7 m.hirata et al, Carbon 42(2004)2929

Disclosure of Invention

Problems to be solved by the invention

In view of the above background, the present invention is intended to provide a transparent conductive film made of graphene and a method for providing the conductive film more easily and stably.

The present invention also provides a multilayer graphene-coated substrate in which a plurality of graphene layers derived from a multilayer graphene aggregate are laminated on a substrate surface.

Means for solving the problems

As a result of intensive studies, the present inventors have found that, if a multilayer graphene aggregate in which a plurality of multilayer graphene are aggregated is used, a multilayer graphene-coated substrate useful as a transparent conductive film and a conductive film can be easily and stably produced by directly laminating multilayer graphene constituting the aggregate on a substrate surface, and have further repeated studies, thereby completing the present invention.

Namely, the present invention relates to the following aspects.

[ 1] A method for producing a multilayer graphene-coated substrate, which comprises a step of laminating a multilayer graphene derived from a multilayer graphene aggregate on a substrate surface.

The production method according to the above [ 1], wherein the multilayer graphene aggregate is a multilayer graphene block in which multilayer graphene extending from the inside to the outside is aggregated.

The production method according to the above [ 1] or [ 2], wherein the multilayer graphene constituting the multilayer graphene aggregate is a material having a thickness of 0.34 to 10 nm.

The production method according to any one of [ 1] to [ 3] above, wherein the stacking is performed by rubbing a multilayer graphene aggregate on a substrate surface.

The production method according to any one of [ 1] to [ 3] above, wherein the stacking is performed by contacting the substrate surface with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate and then removing the solvent from the substrate surface.

The production method according to any one of [ 1] to [ 3] above, wherein the stacking is performed by dip-coating the surface of the substrate with a multilayer graphene dispersion prepared from a multilayer graphene aggregate.

The production method according to any one of [ 1] to [ 3] above, wherein the lamination is performed by spraying a surface of the substrate with a multilayer graphene dispersion prepared from a multilayer graphene aggregate.

The production method according to any one of [ 5] to [ 7] above, wherein the solvent is selected from the group consisting of 1, 2-dichloroethane, benzene, thionyl chloride, acetyl chloride, tetrachloroethylene carbonate, dichloroethylene carbonate, benzoyl fluoride, benzoyl chloride, nitromethane, nitrobenzene, acetic anhydride, phosphorus oxychloride, benzonitrile, selenium oxychloride, acetonitrile, tetramethylsulfone, dioxane, 1, 2-propanediol carbonate, benzyl cyanide, ethylene sulfite, isobutyronitrile, propionitrile, dimethyl carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, ethylene carbonate, phenyl difluorophosphite, methyl acetate, N-butyronitrile, acetone, ethyl acetate, water, phenyl dichlorophosphate, diethyl ether, tetrahydrofuran, diphenyl chlorophosphate, trimethyl phosphate, tributyl phosphate, dimethylformamide, N-methylpyrrolidine, and mixtures thereof, 1 solvent or a mixed solvent of 2 or more selected from N-dimethylacetamide, dimethyl sulfoxide, N-diethylformamide, N-diethylacetamide, pyridine, hexamethylphosphoramide, hexane, carbon tetrachloride, diglyme, chloroform, 2-propanol, methanol, ethanol, propanol, ethylene glycol, methyl ethyl ketone, 2-methoxyethanol, dimethylacetamide, toluene and polybenzimidazole; or the solvent or the mixed solvent to which a dispersant is added.

The production method according to the above [ 6] or [ 8], wherein the temperature of the multilayer graphene dispersion liquid in the dip coating is 40 ℃ or more, and the pulling rate at which the substrate immersed in the multilayer graphene dispersion liquid is pulled from the liquid is 1 to 1000 μm/sec.

The production method according to any one of [ 1] to [ 9] above, wherein the thickness of the layer coated with the multilayer graphene in the multilayer graphene-coated substrate is 0.5 to 10000 nm.

The production method according to any one of [ 1] to [ 10 ] above, wherein the substrate is a resin film formed of a resin selected from the group consisting of polyester resins, acrylic resins, polystyrene resins, polycarbonate resins, polypropylene resins, polyethylene resins, polyvinyl chloride resins, and polytetrafluoroethylene resins; a glass substrate coated with 1 or 2 or more resins selected from polyester resins, acrylic resins, polystyrene resins, polycarbonate resins, polypropylene resins, polyethylene resins, polyvinyl chloride resins, and polytetrafluoroethylene resins; a metal foil, a metal plate, or a metal film formed of a metal selected from copper, nickel, iron, aluminum, and titanium; paper; a glassy carbon substrate; or a sapphire substrate.

[ 12 ] A tool for coating a surface of a workpiece with a multilayer graphene, the tool having a tool surface in contact with the surface of the workpiece, the tool surface holding a multilayer graphene aggregate.

[ 13 ] A method for producing a multilayer graphene-coated substrate having a pattern formed by using the thickness of a coating layer of multilayer graphene,

the manufacturing method comprises the following steps: a transfer mold having surface irregularities conforming to the pattern is prepared, the back surface of the substrate is superimposed on the surface of the transfer mold, and the surface of the substrate is rubbed with the multilayer graphene derived from the multilayer graphene aggregate.

A method for producing a multilayer graphene-coated substrate, which comprises the step of laminating a multilayer graphene derived from a multilayer graphene aggregate on a substrate surface and then pressing the substrate surface.

The production method according to [ 14 ] above, wherein the stacking is performed by spraying a surface of the substrate with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate, a multilayer graphene pulverized liquid, or a residual graphene dispersion liquid.

[ 16 ] A method for producing a multilayer graphene-coated substrate, which comprises a step of laminating a multilayer graphene derived from a multilayer graphene aggregate on a substrate surface,

the lamination is performed by single-fluid spraying the substrate surface with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate, a multilayer graphene pulverized liquid, or a residual graphene dispersion liquid.

[ 17 ] A multilayer graphene-coated substrate produced by laminating a multilayer graphene derived from a multilayer graphene aggregate on a substrate surface.

Effects of the invention

According to the production method of the present invention, since multilayer graphene can be directly laminated on a substrate surface by a simple method by using a multilayer graphene aggregate as a raw material, a multilayer graphene-coated substrate useful as a transparent conductive film, a conductive film, and a heat sink can be obtained more easily and stably than in the conventional method. Therefore, the manufacturing method of the present invention can provide an effective and inexpensive transparent conductive film, and heat sink.

Drawings

FIG. 1 is a sectional view showing the structure of a graphite crucible.

FIG. 2 is a sectional view showing the structure of a graphite crucible, in which a raw material for calcination is charged.

FIG. 3 is a sectional view showing the structure of a graphite crucible, in which a calcined material is charged and the crucible is sealed.

Fig. 4 is a sectional view showing the structure of a graphite crucible, in which the bottom and the upper part of the calcined material 3 are both covered with a spacer and the crucible is sealed.

Fig. 5 is a sectional view showing the structure of a graphite crucible, in which the entire side surface of the raw material for calcination 3 is covered with a sleeve (sleeve) and the crucible is sealed.

Fig. 6 is a sectional view showing the structure of a graphite crucible, in which the bottom, upper part and side surface parts of the calcined material 3 are all covered with a sleeve and a spacer, and the crucible is sealed.

Fig. 7 is a conceptual diagram (cross-sectional view) illustrating a mechanism of producing graphene on the surface of the calcined raw material.

Fig. 8 shows crystal orientations of carbon hexagonal network planes in the crystal structure of graphite.

Fig. 9 is a conceptual diagram illustrating a mechanism in which graphene grows outward (approximately radially) from the surface of the calcined material along the a-axis direction of the graphite crystal.

Fig. 10 is a conceptual diagram (cross-sectional view) showing the formation of graphene around a powdery or granular calcined raw material having various shapes.

Fig. 11 is a conceptual diagram showing a mechanism of anisotropic growth and growth of a conventional graphite material.

Fig. 12 is a conceptual diagram illustrating a mechanism in which graphene grows isotropically from the surface of the calcined raw material.

Fig. 13 is a conceptual diagram (cross-sectional view) showing a mechanism of producing graphene on the outer surface and inside of a spherical calcined raw material.

Fig. 14 is a conceptual diagram (cross-sectional view) showing a mechanism of producing graphene on the outer surface of a spherical calcined raw material to produce a bulk graphene block.

Fig. 15 is a Scanning Electron Microscope (SEM) photograph of the surface of the multi-layered graphene block used in example 1.

Fig. 16 is an optical micrograph of the surface of the transparent conductive film produced in example 1.

Fig. 17 is an SEM photograph of the surface of the transparent conductive film produced in example 1.

Fig. 18 is an enlarged view of the front view.

Fig. 19 is an SEM photograph of the surface of the multilayer graphene-coated substrate obtained in example 2 to 4.

Fig. 20 is an SEM photograph of the surface of the coating layer formed of the multilayer graphene formed on the surface of the PET resin in example 3.

Fig. 21 is an SEM photograph of the surface of the coating layer formed of multi-layer graphene formed on the surface of the acrylic resin in example 3.

Fig. 22 is an SEM photograph of the surface of the coating layer formed of multilayer graphene formed on the surface of the copper plate in example 4.

Fig. 23 is a Transmission Electron Microscope (TEM) photograph of a part of the surface of multilayer graphene in example 7.

Fig. 24 is an enlarged view of the multilayer graphene of the previous figure, which is a view capturing a lattice image of an end thereof.

FIG. 25 is a substitute photograph for drawing showing an electron micrograph of the surface of the product of production example 3-1.

Fig. 26 is a diagram showing a high-magnification image of the previous drawing.

FIG. 27 is an SEM photograph of a cross section of the product of production example 3-1.

FIG. 28 is an SEM photograph showing a cross section of the product of production examples 3 to 5.

FIG. 29 is an SEM photograph showing a cross section of the products of production examples 3 to 6.

FIG. 30 shows the results of Raman spectroscopy measurement of production example 3-1.

FIG. 31 shows the results of Raman spectroscopy measurements of production examples 3 to 5.

Fig. 32 is an SEM photograph of the surface of the product of production example 4.

Fig. 33 is a diagram showing a high-magnification image of the previous drawing. The scale bar in the photograph is 2 μm.

Fig. 34 is an SEM photograph of the surface of the product of production example 5. The scale bar in the photograph is 20 μm.

Fig. 35 is a schematic view showing the structure of the graphite crucible and the glassy carbon spacer used in production example 7, and the state of sample filling.

Fig. 36 is an appearance photograph showing the state of formation of a film-like product formed of vapor-phase-grown graphite (multilayer graphene) formed on the surface of the glassy carbon spacer in production example 7.

Fig. 37 is an SEM photograph of an end portion of the film-like product produced in production example 7.

Fig. 38 is an SEM photograph of a flat-looking portion of the previous drawing after enlargement.

Fig. 39 is an enlarged view of the front view.

FIG. 40 is an SEM photograph of the visually prominent portion of FIG. 37 under magnification.

Fig. 41 is an enlarged view of the front view.

Fig. 42 is an SEM photograph of a substance generated on the surface portion of the sample in production example 8.

Fig. 43 is an enlarged view of the front view.

Fig. 44 is an enlarged view of the front view.

Fig. 45 is an SEM photograph of the product of production example 9.

Fig. 46 is an enlarged view of the front view.

Fig. 47 is an SEM photograph of the product of production example 10.

Fig. 48 is an enlarged view of the front view.

Fig. 49 is an SEM photograph of the multi-layer graphene block produced in production example 11.

Fig. 50 is an enlarged view of the front view.

Fig. 51 shows a multilayer graphene block obtained by locally cleaving multilayer graphene, which is the multilayer graphene block according to the present invention (production example 12).

Fig. 52 is an enlarged view of the front view.

Fig. 53 is a schematic view of a graphene coating tool holding a multilayer graphene aggregate.

Fig. 54 is a photograph substitute for drawing showing the appearance of the graphene coating tool used in example 9.

Fig. 55 is a transfer mold used in example 10.

Fig. 56 shows a multilayer graphene-coated substrate having a pattern formed by the thickness of a coating layer of multilayer graphene obtained in example 10.

Fig. 57 is an SEM photograph of the surface of the multilayer graphene coated on the copy paper obtained in example 11.

Fig. 58 is an enlarged view of the front view.

Fig. 59 is an SEM photograph of the surface of the multilayer graphene coated on the polyester nonwoven fabric obtained in example 11.

Fig. 60 is an appearance photograph of the multilayer graphene-coated substrate of example 12.

Fig. 61 is an SEM photograph of the surface of the multilayer graphene-coated substrate of example 14.

FIG. 62 is an FE-SEM photograph of the surface of the PET film on which droplets were deposited in example 15.

FIG. 63 is an FE-SEM photograph of the surface of the copper plate on which the liquid droplets were deposited in example 15.

Detailed Description

In the present invention, the multilayer graphene aggregate is a material in which a plurality of multilayer graphene are aggregated without being stacked on each other, and the shape, form, size, and the like thereof are not limited. Specifically, there may be mentioned: (A) a multi-layer graphene block in which multi-layer graphene extending from the inside to the outside is aggregated (the present aggregate is in the form of isotropic graphite particles, and may be in the form of a block-shaped graphite structure composed of the same, the size of the graphite particles is about 1 to about 1000 μm, the size of the multi-layer graphene constituting the graphite particles is about 0.1 to about 500 μm in diameter or width, the thickness is about 0.34 to about 100nm, preferably about 0.34 to about 10nm, more preferably about 0.34 to about 3.5nm or less, and the present aggregate is also simply referred to as "multi-layer graphene block"; (B) a multilayer graphene aggregate having a film-like form, wherein each multilayer graphene grows in the a-axis direction of the graphite crystal approximately perpendicularly to a flat plate or a spherical surface, and covers the flat plate surface or the spherical surface to form a film as a whole (the size of the multilayer graphene constituting the aggregate is from about 1 to about 500 μm in diameter or width; from about 0.34 to about 100nm in thickness, preferably from about 0.34 to about 10nm, more preferably from about 0.34 to about 3.5nm or less; the aggregate is also referred to simply as "film-like multilayer graphene aggregate"); (C) a fibrous multi-layer graphene aggregate in which a plurality of such multi-layer graphene are connected and the whole of the multi-layer graphene grows in the a-axis direction of the graphite crystal from the center of the fiber to the outside (the size of the aggregate is a fibrous form having a diameter of 1 to 500 μm and a length of 0.01 to 30mm, the size of the multi-layer graphene constituting the aggregate is 0.1 to 500 μm and a thickness of 1 to 100nm or less, and the aggregate is also referred to simply as "fibrous multi-layer graphene aggregate"); (D) a multi-layer graphene block obtained by locally cleaving the multi-layer graphene constituting the above-mentioned (a) (the thickness of the multi-layer graphene is about 0.34 to about 9nm or less, and the present aggregate is also simply referred to as a "cleaved multi-layer graphene block").

The "multi-layer graphene" constituting the multi-layer graphene aggregate may also include a single layer of graphene. In addition, the "multilayer graphene" has the size and thickness as described above, and more specifically, is a "multilayer graphene sheet". Further, as another preferable example of the "multilayer Graphene", multilayer Graphene (Few-Layer Graphene: multilayer Graphene having a thickness of about 0.34nm to about 3.1nm and as many as about 10 layers) may be mentioned.

As a method for producing the multi-layer graphene block of the above (a) in the multi-layer graphene aggregate, there can be mentioned a production method comprising: powder particles of an organic compound calcined so as to contain residual hydrogen are prepared, the powder particles are charged into a closed container made of a heat-resistant material, and hot isostatic pressing is performed on each container using a pressurized gas atmosphere, and the maximum reaching temperature in the hot isostatic pressing treatment is 900 ℃ or higher and less than 2000 ℃. The following describes the production method.

A sealed container made of a heat-resistant material (for example, a graphite crucible) functions as a reaction container for causing a CVD reaction of a gas such as hydrogen, hydrocarbon, carbon monoxide, and water generated from a calcined raw material in a HIP (hot isostatic pressing) process. Since it is necessary to maintain an isotropic high pressure by the gas pressure and to chemically react the reaction gas generated inside without diffusing to the outside, it is necessary to use an appropriate material and a sealed structure. If the material is too dense, a pressure difference between the inside and outside of the container (e.g., crucible) is generated, and the container (e.g., crucible) is explosively damaged. On the other hand, if the material is too porous, the reaction gas generated inside diffuses to the outside of the container (e.g., crucible), and thus the efficiency of the chemical reaction is lowered.

In addition, in view of the need to take out the HIP-treated product to the outside and to seal the container (e.g., crucible) as easily as possible from the viewpoint of productivity of inserting the raw material before the HIP treatment, exposure to a high temperature of about 900 ℃ or higher at the time of the HIP treatment, and the need to maintain strength capable of withstanding the internal pressure due to generation of the reaction gas from the calcined raw material at a high temperature, it is necessary to form the container (e.g., crucible) from an appropriate material and structure.

Examples of the heat-resistant material constituting the container include, in addition to graphite, ceramics such as alumina, magnesia, and zirconia, metals such as iron, nickel, zirconium, and platinum, and the like. The material of the container (e.g., crucible) is suitably a graphite material. Specifically, the carbon fiber reinforced carbon material can be formed of artificial graphite materials such as extrusion molding, CIP (cold isostatic pressing) molding, vibration molding, and ramming (rammer) molding, hard carbon materials mainly containing glassy carbon molded with a thermosetting resin, carbon fiber reinforced carbon materials, and composite materials thereof. In order to efficiently cause a chemical reaction inside a container (e.g., a crucible), the porosity of the graphite material is important, and a graphite material having an open porosity (apparent porosity) of less than about 20% can be suitably used. If the material has an open porosity of about 20% or more, the reaction gas diffuses to the outside of the container (e.g., crucible), and therefore the concentration required for graphite production cannot be maintained. However, in the case where there is no difference between the volume of the container (e.g., crucible) and the volume of the cell (chamber) in which the HIP treatment is performed, even if the open porosity of the container (e.g., crucible) is about 20% or more, the amount of the reaction gas diffused to the outside of the container (e.g., crucible) is not so large, and therefore, the effectiveness is not greatly affected.

As the graphite crucible in the container used in the present invention, for example, a screw-type graphite crucible (fig. 1 to 3) can be used in order to efficiently fill the crucible with the calcination raw material and take out the product after the HIP treatment. The crucible lid portion 1 is sealed by cutting a screw portion into the inner wall 2a of the upper portion of the crucible main body 2 and the outer peripheral portion 1a of the crucible lid portion 1 by a predetermined tap (tap), and rotating and fastening the crucible lid portion 1 so that the screw portion engages with the raw material 3 after filling.

In order to improve the degree of sealing of the calcined raw material, the reaction gas generated from the calcined raw material 3 can be controlled from the upper and bottom portions of the crucible by using the spacers 4 made of a hard carbon material having a low open porosity, covering the entire (or a part of) the bottom and upper portions of the calcined raw material 3, and subjecting the resultant to the hot isostatic pressing treatment in this state. (FIG. 4)

Further, the hot isostatic pressing treatment is performed in a state (fig. 5) in which the sleeve 5 made of a hard carbon material having a low open porosity is used and the entire (or a part of) the side surface portion of the calcined raw material 3 is covered; alternatively, the whole (or a part) of the periphery of the raw material to be calcined may be covered with the spacer 4 and the sleeve 5 at the same time, and hot isostatic pressing treatment may be performed in this state (fig. 6), whereby the reaction efficiency can be improved. Examples of the carbon material constituting the spacer and the sleeve include glassy carbon, diamond-like carbon, amorphous carbon, and the like, and 1 or 2 or more of them may be used together. The carbon material typically has an open porosity of less than about 0.5%. In addition, even if the entire periphery of the calcined raw material is covered with a material having an open porosity of 0%, a gap is formed at the joint between the spacer and the sleeve, and the calcined raw material cannot be sealed with the spacer and the sleeve.

Examples of the screw thread in the screw-type graphite crucible include a triangular screw thread (a screw thread having a thread ridge whose cross section is formed in a shape close to a regular triangle), a square screw thread, a trapezoidal screw thread, and the like, and among them, a triangular screw thread is preferable.

In the process of producing vapor-grown graphite by HIP treatment using a calcined raw material containing residual hydrogen, regardless of the type of the raw material used, the crystallinity and the true density of the graphite to be produced can be controlled by the calcination temperature, the amount of residual hydrogen in the calcined raw material, the shape of the calcined raw material, the HIP treatment temperature, the pressure, the temperature and pressure raising rate, and the like.

The residual hydrogen amount is not particularly limited as long as it is a hydrogen amount sufficient to generate a gas such as hydrogen, hydrocarbon, carbon monoxide, and water necessary for the CVD reaction in the HIP treatment from the viewpoint of production of the object of the present invention, and is usually about 6500ppm or more, preferably about 10000ppm or more. The calcined raw material of residual hydrogen can be obtained by calcining a powder of an organic compound. In this case, the amount of residual hydrogen generally varies depending on the temperature of calcination. That is, as the calcination temperature increases, the amount of residual hydrogen decreases.

The calcination temperature is preferably about 1000 ℃ or lower, and preferably about 800 ℃ or lower.

The calcined raw material of residual hydrogen thus obtained is subjected to HIP treatment under appropriate conditions. If the temperature at the HIP treatment is about 900 ℃ or higher, vapor-grown graphite can be obtained, but if it is too high (for example, about 2000 ℃), the target is damaged by etching due to the excited hydrogen (fig. 29). Therefore, in the present invention, the maximum reaching temperature at the time of the HIP treatment needs to be about 900 ℃ or more and less than about 2000 ℃. In addition, the maximum reaching temperature at the time of the HIP treatment is in the range of about 1100 ℃ to about 1900 ℃, preferably about 1200 ℃ to about 1800 ℃, from the viewpoint of efficiently producing the object of the present invention.

The value suitable as the maximum reaching pressure in the HIP treatment varies depending on the particle size of the calcination raw material and the like, and the HIP treatment can be appropriately performed usually in the range of about 1MPa to about 300MPa, preferably about 10MPa to about 200MPa, and more preferably about 30MPa to about 200 MPa.

In the HIP treatment, from the viewpoint of production efficiency, it is generally desirable to first raise the pressure to a predetermined pressure (pressure priority mode) before raising the temperature to the vicinity of the temperature at which the calcination is performed, raise the temperature to the vicinity of the calcination temperature after preventing the calcination raw material from splashing, and then raise the temperature and pressure as necessary to reach the maximum reaching temperature and the maximum reaching pressure. The predetermined pressure is about 70 MPa. On the other hand, in the case where the particle size is as small as about 1 μm or less, the HIP treatment can be effectively performed without particularly performing the pressure-priority mode as described above.

The multilayer graphene block of the present invention thus obtained has a high crystallinity. In the present invention, the true density of the multilayer graphene block is preferably 1.85g/cm³The above ratio is more preferably 2.0 or more, still more preferably 2.1 or more, and still more preferably 2.2 or more. However, when the particle size of the calcination raw material is large, the generation ratio of the multilayer graphene block in the product decreases as described later, and therefore, if the true density of the product after the HIP treatment is measured in this state, the true density may sometimes become lower, but if the true density of a part of the generated multilayer graphene block is in the above range, the multilayer graphene block can be suitably used as the multilayer graphene block of the present invention. The total porosity of the multilayer graphene block is preferably 40% or more, and more preferably 50% or more. Among the multi-layer graphene blocks, a multi-layer graphene block in which both the true density and the total porosity satisfy any values of the above "preferred ranges" is more preferred than a multi-layer graphene block in which only either the true density or the total porosity is satisfied. Examples of such a multilayer graphene block include a multilayer graphene block having a true density of 1.85g/cm³A multilayer graphene block having a total porosity of 40% or more and a true density of 2.0g/cm³The multilayer graphene block having a total porosity of 50% or more is not limited to the above-described multilayer graphene block, and any other arbitrary combination is also within the scope of the present invention.

Fig. 7 shows a mechanism of producing multilayer graphene from a calcined raw material. When the raw material particles 6 obtained by calcining an organic compound are subjected to the HIP treatment under predetermined conditions, a gas 6a such as hydrogen, hydrocarbon, carbon monoxide, or carbon dioxide is generated from the inside of the calcined raw material particles 6 heated to a temperature higher than the calcination temperature. The gas 6a reaches the surface of the calcined raw material particle 6 while passing through the pores in the material. In this process, the graphene 7 is physically and chemically generated by being excited by temperature and pressure. The calcined raw material is shrunk by the generation of the reaction gas, and graphene 7 is formed outside and inside.

Since a gas such as argon gas or nitrogen gas is applied with a uniform pressure during the HIP treatment, graphene grows in the in-plane direction 7a of the graphene 7 (the a-axis direction of the graphite crystal) approximately radially from the surface 6s of the calcined raw material particle 6 as shown in fig. 8 and 9. Further, with the graphene 7 formed at the initial stage of the reaction as a starting point, the graphene 7 grows into a plurality of layers while extending in the direction of 7a while connecting the carbon one edges, and stacking the graphene 7 one edges in the direction of 7 c. In this case, since the high-pressure pressurized medium gas exhibits a shielding effect on the surface of graphene and inhibits the graphene from adhering and bonding to each other and forming a multilayer structure, the growth of graphene is further suppressed in the 7c direction and grows more in the radial direction in the 7a direction, and as a result, the multilayer graphene block of the present invention is produced.

The shape of the calcination raw material subjected to the HIP treatment may be any of various shapes such as spherical, oval, columnar, cylindrical, fibrous, and irregular block shapes (fig. 10). In any case, the graphene 7 grows multilayer graphene while extending in a direction in which the carbon edges 7a are connected approximately radially from the surface 6s of the calcined raw material particle 6, and the graphene 7 is laminated in a direction of the edge 7 c. Thus, conventionally, only a graphite material in which graphene 7 grows uniformly in one direction throughout the particle, for example, a large graphite material in which the anisotropy of the direction 7a is selectively selected in the surface of the particle and the direction 7c is selectively selected in the thickness direction of the particle (fig. 11) can be produced, but in the present invention, the growth of graphene 7 is directed in the direction 7a and the growth in the direction 7a is extended in a nearly radial shape, and as a result, a multi-layer graphene block in which multi-layer graphene extending from the inside to the outside is aggregated can be obtained (fig. 12). The multilayer graphene block may be in the form of isotropic graphite particles, or may be a graphite structure in which these particles are connected in a block form.

The degree of graphene generation inside and outside the calcined material 6 is determined by the selection of the calcination temperature, the amount of residual hydrogen, the graphite crucible structure, and the HIP treatment conditions of the calcined material. By selecting appropriate conditions, as shown in fig. 13, graphene 7 can be produced on the outer surface and inside of the calcined raw material 6, and the crystallinity of the bulk graphene block can be increased and the true density can be increased.

The mechanism of graphene generation according to the present invention will be described in more detail. The calcined raw material is isotropically pressurized by a pressure medium such as argon gas, nitrogen gas, or the like in the HIP treatment. Therefore, a high-pressure, high-density phase is first formed around the particles of the calcined raw material at the initial stage of the HIP treatment. When the HIP treatment temperature is higher than the calcination temperature, gas from the calcined raw material starts to be generated, and the diffusion coefficient of the gas into the high-pressure high-density pressure medium decreases, so that a high-concentration reaction gas region (hydrogen, hydrocarbon, carbon monoxide, or the like) is formed around the calcined raw material. Since the HIP treatment is an isotropic pressurization, a reaction gas region is formed uniformly on the outer surface of the particle and similarly to the shape of the particle.

In these reaction gas regions, when the HIP treatment temperature is further increased, specifically, when the HIP treatment temperature is about 900 ℃ or higher, so-called thermal CVD reaction occurs by excitation, and graphene is deposited. In general, the characteristic reaction mechanism of the present invention is: in a reaction gas region generated around the calcined raw material in the graphite crucible container by the HIP device, a CVD reaction is performed by supplying a reaction gas to the surface of the substrate using a CVD device, a plasma CVD device, or the like. Therefore, in the case of a spherical calcined raw material, graphene is grown in an approximately radial shape from the surface of the sphere as shown in fig. 25, and in the case of an amorphous calcined raw material, graphene is grown similarly from each surface as shown in fig. 34.

The reason why the calcination temperature of the raw material is in the optimum range is that in order to efficiently produce graphene by the CVD reaction, it is necessary to form appropriate raw material gas species such as hydrocarbon, hydrogen, and carbon monoxide, and when the calcination temperature is higher than about 900 ℃, for example, the amount of residual hydrogen is reduced, and it is difficult to efficiently precipitate graphene. The reason why the HIP treatment temperature is in the appropriate range is because it is found that the generated gas is hardly thermally excited at a temperature lower than about 900 ℃, the CVD reaction is hardly advanced, and the influence of hydrogen on the etching of the deposited graphene becomes large when the temperature exceeds about 2000 ℃.

In addition, since the CVD reaction mainly occurs on the particle surface with respect to the particle size of the calcination raw material used, the ratio of the surface area to the volume becomes small when the particle size is large, and as a result, the amount of graphene occupied in the resultant product decreases. Therefore, the use of a raw material having a small particle size can further increase the production ratio of graphene 7 (fig. 14). Therefore, from the viewpoint of production efficiency, in the case of using a spherical resin, it is preferable that the particle size (average) used be about 100 μm or less. However, when graphene is grown on the outermost surface of hard carbon particles such as glassy carbon, particles larger than 100 μm can be selected as needed, and the target product can be easily obtained.

Thus, conventionally, only a graphite material having high anisotropy such as a material in which carbon hexagonal mesh surfaces are laminated in a film shape parallel to the surface of a substrate can be produced, but in the present invention, graphene in which the number of layers is effectively controlled is produced in a three-dimensional space, and as a result, a multi-layer graphene block (including isotropic graphite particles and block-shaped graphite structures) in which multi-layer graphene extending from the inside to the outside is aggregated can be produced in a very short time. Therefore, conventionally, it has been difficult to synthesize a large amount of graphene directly because of a method such as peeling from a graphite material or forming on a metal substrate by utilizing a catalytic effect of a metal, but graphene can be produced directly and in a large amount by using a general HIP device and a general organic raw material in the present invention.

Generally, an organic compound is heated to advance polymerization, and oxygen, nitrogen, and hydrogen atoms in the structure are released due to thermodynamic instability, thereby advancing carbonization. Therefore, most organic compounds are promoted to react with each other by heat treatment at about 300 ℃ or higher, and at about 400 ℃ or higher, carbon and a calcination raw material in which hydrogen, oxygen, nitrogen, and the like are moderately remained are obtained.

The organic compound used in the present invention includes the following examples. Specifically, starch, cellulose, protein, collagen, alginic acid, dammar resin, Kovar, rosin, gutta percha, natural rubber, and the like can be used as the natural organic polymer; among semi-synthetic polymers, cellulose resins, cellulose acetates, cellulose nitrates, cellulose acetate butyrates, casein plastics, soybean protein plastics, and the like; as the synthetic polymer, phenol resin, urea resin, melamine resin, benzoguanamine resin, epoxy resin, diallyl phthalate resin, unsaturated polyester resin, bisphenol a type epoxy resin, novolac type epoxy resin, polyfunctional epoxy resin, alicyclic epoxy resin, alkyd resin, urethane resin, and the like, which are thermosetting resins, can be used; and polyester resins (polyethylene terephthalate (PET) resins, polypropylene terephthalate resins, polybutylene terephthalate resins, polyethylene naphthalate resins, polybutylene naphthalate resins, and the like), vinyl chloride resins, polyethylene, polypropylene, polystyrene, and the like as thermoplastic resins; polyisoprene, butadiene, and the like can be used in the synthetic rubber; among the synthetic fibers, nylon, vinylon, acrylic fibers, rayon, and the like can be used; further, polyvinyl acetate, ABS resin, AS resin, acrylic resin, polyacetal, polyimide, polycarbonate, modified polyphenylene ether (PPE), polyarylate, polysulfone, polyphenylene sulfide, polyether ether ketone, fluororesin, polyamideimide, silicone resin, or the like can be used.

Further, petroleum-based pitch, coal-based pitch, petroleum coke, coal coke, carbon black, and activated carbon produced when fossil fuels such as petroleum and coal are refined are naturally used as organic compounds as raw materials, and introduction of carbonization systems has been promoted in various places from the viewpoint of formation of resource-recycling society and effective utilization of carbon in wastes, and waste plastics, waste PET bottles, waste wood, waste plants, and food-based wastes such as kitchen wastes, which are mixtures of the above-described various resins and the like, can also be used as organic compounds as raw materials.

These hydrocarbon-based raw materials are not released as carbon dioxide or carbon monoxide by oxygen combustion, but are mainly fired at a predetermined temperature-raising rate and firing temperature in an inert atmosphere such as a nitrogen gas flow. For the calcination, an external heating type batch furnace, a high continuous multi-tube furnace, an internal heating type rotary kiln incinerator, a rocking kiln incinerator, or the like using electricity, gas, or the like is used.

The film-like multilayer graphene aggregate (B) can be produced by using a substrate made of, for example, glassy carbon, diamond-like carbon, amorphous carbon, graphite, copper, nickel, iron, cobalt, another heat-resistant metal, ceramic, SiC, GaN, Si, another semiconductor, or the like in the method for producing a multilayer graphene block (a) and growing multilayer graphene on the surface of the substrate. In this case, the substrate may be in the form of a flat plate, such as a spacer, or may be in various shapes such as a sphere, a pillar, a pyramid, a cone, and an irregular shape, and the surface thereof may be subjected to rough polishing or mirror polishing. By changing the shape or surface state of the substrate, the productivity and shape of the obtained film-like multilayer graphene aggregate can be controlled.

The fibrous multi-layer graphene aggregate of (C) is a material produced simultaneously in the method for producing a multi-layer graphene block of (a).

The split multilayer graphene block of (D) can be produced by using a graphite Intercalation Compound (Compound in which a sulfate ion, an alkali metal organic complex, or the like penetrates between graphite layers) having the multilayer graphene block of (A) as a host material. That is, intercalation of ions or the like between graphite layers widens the interlayer of the multilayer graphene constituting the multilayer graphene block, thereby generating stress in each part of the multilayer graphene block. Further, by rapidly heating the graphite intercalation compound, the volume of the graphite crystal rapidly expands in the c-axis direction. Through these processes, graphene having a thinner thickness in which multilayer graphene is effectively cleaved can be manufactured.

Since a graphene layer can hold both electrons and holes (holes) as carriers, it is also possible to form an interlayer compound of either an acceptor type that receives electrons or a donor type that donates electrons. As such an interlayer compound, various studies and developments have been made on graphite having a large number of stacked graphene layers, and the interlayer compound is known as a graphite interlayer compound. (Rice-wall doffer, carbon 1989[ 139] 207-213). The graphite intercalation compound having a multilayer graphene block as a host material can be prepared by a conventional method, for example, by adding a multilayer graphene block to a mixed solution of concentrated sulfuric acid and concentrated nitric acid, a tetrahydrofuran solution of an alkali metal and a thick polycyclic hydrocarbon, or the like, and stirring. The method for rapidly heating the graphite intercalation compound thus obtained is not particularly limited, and examples thereof include a method in which the intercalation compound is charged into a magnetic crucible made of ceramic, etc., and then charged into a heated electric furnace. The temperature of the electric furnace in this case is preferably in the range of, for example, 600 to 1000 ℃. By doing so, the multilayer graphene has a thickness of about 0.34 to about 9 nm. The cleaved multi-layer graphene block is preferably used for producing a transparent conductive film having both light transmittance and conductivity because it is composed of single-layer graphene and multi-layer graphene that are thinner than the multi-layer graphene constituting the original "multi-layer graphene block".

The preferred ranges of true density and total porosity for the multilayer graphene aggregates of (B) to (D) thus obtained are the same as those described for the multilayer graphene block (a).

A method of laminating a plurality of graphene layers constituting the thus-obtained multi-layer graphene aggregate on a substrate surface will be described.

The substrate is not particularly limited as long as it is made of a material capable of laminating multilayer graphene, in other words, a material capable of attaching multilayer graphene to the surface thereof by van der waals bonds, and preferable examples thereof include a resin film having a pi electronic bond based on a benzene nucleus, a double bond, or the like in its molecular structure, a metal foil, a metal plate, a metal film, paper, a glassy carbon substrate, a sapphire substrate, and the like. It is known that a resin film having a pi electron bond exhibits a stronger van der waals bond with graphene by overlapping with a pi electron orbit of graphene. Examples of the resin having a pi-electron bond include polyester resins (for example, PET resins, polytrimethylene terephthalate resins, polybutylene terephthalate resins, polyethylene naphthalate resins, polybutylene naphthalate resins, and the like), acrylic resins, polystyrene resins, polycarbonate resins, polypropylene resins, polyethylene resins, polyvinyl chloride resins, polytetrafluoroethylene resins (teflon (registered trademark) resins), and the like, and among them, PET resins, polystyrene resins, and polycarbonate resins are preferable, and PET resins having high mechanical strength are most preferable. In addition to being formed into a film and used as a substrate, these resins may be mixed singly or in a mixture of 2 or more types and coated on the surface of a glass plate or the like to form a glass plate or the like coated with these resins and used as a substrate. Examples of the metal constituting the metal foil, the metal plate, or the metal film include copper, nickel, iron, aluminum, titanium, and the like, and among them, copper is preferable. The paper is one of nonwoven fabrics made of plant fibers (mainly cellulose), and examples thereof include high-quality paper, coated paper (coated paper), drawing paper (kent paper), glossy paper, molded paper, and impregnated paper.

In addition, as the substrate, a "substrate made of a material in which graphene layers can be stacked" may be a nonwoven fabric made of resin fibers. As the resin, a resin having a pi electron bond is more preferable. Further, examples of the "resin having a pi-electron bond" include an aromatic polyamide resin, an aromatic polyimide resin, and a polyester resin.

Since the multilayer graphene is laminated on the substrate surface by van der waals bonds, any method may be suitably used as long as the method allows the multilayer graphene to come into contact with the substrate surface and exhibit van der waals bonds.

Such a method includes, for example, a method of rubbing a multilayer graphene aggregate on the surface of a substrate. The rubbing may be performed by any method as long as the multilayer graphene aggregate is not left in contact with the substrate surface. However, depending on the size of the substrate and the multilayer graphene aggregate, for example, when a multilayer graphene block having a size that can be held by a finger is used for wiping on a 30mm square substrate as in examples 1 to 5, the number of times of wiping from the end to the end of the substrate in 4 directions of the longitudinal direction, the lateral direction, the oblique direction, and the oblique direction may be counted as 1 time, and the wiping may be performed a plurality of times (for example, about 2 to 10 times, preferably about 3 to 8 times, and more preferably about 4 to 6 times).

In order to coat a substrate surface with multilayer graphene with high productivity, it is effective to use a tool for graphene coating. The "graphene coating tool" as used herein is a tool for coating a surface of a workpiece with a multilayer graphene, and is a tool having a tool surface in contact with the surface of the workpiece and holding a multilayer graphene aggregate on the tool surface. The "tool surface" referred to herein means a surface of a tool that functions to rub the multilayer graphene aggregate on the surface of the workpiece by contacting the surface of the workpiece after holding the multilayer graphene aggregate. The tool surface may have any form as long as it functions, and may be, for example, a flat plate shape or a gently curved surface shape. The term "hold" refers to a state in which a certain object is held in a certain place, and the method is not limited. Therefore, the concept also includes a state in which the multilayer graphene aggregate is bonded to the tool surface with an adhesive or the like, for example. As such a graphene coating tool, various types of tools are conceivable, and a schematic view of an example thereof is shown in fig. 53, and an appearance photograph of the rotary tool manufactured in example 9 is shown in fig. 54. In the tool shown in fig. 53, the multilayer graphene aggregate 8 is adhered to the surface (tool surface) of the base 9 via the epoxy resin-based adhesive layer 12. Fig. 53 a is a view of a form in which the device is attached to a predetermined mechanical device by a bolt, a nut, or the like. Fig. 53B is a view showing that the base 9 and the grip portion 10 can be engaged by wiping with a hand. Wiping is performed while holding the grip portion 10 with a hand. In fig. 53C, the multilayer graphene aggregate 8 is adhered to the surface of the base 9 with the adhesive layer 12, and the base 9 is also bonded to the rotating shaft 11. Therefore, the rotary shaft 11 can be attached to a rotary machining apparatus such as a reamer (diameter), a drill (drill), or a machining center (machining center). This makes it possible to wipe the multilayer graphene aggregate 8 onto the substrate material while rotating the multilayer graphene aggregate 8. The material of the tool is not particularly limited as long as it can maintain its shape, and any material may be used, and examples of such a material include stainless steel which is a hard material.

In order to coat the surface of the substrate with multilayer graphene with higher productivity, it is effective to wipe the multilayer graphene aggregate with a graphene coating tool for a substrate material which is composed of a high-strength material, continuously supplied by a roll-to-roll method or the like, and moved at a predetermined speed in a certain direction. The wiping can be performed by pressing a stationary tool or a tool that rotates or vibrates while moving a substrate such as a resin film at a high speed. The tool can be fixed at a desired position, and coating can be continuously performed on a substrate material that is continuously supplied.

Alternatively, another method for stacking may be a method in which the surface of the substrate is brought into contact with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate, and then the solvent is removed from the surface of the substrate.

< multilayer graphene Dispersion >

The preparation of the multilayer graphene dispersion liquid from the multilayer graphene aggregate can be carried out, for example, by preliminarily pulverizing the multilayer graphene aggregate, then adding the pulverized multilayer graphene aggregate to a solvent, applying ultrasonic waves, centrifuging the mixture, and collecting the obtained supernatant; or adding the multilayer graphene aggregate into a solvent, crushing, applying ultrasonic waves, performing centrifugal separation, and collecting the obtained supernatant.

Here, since the pressure medium gas adheres to the surface of the multilayer graphene aggregate, the multilayer graphene aggregate or a material obtained by pulverizing the multilayer graphene aggregate may be subjected to a heat treatment (for example, a temperature of 100 ℃ or higher) as desired to remove the pressure medium gas, and then the resultant may be subjected to a subsequent step.

The pulverization before the solvent is charged is not particularly limited as long as the multi-layer graphene constituting the multi-layer graphene aggregate can be separated from the multi-layer graphene aggregate, and the pulverization may be carried out by physically pulverizing the multi-layer graphene aggregate into fine pieces by using a dry mechanical pulverization apparatus, a wet mechanical pulverization apparatus, a stirrer, a mixer, a ball mill, a vibration mill, an ultrasonic mill, a homogenizer, an ultrasonic crusher, a mortar, or the like.

The pulverization after the solvent is charged is not particularly limited as long as the multilayer graphene constituting the multilayer graphene aggregate can be separated in the solvent, and for example, the pulverization can be carried out by physically thinning the multilayer graphene aggregate in the solvent with a rotary stirrer or the like.

Examples of the solvent include 1, 2-dichloroethane, benzene, thionyl chloride, acetyl chloride, tetrachloroethylene carbonate, dichloroethylene carbonate, benzoyl fluoride, benzoyl chloride, nitromethane, nitrobenzene, acetic anhydride, phosphorus oxychloride, benzonitrile, selenium oxychloride, acetonitrile, tetramethylsulfone, dioxane, 1, 2-propanediol carbonate, benzyl cyanide, ethylene sulfite, isobutyronitrile, propionitrile, dimethyl carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, ethylene carbonate and other carbonates, difluorophenyl phosphite, methyl acetate, N-butyronitrile, acetone, ethyl acetate, water, phenyl dichlorophosphate, diethyl ether, tetrahydrofuran, diphenyl phosphate, trimethyl phosphate, tributyl phosphate, dimethylformamide, N-methylpyrrolidine, N-dimethylacetamide, dimethyl sulfoxide, acetone, ethyl acetate, water, phenyl dichlorophosphate, diethyl ether, tetrahydrofuran, diphenyl phosphate, trimethyl phosphate, tributyl phosphate, dimethylformamide, N-methylpyrrolidine, N-dimethylacetamide, and the like, Polyhydric alcohols such as N-diethylformamide, N-diethylacetamide, pyridine, hexamethylphosphoramide, hexane, carbon tetrachloride, diglyme, chloroform, 2-propanol, methanol, ethanol, propanol, and ethylene glycol, methyl ethyl ketone, 2-methoxyethanol, dimethylacetamide, toluene, and polybenzimidazole. These solvents may be used alone or in combination of 2 or more.

In addition, in these solvents, a dispersant may be added in order to increase the amount of dispersion of graphene or to prevent aggregation of graphene in the solvent. Examples of the dispersant include surfactants, as well as those having weak binding force to graphene and an electrical attraction such as coulombic force, and having a hydrophilic functional group such as a hydroxyl group or a carboxyl group in its structure. Examples of the latter include monomers and polymers of phenols such as phenol and naphthol having a hydroxyl group bonded to the benzene nucleus, monomers and polymers having a carbon double bond such as styrene, propylene, acrylonitrile and vinyl acetate, proteins such as collagen, keratin, actin, myosin, casein, albumin, GFP and RFP, and amino acids such as glycine, tyrosine, threonine and glutamine.

On the other hand, as the surfactant, anionic surfactants (anionic surfactants) such as fatty acid salts (e.g., sodium laurate), cholate salts (e.g., sodium cholate), monoalkylsulfate salts (e.g., sodium lauryl sulfate), alkylpolyoxyethylene sulfate salts, alkylbenzenesulfonate salts (e.g., sodium dodecylbenzenesulfonate), monoalkylphosphate salts, and the like; cationic surfactants (cationic surfactants) such as alkyltrimethylammonium salts (e.g., cetyltrimethylammonium bromide), dialkyldimethylammonium salts (e.g., didecyldimethylammonium chloride), and alkylbenzyldimethylammonium salts (e.g., alkylbenzyldimethylammonium chloride); amphoteric surfactants (amphoteric surfactants) such as alkyldimethylamine oxide and alkylcarboxylbetaine; nonionic surfactants (nonionic surfactants) such as polyoxyethylene alkyl ethers (e.g., polyoxyethylene lauryl ether), sorbitan fatty acid esters, alkylpolyglucosides, fatty acid diethanolamides, and alkyl monoglyceryl ethers. Among them, monoalkyl sulfates are more preferable.

Among the above solvents, dimethylformamide, water to which a dispersant (preferably a surfactant) is added, 2-methoxyethanol, and the like are preferable.

The amount of the dispersant to be added is in the range of 0.001 to 10% by weight, preferably 0.02 to 5% by weight, based on the weight of the solvent, but is not necessarily limited to these ranges when a coating such as a transparent conductive film or a conductive film is formed and then subjected to a cleaning step.

The amount of the multilayer graphene aggregate to be added is in the range of 0.001 to 50 wt%, preferably 0.01 to 10 wt%, based on the weight of the solvent.

The method of applying the ultrasonic wave is not particularly limited, and for example, the ultrasonic wave can be applied by using an ultrasonic cleaning machine. For example, the frequency of the applied ultrasonic waves is preferably in the range of about 20 to about 100 kHz. The application time is preferably about 1 to 60 minutes.

The centrifugation is preferably carried out at an acceleration in the range of about 100 to about 100000G, preferably in the range of about 100 to about 10000G, for about 1 to about 60 minutes, preferably about 5 to about 30 minutes.

In the supernatant after the centrifugal separation thus obtained, graphene is dispersed in a plurality of layers. Additives (for example, a thickener, a dispersant, a diluent, etc.) generally used in this field may be added to the dispersion liquid as desired.

In the case of producing a multilayer graphene-coated substrate that does not require light transmittance, such as an electrode material or a heat sink for a lithium ion battery, it is useful to stack graphene thickly on a substrate surface or to stack multilayer graphene in a concave portion on a substrate surface such as a porous nonwoven fabric.

< multilayer graphene pulverization solution >

The multilayer graphene pulverized liquid may be prepared by previously pulverizing a multilayer graphene aggregate and then adding the same to a solvent or by pulverizing a multilayer graphene aggregate after adding the same to a solvent. Various conditions such as the solvent and dispersant used, the method of pulverization, and the amount of the multilayer graphene aggregate charged are as described in the section of the multilayer graphene dispersion liquid.

< residual graphene Dispersion >

The residual graphene dispersion liquid can be prepared by adding the above-mentioned solvent and a dispersant used as needed to the residue after centrifugation (the residue after removal of the supernatant after centrifugation) obtained in the preparation of the multilayer graphene dispersion liquid. The concentration of the residual graphene in the residual graphene dispersion liquid is preferably 1 to 90% by weight.

The contact between the substrate surface and the multilayer graphene dispersion liquid, the multilayer graphene pulverization liquid, and the residual graphene dispersion liquid (hereinafter, collectively referred to as "multilayer graphene dispersion liquid and the like") may be carried out by any method as long as the object can be achieved. This operation can be carried out by a common coating method such as dip coating, spin coating, die coating, spray coating, etc., and can be suitably carried out by ink jet printing, printing with a dispenser, flexographic printing (letterpress printing), offset printing (lithography), Gravure printing (Gravure printing), screen printing, electrophotography, thermal transfer, laser transfer, slit coating, bar coating, blade coating, melt extrusion molding combined with a resin or an additive, inflation (inflation) method, T-die method, flat die method, solution casting method, calendering method, stretching method, multilayer processing method, co-extrusion by inflation method, multi-manifold method (multi-manifold method), lamination method, extrusion lamination method, lamination method using an adhesive, wet lamination method, dry lamination method, hot melt lamination method, heat sealing method, external heating method, internal heating method, etc, Any one of conventional techniques such as ion plating, ion plating (ion plating), and sputtering. The solvent can be removed from the substrate surface by any method as long as the object can be achieved. This operation can be usually performed by drying the surface of the substrate in contact with the multilayer graphene dispersion liquid or the like by a conventional method. The drying may be natural drying, in addition to heating and/or blowing.

For example, the contacting of the substrate surface with the multilayer graphene dispersion or the like and the removal of the solvent from the substrate surface can be performed by dip-coating the substrate surface with the multilayer graphene dispersion or the like. The conditions for dip coating vary depending on the kind of solvent or substrate used, the amount of the multilayer graphene aggregate charged into the solvent, and the like, and for example, in order to smoothly remove (dry) the solvent from the substrate surface, the temperature of the dispersion is preferably 40 ℃ or higher, more preferably 50 ℃ or higher, and still more preferably 60 ℃ or higher. The substrate pulling rate is preferably 1000 to 1 μm/sec when the film formation is performed 1 time in the case of 1 solution bath, for example, and the film formation is not necessarily limited to these ranges and may be performed at a higher speed in the case of performing the film formation a plurality of times by using a plurality of solution baths.

The thickness of the coating layer of the multilayer graphene-coated substrate thus obtained is about 0.5 to 300nm, preferably about 2 to 100nm, and is useful as a transparent conductive film or a transparent electrode. In addition, in applications where light transmission is not required, such as a conductive film of a lithium ion battery, a material in which the thickness of the coating layer is increased to about 1 to 10 μm is also useful in view of its required properties.

Another method for contacting the substrate surface with the graphene dispersion liquid and removing the solvent from the substrate surface includes spraying (including wet spraying) in which the graphene dispersion liquid is blown onto the substrate surface together with a high-pressure gas. In this method, a mixture of a high-pressure and high-speed gas and a liquid is blown onto the surface of a substrate by a gas-liquid mixing device such as a spray gun (spray gun) or an air gun (airgun) using a compressed gas such as air, nitrogen, or argon compressed by a compressor at 0.1 to 10 MPa. In this case, when the graphene dispersion liquid contacts the substrate surface, the graphene is easily brought into contact with and adhered to the substrate surface, and the gas is easily dried and evaporated by the gas flow. Further, if a liquid or a gas kept at a high temperature is used and/or the substrate surface is separately heated as necessary, graphene can be effectively applied to the substrate surface. When a transparent conductive film, a conductive film, an electrode sheet, or the like is produced in large quantities, a film can be formed with high productivity by supplying a substrate in a roll-to-roll manner and spraying a high-pressure gas and a graphene dispersion liquid onto the surface of the substrate at high speed by spraying.

When light transmission is not required, such as an electrode material or a heat sink of a lithium ion battery, it is useful to form a thick graphene layer (may be referred to as a thin graphite layer) by stacking a plurality of graphene layers on a surface of a substrate or to stack and fill a plurality of graphene layers in a resin substrate such as a porous nonwoven fabric. In this case, it is effective to use a multilayer graphene crushed liquid or a residual graphene dispersion liquid having a higher multilayer graphene concentration as a liquid for spraying.

In the case where high light transmittance is required as in a transparent conductive film for a touch panel, it is effective to stack a small number of layers of graphene on the surface of a substrate in a thin layer, and in this case, in a normal spray coating (two-fluid spray coating using 2 fluids of liquid and gas), the thin graphene is easily scattered by the wind velocity of the compressed gas, and the probability of failing to hit the surface of the substrate may be increased. Therefore, in order to cope with such a situation, it is effective to use a multilayer graphene dispersion liquid containing more dilute graphene or a multilayer graphene dispersion liquid composed of a supernatant liquid obtained by further centrifuging a multilayer graphene dispersion liquid sufficiently, and to improve the hit rate of the multilayer graphene, it is effective to use a dispenser which ejects only the dispersion liquid from a nozzle tip in the form of a minute amount of droplets, or single fluid type spraying such as ink jet. The inner diameter of the nozzle used is preferably about 1 μm to about 1000. mu.m.

In the multilayer graphene-coated substrate of the present invention, as described above, it is preferable that the multilayer graphene is laminated on the surface of the substrate, and then the surface of the substrate is subjected to press working. In particular, it is more preferable for applications such as transparent conductive films to require a thin multilayer graphene with a small number of layers stacked. The graphene of the present invention has a thickness of about 1nm when the number of layers is small, and has a surface roughness or thickness variation of 100 to 1000nm level on the surface of a substrate (e.g., a PET film). Therefore, for example, when the graphene dispersion is laminated by bringing the graphene dispersion into contact with the substrate surface and then removing the solvent, it may be difficult to uniformly and completely adhere the graphene surface to the substrate surface. In this case, it is considered that: the surface of the multilayer graphene is brought close to the surface of the substrate by applying pressure to the interface between the multilayer graphene and the substrate by press working, which is effective in improving the orientation of the multilayer graphene and improving the adhesion to the substrate. In this case, by further heating simultaneously, for example, in the case of a resin substrate or the like, the resin is easily deformed by heating, and the surface of the multilayer graphene can be brought closer to the surface of the substrate. Further, if the surface of the member to which the pressure is applied is precisely polished to improve the surface roughness, parallelism, and flatness, the resin substrate or the like is deformed to follow the shape of the surface of the member, and thus the multilayer graphene can be brought closer to the surface of the substrate more uniformly and completely. In addition, it is also effective to improve the adhesion between the multilayer graphene and the substrate by cleaning or surface-treating the surface of the substrate to be coated in advance by a method such as corona treatment or plasma treatment.

As the press working, any of known methods such as cold rolling and hot rolling can be used, and it is effective to use a device having high mass productivity such as a roll press or a hot press from the viewpoint of improving productivity. It is particularly effective to perform hot pressing after performing rolling under heating (hot rolling). The heating temperature in the roll pressing is preferably about 70 to about 300 ℃, for example, depending on the material of the substrate used. The press load is preferably about 1 to 100000N, and the feed rate is preferably about 0.1 to about 10 cm/sec. The heating temperature in the hot pressing is preferably about 70 to about 300 ℃, the press load is preferably about 1 to about 5000000N, and the time is preferably about 10 seconds to 10 minutes.

Since the number of graphene layers stacked is smaller and the van der waals force is larger than that of conventional graphite, the multi-layer graphene can be stacked and filled in an arbitrary shape by effectively utilizing the van der waals force (adhesive force), and as a result, a graphite structure having high crystallinity can be obtained. In a conventional method for producing a graphite material, a raw material such as a resin is molded, gradually carbonized, and graphitized to a high temperature of about 3000 ℃. In this case, in order to impart various shapes, complicated steps such as cutting and grinding the graphite material by machining or the like, or mixing the graphite-based powder with a binder, coating the mixture, and press-molding the mixture are required. In the present invention, by a simple method of laminating and filling a large number of multilayer graphene manufactured in advance on a substrate having various shapes, advantages such as strength, flexibility, and lightweight properties of the substrate, and advantages such as electrical conductivity, thermal conductivity, electromagnetic wave shielding properties, antibacterial properties, lubricity, heat resistance, and chemical resistance of the graphene and the graphite obtained by laminating the graphene can be provided.

When multilayer graphene is laminated, the morphology and properties of the graphene gradually approach those of graphite as the lamination progresses. Accordingly, by using the method of the present invention, graphite parts of various forms can be produced by a so-called bottom-up (bottom-up) method.

In order to utilize the high thermal conductivity of graphite, it is effective to use a thin graphite sheet as a measure against a hot spot locally heated by heat accumulated in a thin portable terminal such as a smartphone (smartphone). Among conventional graphite members, a method for machining a large and thick member such as an electrode for steel making has been established, but it is difficult to machine a thin sheet-like member. As a result, a graphite film or the like obtained by synthesizing a graphite intercalation compound of graphite and sulfuric acid or the like, rapidly heating and expanding expanded graphite, rolling the thus-synthesized expanded graphite, laminating a thermally press-molded graphite sheet or a resin film which is easily graphitized such as polyimide, and heat-treating the laminate to about 3000 ℃. Graphite sheets having a thickness of approximately 100 μm are practically used, graphite films having a thickness of approximately 50 μm are practically used, and if graphite alone is used, the mechanical strength is low and the adhesion tends to be weak, so that it is difficult to make a material thinner and excellent in mechanical strength and processability.

By laminating a plurality of layers of graphene on a porous resin substrate having a relatively high porosity by applying the method of the present invention, the voids of the substrate are filled with the plurality of layers of graphene, and thus, a member or sheet having a thin thickness, high strength, and excellent characteristics of graphite such as conductivity, thermal conductivity, heat resistance, chemical resistance, and antibacterial property, and having good processability can be manufactured. The step of stacking and filling the multilayer graphene on the substrate is not particularly limited, and various processing methods such as the above-described stacking method of stacking the multilayer graphene on the substrate surface can be employed. In any of these methods, the substrate or the graphene layers can be laminated and filled without an adhesive by utilizing the high adhesive force of the multilayer graphene, particularly, the multilayer graphene including a single layer. Although graphene can be stacked and filled without using an adhesive as described above, the use of an adhesive or a surfactant is not limited to such factors as productivity and large area.

Since a specific method for processing a graphite film is a method via van der waals bonds, any method can be suitably used as long as it can bring multilayer graphene into contact with a substrate surface and develop van der waals bonds. There may be mentioned: a method of rubbing a multi-layer graphene aggregate onto a substrate surface; a method of removing a solvent from a substrate surface after contacting the substrate surface with a multilayer graphene dispersion prepared from a multilayer graphene aggregate; a method of improving the adhesion between the substrate and the graphene using cold rolling, hot rolling, roll pressing, hot pressing, or the like; and a method of repeating these methods in combination as appropriate. In addition, in order to improve the strength of the graphite film, a binder component or an additive (e.g., a thickener, a dispersant, a diluent, etc.) generally used in this field may be added to the graphene dispersion.

In the case of forming a transparent conductive film as a transparent conductive film for a touch panel, high light transmittance is required, and therefore, it is effective to form a conductive path through which a current flows while maintaining light transmittance at a relatively low coverage rate by using fibrous or tubular multi-layer graphene.

< Thick and thin Pattern >

Among the multilayer graphene-coated substrates of the present invention, a multilayer graphene-coated substrate (multilayer graphene-coated substrate with a pattern) having a pattern formed by the thickness of the coating layer of the multilayer graphene can be manufactured by preparing a transfer mold having a surface with irregularities conforming to the pattern, superposing the back surface of a substrate (resin film, nonwoven fabric, paper, etc.) on the surface of the transfer mold, and rubbing the multilayer graphene constituting the multilayer graphene aggregate on the surface of the substrate.

The "pattern" used herein refers to a pattern or pattern formed by one of the coating layers having a small thickness, for example, the one having a large thickness (thick layer), and examples thereof include a lattice pattern, a mesh pattern, and a water-drop pattern, but the pattern is not limited thereto. As the pattern, a layout of a line (e.g., a circuit or the like) may be used. In the pattern, thick layer portions may be used, for example, as conductive layers. The thick layer portion may also be a continuous layer. In addition, a thin coating layer (thin layer portion) can be used to ensure light transmittance, for example.

The "transfer mold" is a support having a pattern formed by surface irregularities, and since the convex portion of the transfer mold supports the substrate from below with a stronger force than the concave portion, the substrate surface on the convex portion is rubbed with the multilayer graphene thicker than the concave portion, thereby playing a role of reproducing the pattern on the substrate surface. The transfer mold may be in the form of a flat plate or a curved surface, for example. The material of the transfer mold is not particularly limited as long as it has a strength capable of withstanding rubbing, and examples of such a material include metals (e.g., aluminum), ceramics, and the like.

In the case where the substrate is a "film made of a resin having a pi electron bond or a nonwoven fabric made of fibers of the resin" in the wiping process, the surface of the substrate may be heated. In this way, the resin is softened and adheres to the transfer mold, and thus the pattern of the transfer mold can be easily reproduced on the surface of the substrate. The heating temperature varies depending on the kind of the resin, and a preferable range is, for example, about 30 to 350 ℃, and more preferably about 50 to 250 ℃. In this case, the substrate can be heated by a conventional method, for example, by using a metal transfer mold having good thermal conductivity, placing the transfer mold on a heating plate set at a predetermined temperature, temporarily holding and heating the surface of the transfer mold, and then stacking the substrate thereon.

In addition, the description of "method for producing a multilayer graphene-coated substrate" can be applied to "method for producing a multilayer graphene-coated substrate" unless the above-mentioned methods are contradictory to each other.

The multilayer graphene-coated substrate with a pattern thus obtained is useful as a transparent conductive film having both transparency and conductivity, and if a wiring is used as the pattern, the film itself can also function as a wiring. The patterned multilayer graphene-coated substrate can also be used as a heat dissipating sheet, a static eliminating sheet, or the like.

In the present invention, the amount of hydrogen is a value measured by the general method for determining the amount of hydrogen in a metal material (JIS Z2614: 1990. analytical method is carried out by an inert gas heating method which is a condition for "steel", specifically, a sample is heated to 2000 ℃ in an argon atmosphere, and the cumulative amount of hydrogen generated is measured by gas chromatography).

The powder or granule is not specifically limited in size or shape of the particles constituting the powder or granule, but includes a powder composed of relatively small particles or a granule composed of an aggregate of relatively coarse particles.

The open porosity (apparent porosity) is a ratio of a volume of a void (open pore) that exists in a volume determined from the outer shape of the material and into which a liquid, a gas, or the like can enter. Generally, a material having a high open porosity has continuous pores and gas permeability. In the present specification, the open porosity can be obtained by the following calculation formula.

Open porosity (%) { (apparent specific gravity-bulk specific gravity)/apparent specific gravity } × 100

Apparent specific gravity: the value obtained by measuring a sample in an uncrushed state with a helium gas displacement densitometer using a densitometer AccuPyc1330-PCW manufactured by Shimadzu corporation

Volume specific gravity: value obtained by dividing the weight of the sample by the volume calculated from the outside dimensions of the sample

The total porosity is a ratio of the volume of total voids (including closed pores in addition to open pores) present in the volume determined from the outer shape of the material. In the present specification, the total porosity is determined by the following calculation formula.

Total porosity (%) { (true specific gravity-bulk specific gravity)/true specific gravity } × 100

The true specific gravity is a specific gravity measured in a state in which the object is pulverized into fine powder in order to minimize an influence of voids contained in the object, and is measured with a powder sample passing through a 74 μm sieve in examples and manufacturing examples of the present invention.

The apparent specific gravity, bulk specific gravity and true specific gravity are synonymous with the apparent density, bulk density and true density, respectively.

In the present specification, the spacer and the sleeve are both members used by being put in a graphite closed container, and are members inserted between the inner wall of the container and the calcination raw material so as not to directly contact the two. The spacer is a member that mainly covers the calcined material from the top-bottom direction, and the sleeve is a member that mainly covers the calcined material from the side surface, and there may be cases where the two are not distinguished from each other depending on the shape of the container.

The "block" in the "block shape", "block state" or "block structure" refers to a material obtained by connecting constituent units as basic constituents.

The average particle diameter (particle size (average)) was measured by a laser diffraction scattering method using a laser diffraction particle size distribution measuring apparatus. That is, the particle group is irradiated with laser light, and the particle size distribution is calculated from the intensity distribution pattern of diffracted and scattered light emitted therefrom.

In the present specification, when a numerical range is, for example, 1200 to 1900, the numerical range means 1200 to 1900.

[ examples ]

The present invention will be described below by way of examples, but the present invention is not limited to these examples.

Example 1

Among the multilayer graphene blocks obtained in production example 1, a graphene block having a size of several mm to several tens of mm and capable of being held by hand was selected. An SEM of the surface of the graphene block is shown in fig. 15. This graphene block is composed of petal-shaped multilayer graphene having a size of several μm and an extremely thin thickness, and is a structure in which a plurality of multilayer graphene are aggregated.

A PET resin film having a thickness of 300 μm was cut into a 30mm X30 mm shape, and the surface was wiped with ethanol impregnated in a cotton swab, followed by cleaning and degreasing to obtain a substrate.

The multilayer graphene block is held by hand on the surface of the substrate and rubbed, and a friction force is generated at the interface between the substrate and the multilayer graphene block, so that the multilayer graphene is laminated on the surface of the substrate to form the coating layer. For the wiping of the multilayer graphene block to the substrate surface, wiping was performed first in one direction (which will be referred to as a longitudinal direction) on the film, then in a transverse direction orthogonal to the longitudinal direction, then in a direction at 45 ° to the longitudinal direction, and a direction at 315 degrees to the longitudinal direction, from end to end respectively from each direction 1 time, which was counted as the number of wiping 1 time, performed a plurality of times, to obtain sufficient surface conductivity, thereby transferring the multilayer graphene to the entire substrate surface.

The surface of the obtained multilayer graphene-coated substrate (transparent conductive film) showed a light gray color, but a type such as newspaper can be read through the film. Fig. 16 shows an optical micrograph of the surface of the transparent conductive film, and fig. 17 and 18 show SEM photographs, respectively. From these figures, it was confirmed that the surface of the substrate can be coated with multilayer graphene without any gap. Since the PET resin film of the substrate is not conductive, when an electron beam is irradiated, the electron density on the surface of the substrate becomes high, and the substrate is deformed by overheating, and thus SEM observation is difficult.

The surface resistance of the obtained transparent conductive film was measured by a constant current application method by a 4-terminal 4-probe method using a surface resistance measuring apparatus (resistivity meter Loresta EP MCP-T360 model) manufactured by mitsubishi chemical Analytech (hereinafter, the surface resistance was also measured by the same method). The light transmittance was measured at wavelengths of 400nm, 500nm, 600nm and 700nm using a visible-ultraviolet spectrophotometer (CE 1021, manufactured by ASONE corporation) (hereinafter, the light transmittance was also measured by the same method). The results are shown in tables 1-1 and 1-2.

In the PET resin film used as a substrate, light in the visible light region was transparent with a transmittance of 87.9%, but since it had no conductivity, the surface resistance became infinite and could not be measured. In contrast, a substrate having a coating layer formed of multilayer graphene on the surface by rubbing a multilayer graphene block has a value that varies depending on the number of times of rubbing, but can obtain sufficient conductivity while maintaining optical transparency, and can obtain a surface resistance value that can be used as an electrical wiring film although the coating layer formed of graphene is extremely thin.

[ tables 1-1]

TABLE 1-1

[ tables 1-2]

Tables 1 to 2

Example 2

The multi-layer graphene blocks of production examples 2-1 to 2-6, the artificial graphite a (IGS 895, new techno Carbon) prepared in production example 2, and the artificial graphite B (MGY-72, tokyo Carbon) prepared in production example 2 were prepared as graphite materials. The true density, apparent density, bulk density and total porosity of these samples are shown in Table 2-1.

Using these graphite materials, a multilayer graphene-coated substrate was produced in the same manner as in example 1. At this time, the number of times of rubbing the substrate with the graphite material was set to 5 times.

Whether or not a coating layer composed of multilayer graphene was formed on the surface of the substrate was observed with an optical microscope for each graphite material. The obtained substrate was measured for light transmittance and surface resistance. The results are shown in tables 2-2 and 2-3.

In commercially available artificial graphite a and B, no coating layer was formed on the surface of the PET resin film, and the surface resistance was infinite because no current was allowed to flow, and thus it was not possible to measure it. On the other hand, in a multi-layer graphene block, the true density is less than 1.85g/cm³In the case of (2), it is difficult to shapeA coating layer based on multilayer graphene, and the true density is considered to be approximately 1.85g/cm³The above and total porosity of approximately 40% or more are necessary for forming the coating layer. In addition, it is also believed that: at a true density of approximately 2.0g/cm³When the total porosity is substantially 50% or more as described above, a good coating layer can be formed, and a uniform coating surface can be obtained. FIG. 19 shows an SEM of the surface of the coating layer of examples 2 to 4. In the figure, the exfoliation of petal-shaped multilayer graphene is observed in part.

[ Table 2-1]

TABLE 2-1

[ tables 2-2]

Tables 2 to 2

[ tables 2 to 3]

Tables 2 to 3

Example 3

A PET resin film having a thickness of 300 μm, an acrylic resin film having a thickness of 500 μm, a polystyrene resin film having a thickness of 200 μm, a polycarbonate resin film having a thickness of 1mm, a polypropylene resin film having a thickness of 50 μm, a polyethylene resin film having a thickness of 100 μm, a polyvinyl chloride film having a thickness of 50 μm, a Teflon (registered trademark) resin film having a thickness of 500 μm, and a glass plate having a thickness of 500 μm were cut into a shape of 30mm × 30mm, and the surfaces thereof were wiped with ethanol impregnated in a cotton swab, washed, and degreased to prepare a substrate.

Using the multi-layer graphene block obtained in production example 1, whether or not a coating layer composed of multi-layer graphene is formed on the surface of each of these substrates was checked in the same manner as in example 1. The number of times the substrate was rubbed with the multilayer graphene block was set to 5 times.

The surface of the substrate obtained above was observed with an optical microscope and SEM to confirm the presence or absence of the formation of the coating layer and the uniformity of the surface, and the results are shown in table 3. A coating layer made of multilayer graphene is formed on a resin other than glass. In particular, a resin having a pi-electron bond such as a benzene nucleus or a double bond in its molecular structure exhibits good coating layer formability. This is considered to be because the overlap with the pi electron orbit of graphene allows stronger van der waals bonds to be developed on the surface of the pi electron-containing resin. Fig. 20 shows an SEM of the surface of a coating layer made of multilayer graphene formed on a PET resin film, and fig. 21 shows an SEM of the surface of a coating layer made of multilayer graphene formed on an acrylic resin film.

[ Table 3]

TABLE 3

	Presence or absence of coating layer	Uniformity of the surface of the coating
			PET resin	Is provided with	Is extremely good
Acrylic resin	Is provided with	Good effect
			Polystyrene resin	Is provided with	Good effect
Polycarbonate resin	Is provided with	Good effect
			Polypropylene resin	Is provided with	Unevenness of
Polyethylene resin	Is provided with	Unevenness of
			Polyvinyl chloride	Is provided with	Unevenness of
Teflon resin	Is provided with	Unevenness of
			Glass	Is free of

Example 4

A copper plate having a thickness of 300 μm, a copper foil having a thickness of 70 μm, an aluminum foil having a thickness of 30 μm, and a titanium plate having a thickness of 200 μm were cut into a shape of 30mm × 30mm, a silicon wafer having a thickness of 125 μm, a SiC substrate having a thickness of 150 μm, an aluminum nitride substrate having a thickness of 125 μm, a GaN substrate having a thickness of 100 μm, a glassy carbon substrate having a thickness of 125 μm, and a sapphire substrate having a thickness of 100 μm were cut into a shape of phi 50mm, the surfaces thereof were wiped with ethanol impregnated in a cotton swab, and then cleaned and degreased to prepare substrates.

Using the multi-layer graphene block obtained in production example 1, whether or not a coating layer composed of multi-layer graphene is formed on the surface of each of these substrates was checked in the same manner as in example 1. The number of times the substrate was rubbed with the multilayer graphene block was set to 5 times.

The surface of the substrate obtained above was observed with an optical microscope and SEM to confirm the presence or absence of the formation of the coating layer and the uniformity of the surface, and the results are shown in table 4. The coating layer composed of multilayer graphene was confirmed on a copper plate, a copper foil, an aluminum foil, a titanium plate, a glassy carbon substrate, and a sapphire substrate. For the uniformity of the clad surface, the copper plate and the copper foil are optimal, and the whole surface is covered by the multilayer graphene. Fig. 22 shows an SEM of the surface of the coating layer formed on the surface of the copper plate and made of multilayer graphene.

[ Table 4]

TABLE 4

	Presence or absence of coating layer	Uniformity of the surface of the coating
			Copper plate	Is provided with	Good effect
Copper foil	Is provided with	Good effect
			Aluminum foil	Is provided with	Is locally attached to
Titanium plate	Is provided with	Is locally attached to
			Silicon wafer	Is free of
SiC substrate	Is free of
			Aluminum nitride substrate	Is free of
Glass-like carbon substrate	Is provided with	Is locally attached to
			Sapphire substrate	Is provided with	Is locally attached to

Example 5

The entire surface of glass slide (26 mm wide, 76mm long, and 0.8mm thick) manufactured by Sonlang glass was wiped with ethanol, and then washed and degreased. A polyester resin (manufactured by Unitika Co., Ltd.) and an acrylic resin were mixed at a weight ratio of 1: 1, and the mixture was immersed in N, N-dimethylformamide to prepare a solution having a resin concentration of 5000 ppm. The resin was applied to the glass surface at a temperature of 50 ℃ and a pull rate of 10 μm/sec using a micro speed dip coater (SDI). The prepared resin-coated glass was air-dried for 24 hours to prepare a substrate for forming a multilayer graphene coating layer.

The substrate surface was treated in the same manner as in example 3 using the multi-layer graphene block obtained in production example 1, and then a coating layer made of multi-layer graphene was formed on the substrate surface, thereby obtaining a transparent composite material made of glass, resin, and graphene.

Example 6

Three solvents, water (water + surfactant), N-Dimethylformamide (DMF), and 2-methoxyethanol, containing 0.1% by weight of sodium lauryl sulfate were prepared. The multi-layer graphene blocks obtained in production example 1 were weighed and mixed so that the weight ratio to each solvent was 0.1 wt%, and then subjected to crushing treatment at 1000rpm for 15 minutes using a wet stirrer having a metal cutter knife, to obtain 3 types of multi-layer graphene dispersions in which the multi-layer graphene blocks were crushed. Each dispersion was charged in a commercially available ultrasonic cleaning machine (ultrasonic cleaning bench W-113, manufactured by Durometer Co., Ltd.), and ultrasonic waves were applied at 42kHz and 100W for 30 minutes. In the solution after the ultrasonic wave is applied, the petal-shaped multilayer graphene is dispersed in the solvent from the multilayer graphene block, and thus appears black. Then, the dispersion was centrifuged at an acceleration of 800G for 30 minutes, and a light black supernatant was collected to prepare a dispersion for graphene dip coating.

A PET resin film having a thickness of 300 μm and a copper plate having a thickness of 300 μm were cut into a width of 20mm X a length of 70mm to prepare a substrate for dip coating.

An attempt was made to form a multilayer graphene coating layer on the substrate surface by dip-coating a PET resin film and a copper plate under the conditions shown in table 5 using a micro-speed dip coater manufactured by SDI corporation.

When the PET resin film was dip-coated with a solvent of water + surfactant, the multilayer graphene coating layer could not be formed even at a pull rate of 10 μm/sec at a solution temperature of 40 ℃, partial adhesion of the multilayer graphene was observed at a solution temperature of 50 ℃, and the coating layer was stably formed at 60 ℃. However, the PET resin film is deformed by heat at 80 ℃. The solvent of 2-methoxyethanol tends to form a coating layer even at a solution temperature of 40 ℃ and stably at 50 ℃, as in the case of dip coating of a PET resin film. In the case of N, N-dimethylformamide solution, the coating layer is formed at a solution temperature of 40 ℃ even in the case of dip coating onto a copper plate, the coating layer is stably formed at 50 ℃ and a uniform coating surface is obtained at 60 ℃.

In the case of dip coating, when the substrate is exposed to the atmosphere from the solvent interface, the solvent is evaporated and dried at the same time, and thus the multilayer graphene dispersed in the solvent is laminated on the substrate surface to form the coating layer. It is considered that when the solution temperature is low, the evaporation rate of the solvent is low, and drying at the interface between the solvent and the substrate does not proceed smoothly, so that the graphene dispersed in the solvent remains in the solvent, and a stable coating layer is not formed.

[ Table 5]

TABLE 5

Dispersion liquid	Water + surfactant	Water + surfactant	Water + surfactant	Water + surfactant
					Substrate	PET	PET	PET	PET
Temperature of the dispersion	40℃	50℃	60℃	80℃
					Application of ultrasound	Is provided with	Is provided with	Is provided with	Is provided with
Pulling rate	10 μm/sec	10 μm/sec	10 μm/sec	10 μm/sec
					Film formation of graphene	Does not occur	Is attached in minute quantity	Film formation in large amounts	Deformation of substrate

Dispersion liquid	2-methoxy ethanol	2-methoxy ethanol	2-methoxy ethanol	2-methoxy ethanol
					Substrate	PET	PET	PET	PET
Temperature of the dispersion	30℃	40℃	50℃	80℃
					Application of ultrasound	Is provided with	Is provided with	Is provided with	Is provided with
Pulling rate	10 μm/sec	10 μm/sec	10 μm/sec	10 μm/sec
					Film formation of graphene	Does not occur	Is attached in minute quantity	Film formation in large amounts	Deformation of substrate

Dispersion liquid	DMF	DMF	DMF	DMF
					Substrate	Copper plate	Copper plate	Copper plate	Copper plate
Temperature of the dispersion	30℃	40℃	50℃	60℃
					Application of ultrasound	Is provided with	Is provided with	Is provided with	Is provided with
Pulling rate	10 μm/sec	10 μm/sec	10 μm/sec	10 μm/sec
					Film formation of graphene	Does not occur	Is attached in minute quantity	Film formation in large amounts	Uniformly forming a film

Example 7

The multilayer graphene block obtained in production example 11 was pulverized in an agate mortar, and the pulverized sample was put into dimethylformamide to prepare a mixed solution having a graphite amount of 5 wt%. The mixed solution was subjected to ultrasonic wave (30 minutes at a frequency of 42kHz and 100W in power) by an ultrasonic cleaning machine (W-113, manufactured by Togaku corporation), and then the solid content was settled by centrifugal separation (30 minutes at an acceleration of 700G). The obtained supernatant of the solution was used to filter the graphene dispersed in the solution with a microgrid (micro grid) for TEM observation, and TEM observation was performed on the components captured on the microgrid. As a result of TEM observation, many substances (multilayer graphene) present in a thin sheet shape were observed as shown in fig. 23. Fig. 24 shows a TEM lattice image of an end portion of a multilayer graphene obtained in a thin sheet shape, and it was confirmed that about 7 graphene layers were laminated, and thus multilayer graphene having a thickness of about 2.1nm was obtained.

Example 8

Water (water + surfactant) containing 0.1 wt% of sodium lauryl sulfate was prepared, and the treatment was performed in the same manner as in example 6 to obtain a multilayer graphene dispersion liquid. This dispersion was used as a dispersion for graphene spray coating.

A mini-compressor (mini-compressor) (TYPE226) of Kiso Power Tool, Inc. was prepared and connected to an air brush (air brush) (E1307N) of Kiso Power Tool, Inc. The dispersion liquid was charged into a liquid container of an air brush, and the pressure of the dispersion liquid was adjusted so that the dispersion liquid could be discharged at an air pressure of 0.2 MPa. The nozzle diameter of the air brush was set to 0.4mm in inside diameter. A30 mm X300 μm thick PET resin film was placed on the surface of a metal heating plate, and the dispersion was blown onto the surface to observe the surface. When the heating plate is not heated, liquid droplets remain on the surface and graphene is not adhered to the film surface, and when the heating plate is heated to 60 ℃, graphene is adhered to obtain a multilayer graphene-coated substrate.

Example 9

The multilayer graphene block obtained in production example 11 was cut into a shape of approximately 3 to 5mm with a cutter knife, and was formed into a chip. A tool was prepared in which a base having a disc-shaped surface (tool surface) with an outer diameter of 20mm was joined to a rotating shaft made of steel and having a diameter of 3mm × a length of 30mm, and small pieces of a multilayer graphene block were bonded to the tool surface (however, the multilayer graphene block was not bonded to a portion having a diameter of about 9mm from the center of the tool surface). An epoxy resin elastic adhesive (Cemedine EP001N) was used for bonding. The adhesive was left for 24 hours to cure sufficiently. Fig. 54 is a photograph showing the appearance of the completed graphene coating tool. One can see how a small piece of multi-layer graphene block is adhered to the tool surface. The prepared tool was mounted on an electric graver (HR100) manufactured by RYOBI corporation, and the entire surface of a PET resin film 30mm × 30mm × 300 μm thick was moved while pressing the film for 3 minutes by using a rotation control memory 1, to obtain a multilayer graphene-coated substrate.

Example 10

The surface of a PET resin film 120 μm thick, 150mm wide and 150mm long was wiped with ethanol impregnated in a cotton swab, and then cleaned and degreased to prepare a substrate. Further, as a transfer mold, an aluminum plate having holes of 160mm in width, 160mm in length, 3mm in thickness, and 5mm in diameter in circular shape was prepared on the entire surface at a pitch of 9mm hole center positions (FIG. 55).

The aluminum plate was placed on a heating plate having a surface temperature of 70 ℃ and held for 5 minutes, and then the back surface of the PET resin film was superimposed on the aluminum plate, and the outer peripheral portion was fixed with a heat-resistant tape. The surface of the PET resin film (substrate) was rubbed with the multilayer graphene block obtained in production example 13, and the multilayer graphene was coated so that the shape of the transfer mold was allowed to emerge on the surface. The time required to coat the entire surface of the substrate is approximately 5 minutes or so. After coating, the outer periphery of the PET resin film is cut into pieces having a width of 10 to 20mm, and defective portions such as adhesive marks on the heat-resistant tape are removed. In this way, a PET resin film (patterned multilayer graphene-coated substrate) having a width of 130mm, a length of 130mm, and a thickness of 120 μm was obtained, in which the multilayer graphene was relatively thickly coated to a thickness of about 0.5 μm in the portions excluding the portions of the circular holes of the transfer mold, while only the very thin multilayer graphene was coated in the portions of the circular holes of the transfer mold, thereby obtaining a pattern formed by the thickness of the multilayer graphene coating layer. Fig. 56 is a photograph showing the appearance of the film.

With respect to the multilayer graphene-coated substrate with a pattern obtained in this way, the surface resistances of the portion where graphene was thickly applied and the portion where only graphene was thinly applied were measured 3 times, respectively, and the average value thereof was obtained. The light transmittance was measured at wavelengths of 400nm, 500nm, 600nm, and 700nm, and the average value was determined.

The surface resistance (average value) was 800 Ω/□ in the thickly coated portion and 85000 Ω/□ in the only thinly coated portion, and the average transmittance under visible light was 33.5% in the thickly coated portion and 85% in the only thinly coated portion. Therefore, a transparent conductive film having both light-transmitting property and conductivity and having a pattern formed by the thickness of the multilayer graphene coating layer is obtained on the entire surface of the film.

Example 11

The paper was made to have a thickness of about 90 μm, a whiteness of about 84% and a weight per unit area of 70g/m²The transfer sheet (product name: Multipaper Super Select Smooth, manufactured by ASKUL) was cut into a width of 150mm and a length of 150mm to prepare a substrate. Further, a 70 μm thick polyester nonwoven fabric made of polyester fibers having a diameter of 10 μm was cut into a width of 150mm and a length of 150mm to prepare another substrate. The surface of each of these substrates was coated with the multilayer graphene block obtained in production example 13 and simultaneously coated with the multilayer graphene. The coating was repeatedly performed on the surface of each substrate until the resistance measurement value of the tester reached 1000 Ω. The substrate was turned over, the back surface was coated in the same manner, and both the front surface and the back surface were coated until the resistance values measured at arbitrary 10 sites were less than 1000 Ω and electrical continuity between the front surface and the back surface could be obtained. The time required in the process is about 6 minutes in copy paperThe polyester nonwoven fabric was about 8 minutes. The tester used was an analog tester EAT-01B manufactured by ELPA.

SEM of the surface of the multilayer graphene coated on the transfer paper is shown in fig. 57 and fig. 58 (enlarged view of the previous figure), and SEM of the surface of the multilayer graphene coated on the polyester nonwoven fabric is shown in fig. 59. In the case of paper, a multilayer graphene-coated substrate coated with multilayer graphene without an adhesive is obtained on the surface of cellulose fibers, and in the case of polyester nonwoven fabric, a multilayer graphene-coated substrate coated with multilayer graphene without an adhesive is obtained on the surface of polyester fibers.

< rubbing/hot rolling/hot pressing >

Example 12

(1) The thickness is 110 μm, and the weight per unit area is 75g/m²The polyester nonwoven fabric of (2) was fixed to a heating plate, and the temperature of the heating plate was set to 80 ℃. The multilayer graphene block obtained in production example 13 was laminated while being rubbed on a polyester nonwoven fabric (treatment product 1).

(2) The above-mentioned treated product 1 was hot-rolled at a feed rate of 2cm/sec, a load of 280N and a roll temperature of 80 ℃ (treated product 2).

(3) The processed product 2 was subjected to a hot press treatment (processed product 3) at a hot plate temperature of 80 ℃ under a load of 10000N for 10 min.

(4) The thickness, bulk density and resistivity of the above-mentioned processed products 1 to 3 were measured. Fig. 60 shows appearance photographs of the multilayer graphene-coated substrates of treatments 1, 2, and 3. The treated product 1 was black in appearance, while the treated products 2 and 3 showed metallic luster, and the multilayer graphene-coated substrate of the treated product 3 showed metallic luster the most. The thickness of the treated articles 1, 2 and 3 after coating was 83 μm, 66 μm and 61 μm, respectively, and the volume density (unit: g/cm) was calculated from the shape and weight³) 1.0, 1.3 and 1.5 respectively, and realizes high densification by rolling and hot pressing. The intrinsic resistance is reduced by the densification,the processed products 1, 2, and 3 were 3.5. omega. cm, 1.5. omega. cm, and 0.1. omega. cm, respectively. The intrinsic resistance was measured by a surface resistance meter (Hirester UP, manufactured by DIAINSTRUMENTS).

(5) The above-mentioned processed product 3 was cut into a disk shape having a diameter of 10 mm. A multilayer graphene-coated substrate dried at 120 ℃ for 1 hour was used as a working electrode, and lithium metal was used as a counter electrode in an argon atmosphere in a glove box, and LiBF was used as an electrolyte₄The two-electrode unit cell is constructed, and the charge-discharge characteristics are measured in a potential range of 0 to 3V and a current density of 40 mA/g. The measured reversible capacity of the 35 th cycle of charge and discharge was 210mAh/g, and the coulombic efficiency was 90.1%, and the lithium ion battery sufficiently functioned as a negative electrode material and a current collector.

(6) The thermal diffusivities of the above-mentioned treated materials 1 to 3 and the above-mentioned polyester nonwoven fabric were measured using a thermal diffusivity measuring apparatus (MODELLASERPIT-M2) manufactured by ULVAC physical industries. Thermal diffusivity of polyester nonwoven Fabric (10)^-6m²S) was 0.02, and the thermal diffusivity of the treated product 3 was about 1000 times higher than that of the polyester nonwoven fabric in the treated products 1 to 3 by increasing the thermal diffusivity to 0.318, 0.635 and 2.502, respectively.

< coating of residual graphene dispersion/Hot Rolling/Hot pressing >

Example 13

(1) A solvent of 2-propanol with reagent special grade purity (Wako pure chemical industries) was prepared. The multilayer graphene blocks obtained in production example 1 were weighed and mixed so that the weight ratio to the solvent was 0.1 wt%, and then crushed at 1000rpm using a wet stirrer having a metal cutter for 15 minutes, and the mixed solution was charged into a commercially available ultrasonic cleaner (desktop ultrasonic cleaner W-113, manufactured by this company, inc.) and subjected to ultrasonic waves at 42kHz and 100W for 30 minutes. In the mixed liquid after the ultrasonic wave application, petal-shaped multilayer graphene is dispersed from the multilayer graphene block into the solvent, and thus appears black. Then, the dispersion was centrifuged at an acceleration of 800G for 30 minutes, and the supernatant was removed. The black residue was recovered, and 2-propanol was poured into the residue so that the graphene dispersion amount was 30 wt%, and the mixture was stirred to prepare a residue graphene dispersion.

(2) A thickness of 110 μm and a weight per unit area of 75g/m were prepared²And a polyester nonwoven fabric E having a thickness of 50 μm and a weight per unit area of 40g/m²The polyester nonwoven fabric F was set on a heating plate set at 80 ℃. After manually applying a brush coating to the residual graphene dispersion liquid prepared in (1), hot rolling was performed at a feed rate of 1cm/sec, a load of 500N, and a roll temperature of 80 ℃, and then hot pressing was performed at a hot plate temperature of 80 ℃, a load of 10000N, and a time of 10 min. The electrical resistivity of the coated side and the back side was measured by using a surface resistance meter (Hirester UP manufactured by DIAINSTRUMENTS), and as a result, the electrical resistivity was 10. omega. cm in the nonwoven fabric E when measured on the coated side and could not be measured (overrange due to excessive electrical resistance) when measured on the back side. The nonwoven fabric F thus measured had a bulk density of 1.7 increased to less than 0.1 Ω · cm on both sides.

< spray coating/Hot Rolling/Hot pressing >

Example 14

(1) A solvent of 2-propanol with reagent special grade purity (Wako pure chemical industries) was prepared. The multilayer graphene blocks obtained in production example 1 were weighed and mixed so that the weight ratio to the solvent was 0.1 wt%, and then crushed at 1000rpm using a wet stirrer having a metal cutter for 15 minutes, and the mixed solution was charged into a commercially available ultrasonic cleaner (desktop ultrasonic cleaner W-113, manufactured by this company, inc.) and subjected to ultrasonic waves at 42kHz and 100W for 30 minutes. In the mixed liquid after the ultrasonic wave application, petal-shaped multilayer graphene is dispersed from the multilayer graphene block into the solvent, and thus appears black. Then, the dispersion was centrifuged at an acceleration of 800G for 30 minutes, and the supernatant was collected to obtain a multilayer graphene dispersion having a dispersion amount of 0.05 mg/ml.

(2) A mini compressor (TYPE226) of Kiso Power Tool, K.K. was prepared and connected to an air brush (E1307N) of Kiso Power Tool, K.K. The multilayer graphene dispersion prepared in (1) above was filled in a liquid container of an air brush, and the dispersion was adjusted so that the dispersion could be ejected at an air pressure of 0.2 MPa. The nozzle diameter of the air brush was set to 0.4mm in inside diameter. A PET film having a thickness of 100 μm and a square width of 50mm was placed on the surface of a metal heating plate set to a temperature of 80 ℃, and 20ml of a dispersion was sprayed while setting the distance between an air brush and a substrate to 110 mm. After the spraying, a roll press with a load of 400N was performed between rolls set to 120 ℃ and then hot press with a load of 10000N was performed for 5 minutes with a hot plate set to 140 ℃. The surface resistance of the multilayer graphene laminate after spraying and hot pressing was measured using a Hirester UP manufactured by DIAINSTRUMENTS, Inc., and the light transmittance at a wavelength of 550nm was measured using an ultraviolet-visible spectrophotometer (Aurius CE2021 manufactured by CECIL, Inc.). The light transmittance immediately after spraying was 70% and the surface resistance was 800000 Ω/□, while the light transmittance after hot pressing was reduced to 55% and the surface resistance was improved to 1500 Ω/□. The surfaces of the sprayed film and the films further subjected to hot rolling and hot pressing were observed by FE-SEM (fig. 61 (a): the sprayed film, and fig. 61 (b): the films further subjected to hot rolling and hot pressing). Although a state in which graphene is condensed is all observed, graphene is bonded on the surface of the film using a hot roll and a hot press process, and contact points between graphene are increased, promoting conductive path formation.

< Single fluid type spray coating >

Example 15

Using the multilayer graphene dispersion liquid prepared in example 14(1), single-fluid type spraying was performed using a precision dispenser that ejects the dispersion liquid in a cylinder from a nozzle having a fine tip in a minute amount by air pressure. That is, a nozzle having an inner diameter of 100 μm was used to drop a minute amount of droplets having a size of approximately 500 μm onto a heated substrate at an interval of 0.5mm by adjusting the opening/closing time, the opening/closing distance, and the applied air pressure of an electromagnetic valve for supplying the dispersion. As the substrate, a PET film and a copper plate were used, and the heating temperature was set to 90 ℃. The condition of the surface of each substrate of the spot portion was observed by FE-SEM (FIG. 62 (a): the condition of the surface of the PET film, FIG. 62 (b): the enlarged view of (a), FIG. 63 (a): the condition of the surface of the copper plate, and FIG. 63 (b): the enlarged view of (a)). Many graphene sheets having a size of about 10 μm and a small thickness were observed to be coated while being shrunk into a roll shape. Since such thin graphene is not observed in the two-fluid type spray coating of example 14 and the like, it is considered that the thin graphene is blown off by the air flow in many portions in the two-fluid type. In contrast, in the case of the single fluid type, since almost all of the discharged droplets hit the substrate or the film surface, it is confirmed that the method is suitable for a process of coating thin graphene.

< Multi-layer graphene Block (A) >

Production example 1

The granulated PET resin (average particle diameter 3mm) was calcined at a maximum reaching temperature of 600 ℃ in an inert gas atmosphere. The residual hydrogen content of the calcined raw material was 22000 ppm. The calcined raw material was charged into a screw-type (triangular screw-type) graphite crucible made of a material having a bulk density of 1.80 and an open porosity of 10%, and the screw was tightened while rotating a screw-type upper lid to seal the calcined raw material. The graphite crucible was loaded in a hot isostatic pressing apparatus, and then heated and pressurized at a temperature of 600 ℃ and a pressure of 70MPa for 1 hour using argon gas, and then heated and pressurized at a temperature-raising rate of 500 ℃ per hour, and raised at a maximum reaching pressure of 190MPa and a maximum reaching temperature of 1500 ℃ respectively, and held at the maximum reaching temperature pressure for 1 hour, cooled to room temperature, and depressurized. As a sample after the treatment, a multilayer graphene block (true density 2.08, apparent density 1.33, bulk density 0.75, total porosity 63.9) was obtained.

Production example 2

Each sample (production example 2-1 to production example 2-6) was obtained by the same treatment as in production example 1, except that a phenol-formaldehyde resin (average particle size 20 μm) was used as a raw material in place of the PET resin and the treatment conditions shown in Table 6 were used.

[ Table 6]

TABLE 6

(production example 3)

Phenol-formaldehyde resin powder having an average particle diameter of 20 μm was calcined in an inert gas atmosphere at respective maximum reaching temperatures of 600, 700, 900 and 1000 ℃. The calcined raw material was analyzed for the amount of residual hydrogen, and the results are shown in table 7. The calcined raw materials calcined at each temperature were charged into a screw-type (triangular screw-type) graphite crucible made of a material having a bulk density of 1.80 and an open porosity of 10%, and the screw was tightened while rotating a screw-type upper lid to seal the calcined raw materials. The graphite crucible was loaded in a hot isostatic pressing apparatus, and then heated and pressurized at a temperature of 600 ℃ and a pressure of 70MPa for 1 hour using argon gas, and then heated and pressurized at a temperature-raising rate of 500 ℃ per hour, and raised in temperature and pressure at respective maximum reaching temperatures of 190MPa, 1400 ℃, 1800 ℃, 2000 ℃ and 2500 ℃, and held at the maximum reaching temperature pressure for 1 hour, and then cooled to room temperature and depressurized. The time required from the insertion of the graphite crucible to the removal of the graphite crucible is 8 to 12 hours. The bulk density, porosity and true density of the treated samples were measured and are shown in table 7.

[ Table 7]

TABLE 7

As shown in Table 7, the true density closest to the theoretical density of graphite was obtained when the calcination temperature was 600 ℃ and the residual hydrogen amount by the measurement method was 20000ppm (production examples 3-1 and 2), the value of the true density decreased as the calcination temperature increased (production examples 3-3 and 4), and the true density was 1.88 when the calcination temperature was 900 ℃ and the residual hydrogen amount by the measurement method was 5000ppm (production example 3-4). Further, the value of the true density is less than 2.0 at the calcination temperature of 900 ℃ or 1000 ℃ even when the maximum reaching temperature in the hot isostatic pressing treatment is 2000 ℃ or 2500 ℃. FIG. 25 shows the surface of a sample of production example 3-1, FIG. 26 shows an electron micrograph obtained by enlarging the surface of FIG. 25, FIG. 27 shows an electron micrograph of a cross section of a sample of production example 3-1, and graphene is grown in a radial vapor phase on the surface of a spherical calcined material.

FIG. 28 is an electron micrograph showing a cross section of a sample of production example 3-5, and FIG. 29 is an electron micrograph showing a cross section of a sample of production example 3-6. in comparison with production example 3-1, the degree of growth of graphene is low, and particularly in the case of production example 3-6, etching traces of graphite due to hydrogen excited at a high temperature of 2000 ℃ or higher can be seen.

FIG. 30 shows the results of Raman spectroscopy measurement of production example 3-1. 1580cm was observed^-1Nearby SP²The sharp peak generated by graphite bonding was not substantially observed and 1360cm indicating a turbostratic structure was not observed^-1Nearby peaks in their intensity ratio I₁₃₆₀/I₁₅₈₀(I_D/I_G) The R value represented shows a value close to 0, and is a structure extremely excellent in crystallinity. On the other hand, the results of Raman spectrum measurement in production examples 3 to 5 are shown in FIG. 31, and 1360cm was observed^-1Nearby peak, intensity ratio I₁₃₆₀/I₁₅₈₀(I_D/I_G) Showing a large value.

Production example 4

Phenol-formaldehyde resin powder having an average particle diameter of 500 μm was calcined in an inert gas atmosphere at a maximum reaching temperature of 600 ℃. The calcined raw material was treated in the same manner as in production example 3, except that the maximum reaching temperature in the hot isostatic pressing treatment was 1400 ℃. The time required from insertion of the graphite crucible to removal of the graphite crucible was 12 hours. An electron micrograph of the treated sample is shown in fig. 32, and an enlarged photograph of the surface thereof is shown in fig. 33. Vapor-phase-grown graphite grown radially was observed on the entire surface of the spherical particles, but a bulk structure in which the particles were bonded was not obtained. The true density of the resulting sample was 1.80.

Production example 5

Waste materials of plastic bottles for beverages were finely cut to about 200 μm (the longest dimension in the vertical and horizontal directions) on average, and were calcined at a maximum reaching temperature of 600 ℃ in an inert gas atmosphere. The calcined raw material was pulverized in a stainless steel mortar to prepare a granular material, and then treated in the same manner as in production example 4. The time required from insertion of the graphite crucible to removal of the graphite crucible was 12 hours. Fig. 34 shows an electron micrograph of the treated sample. Graphene grown in an approximately radial shape was seen over the entire surface of the amorphous particles. The true density of the resulting sample was 1.90.

(production example 6)

Phenol-formaldehyde resin powder having an average particle diameter of 20 μm was calcined in an inert gas atmosphere at a maximum reaching temperature of 700 ℃. The calcined raw materials were charged into each of the graphite crucibles shown in table 8, and the calcined raw materials were sealed by screwing a screw-type upper lid. This graphite crucible was treated in the same manner as in production example 4, except that the maximum reaching temperature in the hot isostatic pressing treatment was 1500 ℃.

[ Table 8]

TABLE 8

As the material of the graphite crucible was used, the true density of the sample after treatment gradually decreased as the material had a higher porosity and a lower bulk density (production example 6-1 to production example 6-3). The graphite crucible had a lower true density than that of production example 6-1 when the pitch of the screw shape was 2mm (production example 6-6) and when the number of screws was small (production example 6-4 and production example 6-5). In addition, lower true densities were obtained for the square screw (production example 6-7) and the trapezoidal screw (production example 6-8) as compared with the case where the screw shape of the graphite crucible was the triangular screw (production example 6-1).

When the calcined material was inserted into the graphite crucible and sealed, the true density was increased to 2.19 in the case where the spacers were made of glassy carbon having low gas permeability and an open porosity of 0% and were provided so as to cover the entire upper and lower portions of the calcined material (fig. 4, production examples 6 to 9), and in production examples 6 to 10 in which the sleeve was used together so as to cover the entire side surface portion of the calcined material (fig. 6), a true density of 2.23 was obtained.

< film-shaped multilayer graphene aggregate (B) >

Production example 7

Phenol-formaldehyde resin powder having an average particle diameter of 20 μm was calcined in an inert gas atmosphere at a maximum reaching temperature of 500 ℃. The residual hydrogen content of the calcined raw material was 40000 ppm. The calcined raw material was sealed in a screw-type graphite crucible made of a material having a bulk density of 1.80 and an open porosity of 10% in a state sandwiched between spacers made of glassy carbon. Further, as shown in fig. 35, by screwing the screw of the upper lid of the graphite crucible, the upper spacer is pressed against the guide portion of the graphite crucible by the fastening force of the screw, thereby improving the sealing degree. The graphite crucible was loaded in a hot isostatic pressing apparatus, heated to 700 ℃ and 70MPa for 1 hour using argon gas, heated and pressurized at a temperature-raising rate of 500 ℃ per hour, heated and pressurized at a maximum reaching pressure of 190MPa and a maximum reaching temperature of 1800 ℃, held at the maximum reaching temperature and pressure for 1 hour, cooled to room temperature, and depressurized. The glass-like carbon spacer was mirror-polished.

As a result of taking out the treated sample, as shown in fig. 36, a film-like product exhibiting a silver color and a metallic luster was deposited on the surface of the glassy carbon spacer. The film-like product can be easily peeled from the spacer, and has a strength that enables the film to be independently formed. As a result of observing the surface of the obtained film-like product with an electron microscope, it was observed that each of the multi-layer graphene growing in a direction substantially perpendicular to the surface of the spacer was aggregated as one form of a multi-layer graphene aggregate in which the multi-layer graphene extending from the inside to the outside was aggregated. In addition, the graphene also includes a graphene in which a plurality of layers are grown like petals (a graphene block in a plurality of layers). (FIGS. 37 to 41)

< fibrous Multi-layer graphene aggregate (C) >

Production example 8

Phenol-formaldehyde resin powder having an average particle diameter of 20 μm was fired at a maximum reaching temperature of 600 ℃ in an inert gas atmosphere. The calcined raw material was charged into a screw-type graphite crucible made of a material having a bulk density of 1.80 and an open porosity of 10%, and the screw was tightened while rotating a screw-type top lid, thereby sealing the calcined raw material. After the graphite crucible sealed was loaded in a hot isostatic pressing device, the graphite crucible was heated and pressurized at a temperature of 700 ℃ and a pressure of 70MPa for 1 hour by using argon gas, and then heated and pressurized at a temperature rise rate of 300 ℃ per hour, and the temperature and pressure were raised at a maximum reaching pressure of 190MPa and a maximum reaching temperature of 1400 ℃ and held at the maximum reaching temperature and pressure for 1 hour, and then cooled to room temperature and depressurized. The apparent density of the treated sample was 1.60 and the true density was 2.09.

In the treated sample, fibrous vapor grown carbon fibers having a diameter of several μm and a length of several μm to several mm were produced (fig. 42 to 44). The fiber exhibits one form of a multilayer graphene aggregate in which multilayer graphene extending from the inside to the outside is aggregated, and the multilayer graphene is formed into a special shape in which a graphite crystal of the fiber grows outward from the center of the fiber. Although the fibrous aggregates are also present inside the material, they grow into rather long aggregates at the surface portion.

Production example 9

The same procedure as in the previous production example was carried out except that the HIP treatment was carried out under conditions such that the temperature increase rate after 700 ℃ was 700 ℃ per hour and the maximum reaching temperature was 1450 ℃. The apparent density of the treated sample was 1.66 and the true density was 2.05.

In the treated sample, a product having the same form as that of the product of the previous production example was similarly produced (fig. 45 to 46).

Production example 10

The same procedure as in the previous production example was carried out except that the highest temperature reached by the calcination was 500 ℃, the temperature increase rate after 700 ℃ was 500 ℃ per hour under the HIP treatment conditions, and the highest temperature reached was 1800 ℃. The apparent density of the treated sample was 1.77 and the true density was 2.07.

In the treated sample, a product having the same form as that of the product of the previous production example was similarly produced (fig. 47 to 48).

< Multi-layer graphene Block (A) >

Production example 11

Phenol-formaldehyde resin powder having an average particle diameter of 20 μm was calcined in an inert gas atmosphere at a maximum reaching temperature of 600 ℃. The residual hydrogen content of the calcined raw material was 20000 ppm. The calcined material was charged into a screw-type graphite crucible made of a material having a volume density of 1.80 and an open porosity of 10%, and the screw was tightened while rotating a screw-type top lid, thereby sealing the calcined material. After the graphite crucible sealed was loaded in a hot isostatic pressing device, the temperature of 700 ℃ and the pressure of 70MPa were reached for 1 hour by using argon gas, and thereafter, heating and pressing were carried out at a temperature rise rate of 500 ℃ per hour, the temperature and pressure were raised at the maximum reaching pressure of 190MPa and the maximum reaching temperature of 1800 ℃, the temperature and pressure were maintained at the maximum reaching temperature and pressure for 1 hour, and the temperature was lowered to room temperature and the pressure was lowered. The true density of the resultant cake was 2.17. Further, an SEM of the obtained vapor-grown graphite is shown in fig. 49, and an enlarged graph thereof is shown in fig. 50, and the multilayer graphene extending from the inside to the outside is aggregated to form a bulk.

< cleaved Multi-layer graphene Block (D) >

Production example 12

5g of the multi-layer graphene block of production example 3-2 was weighed in a glass Erlenmeyer flask, and a mixed solution of 80ml of concentrated sulfuric acid and 20ml of concentrated nitric acid was added thereto, and the mixture was reacted for 24 hours while stirring with a stirring rod made of Teflon (registered trademark). The massive sample gradually collapsed from about 30 minutes after the start of the reaction, with the formation of the graphite sulfate intercalation compound in which sulfate ions intruded between the graphite layers, and became a state in which fine particles were dispersed in the solution after the end of the reaction. The sample after the reaction was dried and then charged into a magnetic crucible made of ceramic, and the sample was put into an electric furnace heated to 700 ℃ together with the magnetic crucible and subjected to a rapid heat treatment. Due to the rapid heat treatment in an electric furnace set at 700 ℃, the heat-treated sample expanded about 3 times in volume. Fig. 51 and 52 show SEM of the sample after the heat treatment, and the sample is cleaved into thinner multi-layer graphene due to rapid decomposition and release of sulfate ions between the layers of the multi-layer graphene by the heat treatment.

< Multi-layer graphene Block (A) >

Production example 13

The granulated PET resin (average particle diameter: 3mm) was calcined at a maximum reaching temperature of 600 ℃ in an inert gas atmosphere. The calcined raw material (calcined raw material) is crushed and sieved to obtain a calcined raw material having an average particle size of about 10 to 100 μm. The residual hydrogen content of the calcined raw material was 22000 ppm. The calcined raw material was charged into a screw-type (triangular screw) graphite crucible made of a material having a bulk density of 1.80 and an open porosity of 10%, and the screw was tightened while rotating a screw-type top lid, thereby sealing the calcined raw material. The graphite crucible was loaded in a hot isostatic pressing apparatus, and then heated and pressurized at a temperature of 600 ℃ and a pressure of 70MPa for 1 hour using argon gas, and then heated and pressurized at a temperature rise rate of 500 ℃ per hour, and then heated and pressurized at a maximum reaching pressure of 190MPa and a maximum reaching temperature of 1500 ℃ respectively, and held at the maximum reaching temperature pressure for 1 hour, and then cooled to room temperature and depressurized. As a sample after the treatment, a multilayer graphene block (true density 2.08, apparent density 1.33, bulk density 0.75, total porosity 63.9) was obtained.

Industrial applicability of the invention

The present invention provides a novel method for producing a multilayer graphene-coated substrate. The multilayer graphene-coated substrate can be used as a transparent conductive film or a conductive film for a panel electrode of a liquid crystal display, a plasma display, or the like, a display element electrode of a notebook personal computer, a mobile phone, a touch panel, or the like, or an electrode of a lithium ion battery, a lithium ion capacitor, a fuel cell, a thin film solar cell, another primary battery, a secondary battery, or the like.

Description of the symbols

1 crucible cover

1a outer peripheral portion of the crucible cover

2 crucible body

2a inner wall of upper part of crucible body

3 calcining the raw materials

4 spacer

5 sleeve barrel

6 calcining the raw material particles

6a gas

6s calcination of the surface of the raw Material particle

7 graphene

7a in-plane direction of hexagonal graphite mesh surface (a-axis direction of graphite crystal)

C-axis direction of 7c graphite crystal

8 Multi-layer graphene aggregates

9 base

10 grip part (part to be held by hand)

11 rotating shaft

12 adhesive layer (layer of adhesive material adhering the multilayer graphene aggregate to the base)

Claims (17)

1. A method for producing a multilayer graphene-coated substrate, comprising a step of laminating a multilayer graphene from a multilayer graphene aggregate on a substrate surface.

2. The production method according to claim 1, wherein the multilayer graphene aggregate is a multilayer graphene block in which multilayer graphene extending from inside to outside is aggregated.

3. The production method according to claim 1 or 2, wherein the multilayer graphene constituting the multilayer graphene aggregate is a material having a thickness of 0.34 to 10 nm.

4. The production method according to any one of claims 1 to 3, wherein the stacking is performed by rubbing a multilayer graphene aggregate on a surface of a substrate.

5. The production method according to any one of claims 1 to 3, wherein the stacking is performed by contacting the substrate surface with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate and then removing the solvent from the substrate surface.

6. The production method according to any one of claims 1 to 3, wherein the stacking is performed by dip-coating the surface of the substrate with a multilayer graphene dispersion prepared from a multilayer graphene aggregate.

7. The production method according to any one of claims 1 to 3, wherein the stacking is performed by spraying a surface of the substrate with a multilayer graphene dispersion prepared from a multilayer graphene aggregate.

8. The production method according to any one of claims 5 to 7, wherein the solvent is selected from the group consisting of 1, 2-dichloroethane, benzene, thionyl chloride, acetyl chloride, tetrachloroethylene carbonate, dichloroethylene carbonate, benzoyl fluoride, benzoyl chloride, nitromethane, nitrobenzene, acetic anhydride, phosphorus oxychloride, benzonitrile, selenium oxychloride, acetonitrile, tetramethylsulfone, dioxane, 1, 2-propanediol carbonate, benzyl cyanide, ethylene sulfite, isobutyronitrile, propionitrile, dimethyl carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, ethylene carbonate, phenyl difluorophosphite, methyl acetate, N-butyronitrile, acetone, ethyl acetate, water, phenyl dichlorophosphate, diethyl ether, tetrahydrofuran, diphenyl chlorophosphate, trimethyl phosphate, tributyl phosphate, dimethylformamide, N-methylpyrrolidine, and mixtures thereof, 1 solvent or a mixed solvent of more than 2 solvents selected from N-dimethylacetamide, dimethyl sulfoxide, N-diethylformamide, N-diethylacetamide, pyridine, hexamethylphosphoramide, hexane, carbon tetrachloride, diglyme, chloroform, 2-propanol, methanol, ethanol, propanol, ethylene glycol, methyl ethyl ketone, 2-methoxyethanol, dimethylacetamide, toluene and polybenzimidazole; or the solvent or the mixed solvent to which a dispersant is added.

9. The production method according to claim 6 or 8, wherein in the dip coating, the temperature of the multilayer graphene dispersion liquid is 40 ℃ or higher, and the pulling rate at which the substrate immersed in the multilayer graphene dispersion liquid is pulled from the liquid is 1 to 1000 μm/sec.

10. The production method according to any one of claims 1 to 9, wherein the thickness of the layer coated with the multilayer graphene in the multilayer graphene-coated substrate is 0.5 to 10000 nm.

11. The production method according to any one of claims 1 to 10, wherein the substrate is a resin film formed of a resin selected from the group consisting of a polyester resin, an acrylic resin, a polystyrene resin, a polycarbonate resin, a polypropylene resin, a polyethylene resin, a polyvinyl chloride resin, and a polytetrafluoroethylene resin; a glass substrate coated with 1 or 2 or more resins selected from polyester resins, acrylic resins, polystyrene resins, polycarbonate resins, polypropylene resins, polyethylene resins, polyvinyl chloride resins, and polytetrafluoroethylene resins; a metal foil, a metal plate, or a metal film formed of a metal selected from copper, nickel, iron, aluminum, and titanium; paper; a glassy carbon substrate; or a sapphire substrate.

12. A tool for coating a surface of a workpiece with a multilayer graphene, the tool having a tool surface in contact with the surface of the workpiece, wherein a multilayer graphene aggregate is held on the tool surface.

13. A method for producing a multilayer graphene-coated substrate having a pattern formed by using the thickness of a coating layer of multilayer graphene,

the manufacturing method comprises the following steps: a transfer mold having surface irregularities conforming to the pattern is prepared, the back surface of the substrate is superimposed on the surface of the transfer mold, and the surface of the substrate is rubbed with the multilayer graphene derived from the multilayer graphene aggregate.

14. A method for producing a multilayer graphene-coated substrate, comprising a step of laminating a multilayer graphene derived from a multilayer graphene aggregate on a substrate surface and then subjecting the substrate surface to press working.

15. The production method according to claim 14, wherein the stacking is performed by spraying the surface of the substrate with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate, a multilayer graphene pulverization liquid, or a residual graphene dispersion liquid.

16. A method for producing a multilayer graphene-coated substrate, comprising a step of laminating a multilayer graphene from a multilayer graphene aggregate on a substrate surface,

the lamination is performed by single-fluid spraying the substrate surface with a multilayer graphene dispersion liquid prepared from a multilayer graphene aggregate, a multilayer graphene pulverized liquid, or a residual graphene dispersion liquid.

17. A multilayer graphene-coated substrate is manufactured by laminating multiple graphene layers from a multilayer graphene aggregate on a substrate surface.