Method for continuously producing graphene film composed of collection of graphens with flat surfaces of graphene overlapped with and bonded to each other

Abstract

To provide a method for preparing suspension in which flat surfaces of graphenes are overlapped with each other through liquid, and continuously molding a first sheet, using the suspension, to provide a method for continuously molding a second sheet having thickness close to that of a graphene film, using a first sheet, and to provide a method for continuously producing a graphene film, using a second sheet.SOLUTION: A method separates a collection of aggregates of graphenes in first alcohol into graphenes one by one, mixes the separated graphenes with second alcohol having viscosity higher than that of the first alcohol, then repeatedly adds vibration acceleration in three directions, aligns the collection of the graphenes in a planar shape with the flat surface upward, and then continuously extrudes a sheet from a lip of a T die of an extrusion molding machine. The method compresses the extruded sheet by a first multistage rolling machine, makes the thickness of the sheet close to a graphene film, further compresses the sheet by a second multistage rolling machine, and continuously molds the graphene film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is a method for continuously producing a graphene film consisting of an assembly of graphene in which flat planes of graphene are overlapped and bonded to each other, by continuously carrying out a process consisting of the following five steps: Note that, because the thickness of the produced graphene film is on the nanometer level, the assembly of graphene is referred to as a graphene film. In the first step, the interlayer bonds of the graphite crystals that form the graphite particles are broken in a first alcohol having a viscosity of 1-2 mPa·sec at 20°C, and the graphene aggregates separated into individual graphene sheets are dispersed in the first alcohol. In the second step, a second alcohol with a viscosity of 6-10 mPa·sec at 20°C is mixed in, so that the viscosity of the mixture of the two alcohols at 20°C is 4-6 mPa·sec, and a suspension consisting of aggregates of graphene in which the flat surfaces of the graphene overlap each other is created via the mixture of the two alcohols. In the third step, the suspension is continuously filled into the hopper of an extruder, and after passing through a manifold of a T-die of the extruder, a sheet made of the suspension, having the width of the graphene film to be produced and a thickness 10 to 20 times the thickness of the graphene film to be produced, is continuously extruded from the lip of the T-die. In the fourth step, the sheet-like suspension is continuously compressed in the gap between two work rolls of a first multi-high rolling mill having five characteristics: first, the work rolls have the same width as the graphene film to be produced, but are wider than the width of the graphene film to be produced; second, the work rolls have the same diameter but are smaller than 1 / 10 of the width of the graphene film to be produced; third, the gap is set to be 5 times the thickness of the graphene film to be produced; fourth, the work rolls rotate in opposite directions to each other at the same peripheral speed, with the time required for one rotation being longer than 10 seconds; and fifth, the temperature is raised to a temperature 10°C higher than the boiling point of the first alcohol in the suspension. In a fifth step, the sheet-like suspension is continuously compressed in the gap between the two work rolls of a second multi-high rolling mill, which has the same width and diameter as the two work rolls of the first multi-high rolling mill, rotates in opposite directions at the same peripheral speed, has a gap set to the thickness of the graphene film to be produced, and is heated to a temperature 10°C higher than the boiling point of the second alcohol, to continuously produce graphene films. Graphene is a two-dimensional layered substance in which carbon atoms form a two-dimensional hexagonal network structure, and is a single-crystal material composed of an assembly of carbon atoms. In the present invention, a collection of graphene sheets with a nanometer-level thickness, in which the flat surfaces of the collection of graphene are directly overlapped and directly bonded, is called a graphene film. On the other hand, graphite particles are composed only of graphite single crystals and are the most inexpensive carbon material in which graphite crystallization is 100% advanced. Therefore, in the present invention, the interlayer bonds of the graphite crystals that form the graphite particles are simultaneously broken, and an assembly of graphene composed of the basal planes of the graphite crystals is produced. In a prior application similar to the present invention, the present inventors have filed a patent application (Japanese Patent No. 7195513) for a technology for manufacturing a graphene sheet, which is made up of an assembly of graphene in which flat surfaces of graphene overlap and bond together, in the shape of the bottom surface of a container. The difference is that the prior application is a batch process, whereas the present application is a continuous process. [Background technology]

[0002] In 2004, physicists at the University of Manchester in the UK used cellophane tape to peel off a single crystallite from graphite, i.e., the basal plane that forms a two-dimensional hexagonal network of carbon atoms, and succeeded for the first time in extracting a planar material whose thickness is the size of the carbon atom. This new material was called graphene. For this research achievement, he was awarded the Nobel Prize in Physics in 2010.

[0003] Graphene is a two-dimensional layered material whose thickness corresponds to the size of a carbon atom, and the flat surface properties of two-dimensional layered graphene are the properties of graphene. Also, because its thickness corresponds to the size of a carbon atom, it has almost no mass. For this reason, its physical properties are significantly different from those of conventional materials, and it is attracting attention as a material with a wide range of applications. For example, it is the thinnest material with a thickness of 0.332 nm. Also, the surface area per unit mass is 3000 m 2 / g. Furthermore, it has a large Young's modulus of 1020 GPa, making it the most stretchable and bendable material. It also has a large shear modulus of 440 GPa, making it the strongest material. Furthermore, its thermal conductivity is 19.5 W / Cm, which is 4.5 times that of silver, the metal with the highest thermal conductivity. It also has a maximum current density of 360 MA / cm. 2 Its electrical conductivity is only 23 times that of copper, and its electron mobility is 15,000 cm 2 / Volt·sec, and the mobility of silicone is 1400 cm 2 Its thermal conductivity is more than one order of magnitude higher than that of SiO2 / Volt·seconds. Furthermore, its melting point exceeds 3000°C, making it a highly heat-resistant material. Furthermore, because it is a single-crystal material made up of a collection of carbon atoms, it has excellent corrosion resistance and does not react with acids or alkalis.

[0004] Graphene can be produced in a variety of ways. For example, the aforementioned professor at the University of Manchester physically peeled graphene off graphite by hand. This method makes it difficult to peel off a large amount of graphene in a short time, and the peeled material does not necessarily become a single layer of graphite crystals, i.e., graphene. Patent Document 1 also describes a method for producing graphene by pyrolyzing silicon carbide single crystals. Specifically, silicon carbide is heated in an inert atmosphere to pyrolyze its surface. During this process, silicon, which has a relatively low sublimation temperature, preferentially sublimes, and graphene is produced from the remaining carbon. However, silicon carbide single crystals are very expensive materials. Furthermore, silicon is sublimated at high temperatures exceeding 1600°C in a highly vacuum atmosphere. However, even if a small amount of silicon remains, graphene is not produced as a residue after pyrolysis. Therefore, the costs associated with producing silicon carbide single crystals and pyrolyzing the single crystals are very expensive. Furthermore, producing large quantities of graphene requires even greater costs. Furthermore, Patent Document 2 describes a method for producing graphene by contacting a sheet-like single-crystal graphitized metal catalyst with a carbon-based material and heat-treating the catalyst in a reducing atmosphere. However, this production method is neither inexpensive nor suitable for mass production. First, the production cost of a single-crystal graphitized metal catalyst is even higher than that of a silicon carbide single crystal. Second, the method of contacting a single-crystal graphitized metal catalyst with a carbon-based material is poorly suited for mass production. Third, the method of reducing a graphitized metal catalyst at a high temperature exceeding 1000°C in an atmosphere rich in nitrogen gas containing hydrogen gas requires expensive heat treatment. Therefore, producing large quantities of graphene requires even higher costs.

[0005] First, none of the graphene production methods available to date are capable of simultaneously producing large quantities of graphene at low cost. Second, the graphene produced is not necessarily graphene. In other words, graphene is a single-crystal material consisting of a collection of carbon atoms that form a two-dimensional hexagonal network structure. Graphene cannot be produced unless the carbon atoms can grow in an impurity-free atmosphere. Furthermore, the produced graphene is extremely thin and lightweight, making it difficult to confirm that it is graphene. For this reason, the present inventors have discovered a method for instantly producing large quantities of graphene in an extremely simple manner, in which all the produced graphene is perfect graphene (Patent Document 3). Specifically, the method involves crushing clumps of natural graphite crystals, which are the least expensive carbon material and consist solely of graphite single crystals, with 100% graphite crystallization, and then selecting clusters of flake graphite particles or clusters of clumped graphite particles from the crushed graphite crystals. The clusters of graphite particles are then spread between two parallel flat electrodes, and an electric field is applied to the two parallel flat electrodes. The application of the electric field simultaneously destroys the interlayer bonds of all the graphite crystals that form the graphite particles, resulting in the mass production of graphene consisting of the basal planes of the graphite crystals. According to this production method, 1.62 × 10 graphene can be produced from just 1 g of flake graphite particles or clusters of clumped graphite particles. 13 A collection of up to 100 graphene particles can be obtained instantly. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-110485 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-143799 [Patent Document 3] Patent No. 6166860 Summary of the Invention [Problem to be solved by the invention]

[0007] As explained in paragraph 3, graphene is a two-dimensional layered material, and therefore possesses astonishing physical properties that are completely different from those of conventional materials. For this reason, research and development of various components and devices using graphene is being conducted. Therefore, if a method is found to inexpensively produce graphene aggregates and then use the graphene aggregates to inexpensively produce graphene films by directly overlapping and bonding the flat surfaces of the graphene, the practical application of inexpensive components and devices using graphene films will progress. In other words, because graphene is a two-dimensional layered material, the properties of the flat surfaces of graphene become the properties of graphene. Therefore, a graphene sheet, in which the flat surfaces of graphene are directly bonded, possesses the properties of graphene. Furthermore, if graphene films could be directly bonded to the surfaces of substrates and components made of various materials, the properties of graphene could be imparted to the surfaces of the substrates and components. On the other hand, while the production method described in Patent Document 3 can instantly produce large amounts of graphene, no method has been found for producing graphene films in which graphene flat surfaces are directly bonded together. Furthermore, graphene is an extremely thin material consisting of a single crystallite, and is extremely lightweight and has almost no mass. Therefore, when applying an electric field as described in Patent Document 3 to simultaneously destroy the interlayer bonds of graphite crystals in graphite particles to produce a cluster of graphene, the graphene is very easily scattered during and after production. Furthermore, because graphene is extremely thin, it has flat surfaces with an extremely large aspect ratio, which is the ratio of the size of the crystal plane to the thickness. Furthermore, because graphite particles have a uniform shape, but the shapes of graphite particles are not uniform, the aspect ratios of graphene produced by simultaneously destroying the interlayer bonds of graphite crystals in graphite particles vary from one graphene to another. Therefore, with the production method described in Patent Document 3, the flat surfaces of graphene easily overlap each other during graphene production. Furthermore, the number of overlapping graphene sheets is not constant. Furthermore, it is extremely difficult to distinguish whether or not the flat surfaces are overlapping, and this can only be determined by observation under an electron microscope. However, even if the flat surfaces of graphene are merely physically overlapping, the bonding force between the flat surfaces is extremely small, and graphene has almost no mass. Therefore, if a load is applied directly to the bond between the flat surfaces of graphene, the overlapping graphene will separate. Therefore, when manufacturing a graphene film in which the flat surfaces of graphene are directly overlapped and bonded together, there are seven issues that need to be resolved: First, we found a method to produce a large amount of graphene aggregates in a container filled with a liquid with low viscosity and a low boiling point. This prevents the graphene precipitated in the liquid from scattering during and after production. However, there remains a problem that some of the graphene aggregates overlap with each other during production. Second, we discovered a method for separating the graphene aggregates precipitated in the container into individual graphene sheets, then overlapping the flat surfaces of the graphene aggregates with a liquid, and dispersing the graphene aggregates in the liquid to create a suspension. As a result, all of the graphene comes into contact with the liquid, and the graphene has an extremely large aspect ratio and is extremely lightweight, so that the flat surfaces of the graphene do not overlap again in subsequent processing. Third, we found a method for creating a new suspension with increased viscosity, which allows for continuous molding of thin sheets made from the new suspension. Fourth, we will find a method for continuously forming a sheet with the width of the graphene film to be produced and a thickness greater than the thickness of the graphene film to be produced using a new suspension, thereby finding a method for forming a graphene film. Fifth, we found a method to evaporate some of the liquid from a sheet of the new suspension, and then continuously compress the sheet, causing the excess liquid to seep out of the graphene aggregates, thereby continuously forming sheets with a thickness approaching that of a graphene film. Sixth, we find a method to continuously produce graphene films in which the flat surfaces of the graphene directly overlap each other by evaporating all the liquid from the sheets and then continuously compressing the sheets. Seventh, we have discovered a method for producing a graphene film in which all processes in the process for producing the graphene film are extremely simple and the materials used are inexpensive and general-purpose. This makes it possible to produce a graphene aggregate by an inexpensive production method using an aggregate of inexpensive graphite particles, and to produce a graphene film by an inexpensive method. The problems that the present invention aims to solve are the seven problems mentioned above. [Means for solving the problem]

[0008] The method of the present invention for continuously producing a graphene film composed of an assembly of graphene in which flat planes of graphene directly overlap and bond with each other includes the steps of: One of the two parallel plate electrodes is placed in a container, and a collection of flake graphite particles or a collection of lump graphite particles having a weight predetermined according to the width, thickness, and length of the graphene film to be produced is evenly spread on the surface of the one parallel plate electrode. Furthermore, a graphene film having a boiling point of 100°C or less and a density at 20°C of 0.80 g / cm is used. 3 a first alcohol having a viscosity of 1-2 mPa·sec at 20°C is weighed out in an amount more than 10 times the weight of the clusters of flake graphite particles or the clusters of massive graphite particles, the weighed first alcohol is filled into the container, the clusters of flake graphite particles or the clusters of massive graphite particles are immersed in the first alcohol, and another parallel plate electrode is placed on top of the one parallel plate electrode via the clusters of flake graphite particles or the clusters of massive graphite particles, so that the two parallel plate electrodes are separated from each other via the clusters of flake graphite particles or the clusters of massive graphite particles, and the two parallel plate electrodes are immersed in the first alcohol; Thereafter, a direct current potential difference having a predetermined magnitude is applied to the gap between the two parallel plate electrodes, whereby an electric field corresponding to the value obtained by dividing the magnitude of the potential difference by the size of the gap between the two parallel plate electrodes is applied to the collection of flake graphite particles or the collection of massive graphite particles, and the application of the electric field simultaneously applies a Coulomb force sufficient to destroy the interlayer bonds between the basal planes of graphite crystals to all of the collections of graphite particles, to all of the π electrons that are responsible for the interlayer bonds between the basal planes that form the graphite particles, whereby all of the interlayer bonds between the basal planes that form the flake graphite particles or the massive graphite particles are simultaneously destroyed, and collections of graphene corresponding to the basal planes are precipitated in the gap between the two parallel plate electrodes. Thereafter, the gap between the two parallel-plate electrodes is enlarged, and the two parallel-plate electrodes are tilted in the first alcohol. Furthermore, vibration accelerations of 0.2 to 0.3 G in three directions, left and right, front and back, and up and down, are repeatedly applied to the container, so that the graphene aggregates are moved from the gap between the two parallel-plate electrodes into the first alcohol. Thereafter, the two parallel-plate electrodes are removed from the container. a first step of operating an ultrasonic homogenizer in the first alcohol in the container to continuously apply shock waves to the graphene aggregates through the first alcohol, thereby separating the graphene aggregates into individual graphene sheets in the first alcohol and dispersing the separated graphene aggregates in the first alcohol; and thereafter removing the homogenizer from the container; The boiling point is higher than that of the first alcohol, and the density at 20°C is 0.83 g / cm 3a second alcohol having a viscosity of 6-10 mPa·sec at 20°C and also having the property of being soluble in or miscible with the first alcohol is mixed into the container in an amount such that a mixture with the first alcohol has a viscosity of 4-6 mPa·sec at 20°C, whereby the second alcohol dissolves in or is miscible with the first alcohol to form a mixture of two types of alcohols, and the graphene separates into individual graphene sheets in the mixture of the two types of alcohols, and the separated clusters of graphene are dispersed in the mixture of the two types of alcohols; a second step of repeatedly applying vibration accelerations of 0.3 to 0.5 G in three directions, i.e., forward / backward, left / right, and up / down, to the container, thereby forming a suspension made of an aggregate of graphene in which flat surfaces of the graphene overlap each other via the mixed solution of the two types of alcohol; a third step of preparing an extruder having a T-die lip with a gap that is 10 to 20 times the width and thickness of a graphene film to be produced in advance, continuously filling a hopper of the extruder with the suspension prepared in the second step, and continuously operating a screw of the extruder to continuously extrude the suspension filled in the hopper into the T-die of the extruder, whereby the suspension that has entered the T-die passes through a manifold of the T-die and is then continuously extruded from the lip of the T-die to form a sheet made of the suspension and having a thickness that is 10 to 20 times the width and thickness of a graphene film to be produced, and winding up the extruded sheet by a first winder that rotates at a peripheral speed that takes more than 10 seconds for one rotation; The two work rolls of the multi-high rolling mill have five characteristics: first, they have the same width, which is wider than the width of the graphene film to be produced; second, they have the same diameter, which is smaller than 1 / 10 of the width of the graphene film to be produced; third, they have a gap set to a thickness five times that of the graphene film to be produced; fourth, they rotate in opposite directions to each other at the same peripheral speed as the first winder; and fifth, they are heated to a temperature 10°C higher than the boiling point of the first alcohol. A multi-high rolling mill having the two work rolls is prepared in advance as a first multi-high rolling mill, and in the third step, a gap is set between the two work rolls. a fourth step in which a leading end of the wound sheet is inserted and the sheet is continuously compressed in the gap between the two work rolls, in which the first alcohol is first evaporated from the sheet, and the sheet becomes a sheet consisting of an assembly of graphene whose flat surfaces are overlapped with each other via the second alcohol, and then the sheet is continuously compressed in the gap between the two work rolls, and the excess second alcohol seeps out of the sheet and moves to the surface of the sheet, and the sheet becomes a sheet consisting of an assembly of graphene whose flat surfaces are overlapped with each other via the reduced amount of second alcohol; The two work rolls of a multi-high rolling mill have four characteristics: first, they have the same width and diameter as the two work rolls of the first multi-high rolling mill; second, they rotate in opposite directions to each other at the same peripheral speed as the two work rolls of the first multi-high rolling mill; third, the gap is set to the thickness of the graphene film to be produced; and fourth, they are heated to a temperature 10°C higher than the boiling point of the second alcohol. A multi-high rolling mill having the two work rolls is prepared as a second multi-high rolling mill, and the leading end of the sheet produced in the fourth step is inserted into the gap between the two work rolls, and the sheet is continuously compressed in the gap between the two work rolls. First, the second alcohol vaporizes from the sheet. a fifth step in which the sheet is compressed to form an assembly of graphene whose flat surfaces are directly overlapping each other, and then, in the gap between the two work rolls, the assembly of graphene whose flat surfaces are directly overlapping each other is continuously compressed, frictional heat is generated at the flat surfaces of the graphene whose flat surfaces are directly overlapping each other, and the directly overlapping flat surfaces are bonded together by the frictional heat, thereby forming a graphene film consisting of the assembly of graphene whose flat surfaces are directly overlapping and bonded together, and the graphene film is discharged from the gap between the two work rolls, and the discharged graphene film is taken up by a second winder rotating at the same peripheral speed as the first winder, A method of continuously carrying out all of these five steps is a method of continuously producing a graphene film consisting of an assembly of graphene in which the flat surfaces of the graphene are directly overlapped and bonded together.

[0009] The above-mentioned method for continuously producing graphene films consists of the following five steps. The first step involves sequentially carrying out the following four treatments to separate the graphene into individual sheets in a first alcohol, and then dispersing the separated graphene aggregates in the first alcohol. In the first treatment, a collection of flake graphite particles or a collection of lump graphite particles having a weight predetermined according to the width, thickness, and length of the graphene film to be produced is first spread evenly on the surface of one of two parallel plate electrodes. 3 A first alcohol having a viscosity of 1-2 mPa·sec at 20°C is weighed out in an amount more than 10 times the weight of the graphite particle cluster and filled into a container. This causes the graphite particle cluster spread across one of the parallel-plate electrodes to be immersed in the first alcohol. The other parallel-plate electrode is then placed on top of the first parallel-plate electrode, with a cluster of flake graphite particles or a cluster of lump graphite particles between them. The two parallel-plate electrodes are then separated by the cluster of flake graphite particles or a cluster of lump graphite particles, and the two separated parallel-plate electrodes are then immersed in the first alcohol. In other words, the interlayer bonds of the graphite crystals that form the graphite particles are broken, and graphene clusters are precipitated in the gap between the two parallel-plate electrodes. The two parallel-plate electrodes, separated by the cluster of graphite particles, are then immersed in the first alcohol. For this reason, the weight of the first alcohol was set to be more than 10 times the weight of the collection of graphite particles. The second process involves applying a direct current potential difference of a predetermined magnitude to the gap between two parallel-plate electrodes. This applies an electric field, equivalent to the magnitude of the potential difference divided by the size of the gap between the two parallel-plate electrodes, to the collection of flake graphite particles or the collection of lump graphite particles. This electric field simultaneously applies a Coulomb force sufficient to break the interlayer bonds between the basal planes of the graphite crystals in all of the graphite particles to all of the π electrons that are responsible for the interlayer bonds between the basal planes. This simultaneously breaks all of the interlayer bonds between the basal planes that form the flake graphite particles or the lump graphite particles, resulting in the deposition of a collection of graphene corresponding to the basal planes in the gap between the two parallel-plate electrodes. The deposited graphene is a genuine material containing no impurities and consisting only of graphite crystals. Furthermore, because the two parallel-plate electrodes are immersed in the first alcohol, the graphene aggregates deposited in the gap between the two parallel-plate electrodes do not scatter. This solves the first problem described in paragraph 7. Furthermore, because the first alcohol is an insulator, when a potential difference is applied between the two parallel-plate electrodes immersed in the first alcohol, an electric field is generated in the gap between the two parallel-plate electrodes. In other words, most organic compounds, except for ionic liquids, are insulators. Here, we explain the phenomenon in which an electric field applied to the gap between two parallel plate electrodes simultaneously destroys the interlayer bonds of the basal planes of graphite crystals that form the graphite particles laid out in the gap between the two parallel plate electrodes. The carbon atoms that form the graphite crystals in graphite particles have four valence electrons. Three of these valence electrons are σ electrons that form the basal plane, i.e., graphene. These σ electrons are covalently bonded to the σ electrons of three adjacent carbon atoms on the basal plane at 120° angles to each other, forming a two-dimensional, strong hexagonal network structure. The remaining valence electron is a π electron, located in a π orbital extending perpendicular to the basal plane. This π electron weakly bonds with the π electrons of adjacent carbon atoms in the vertical direction perpendicular to the basal plane, and this weak bonding force allows the basal planes to be stacked in layers. In other words, the basal planes, i.e., graphene, are bonded to each other in layers through the interaction of the weakly bonding π orbitals. This makes graphite particles prone to peeling at the basal planes of the graphite crystals, i.e., mechanical anisotropy. This mechanical anisotropy is well known as the lubricity of graphite particles. That is, the mechanical anisotropy is based on the anisotropy of the electronic structure between the σ electron bond and the π electron bond. When an electric field is applied to such graphite particles, a Coulomb force due to the electric field acts on all π electrons. When the Coulomb force acting on the π electrons acts on them with a force greater than the π orbital interaction acting on them, the π electrons are released from the constraints on the π orbitals. As a result, all π electrons leave the π orbitals and become free electrons. As a result, all π electrons that are responsible for the interlayer bonds on the basal plane are no longer on the π orbitals, and all interlayer bonds on the basal plane are simultaneously broken. In other words, when a π electron moves a distance of b between the basal plane layers due to the Coulomb force F, the π electron performs work W (W = b·F). This work W is calculated as 35 millielectronvolts (an electron volt is a unit that represents the amount of energy possessed by an electron, and 1 electron volt is 1.62 x 10 -19When the applied electric field exceeds the energy limit (corresponding to a joule), the π electrons are released from the constraints of the π orbital interactions and become free electrons. For example, if two parallel plate electrodes are separated by a gap of 100 μm and a direct current potential difference of 10.6 kV or more is applied across the gap, the interlayer bonds of the basal planes are instantly destroyed. In this way, large quantities of graphene can be produced inexpensively by the extremely simple method of applying an electric field to a collection of inexpensive graphite particles. Furthermore, because all interlayer bonds of the basal planes of the graphite crystals are destroyed simultaneously, the resulting fine material is certainly graphene, with a basal plane made of graphite crystals. The term "aggregate of graphite particles" used here refers to a relatively small amount of graphite particles, approximately 1 g to 100 g. In other words, flake graphite particles or lump graphite particles have a bulk density of 0.2-0.5 g / cm. 3 Graphite is a fine particle with a particle size distribution ranging from 1 to 300 microns. Therefore, it is easy to distribute a collection of graphite particles between two parallel-plate electrodes, and it is also easy to apply a potential difference between the two parallel-plate electrodes. When a potential difference is applied across the gap between the two parallel-plate electrodes, an electric field is generated throughout the entire area where the graphite particles are distributed. The electric field acts on the π electrons as a Coulomb force greater than the π orbital interaction, and the π electrons are released from the constraints of the π orbitals and become free electrons. As a result, all interlayer bonds on the basal plane of the graphite crystals in the graphite particles are simultaneously broken, and a collection of graphene is precipitated in the gap between the two parallel-plate electrodes. Here, the number of graphenes precipitated in the first alcohol is calculated by arithmetic. Here, it is assumed that all graphite particles are composed of spheres with a diameter of 25 microns, and the true density of graphite is 2.25 × 10 3 kg / m 3 Therefore, the weight of one graphite particle is only 1.84 × 10 -8g. Also, assuming that the average thickness of a graphite particle is 10 microns, the interlayer distance is 3.354 angstroms, so a flake graphite particle with a thickness of 10 microns is made up of 297,265 stacked graphenes. Therefore, if all the interlayer bonds on the basal plane are destroyed, a collection of 297,265 graphenes can be obtained from just one spherical graphite particle. Therefore, if all the interlayer bonds on the basal plane are destroyed for a collection of spherical graphite particles weighing just 1 g, the number of graphenes that can be obtained is 1.62 × 10 13 In this way, with this manufacturing method, a huge number of graphene aggregates can be obtained from a small amount of graphite particles. The third step involves widening the gap between the two parallel-plate electrodes and tilting the two parallel-plate electrodes in the first alcohol. The container is then repeatedly subjected to vibration accelerations of 0.2-0.3 G in three directions (left and right, front and back, and up and down) depending on the width and thickness of the graphene film to be produced, i.e., the amount of first alcohol in the container, to move the graphene aggregates from the gap between the two parallel-plate electrodes into the first alcohol. The two parallel-plate electrodes are then removed from the container. In the fourth process, an ultrasonic homogenizer is operated in the first alcohol in the container, and shock waves are continuously applied to the graphene aggregates through the first alcohol. As a result, the graphene aggregates are separated into individual graphene sheets in the first alcohol, and the separated graphene aggregates are dispersed in the first alcohol. After this, the homogenizer is removed from the container. This solves the second problem described in paragraph 7. In other words, when an ultrasonic homogenizer is operated in the first alcohol, a huge number of extremely fine bubbles, each one order of magnitude smaller than the flat surface of graphene, are generated, and the bubbles instantly disappear. This phenomenon is continuously repeated in the first alcohol according to the vibration period of the ultrasonic vibration frequency (this phenomenon is called cavitation), and the shock waves generated when the huge number of bubbles burst are continuously applied to the entire collection of graphene via the first alcohol. Therefore, shock waves are also applied to the flat surfaces of graphene, where flat surfaces overlap each other. The first alcohol has a low viscosity of 1-2 mPa·sec, and a density of 0.80 g / cm at 20°C. 3 Because the shock wave is small (<0.332 nm), the rate at which the first alcohol is excited by the shock wave is low, and much of the shock wave's energy is irradiated onto the graphene without being lost. Meanwhile, the bonding between the graphene flats is simply a matter of the flats overlapping, and the bonding force between the flats is extremely small. Furthermore, because graphene is extremely thin (0.332 nm), it has almost no mass. Therefore, when a shock wave is applied to the area where the flats overlap, the overlapping flats separate, and the first alcohol penetrates into the gaps between the separated graphene, separating them into individual graphene sheets in a short period of time. The graphene produced by destroying the interlayer bonds of the basal planes of graphite particles is a genuine material composed only of graphite crystals, free of impurities. Furthermore, the graphene separated into individual graphene sheets is also a genuine material composed only of graphite crystals, free of impurities, because the treatment in the first alcohol continues. The second step involves the following two processes to form a suspension in a container consisting of graphene aggregates in which the flat surfaces of the graphene are stacked together via a mixture of two types of alcohol. The first treatment is a mixture of alcohols having a boiling point higher than that of the first alcohol and a density of 0.83 g / cm at 20°C. 3Below, a second alcohol, which has a viscosity of 6-10 mPa·sec at 20°C and is soluble or miscible in the first alcohol, is mixed into a container in an amount that corresponds to the width and thickness of the graphene film to be produced, so that the viscosity of the mixture with the first alcohol is 4-6 mPa·sec at 20°C. As a result, the second alcohol dissolves or becomes miscible in the first alcohol, forming a mixture of two alcohols. Graphene separates into individual graphene sheets in the mixture of the two alcohols, and the separated graphene clusters are dispersed in the mixture of the two alcohols. In order to achieve a viscosity of 4-6 mPa·sec at 20°C by mixing a first alcohol with a viscosity of 1-2 mPa·sec at 20°C and a second alcohol with a viscosity of 6-10 mPa·sec at 20°C, a volume of the second alcohol must be greater than that of the first alcohol. Meanwhile, in the first step, a volume of the first alcohol exceeding 10 times the weight of the graphite particles was used. This resulted in the graphene clusters being dispersed in a mixture of two alcohols with a weight well over 20 times the weight of the graphite particles. This resulted in a density of the mixture of two alcohols of 0.82 g / cm. 3 It becomes smaller. The second process involves repeatedly applying vibration accelerations of 0.3-0.5 G in three directions (front-back, left-right, and up-down) to the container, depending on the width and thickness of the graphene film to be produced, i.e., depending on the amount of the mixed solution of two types of alcohol in the container. This results in the formation of a suspension in the container consisting of graphene aggregates in which the flat surfaces of the graphene overlap with each other via the mixed solution of two types of alcohol. This solves the third problem described in paragraph 7. In other words, graphene is extremely thin, with a thickness of 0.332 nm, and an extremely large aspect ratio, which is the ratio of the size of the crystal plane to the thickness. Graphene also has almost no mass. Furthermore, the flat surfaces of each separated graphene sheet are in contact with the mixture of two types of alcohol. On the other hand, the mixture of two types of alcohol has a density of 0.82 g / cm 3Because the viscosity of the two alcohols is relatively low (4-6 mPa·sec at 20°C), when vibration acceleration is applied to the container, the mixture of two alcohols moves in the direction of the vibration acceleration. As the mixture of two alcohols moves, the graphene also moves. On the other hand, graphene with an extremely large aspect ratio moves through the liquid with its flat surface facing up, which places the least stress on the graphene. Therefore, when vibration acceleration is repeatedly applied in three directions, the flat surfaces of the graphene form a cluster of graphene in which they overlap each other through the mixture of two alcohols. Even when a load is applied to the cluster of graphene in which the flat surfaces of the graphene overlap each other through the mixture of two alcohols, the flat surfaces of the graphene remain overlapped due to the extremely large aspect ratio of the graphene. In the third step, a sheet made from the suspension is continuously formed. To this end, an extruder is prepared in advance, which has a T-die lip with a gap 10-20 times the width and thickness of the graphene film to be produced. Next, the suspension is continuously filled into the hopper of the extruder, and the extruder screw is continuously operated to continuously extrude the suspension filled in the hopper into the T-die of the extruder. The suspension that has entered the T-die passes through the T-die manifold by the movement of the screw, and is then continuously extruded from the lip of the T-die as a sheet-like suspension with a thickness 10-20 times the width and thickness of the graphene film. The extruded sheet-like suspension has a thickness of submicron, and the mixture of two types of alcohol has a density of 0.82 g / cm. 3The viscosity of the extruded sheet suspension is smaller than that of the extruded sheet suspension, and its viscosity is 4-6 mPa·sec at 20°C. Therefore, the extruded sheet suspension is lightweight and has a viscosity of 4-6 mPa·sec. Because the extrusion speed is slow, the adsorption force based on the viscosity of the mixture of the two alcohols acts on the sheet suspension, preventing it from breaking during transport. Meanwhile, the width of the graphene film produced varies widely, from 20-200 cm depending on the application. Therefore, the wider the graphene film produced, the heavier the weight of the extruded sheet suspension. Therefore, the wider the graphene film produced, the narrower the gap between the T-die lips, which reduces the weight increase of the extruded sheet suspension. That is, as described above, the weight of the two-alcohol mixture in the suspension is easily more than 20 times the weight of the graphite particles. Therefore, the gap between the T-die lips is set to 10-20 times the thickness of the graphene film to be produced. When the suspension is extruded through the T-die lips, a portion of the excess two-alcohol mixture seeps out of the suspension, resulting in an extruded sheet-like suspension with a thickness 10-20 times the thickness of the graphene film to be produced. Furthermore, the extruded sheet-like suspension is continuously wound up by a first winder that rotates at a peripheral speed longer than 10 seconds per rotation. This solves the fourth problem described in paragraph 7. The seeped two-alcohol mixture is recovered and reused. In the fourth step, the sheet-shaped suspension is converted into a new sheet-shaped suspension consisting of graphene aggregates whose flat surfaces overlap with each other via the remaining second alcohol. To this end, a multi-high rolling mill having two work rolls with five characteristics is prepared in advance as a first multi-high rolling mill: first, the width is wider than the width of the graphene film to be produced; second, the diameter is the same as the width of the graphene film to be produced but smaller than 1 / 10 of the width; third, the gap is set to be five times the thickness of the graphene film to be produced; fourth, the work rolls rotate in opposite directions at the same peripheral speed as the first winder; and fifth, the work rolls are heated to a temperature 10°C higher than the boiling point of the first alcohol. Next, the leading end of the sheet-shaped suspension wound in the third step is inserted into the gap between the two work rolls, and the sheet-shaped suspension is continuously compressed in the gap between the two work rolls. First, the first alcohol evaporates from the sheet-shaped suspension, and the sheet-shaped suspension becomes a sheet-shaped suspension consisting of graphene aggregates whose flat surfaces overlap with each other via the second alcohol. Next, the sheet-like suspension is continuously compressed in the gap between the two work rolls. During this process, excess second alcohol seeps out of the sheet-like suspension and moves to the surface of the sheet-like suspension, and the sheet-like suspension becomes a new sheet-like suspension consisting of clusters of graphene whose flat surfaces overlap with each other via the remaining second alcohol. This new sheet-like suspension is continuously discharged from the gap between the two work rolls. This solves the fifth problem described in paragraph 7. Although the width of the two work rolls is wider than the width of the graphene film to be produced, the diameter of the two work rolls is smaller than 1 / 10 of the width of the graphene film, so when the two work rolls rotate in opposite directions, they undergo elastic deformation. A multi-high rolling mill was used to suppress the elastic deformation of the two work rolls by rotating the other backup roll. This allows a constant compressive stress to be continuously applied to the sheet-like suspension in the gap between the two work rolls. An example of a multi-high rolling mill is a 12-high rolling mill. Furthermore, the rotation speed of the two work rolls is a peripheral speed that requires more than 10 seconds for one rotation, and the diameter of the two work rolls is smaller than 1 / 10 of the width of the graphene film, so that the contact time between the two work rolls and the sheet-like suspension can be ensured. Therefore, when the sheet-like suspension is compressed in the gap between the two work rolls, a new sheet-like suspension consisting of a collection of graphene whose flat surfaces overlap each other is continuously discharged from the gap between the two work rolls via the reduced amount of second alcohol. In a fifth step, a graphene film is continuously formed in the nip between two work rolls, with the flat surfaces of the graphene directly overlapping and bonded together. The graphene film is continuously discharged from the nip between the two work rolls, and the discharged graphene film is continuously wound up by a second winder rotating at the same peripheral speed as the first winder. To this end, a multi-high rolling mill having two work rolls with four characteristics is prepared in advance as a second multi-high rolling mill: first, the two work rolls have the same width and diameter as the two work rolls of the first multi-high rolling mill; second, the two work rolls rotate in opposite directions to each other at the same peripheral speed as the two work rolls of the first multi-high rolling mill; third, the gap is set to correspond to the thickness of the graphene film to be produced; and fourth, the temperature is raised to a temperature 10°C higher than the boiling point of the second alcohol. Next, the leading edge of the sheet produced in the fourth step is inserted into the nip between the two work rolls, and the sheet is continuously compressed in the nip between the two work rolls. The rotation speed of the two work rolls is a peripheral speed that requires a time for one rotation longer than 10 seconds, and the diameter of the two work rolls is smaller than 1 / 10 of the width of the graphene film, ensuring sufficient contact time between the two work rolls and the sheet. First, the second alcohol evaporates from the sheet, and the sheet becomes a collection of graphene with flat surfaces directly overlapping each other. Next, in the nip between the two work rolls, the collection of graphene with flat surfaces directly overlapping each other is continuously compressed, generating frictional heat between the flat surfaces directly overlapping each other. This frictional heat bonds the directly overlapping flat surfaces together, forming a graphene film consisting of a collection of graphene with flat surfaces directly overlapping each other and bonded together. The graphene film is continuously discharged from the nip between the two work rolls. Furthermore, the discharged graphene film is continuously wound up by a second winder that rotates at the same peripheral speed as the first winder. This solves the sixth problem described in paragraph 7. Note that the peripheral speed of the first winder that winds up the sheet extruded from the lip of the T-die, the peripheral speed at which the two work rolls of the first multi-stage rolling mill rotate, the peripheral speed at which the two work rolls of the second multi-stage rolling mill rotate, and the peripheral speed of the second winder that winds up the graphene film discharged from the gap between the two work rolls are all the same, and therefore graphene films are produced continuously. That is, graphene has a breaking strength of 42 N / m, more than 100 times that of steel. Therefore, even if a collection of graphene whose flat surfaces are directly overlapping each other is continuously compressed in the gap between two work rolls, the graphene flat surfaces do not deform or break. Therefore, the applied compressive stress is applied to the directly overlapping flat surfaces of the graphene without reducing the applied compressive stress. This generates frictional heat in the directly overlapping flat surfaces, which directly bond the flat surfaces together, forming a graphene film consisting of the collection of graphene whose flat surfaces are directly overlapping and bonded together. As described above, graphene is a genuine material containing no impurities and consisting only of graphite crystals. Furthermore, graphene has an extremely large aspect ratio and almost no mass. Because the flat surfaces of the graphene are directly bonded together by frictional heat, they are firmly bonded together. All of the treatments in the above five steps are extremely simple. Furthermore, the graphite particles used are a general-purpose industrial material, and the two types of alcohols are general-purpose organic compounds. Furthermore, the ultrasonic homogenizer, extruder, and multi-stage rolling mill are general-purpose processing devices. Therefore, a graphene cluster can be produced by a low-cost production method using a low-cost graphite particle cluster, and further, a graphene film can be produced by a low-cost method. As a result, a low-cost graphene film can be produced. This solves the seventh problem described in paragraph 7. As a result, all of the problems described in paragraph 7 are solved. The graphene film produced by the above-described production method provides the following effects. First, graphene is extremely lightweight, has almost no mass, and is highly transparent, with a thickness of 0.332 nm, equivalent to the size of a carbon atom. Therefore, its presence cannot be confirmed with the naked eye, making it difficult to handle individual graphene sheets. In contrast, a graphene film, in which graphene sheets are directly bonded together via flat surfaces, has a fixed area and thickness, and can therefore be handled as a graphene film. Second, graphene films have the flattened properties of graphene because the flattened surfaces of graphene are directly bonded to each other. On the other hand, because graphene is an extremely thin two-dimensional layered material, the flattened properties of graphene become the properties of graphene. Therefore, graphene films have the various properties of graphene described in paragraph 3. Furthermore, graphene films can be used as an inexpensive industrial material that can be produced using inexpensive materials and methods. This opens up the possibility of using graphene films in a variety of industrial products. Third, by continuously molding a sheet-like suspension having a shape similar to the lip of a T-die of an extruder and then continuously compressing the sheet-like suspension in the gap between two work rolls of a multi-stage rolling mill, a graphene film having a thickness determined by the gap between the two work rolls can be produced. This makes it possible to continuously produce graphene films having a shape and thickness that correspond to a predetermined shape of the lip of the T-die and the gap between the two work rolls. In other words, the width and thickness of the graphene film to be produced can be set in advance. Fourth, graphene films are thin, measuring nanometers in thickness. Although graphene has a high shear modulus of 440 GPa, its thin nanometer-sized thickness allows it to be cut. This allows graphene films to be freely processed into graphene films of any size and shape, from small electrodes and contacts to long, thin wiring patterns and large conductive and thermally conductive sheets. Fifth, the graphene film is made of pure graphene, a material free of impurities and consisting only of the basal plane of graphite crystals. The extremely lightweight, high-aspect-ratio flat surfaces are directly bonded together by frictional heat, resulting in a strong bond between the flat surfaces. Furthermore, the step height on the graphene film surface where the flat surfaces are bonded together is 0.332 nm, equivalent to the thickness of the graphene. This allows the graphene film surface to form a sliding surface with low frictional resistance. Furthermore, because the graphene film is composed entirely of graphene, which has a melting point exceeding 3000°C, the graphene film possesses the heat resistance of graphene. Therefore, the graphene film will not deteriorate over time, even when used in harsh environments. As described above, graphene films having the properties of graphene exhibit various functions and effects and are therefore used as industrial materials in a variety of fields.

[0010] The method for continuously producing a graphene film described in paragraph 8 includes: The first alcohol described in paragraph 8 is either ethanol or 1-propanol, and the method for continuously carrying out all of the five steps described in paragraph 8 using the alcohol as the first alcohol described in paragraph 8 is: 8. The method for continuously producing a graphene film as described in paragraph 8.

[0011] Ethanol has a boiling point of 78°C and a density of 0.789g / cm at 20°C. 3 The viscosity at 20°C is 1.20 mPa·sec. Therefore, ethanol has a boiling point of 100°C or less as described in paragraph 8, and a density of 0.80 g / cm at 20°C. 3 Below, it is the first alcohol to have the properties of a viscosity of 1-2 mPa·sec at 20°C. In addition, 1-propanol has a boiling point of 98°C and a density of 0.803 g / cm at 20°C. 3 and its viscosity at 20°C is 1.94 mPa·sec. Therefore, 1-propanol has a boiling point of 100°C or less as described in paragraph 8, and a density of 0.80 g / cm at 20°C. 3Below, it is the first alcohol to have the properties of a viscosity of 1-2 mPa·sec at 20°C. Therefore, if either ethanol or 1-propanol is used as the first alcohol described in paragraph 8 and all of the five steps described in paragraph 8 are carried out consecutively, graphene films can be produced continuously.

[0012] The method for continuously producing a graphene film described in paragraph 8 includes: The second alcohol described in paragraph 8 is any one of 1-heptanol, 3-pentanol, 1-octanol, and 2-ethylhexanol, and the method using the one alcohol as the second alcohol described in paragraph 8 and continuously carrying out all of the treatments consisting of the five steps described in paragraph 8 is: 8. The method for continuously producing a graphene film as described in paragraph 8.

[0013] 1-Heptanol has a boiling point of 177°C, a viscosity of 5.8 mPa·s at 20°C, and a density of 0.822 g / cm at 20°C. 3 It is soluble or miscible in ethanol and 1-propanol. Therefore, 1-heptanol has a boiling point higher than that of the first alcohol and a density of 0.83 g / cm at 20 °C. 3 Below this, the second alcohol has a viscosity of 6-10 mPa·sec at 20°C and is soluble or miscible in the first alcohol. 3-Pentanol has a boiling point of 115°C and a density of 0.815g / cm at 20°C. 3 It has a viscosity of 6.5 mPa·s at 20°C and is soluble or miscible in both ethanol and 1-propanol. Therefore, 3-pentanol has a boiling point higher than that of the first alcohol and a density of 0.83 g / cm at 20°C. 3 Below this, the second alcohol has a viscosity of 6-10 mPa·sec at 20°C and is soluble or miscible in the first alcohol. 1-octanol has a boiling point of 195°C and a density of 0.827g / cm at 20°C. 3It has a viscosity of 7.3 mPa·s at 20°C and is soluble or miscible in ethanol and 1-propanol. Therefore, 1-octanol has a higher boiling point than the first alcohol and a density of 0.83 g / cm at 20°C. 3 Below this, the second alcohol has a viscosity of 6-10 mPa·sec at 20°C and is soluble or miscible in the first alcohol. 2-Ethylhexanol has a boiling point of 182°C and a density of 0.833 g / cm at 20°C. 3 It has a viscosity of 9.8 mPa·s at 20°C and is soluble or miscible in ethanol and 1-propanol. Therefore, 2-ethylhexanol has a boiling point higher than that of the first alcohol and a density of 0.83 g / cm at 20°C. 3 Below this, the second alcohol has a viscosity of 6-10 mPa·sec at 20°C and is soluble or miscible in the first alcohol. Therefore, when any one of 1-heptanol, 3-pentanol, 1-octanol, and 2-ethylhexanol is used as the second alcohol described in paragraph 8 and all of the five steps described in paragraph 8 are performed continuously, a graphene film can be continuously produced.

[0014] A method for continuously producing a graphene film by the method described in paragraph 8, cutting a portion of the graphene film into the shape of a surface of a substrate, and bonding the cut graphene film to one surface or both surfaces of the substrate, includes: a method for continuously producing a graphene film according to paragraph 8, cutting a portion of the graphene film into the shape of a surface of a substrate, superposing the cut graphene film on one surface or both surfaces of the substrate, and evenly compressing the entire surface of the superposed graphene film with a jig attached to a compressor, thereby causing the surface of the superposed graphene film to come into contact with convex portions of the uneven surface of one surface or both surfaces of the substrate, generating frictional heat at the convex portions, which bonds the convex portions to one surface or both surfaces of the graphene film due to the frictional heat, and bonding the cut graphene film to one surface or both surfaces of the substrate, and then separating the jig from the graphene film; A method for continuously producing a graphene film by the method described in paragraph 8, cutting a portion of the graphene film into a shape of a surface of a substrate, and bonding the cut graphene film to one surface or both surfaces of the substrate.

[0015] In other words, although graphene has a large shear modulus of 440 GPa, the graphene film is thin at the nano-level, making it possible to cut the graphene film. This allows parts of the continuously produced graphene film to be cut into graphene films of various sizes and shapes. Furthermore, since the thickness of the graphene film is determined by the gap between the two work rolls, the thickness of the graphene film to be produced can be set in advance. On the other hand, the surface of the graphene film has steps of only 0.332 nm, which corresponds to the thickness of the graphene. In contrast, one or both surfaces of the substrate have submicron irregularities. Therefore, when a graphene film cut to the shape of the substrate surface is superimposed on one or both surfaces of the substrate, and the entire surface of the superimposed graphene film is uniformly compressed using a jig attached to a compressor, the surface of the superimposed graphene film comes into contact with the convex portions of the irregularities on one or both surfaces of the substrate, generating frictional heat at the convex portions of the irregularities on the substrate surface. This frictional heat bonds the convex portions to the surface of the superimposed graphene film. Note that because the convex portions of the irregularities on one or both surfaces of the substrate are formed at submicron intervals, the number of convex portions is enormous. Therefore, an extremely lightweight graphene film with an extremely large aspect ratio and an extremely large number of protrusions spaced at submicron intervals is bonded to one or both surfaces of a substrate, thereby firmly bonding the graphene film to the entire surface of one or both surfaces of the substrate. Furthermore, frictional heat generated in the protrusions on one or both surfaces of the substrate is generated and dissipated in a short time. Furthermore, the volume of the protrusions where frictional heat is generated is extremely small. Therefore, even if the substrate is made of a material with low heat resistance, such as a synthetic resin, the graphene film can be directly bonded to one or both surfaces of the substrate by friction welding. As a result, the graphene film can be directly bonded to one or both surfaces of substrates made of various materials, and the various properties of graphene described in paragraph 3 and the various properties of the graphene film described in paragraph 9 are imparted to one or both surfaces of the substrate.

[0016] A method for continuously producing a graphene film by the method described in paragraph 8, cutting a portion of the graphene film into a predetermined shape, and bonding the cut graphene film to a predetermined position on a surface of a substrate or a component, includes the steps of: a method for continuously producing a graphene film according to paragraph 8, cutting a portion of the graphene film into a predetermined shape, overlapping the cut graphene film at a predetermined position on the surface of a substrate or a part, and evenly compressing the entire surface of the overlapped graphene film with a jig attached to a compressor, thereby bringing the surface of the overlapped graphene film into contact with the convex portions of the uneven surface of the substrate or the part, generating frictional heat at the convex portions, which bonds the convex portions to the surface of the overlapped graphene film, and the overlapped graphene film being bonded to the predetermined position on the surface of the substrate or the part, and then separating the jig from the graphene film; A method for continuously producing a graphene film by the method described in paragraph 8, cutting a portion of the graphene film into a predetermined shape, and bonding the cut graphene film to a predetermined position on the surface of a substrate or a component.

[0017] In other words, although graphene has a large shear modulus of 440 GPa, the graphene film is thin at the nano-level, making it possible to cut the graphene film. This allows parts of the continuously produced graphene film to be cut into graphene films of various sizes and shapes. Furthermore, since the thickness of the graphene film is determined by the gap between the two work rolls, the thickness of the graphene film to be produced can be set in advance. On the other hand, the surface of a graphene film has steps of only 0.332 nm, equivalent to the thickness of the graphene. In contrast, the surface of a substrate or component has irregularities with a submicron height. Therefore, when a cut graphene film is superimposed on a predetermined position on the surface of a substrate or component, and the entire surface of the superimposed graphene film is uniformly compressed using a jig attached to a compression machine, the surface of the graphene film comes into contact with the convex portions of the irregularities on the surface of the substrate or component, generating frictional heat at these convex portions, which bonds the convex portions to the surface of the graphene film. In this way, the superimposed graphene film is bonded to the predetermined position on the surface of the substrate or component. Note that because the convex portions of the irregularities on the surface of the substrate or component are formed at submicron intervals, there are an enormous number of convex portions. Therefore, the extremely lightweight graphene film with an extremely high aspect ratio, which is bonded to the surface of the substrate or component by an extremely large number of convex portions spaced at submicron intervals, is firmly bonded to the predetermined position on the surface of the substrate or component. Furthermore, frictional heat generated at the convex portions on the surface of the substrate or part is generated and dissipated in a short time. Furthermore, the volume of the convex portions where frictional heat is generated is extremely small. Therefore, even for substrates or parts made of a material with low heat resistance, such as synthetic resin, cut graphene films can be directly friction-welded to predetermined positions on the surface of the substrate or part. As a result, cut graphene films can be directly bonded to predetermined positions on the surface of substrates or parts made of various materials, and the various properties of graphene described in paragraph 3 and the various properties of graphene films described in paragraph 9 can be imparted to the predetermined positions on the substrate or part. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is an explanatory diagram showing a schematic enlarged view of a part of the side surface of the produced graphene film. [Figure 2] FIG. 10 is a diagram showing the shape of a groove formed in a glass epoxy substrate, into which the prepared graphene film is joined by friction welding. DETAILED DESCRIPTION OF THE INVENTION

[0019] Example 1 This example is an example in which graphene aggregates are precipitated in a first alcohol, the precipitated graphene aggregates are separated into individual graphene sheets in the first alcohol, and the separated graphene aggregates are dispersed in the first alcohol, in accordance with the description in paragraph 7. Note that ethanol having a boiling point of 78°C and a viscosity of 1.20 mPa·sec at 20°C was used as the first alcohol. Furthermore, flake graphite particles were used as the graphite particles. First, 2 liters of ethanol were filled into a shallow container with a base of 1.2 m x 1.2 m. Next, two parallel-plate electrodes with an effective electrode area of ​​1 m x 1 m, where an electric field was generated in the gap between the two parallel-plate electrodes, were prepared. 100 g of flake graphite particles (e.g., XD100 from Ito Graphite Industries Co., Ltd.) were evenly spread on the surface of one of the parallel-plate electrodes. Then, one of the parallel-plate electrodes was placed in the container, and the flake graphite particle cluster spread on the first parallel-plate electrode was immersed in ethanol. The other parallel-plate electrode was then placed on top of the first parallel-plate electrode, with the flake graphite particle cluster sandwiched between them, so that the gap between the two parallel-plate electrodes was 100 μm. Specifically, to destroy the interlayer bonds of the graphite crystals that form the graphite particles and precipitate graphene clusters in the gap between the two parallel flat electrodes, the two parallel flat electrodes were immersed in ethanol, an insulating liquid, with the weight of ethanol being nearly 16 times the weight of the graphite particle cluster. The graphite particle cluster spread between the two parallel flat electrodes was immersed in ethanol and an electric field was applied to the cluster, destroying all interlayer bonds of the graphite crystals that form the graphite particles simultaneously. Assuming that the graphite particles are spherical with a particle size of 25 μm and that the average thickness of the graphite particles is 10 μm, if the graphite particles are evenly spread across the 100 μm gap created by two parallel plate electrodes, the electric field will be 6.4 × 10 7When a DC voltage of 10.6 kV or more is applied to this collection of graphite particles, the interlayer bonds on the basal planes of all the graphite particles are simultaneously destroyed. 13 A cluster of graphene particles was obtained, and the cluster of graphite particles used was only 1.18 g. Next, a 12-kilovolt DC voltage was applied between the two parallel-plate electrodes, simultaneously destroying all interlayer bonds between the graphite crystals that form the graphite particles, resulting in the deposition of graphene aggregates in the gap between the two parallel-plate electrodes. The gap between the two parallel-plate electrodes was then enlarged, and the two parallel-plate electrodes were tilted in ethanol. A three-dimensional vibration acceleration of 0.3 G was applied to the container three times, after which the two parallel-plate electrodes were removed from the container. An ultrasonic homogenizer (LUH300, manufactured by Yamato Scientific Co., Ltd.) was then operated in the ethanol in the container, applying ultrasonic vibrations at 20 kHz for two minutes.

[0020] Example 2 This example is an example in which a suspension consisting of an aggregate of graphene in which the flat surfaces of the graphene overlap each other via a mixed liquid of two types of alcohol is prepared. 3-pentanol was used as the second alcohol. 3-pentanol dissolves in ethanol, has a boiling point of 115°C, and a density of 0.815 g / cm at 20°C. 3 and its viscosity at 20°C is 6.5 mPa·sec. The graphene prepared in Example 1 was separated into individual graphene sheets in ethanol, and the separated graphene aggregates were dispersed in the ethanol in a container. 4 liters of 3-pentanol was then mixed into the container. As a result, the viscosity of the mixture of the two alcohols became 4.73 mPa·sec and the density was 0.806 g / cm. 3 In other words, when 3-pentanol dissolves in ethanol, the ethanol becomes a mixture of two types of alcohol, and the graphene separates into individual graphene sheets in the mixture of two types of alcohol, and the clusters of separated graphene are dispersed in the mixture of two types of alcohol. As a result, the weight of the mixture of two types of alcohol increases by 48 times compared to the weight of the cluster of graphite particles. Thereafter, vibration accelerations of 0.5 G in three directions, front-back, left-right, and up-down, were repeatedly applied to the container five times.

[0021] Example 3 In this example, a sheet made of the suspension prepared in Example 2 and having a width equal to the width of the graphene film to be produced and a thickness 10 times the thickness of the graphene film to be produced is continuously extruded from the lip of a T-die of an extruder. For this purpose, an extruder was prepared which had a T-die lip having a width of 100 cm, the same as the width of the graphene film to be produced, and a gap of 100 nm, which was 10 times the thickness of the graphene film to be produced. The suspension prepared in Example 2 was continuously filled into the hopper of an extruder, and the screw of the extruder was continuously operated to continuously extrude the suspension filled in the hopper into a T-die of the extruder. As a result, the suspension that entered the T-die passed through the manifold of the T-die, and then a sheet having a width of 100 cm and a thickness of 100 nm was continuously extruded from the lip of the T-die, and the extruded sheet was continuously wound up by a first winder that rotated at a peripheral speed of 15 seconds per rotation.

[0022] Example 4 In this example, ethanol is evaporated from the sheet produced in Example 3, and the sheet is then compressed in the gap between two work rolls of a 12-high rolling mill to form a sheet having the width of the graphene film to be produced and five times the thickness of the graphene film to be produced. That is, the thickness of 100 nm of the sheet produced in Example 3 is reduced to 50 nm in the first stage, and then further reduced to 10 nm in the second stage. First, the two work rolls of the 12-high rolling mill had five characteristics: first, they had the same width of 110 cm; second, they had the same diameter of 10 cm; third, they had a gap of 50 nm; fourth, they rotated in opposite directions to each other at the same peripheral speed as the first winder; and fifth, they were heated to 88°C, which was 10°C higher than the boiling point of the ethanol that constituted the suspension.A 12-high rolling mill with these two work rolls was prepared as a first 12-high rolling mill (for example, a small-diameter 12-high cold rolling mill manufactured by IHI Corporation). Next, the leading end of the sheet wound in Example 3 was inserted into the nip between the two work rolls, and the sheet was continuously compressed between the two work rolls. First, ethanol evaporated from the sheet, and the sheet became a collection of graphene with flat surfaces overlapping each other via 3-pentanol. Next, the sheet continued to be compressed between the two work rolls, and excess 3-pentanol seeped out of the sheet and moved to the surface of the sheet, and the sheet became a collection of graphene with flat surfaces overlapping each other via the remaining 3-pentanol. After this, the sheet was continuously discharged from the nip between the two work rolls.

[0023] Example 5 In this example, 3-pentanol is evaporated from the sheet produced in Example 4, turning the sheet into an assembly of graphene in which flat surfaces overlap each other, and the sheet is then compressed in the gap between two work rolls of a 12-high rolling mill to form a graphene film consisting of an assembly of graphene in which flat surfaces of the graphene are directly overlapped and bonded together. First, the two work rolls of the 12-high rolling mill had the following four characteristics: first, they had the same width and diameter as the two work rolls of the first 12-high rolling mill used in Example 4; second, they rotated in opposite directions to each other at the same peripheral speed as the two work rolls of the first 12-high rolling mill; third, the gap was set to 10 nm, which is the thickness of the graphene film to be produced; and fourth, they were heated to 125°C, which is 10°C higher than the boiling point of 3-pentanol. A 12-high rolling mill having these two work rolls was prepared as a second 12-high rolling mill (for example, a small-diameter 12-high cold rolling mill manufactured by IHI Corporation). Next, the leading end of the sheet prepared in Example 4 was inserted into the gap between the two work rolls, and the sheet was continuously compressed between the two work rolls. First, 3-pentanol evaporated from the sheet, and the sheet became an assembly of graphene in which the flat surfaces of the graphene directly overlapped each other. Next, the assembly of graphene in which the flat surfaces of the graphene directly overlapped each other was continuously compressed between the two work rolls. During this process, frictional heat was generated between the flat surfaces of the graphene directly overlapping each other, and this frictional heat caused the directly overlapping flat surfaces to bond together, forming a graphene film consisting of an assembly of graphene in which the flat surfaces directly overlapped and bonded each other. This graphene film was continuously discharged from the gap between the two work rolls, and the discharged graphene film was continuously wound up by a second winder rotating at the same peripheral speed as the first winder. Next, the top and side surfaces of the produced graphene film were observed and analyzed using an electron microscope. The electron microscope used was an ultra-low accelerating voltage SEM from JFE Techno-Research Corporation. This device is capable of surface observation at ultra-low accelerating voltages starting from 100 volts, and has the advantage of being able to directly observe the surface of a sample without forming a conductive coating on the sample. First, secondary electron beams between 900-1000 volts were extracted from the reflected electron beams from the flat surface of the sample and image processing was performed. Extremely thin steps were confirmed on the flat surface of the sample. Next, secondary electron beams between 900-1000 volts were extracted from the reflected electron beams from the side of the sample and image processing was performed. 30 extremely thin layers of material were stacked to form a thickness of 10 nm. Furthermore, image processing of the energy and intensity of the characteristic X-rays confirmed that only carbon atoms were present and that the sample was a graphene film in which flat surfaces of graphene directly overlap each other. Figure 1 shows an enlarged schematic representation of a portion of the side of a graphene film in which flat surfaces of graphene directly overlap each other and are bonded. 1 indicates the stacked graphene that makes up the graphene film. Furthermore, even when a 50 kg weight was placed on the graphene film, the graphene film did not break, indicating that the flat surfaces of the graphene are bonded together with a certain bonding force. Furthermore, the surface resistance of multiple points on the surface of the sample was measured using a surface resistance meter (for example, a surface resistance meter ST-4 manufactured by Simco Japan Co., Ltd.). The surface resistivity was around 10 μΩ, which is the same as the resistivity of graphene (10 μΩ). -6 The resistivity was close to Ω·cm, confirming that the surface of the graphene film possesses the properties of graphene. Since graphene has an extremely thin thickness of 0.332 nm, it has the properties of a flat surface. Therefore, a graphene film in which flat surfaces are bonded together has not only the electrical conductivity described above, but also the various properties of graphene described in paragraph 3 and the various properties of a graphene film described in paragraph 9. The five steps for continuously producing a graphene film described in paragraph 8 have been described above in five examples. The five steps are not limited to the described examples. That is, in Example 1, the first alcohol is not limited to ethanol and 1-propanol can also be used. Furthermore, in Example 2, the second alcohol is not limited to 3-pentanol and 1-heptanol, 1-octanol, or 2-ethylhexanol can also be used. In Example 3, the shape of the lip of the T-die is not limited to a width of 100 cm and a thickness of 200 nm. The shape of the lip of the T-die can be freely changed depending on the shape of the graphene film to be produced. In Example 4, the sizes of the two work rolls of the 12-high rolling mill are not limited to a width of 110 cm and a diameter of 10 cm. The sizes of the two work rolls can be freely changed depending on the shape of the graphene film to be produced. In Example 5, the thickness of the graphene film is not limited to 10 nm. The thickness of the graphene film can be changed by changing the gap between the two work rolls depending on the application of the graphene film.

[0024] Example 6 In Example 6, a plain woven fabric made of 100% cotton threads with a thickness of 0.5 mm was used as the substrate, and the film prepared in Example 5 was joined to both surfaces of the fabric by friction welding. First, two pieces of film prepared in Example 5 were prepared by cutting them into 20 cm x 20 cm pieces. Also, a piece of fabric cut into 20 cm x 20 cm pieces was prepared. Next, two flat plates measuring 22 cm x 22 cm x 1 cm (thickness) were prepared. Three sheets of film, fabric, and film were stacked on one of the plates in this order, and then another flat plate was placed on top of them. A compressive load equivalent to 50 kg was then evenly applied to the entire surface of the stacked plates using a jig attached to a compressor. After removing the jig, a 0.3 G impact acceleration was applied simultaneously to five locations on the side of the lower plate in the left-right direction, and the lower plate was peeled off from the sample. A 0.3 G impact acceleration was also applied simultaneously to five locations on the side of the upper plate in the left-right direction, and the upper plate was peeled off from the sample, and the sample was removed. First, the adhesive strength of the film on the sample was measured based on the tensile strength test for plastic films (ISO 527-3:2012), and the tensile strength was found to be 55 MPa. Therefore, despite its thin thickness of 10 nm, the film prepared in Example 5 was bonded with a consistent adhesive strength to the surface of a plain-woven fabric made of 0.5 mm-thick yarn. As a result, the surface of the sample possessed the various properties of graphene described in paragraph 3 and the various properties of graphene films described in paragraph 9. The surface resistance of the sample was measured at multiple points on the surface using the surface resistance meter used in Example 5. The surface resistivity was approximately 10 μΩ, which is considered to be the resistivity of graphene of 10 μΩ. -6 The resistivity was close to Ω·cm, and the surface of the sample had the properties of graphene. After this, the surface of the sample was washed with water to remove the water, and the surface resistance was measured again at several points on the surface of the sample, but the surface resistivity remained unchanged at around 10 μΩ, indicating that the surface of the sample was water-repellent and water did not penetrate into the sample. For this reason, the sample is corrosion-resistant to a variety of chemicals, including acids and alkalis. In Example 6, the graphene film was directly bonded to a fabric made of cotton yarn by friction welding. Therefore, the substrate to which the graphene film is bonded by friction welding is not limited to a base fabric made of cotton yarn, and the graphene film can be directly bonded by friction welding to base fabrics, fabrics, and nonwoven fabrics made of various materials, and the properties of graphene can be imparted to base fabrics, fabrics, and nonwoven fabrics made of various materials.

[0025] Example 7 In Example 7, a glass epoxy substrate was used as the base material, which was made by impregnating glass fiber with epoxy resin and then heat-curing it. The graphene film produced in Example 5 was joined to one side of the glass epoxy substrate by friction welding. First, the film prepared in Example 5 was cut to a size of 20 cm x 20 cm. A 5 mm thick glass epoxy substrate (e.g., a product of Yumoto Electric Co., Ltd.) was cut to a size of 20 cm x 20 cm. Next, two flat plates measuring 22 cm x 22 cm x 1 cm (thickness) were prepared. The glass epoxy substrate and film were placed on one of the flat plates in that order, and then another flat plate was placed on top of it. A compressive load equivalent to 50 kg was applied evenly to the entire surface of the overlapping flat plates using a jig attached to a compressor, and then the jig was removed from the film. A 0.3 G impact acceleration was applied simultaneously to five locations on the side of the lower flat plate in the lateral direction, and the lower flat plate was peeled off from the sample. A 0.3 G impact acceleration was applied simultaneously to five locations on the side of the upper flat plate in the lateral direction, and the upper flat plate was peeled off from the sample. First, as in Example 6, the adhesive strength of the film in the sample was measured based on a tensile strength test for plastic films, and the tensile strength was found to be 75 MPa. Therefore, despite the film prepared in Example 5 being thin at 10 nm, it was bonded to a 5 mm thick glass epoxy substrate with a certain bonding strength. Therefore, the surface of the sample possesses the various properties of graphene described in paragraph 3 and the various properties of graphene films described in paragraph 9. The surface resistance of the sample was measured at multiple points on the surface using the surface resistance meter used in Example 5. The surface resistivity was around 10 μΩ, which was close to the resistivity of graphene, 10 μΩ cm. On the other hand, the resistivity of the glass epoxy substrate was 10 14-16 Ω·cm. As a result, the surface of the sample has the properties of graphene. This gives the surface of the glass epoxy substrate the properties of graphene. After this, the sample was washed with water to remove the water from the surface, and the surface resistance was measured again at several points on the sample surface, but the surface resistivity remained unchanged at around 10 μΩ. As a result, the film surface was water-repellent, and water did not penetrate the sample. Therefore, the sample surface was corrosion-resistant to a variety of chemicals, including acids and alkalis. In Example 7, the graphene film was directly bonded to one surface of a glass epoxy substrate by friction welding. Therefore, the substrate to which the graphene film is bonded by friction welding is not limited to a glass epoxy substrate, and the graphene film can be directly bonded by friction welding to substrates made of various materials.

[0026] Example 8 In Example 8, a component made of a glass epoxy substrate is used as the component, and the graphene film produced in Example 5 is joined by friction welding. The component made of a glass epoxy substrate has a groove with a depth of 0.1 mm and having the shape shown in Fig. 2 formed therein, and the graphene film is joined into this groove by friction welding. First, a component made of a glass epoxy substrate was created. The glass epoxy substrate was cut into a 50 cm × 15 cm piece, and a 0.1 mm deep groove with the shape shown in Figure 2 was formed. The graphene film produced in Example 5 was then cut into the same shape as the groove. The cut graphene film was then placed on top of the groove, and a compressive load equivalent to 30 kg was applied evenly to the entire surface of all the graphene films using a jig attached to a compressor. The jig was then detached from the film. The bonding strength of the film in the sample was then measured using a plastic film tensile strength test, as in Example 7. The tensile strength was found to be 60 MPa. Therefore, the film was bonded to the glass epoxy substrate with a certain bonding force. Therefore, the surface of the film possesses the various properties of graphene described in paragraph 3 and the various properties of graphene films described in paragraph 9. In Example 8, a part made of a glass epoxy substrate was used, and the graphene film was directly joined by friction welding to a groove provided in the glass epoxy substrate. Therefore, parts to which a graphene film is joined by friction welding are not limited to parts made of a glass epoxy substrate, and graphene films can be directly joined by friction welding to parts made of various materials. [Explanation of symbols]

[0027] 1. Stacked graphene that makes up the graphene film

Claims

1. A method for continuously producing a graphene film composed of an assembly of graphene in which flat surfaces of the graphene directly overlap and bond with each other includes the steps of: One of the two parallel plate electrodes is placed in a container, and a collection of flake graphite particles or a collection of blocky graphite particles having a weight predetermined according to the width, thickness, and length of the graphene film to be produced is evenly spread on the surface of the one parallel plate electrode. Furthermore, a graphene film having a boiling point of 100°C or less and a density at 20°C of 0.80 g / cm is used. ３ a first alcohol having a viscosity of 1-2 mPa·sec at 20°C is weighed out in an amount more than 10 times the weight of the cluster of flake graphite particles or the cluster of massive graphite particles, the weighed first alcohol is filled into the container, and the cluster of flake graphite particles or the cluster of massive graphite particles is immersed in the first alcohol; and the other parallel plate electrode is placed on top of the one parallel plate electrode via the cluster of flake graphite particles or the cluster of massive graphite particles, so that the two parallel plate electrodes are separated from each other via the cluster of flake graphite particles or the cluster of massive graphite particles, and the two parallel plate electrodes are immersed in the first alcohol; Thereafter, a direct current potential difference having a predetermined magnitude is applied to the gap between the two parallel plate electrodes, whereby an electric field corresponding to the value obtained by dividing the magnitude of the potential difference by the size of the gap between the two parallel plate electrodes is applied to the collection of flake graphite particles or the collection of massive graphite particles, and the application of the electric field simultaneously applies a Coulomb force sufficient to destroy the interlayer bonds between the basal planes of graphite crystals to all of the collections of graphite particles, to all of the π electrons that are responsible for the interlayer bonds between the basal planes that form the graphite particles, whereby all of the interlayer bonds between the basal planes that form the flake graphite particles or the massive graphite particles are simultaneously destroyed, and collections of graphene corresponding to the basal planes are precipitated in the gap between the two parallel plate electrodes. Thereafter, the gap between the two parallel-plate electrodes is enlarged, and the two parallel-plate electrodes are tilted in the first alcohol. Furthermore, vibration accelerations of 0.2 to 0.3 G in three directions, left and right, front and back, and up and down, are repeatedly applied to the container, thereby moving the graphene clusters from the gap between the two parallel-plate electrodes into the first alcohol. Thereafter, the two parallel-plate electrodes are removed from the container. a first step of operating an ultrasonic homogenizer in the first alcohol in the container and continuously applying shock waves to the graphene aggregates through the first alcohol, thereby separating the graphene aggregates into individual graphene sheets in the first alcohol, and dispersing the separated graphene aggregates in the first alcohol; and thereafter removing the ultrasonic homogenizer from the container; The boiling point is higher than the boiling point of the first alcohol, and the density at 25°C is 0.83 g / cm ３ a second alcohol having a viscosity of 6-10 mPa sec at 20°C and also having the property of being soluble in or miscible with the first alcohol is mixed into the container in an amount such that a mixture with the first alcohol has a viscosity of 4-6 mPa sec at 20°C; thereby, the second alcohol is dissolved in or miscible with the first alcohol to form a mixture of two types of alcohols, and the graphene is separated into individual graphene sheets in the mixture of the two types of alcohols, and the separated clusters of graphene are dispersed in the mixture of the two types of alcohols; a second step of repeatedly applying vibration accelerations of 0.3 to 0.5 G in three directions, i.e., forward / backward, left / right, and up / down, to the container, thereby forming a suspension in the container, the suspension being made up of an aggregation of the graphene in which the flat surfaces of the graphene overlap with each other via the mixed liquid of the two types of alcohol; a third step of preparing in advance an extruder having a T-die lip with a gap that is 10 to 20 times the width and thickness of the graphene film to be produced, continuously filling a hopper of the extruder with the suspension prepared in the second step, and continuously operating a screw of the extruder to continuously extrude the suspension filled in the hopper into the T-die of the extruder, whereby the suspension that has entered the T-die passes through a manifold of the T-die and is then continuously extruded from the lip of the T-die as a sheet made of the suspension and having a thickness that is 10 to 20 times the width and thickness of the graphene film to be produced, and continuously winding up the extruded sheet by a first winder that rotates at a peripheral speed that takes more than 10 seconds for one rotation; the two work rolls of a multi-high rolling mill have five characteristics: first, they have the same width which is wider than the width of the graphene film to be produced; second, they have the same diameter which is smaller than 1 / 10 of the width of the graphene film to be produced; third, they are set with a gap which is five times the thickness of the graphene film to be produced; fourth, they rotate in opposite directions to each other at the same peripheral speed as the first winder; and fifth, they are heated to a temperature which is 10°C higher than the boiling point of the first alcohol; a multi-high rolling mill having the two work rolls is prepared in advance as a first multi-high rolling mill; and the leading end of the sheet wound in the third step is inserted into the gap between the two work rolls; a fourth step in which the sheet is continuously compressed in the nip between the two work rolls, first, the first alcohol evaporates from the sheet, and the sheet becomes a sheet consisting of an assembly of graphene whose flat surfaces overlap with each other via the second alcohol, then the sheet is continuously compressed in the nip between the two work rolls, and the excess second alcohol seeps out of the sheet and moves to the surface of the sheet, and the sheet becomes a sheet consisting of an assembly of graphene whose flat surfaces overlap with each other via the reduced amount of second alcohol, and the sheet is continuously discharged from the nip between the two work rolls; The two work rolls of a multi-high rolling mill have four characteristics: first, they have the same width and the same diameter as the two work rolls of the first multi-high rolling mill; second, they rotate in opposite directions to each other at the same peripheral speed as the two work rolls of the first multi-high rolling mill; third, a gap is set to the thickness of the graphene film to be produced; and fourth, they are heated to a temperature 10°C higher than the boiling point of the second alcohol. A multi-high rolling mill having the two work rolls is prepared in advance as a second multi-high rolling mill, and the leading end of the sheet produced in the fourth step is inserted into the gap between the two work rolls, and the sheet is continuously compressed in the gap between the two work rolls. First, the second alcohol is removed from the sheet. a fifth step in which the graphene sheet is vaporized, and the sheet becomes an assembly of graphene in which flat surfaces of the graphene directly overlap each other, and then the assembly of graphene is continuously compressed in the gap between the two work rolls, frictional heat is generated at the flat surfaces where the flat surfaces of the graphene directly overlap each other, and the directly overlapping flat surfaces are bonded together by the frictional heat, thereby forming a graphene film made up of the assembly of graphene in which the flat surfaces are directly overlapped and bonded together, and the graphene film is continuously discharged from the gap between the two work rolls, and the discharged graphene film is continuously wound up by a second winder rotating at the same peripheral speed as the first winder, A method for continuously carrying out all of these five steps is a method for continuously producing a graphene film consisting of an assembly of graphene in which the flat surfaces of the graphene are directly overlapped and bonded together.

2. The method for continuously producing a graphene film according to claim 1 includes the steps of: The first alcohol according to claim 1 is either ethanol or 1-propanol, and the method for continuously producing a graphene film according to claim 1 is a method using the alcohol as the first alcohol according to claim 1 and continuously carrying out all of the treatments consisting of the five steps according to claim 1.

3. The method for continuously producing a graphene film according to claim 1 includes the steps of: The second alcohol according to claim 1 is any one kind of alcohol selected from the group consisting of 1-heptanol, 3-pentanol, 1-octanol, and 2-ethylhexanol, and the method for continuously producing a graphene film according to claim 1 is a method for continuously performing all of the treatments consisting of the five steps according to claim 1 using the one kind of alcohol as the second alcohol according to claim 1.

4. A method for continuously producing a graphene film by the method according to claim 1, cutting a part of the graphene film into a shape of a surface of a substrate, and bonding the cut graphene film to one surface or both surfaces of the substrate, comprises the steps of: A graphene film is continuously produced by the method according to claim 1, a portion of the graphene film is cut into a shape of a surface of a substrate, the cut graphene film is superimposed on one surface of the substrate or on both surfaces of the substrate, and the entire surface of the superimposed graphene film is uniformly compressed by a jig provided on a compressor, whereby the surface of the superimposed graphene film comes into contact with convex portions of the unevenness on one surface of the substrate or on both surfaces of the substrate, frictional heat is generated in the convex portions, and the frictional heat bonds the convex portions to one surface of the graphene film or to both surfaces of the graphene film, and the cut graphene film is bonded to one surface of the substrate or to both surfaces of the substrate, and then the jig is separated from the graphene film.

10. A method for continuously producing a graphene film by the method according to claim 1, cutting a portion of the graphene film into a shape of a surface of a substrate, and bonding the cut graphene film to one surface or both surfaces of the substrate.

5. A method for continuously producing a graphene film by the method according to claim 1, cutting a part of the graphene film into a predetermined shape, and bonding the cut graphene film to a predetermined position on a surface of a substrate or a component, comprising the steps of: A graphene film is continuously produced by the method according to claim 1, a portion of the graphene film is cut into a predetermined shape, the cut graphene film is superimposed on a predetermined position on the surface of a substrate or a part, and the entire surface of the superimposed graphene film is uniformly compressed by a jig provided on a compressor, whereby the surface of the superimposed graphene film comes into contact with convex portions of the uneven surface of the substrate or the part, and frictional heat is generated in the convex portions, and the frictional heat bonds the convex portions to the surface of the superimposed graphene film, and the cut graphene film is bonded to the predetermined position on the surface of the substrate or the part, and then the jig is separated from the graphene film. A method for continuously producing a graphene film by the method described in claim 1, cutting a portion of the graphene film into a predetermined shape, and bonding the cut graphene film to a predetermined position on a surface of a substrate or a component.

Images