Method for producing carbon fiber structure, and apparatus for producing carbon fiber structure

Abstract

To provide a method for producing a carbon fiber structure capable of easily producing a carbon fiber structure having desired characteristics, and an apparatus for producing a carbon fiber structure.SOLUTION: A method for producing a carbon fiber structure includes: a defibrating process of defibrating a material including a cellulose fiber to generate a defibrated product; a depositing process of depositing the defibrated product to generate a deposit product; and a carbonization treatment process of subjecting the deposit product to heat treatment to generate a carbon fiber structure by carbonizing the cellulose fiber. In addition, the method for producing a carbon fiber structure includes a density-adjusting process of adjusting a density of the deposit product, which is executed between the deposit process and the carbonization treatment process.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a carbon fiber structure and an apparatus for manufacturing a carbon fiber structure. [Background technology]

[0002] Carbon fiber filters are known that remove substances suspended or dissolved in various fluids by filtration and adsorption. For example, the carbon fiber filter described in Patent Document 1 has a carbon fiber layer, a nonwoven fabric layer provided on one side of the carbon fiber layer, and a nonwoven fabric layer provided on the other side of the carbon fiber layer. Such a carbon fiber filter is manufactured as follows.

[0003] First, the carbon fibers are provided on a nonwoven fabric, and the nonwoven fabric is laminated thereon to obtain a laminate. Then, the laminate is pressed under predetermined conditions to obtain a carbon fiber filter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-267009 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the manufacturing method described in Patent Document 1, the carbon fibers are prepared in advance, and various conditions such as the length, thickness, density, and surface roughness of the carbon fibers are determined, making it difficult to appropriately adjust these conditions according to the desired filter properties. In other words, there is a drawback in that it is not possible to obtain a filter having desired properties by appropriately adjusting various conditions of the carbon fibers used in the filter manufacturing process. [Means for solving the problem]

[0006] The method for producing carbon fibrous structures of the present invention includes a defibration step of defibrating a material containing cellulose fibers to produce a defibrated material; a depositing step of depositing the defibrated material to generate a deposit; and a carbonization step of subjecting the deposit to a heat treatment to carbonize the cellulose fibers to produce a carbon fibrous structure.

[0007] The carbon fibrous structure manufacturing apparatus of the present invention comprises: a defibrator unit for defibrating a material containing cellulose fibers to produce a defibrated material; a depositing section that deposits the defibrated material to generate a deposit; and a carbonization processing unit that performs a heat treatment on the deposit to carbonize the cellulose fibers and produce carbon fibrous structures. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a carbon fibrous structure manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a partial cross-sectional view showing the configurations of a density adjusting unit and a carbonization processing unit included in the carbon fibrous structure manufacturing apparatus shown in FIG. [Diagram 3] FIG. 3 is a block diagram of the carbon fiber structure manufacturing apparatus shown in FIG. [Figure 4] FIG. 4 is a flow chart showing an example of the method for producing carbon fibrous structures executed by the carbon fibrous structure producing apparatus shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a carbon fibrous structure and an apparatus for producing a carbon fibrous structure according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

[0010] <Embodiment> Fig. 1 is a schematic diagram showing a configuration of a carbon fibrous structure manufacturing apparatus according to an embodiment of the present invention. Fig. 2 is a partial cross-sectional view showing the configuration of a density adjusting unit and a carbonization processing unit provided in the carbon fibrous structure manufacturing apparatus shown in Fig. 1. Fig. 3 is a block diagram of the carbon fibrous structure manufacturing apparatus shown in Fig. 1. Fig. 4 is a flowchart showing an example of a method for manufacturing carbon fibrous structures executed by the carbon fibrous structure manufacturing apparatus shown in Fig. 1.

[0011] In the following, the upper side of Fig. 1 and Fig. 2 may be referred to as "upper" or "upper side", and the lower side may be referred to as "lower" or "lower side". Fig. 1 is a schematic diagram, and the positional relationship, direction, size, etc. of each part of the carbon fiber structure manufacturing apparatus 100 are not limited to those shown in the figure. In Fig. 1, the direction in which the coarsely crushed pieces M2, the defibrated material M3, the first sorted material M4-1, the second sorted material M4-2, the first web M5, the finely divided body M6, the second web M7, and the carbon fiber structures S are transported, that is, the direction indicated by the arrow, is also referred to as the transport direction. In Fig. 1, the tip side of the arrow is also referred to as the "downstream side" in the transport direction, and the base side of the arrow is also referred to as the "upstream side" in the transport direction.

[0012] The carbon fiber structure manufacturing apparatus 100 shown in Fig. 1 is an apparatus for producing carbon fiber structures S from a raw material M1, which is waste paper such as used copy paper. In this embodiment, the carbon fiber structures S are described as being in a sheet shape. However, the carbon fiber structures S are not limited to this configuration, and may be in a shape other than a sheet shape, such as a rod shape, a sphere shape, a block shape, or a three-dimensional structure.

[0013] The uses of the carbon fiber structures S are not particularly limited, and examples thereof include filters for adsorbing foreign matter, other filters and adsorbents, heat conductive materials, reinforcing materials, and conductive materials.

[0014] In particular, the carbon fiber structure S is preferably used as a filter for adsorbing foreign matter. As described later, the surface of the cellulose fiber becomes rough by going through a defibration process. By carbonizing the cellulose fiber having a rough surface, carbon fiber having a rough surface can be obtained. For this reason, by using the carbon fiber structure S as a filter, an excellent foreign matter adsorption effect can be achieved.

[0015] Hereinafter, each part of the carbon fibrous structure manufacturing apparatus 100 will be described with reference to Figs.

[0016] As shown in FIG. 1, the carbon fiber structure manufacturing apparatus 100 includes a raw material supply section 11, a coarse crushing section 12, a defibrating section 13 of the present invention, a sorting section 14, a web forming section 15, a subdivision section 16, a dispersion section 18, a deposition section 19, a density adjustment section 23, a carbonization processing section 3, a molding section 20, a cutting section 21, a storage section 22, and a recovery section 27.

[0017] The carbon fiber structure manufacturing apparatus 100 also includes a humidifier unit 231, a humidifier unit 232, a humidifier unit 233, a humidifier unit 234, a humidifier unit 235, and a humidifier unit 236. In addition, the carbon fiber structure manufacturing apparatus 100 also includes a blower 261, a blower 262, and a blower 263.

[0018] In addition, in the carbon fiber structure manufacturing apparatus 100, as shown in Figure 4, a raw material supply process, a coarse crushing process, a defibration process, a sorting process, a web formation process, a cutting process, a dispersion process, a deposition process, a density adjustment process, a carbonization process, a molding process, and a cutting process are carried out in this order.

[0019] The configuration of each part of the carbon fibrous structure manufacturing apparatus 100 and each step of the method for manufacturing carbon fibrous structures will be described in detail below.

[0020] The raw material supplying section 11 is a section that performs a raw material supplying step of supplying raw material M1 to the crushing section 12. This raw material M1 is a sheet-like material made of a fiber-containing material including cellulose fibers. The cellulose fibers may be fibrous and contain cellulose as a compound as the main component, and may contain hemicellulose and lignin in addition to cellulose. The raw material M1 may be in any form, such as woven fabric or nonwoven fabric. The raw material M1 may be, for example, recycled paper produced by disintegrating waste paper and regenerating it, or synthetic paper such as Yupo paper (registered trademark), or it may not be recycled paper.

[0021] The crushing unit 12 is a section that performs a crushing step of crushing the raw material M1 supplied from the raw material supply unit 11 in air such as the atmosphere. The crushing unit 12 has a pair of crushing blades 121 and a chute 122.

[0022] The pair of crushing blades 121 rotate in opposite directions to each other, and can crush the raw material M1 between them, that is, cut it into crushed pieces M2. The shape and size of the crushed pieces M2 are preferably suitable for defibration processing in the defibration unit 13. Examples of the shape of the crushed pieces M2 include small pieces with a square planar shape, rectangular pieces, and particularly small pieces with a strip shape. The size of the crushed pieces M2 is preferably small pieces with an average side length of 100 mm or less, and more preferably small pieces with an average side length of 3 mm or more and 70 mm or less. The shape of the small pieces may be other than square or rectangular. The thickness is preferably 0.07 mm or more and 0.10 mm or less.

[0023] The chute 122 is disposed below the pair of crushing blades 121 and has, for example, a funnel shape. This allows the chute 122 to receive the coarsely crushed pieces M2 that have been crushed by the crushing blades 121 and dropped.

[0024] Moreover, above the chute 122, a humidifying section 231 is disposed adjacent to the pair of coarse crushing blades 121. The humidifying section 231 humidifies the coarsely crushed pieces M2 in the chute 122. This humidifying section 231 is configured as an evaporation type humidifier that has a moisture-containing filter (not shown) and supplies humidified air with increased humidity to the coarsely crushed pieces M2 by passing air through the filter. By supplying the humidified air to the coarsely crushed pieces M2, it is possible to suppress adhesion of the coarsely crushed pieces M2 to the chute 122 and the like due to electrostatic forces.

[0025] The chute 122 is connected to the upstream side of the defibrating unit 13 via a pipe 241. That is, the downstream end of the pipe 241 is connected to an inlet (not shown) of the defibrating unit 13. The coarse fragments M2 collected in the chute 122 pass through the pipe 241 and are transported to the defibrating unit 13.

[0026] As shown in FIG. 1, the defibrating unit 13 is a section that performs a defibrating process in which the coarsely crushed pieces M2 are defibrated in the air, i.e., in a dry manner. The defibrating process in this defibrating unit 13 makes it possible to generate a defibrated material M3 from the coarsely crushed pieces M2. Here, "defibrating" refers to untangling the coarsely crushed pieces M2, which are made up of multiple fibers bound together, into individual fibers. This untangled material becomes the defibrated material M3. The shape of the defibrated material M3 is linear or band-like. The defibrated material M3 may also be present in a state where it is entangled with other pieces to form a mass, that is, in a state where it forms so-called "lumps."

[0027] Furthermore, the defibrating unit 13 can generate an air flow from the crushing unit 12 toward the sorting unit 14, i.e., an airflow, by the rotation of a rotor (not shown). This allows the coarsely crushed pieces M2 to be introduced from the pipe 241 to the upstream side of the defibrating unit 13, and after defibration processing, the defibrated material M3 can be sent to the sorting unit 14 via the pipe 242.

[0028] Furthermore, the defibrating unit 13 has a motor (not shown) that rotates and drives the rotor. The motor is electrically connected to a control device 28 shown in FIG. 3. The control device 28 controls the energization conditions for the motor via a motor driver (not shown), thereby adjusting the rotation speed of the rotor. This makes it possible to adjust the defibrating ability in the defibrating unit 13. Therefore, it is possible to adjust the surface roughness and average fiber length of the cellulose fibers in the defibrated material M3.

[0029] A pipe 242 is connected to the downstream side of the defibrating unit 13. A blower 261, which is composed of, for example, a turbo fan, is installed midway through the pipe 242. The blower 261 is an airflow generating device that generates an airflow toward the sorting unit 14. This promotes the introduction of the coarsely crushed pieces M2 into the defibrating unit 13 and the sending out of the defibrated material M3 to the sorting unit 14. As will be described later, the defibrating unit 13 has a structure that allows the coarsely crushed pieces M2, which are the raw material, to pass through and be defibrated smoothly, but the operation of the blower 261 installed downstream of the defibrating unit 13 promotes the passage of the coarsely crushed pieces M2 within the defibrating unit 13 and the defibration process. The blower 261 may be installed upstream of the defibrating unit 13.

[0030] The sorting unit 14 is a section that performs a sorting process in which the defibrated material M3 is sorted according to the fiber length. In the sorting unit 14, the defibrated material M3 is sorted into a first sorted material M4-1 and a second sorted material M4-2 having a fiber length longer than that of the first sorted material M4-1. The first sorted material M4-1 has a size suitable for the subsequent production of the carbon fiber structure S. On the other hand, the second sorted material M4-2 includes, for example, insufficiently defibrated material and material in which defibrated fibers are excessively aggregated.

[0031] The sorting unit 14 has a drum unit 141 and a housing unit 142 that houses the drum unit 141.

[0032] The drum part 141 is a sieve composed of a cylindrical mesh body and rotates around its central axis. The defibrated material M3 flows into this drum part 141. Then, as the drum part 141 rotates, the defibrated material M3 smaller than the mesh opening is sorted as the first sorted material M4-1, and the defibrated material M3 larger than the mesh opening is sorted as the second sorted material M4-2.

[0033] The first sorted item M4-1 falls from the drum portion 141. Meanwhile, the second sorted material M4-2 is sent out to a pipe 243 connected to the drum section 141. The end of the pipe 243 opposite the drum section 141, i.e., the downstream end, is connected midway through the pipe 241. The second sorted material M4-2 that passes through this pipe 243 merges with the coarsely crushed pieces M2 inside the pipe 241 and flows into the defibrating section 13 together with the coarsely crushed pieces M2. As a result, the second sorted material M4-2 is returned to the defibrating section 13 and is defibrated together with the coarsely crushed pieces M2.

[0034] The first selected material M4-1 that has fallen from the drum unit 141 falls while being dispersed in the air, and heads toward the web forming unit 15 located below the drum unit 141. The web forming unit 15 is a section that carries out a web forming step of forming a first web M5 from the first selected material M4-1. The web forming unit 15 has a mesh belt 151, three tension rollers 152, and a suction unit 153.

[0035] The mesh belt 151 is an endless belt on which the first sorted material M4-1 is accumulated. The mesh belt 151 is wound around three tension rollers 152. As the tension rollers 152 rotate, the first sorted material M4-1 on the mesh belt 151 is transported downstream.

[0036] The size of the first sorted material M4-1 is equal to or larger than the mesh size of the mesh belt 151. This restricts the passage of the first sorted material M4-1 through the mesh belt 151, and therefore the first sorted material M4-1 can be piled up on the mesh belt 151. Furthermore, the first sorted material M4-1 is transported downstream together with the mesh belt 151 while being piled up on the mesh belt 151, and is thus formed as a layered first web M5.

[0037] In addition, the first sorted material M4-1 may contain, for example, dust or dirt. Dust or dirt may be generated, for example, by crushing or defibrating. Such dust or dirt will be collected in the collection section 27, which will be described later.

[0038] The suction unit 153 is a suction mechanism that sucks air from below the mesh belt 151. This makes it possible to suck in dust and dirt that has passed through the mesh belt 151 together with the air.

[0039] In addition, the suction unit 153 is connected to the collection unit 27 via a pipe 244. The dust and dirt sucked by the suction unit 153 is collected in the collection unit 27.

[0040] A pipe 245 is further connected to the collection unit 27. A blower 262 is installed in the middle of the pipe 245. By operating the blower 262, a suction force can be generated in the suction unit 153. This promotes the formation of the first web M5 on the mesh belt 151. Dust and dirt are removed from this first web M5. By operating the blower 262, the dust and dirt pass through the pipe 244 and reach the collection unit 27.

[0041] The housing part 142 is connected to the humidifier part 232. The humidifier part 232 is configured with an evaporative humidifier. This allows humidified air to be supplied into the housing part 142. The first sorted object M4-1 can be humidified by this humidified air, and therefore, the first sorted object M4-1 can be prevented from adhering to the inner wall of the housing part 142 due to electrostatic force.

[0042] A humidifying section 235 is disposed downstream of the sorting section 14. The humidifying section 235 is configured with an ultrasonic humidifier that sprays water. This allows moisture to be supplied to the first web M5, and thus the moisture content of the first web M5 is adjusted. This adjustment makes it possible to suppress adhesion of the first web M5 to the mesh belt 151 due to electrostatic force. As a result, the first web M5 is easily peeled off from the mesh belt 151 at the position where the mesh belt 151 is folded back by the tension roller 152.

[0043] The segmentation unit 16 is disposed downstream of the humidification unit 235. The segmentation unit 16 is a section that performs a segmentation step of segmenting the first web M5 peeled off from the mesh belt 151. The segmentation unit 16 has a rotatably supported propeller 161 and a housing portion 162 that houses the propeller 161. The rotating propeller 161 can segment the first web M5. The segmented first web M5 becomes segmented bodies M6. The segmented bodies M6 move down inside the housing portion 162.

[0044] The housing part 162 is connected to the humidifier part 233. The humidifier part 233 is configured by an evaporation type humidifier. This allows humidified air to be supplied into the housing part 162. This humidified air can also prevent the fragmented bodies M6 from adhering to the propeller 161 and the inner wall of the housing part 162 due to electrostatic force.

[0045] The upstream end of a pipe 172 is connected to the downstream side of the subdivision section 16. The pipe 172 connects the housing section 162 of the subdivision section 16 and the housing 182 of the dispersion section 18, and is a flow path through which the subdivision body M6 passes.

[0046] Further, a blower 173 is installed in the middle of the pipe 172. An airflow toward the dispersion section 18 can be generated by the action of a rotating part such as a blade of the blower 173. This airflow can agitate the fragmented bodies M6 in the pipe 172. Therefore, the fragmented bodies M6 are loosened in the process of passing through the pipe 172, and become finer fibrous.

[0047] The blower 173 is electrically connected to the control device 28 shown in Fig. 3, and the operation of the blower 173 is controlled by the control device 28. The amount of air sent into the drum 181 can be adjusted by adjusting the airflow rate of the blower 173.

[0048] Although not shown in the figure, the end of pipe 172 on the drum 181 side is branched into two, and the branched ends are each connected to an inlet port (not shown) formed on the end face of drum 181.

[0049] 1 is a section that performs a dispersion process for loosening and dispersing entangled fibers in the fragmented body M6. The dispersion section 18 has a drum 181 that introduces and discharges the fragmented body M6, which is a defibrated material, and a housing 182 that contains the drum 181.

[0050] The drum 181 is a sieve that is composed of a cylindrical mesh body and rotates around its central axis. As the drum 181 rotates, fibers and the like of the fragmented bodies M6 that are smaller than the mesh openings can pass through the drum 181. At that time, the fragmented bodies M6 are loosened and discharged together with air. That is, the drum 181 functions as a discharge section that discharges material containing fibers.

[0051] The drum 181 is connected to a drive source (not shown) and rotates by a torque output from the drive source. The drive source is electrically connected to the control device 28, and the operation of the drive source is controlled by the control device 28.

[0052] The housing 182 is also connected to the humidifier 234. The humidifier 234 is configured with an evaporative humidifier. This allows humidified air to be supplied into the housing 182. The inside of the housing 182 can be humidified by this humidified air, and therefore, adhesion of the fragmented bodies M6 to the inner wall of the housing 182 due to electrostatic force can also be suppressed.

[0053] The fragmented bodies M6 discharged from the drum 181 drop while being dispersed in the air, and head toward the accumulation section 19 located below the drum 181. The accumulation section 19 is a section where an accumulation step is carried out in which the fragmented bodies M6 are accumulated to form a second web M7, which is a deposit. The accumulation section 19 has a mesh belt 191, a tension roller 192, and a suction section 193.

[0054] The mesh belt 191 is a mesh member, and in the illustrated configuration, is configured as an endless belt. The fragmented bodies M6 dispersed and discharged by the dispersion section 18 are accumulated on the mesh belt 191. The mesh belt 191 is wound around four tension rollers 192. The tension rollers 192 are driven to rotate, and the fragmented bodies M6 on the mesh belt 191 are transported downstream.

[0055] In the illustrated configuration, the mesh belt 191 is used as an example of the mesh member, but the present invention is not limited to this, and the mesh member may be, for example, a flat plate-shaped member.

[0056] Moreover, most of the fragmented bodies M6 on the mesh belt 191 are larger than the mesh openings of the mesh belt 191. This restricts the passage of the fragmented bodies M6 through the mesh belt 191, and thus the fragmented bodies M6 can be accumulated on the mesh belt 191. Moreover, the fragmented bodies M6 are transported downstream together with the mesh belt 191 while being accumulated on the mesh belt 191, and are thus formed as a layered second web M7.

[0057] The suction unit 193 is a suction mechanism that sucks air from below the mesh belt 191. This makes it possible to suck the fragmented bodies M6 onto the mesh belt 191, thereby facilitating the accumulation of the fragmented bodies M6 on the mesh belt 191.

[0058] A pipe 246 is connected to the suction unit 193. A blower 263 is provided midway through the pipe 246. By operating the blower 263, the suction unit 193 can generate a suction force.

[0059] The humidifying section 236 is disposed downstream of the dispersion section 18. The humidifying section 236 is configured with an ultrasonic humidifier similar to the humidifying section 235. This allows moisture to be supplied to the second web M7, and thus the moisture content of the second web M7 is adjusted. This adjustment makes it possible to suppress adhesion of the second web M7 to the mesh belt 191 due to electrostatic force. This allows the second web M7 to be easily peeled off from the mesh belt 191 at the position where the mesh belt 191 is folded back by the tension roller 192.

[0060] The total amount of moisture added from the humidifying units 231 to 236 is preferably, for example, 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the material before humidification.

[0061] As shown in Fig. 1 and Fig. 2, a density adjusting section 23 that adjusts the density of the second web M7 is disposed downstream of the accumulation section 19. The density adjusting section 23 is a section that performs a density adjusting process. The density adjusting section 23 has a pair of calendar rollers 230, 230 and a roller axis distance adjusting mechanism 238. In the density adjusting section 23, the second web M7 is passed between the pair of calendar rollers 230, 230, so that the second web M7 can be pressed in its thickness direction, thereby increasing the density of the second web M7.

[0062] In the density adjusting unit 23, the axis distance (separation distance) of the pair of calendar rollers 230, 230 can be adjusted by operating the roller axis distance adjusting mechanism 238. This allows the pressure applied to the passing second web M7 to be adjusted, and the density of the second web M7 to be adjusted to a desired value.

[0063] As shown in FIG. 3, the roller axis distance adjustment mechanism 238 is electrically connected to the control device 28, and the control device 28 controls the conditions of current supply to the roller axis distance adjustment mechanism 238 to adjust the axis distance between the pair of calendar rollers 230, 230, i.e., the pressure applied to the second web M7.

[0064] The second web M7, which has been pressurized by passing between the pair of calendar rollers 230 and adjusted to a desired density, is transported toward the carbonization processing section 3 where the next process is performed. One of the pair of calendar rollers 230 is a driven roller driven by the operation of a motor (not shown), and the other is a driven roller. The pair of calendar rollers 230 has both a function of transporting the second web M7 downstream and a function of adjusting the density by pressurization. The motor that drives the calendar roller 230 is electrically connected to a control device 28, and the rotation speed, rotation timing, etc. are controlled.

[0065] As described above, by appropriately setting the center distance between the pair of calendar rollers 230, 230, it is possible to adjust the thickness of the second web M7 sent to the carbonization processing unit 3 and appropriately adjust the density of the obtained carbon fiber structures S. The relationship between the center distance between the pair of calendar rollers 230, 230, the relationship between the thickness of the second web M7 sent to the carbonization processing unit 3, and the relationship between the density of the carbon fiber structures S that have passed through the carbonization processing unit 3 all correspond to each other.

[0066] In addition, by adjusting the density (thickness) of the second web M7 before the heat treatment, it is also possible to adjust properties other than the density of the carbon fiber structure S that has been subjected to the carbonization processing unit 3, such as strength, toughness, electrical conductivity, thermal conductivity, and foreign matter adsorption ability.

[0067] The carbonization processing section 3 is disposed downstream of the density adjusting section 23. 2 is a section that performs a carbonization process. That is, the carbonization section 3 performs a heat treatment on the second web M7 to carbonize the cellulose fibers and produce the carbon fibrous structures S.

[0068] The term "carbonization" includes the conversion of cellulose fibers to carbon by dehydration, the conversion to activated carbon, and graphitization. Furthermore, the term "carbonizing cellulose fibers" refers to carbonizing 75% by weight or more, and preferably 90% by weight or more, of the cellulose fibers contained in the second web M7.

[0069] The carbonization section 3 has a chamber 31 , a heater 32 and a heater 33 provided in the chamber 31 , an inert gas supply section 34 , and a pressure reduction section 35 .

[0070] The chamber 31 has an internal space S0, a supply port 311 through which the second web M7 is supplied, and a discharge port 312 through which the carbon fiber structures S are discharged. The supply port 311 is provided in a side wall on the upstream side of the chamber 31, and the discharge port 312 is provided in a side wall on the downstream side of the chamber 31.

[0071] Although not shown, it is preferable that the supply port 311 and the discharge port 312 are provided with a seal member or a labyrinth structure for ensuring or improving airtightness.

[0072] The belt-like second web M7 supplied from the supply port 311 to the internal space S0 of the chamber 31 is heat-treated in the internal space S0, and the cellulose fibers contained in the second web M7 are carbonized into carbon fibers, thereby producing the carbon fiber structures S. The produced carbon fiber structures S are discharged from the discharge port 312 in the belt-like form.

[0073] Furthermore, in the carbonization processing unit 3, the heat treatment is continuously performed on the second web M7 without stopping the conveyance of the second web M7, so that the carbonization by the heat treatment can be performed quickly and uniformly, and the productivity of the carbon fibrous structures S can be increased.

[0074] The heater 32 is disposed in the internal space S0 above the second web M7 or the carbon fiber structure S, and the heater 33 is disposed in the internal space S0 below the second web M7 or the carbon fiber structure S. This allows the second web M7 to be heated from both sides, and allows the second web M7 to be heat-treated quickly and evenly.

[0075] 3, the heaters 32 and 33 are electrically connected to a control device 28, which controls the conditions of current supply to the heaters 32 and 33. This allows the heaters 32 and 33 to generate heat at a desired timing and with a desired amount of heat, thereby performing a heat treatment on the second web M7.

[0076] The heating temperature of the second web M7 by the operation of the heaters 32 and 33 is not particularly limited as long as the second web M7 can be carbonized when the second web M7 passes through the internal space S0, but is preferably, for example, from 200° C. to 1500° C., and more preferably from 300° C. to 800° C. This allows the cellulose fibers contained in the second web M7 to be carbonized quickly and uniformly.

[0077] In particular, by heating the second web M7 to a temperature of 300° C. or higher by operating the heaters 32 and 33, the cellulose fibers contained in the second web M7 can be carbonized more quickly and more uniformly.

[0078] When the heating temperature of the second web M7 by the operation of the heaters 32 and 33 is 300° C. or more and 800° C. or less, the heating time of the second web M7 is preferably 10 seconds or more and 300 seconds or less, and more preferably 30 seconds or more and 100 seconds or less, which allows the cellulose fibers contained in the second web M7 to be carbonized more quickly and uniformly.

[0079] When the heating temperature of the second web M7 by the operation of the heaters 32 and 33 is 800° C. or more and less than 1500° C., the heating time of the second web M7 is preferably 10 seconds or more and 50 seconds or less, and more preferably 20 seconds or more and 80 seconds or less, which allows the cellulose fibers contained in the second web M7 to be carbonized more quickly and uniformly.

[0080] The heating time of the second web M7 refers to the time during which the second web M7 remains in the internal space S0 of the chamber 31. In other words, when focusing on an arbitrary portion of the second web M7, the time during which the arbitrary portion remains in the internal space S0 of the chamber 31 is defined as the heating time.

[0081] The control device 28 can adjust the rotation speed and timing of each of the tension roller 192, the calendar rollers 230, 230, and the calendar rollers 201, 201, thereby making it possible to adjust to desired conveyance speed and conveyance timing of the second web M7 and the carbon fiber structure S. In addition, the control device 28 controls the heat generation amount (heating temperature) of the heaters 32, 33 and also controls the conveyance speed of the second web M7 passing through the internal space S0, thereby adjusting the heating time of the second web M7 and realizing appropriate carbonization of the second web M7.

[0082] The inert gas supply unit 34 supplies an inert gas G, such as nitrogen gas, to the internal space S0 of the chamber 31. This allows the heat treatment to be performed in an inert gas atmosphere, i.e., a non-oxidizing atmosphere. This allows the cellulose fibers contained in the second web M7 to be carbonized more uniformly.

[0083] The inert gas supply unit 34 includes an inert gas storage unit 341, a supply pipe 342 that connects the inert gas storage unit 341 and the chamber 31, and an electromagnetic valve 343 that opens and closes the supply pipe 342. As shown in Fig. 3, the electromagnetic valve 343 is electrically connected to the control device 28, and the opening degree and opening / closing timing of the electromagnetic valve 343 are adjusted under the control of the control device 28. By adjusting the opening degree and opening / closing timing of the electromagnetic valve 343, the amount of inert gas G supplied into the chamber 31 can be adjusted.

[0084] The inert gas G is not particularly limited, but examples thereof include nitrogen gas, argon gas, helium gas, neon gas, etc., which may be used alone or in appropriate mixture.

[0085] The decompression section 35 reduces the pressure in the internal space S0 of the chamber 31. By carrying out the heat treatment in a reduced pressure atmosphere, the cellulose fibers contained in the second web M7 can be carbonized more uniformly.

[0086] The decompression unit 35 has a suction pump 351 and a suction pipe 352 that connects the suction pump 351 and the chamber 31. As shown in Fig. 3, the suction pump 351 is electrically connected to the control device 28, and the conditions of energization to the suction pump 351 are controlled by the operation of the control device 28. This allows the suction pump 351 to perform suction at a desired timing and with a desired suction force, thereby reducing the pressure of the internal space S0 of the chamber 31.

[0087] The pressure in the internal space S0 of the chamber 31 is preferably 500 kPa or less, and more preferably 300 kPa or less, so that the cellulose fibers contained in the second web M7 can be carbonized more uniformly.

[0088] The heat treatment in the carbonization unit 3 is preferably carried out in a non-oxidizing atmosphere at a pressure of 500 kPa or less, so that the cellulose fibers contained in the second web M7 can be carbonized more uniformly.

[0089] In particular, the carbonization step is preferably performed in a non-oxidizing atmosphere with a pressure of 500 kPa or less and at a heating temperature of 200° C. or more and 1500° C. or less, and more preferably in a non-oxidizing atmosphere with a pressure of 300 kPa or less and at a heating temperature of 300° C. or more and 800° C. or less, which allows the cellulose fibers contained in the second web M7 to be carbonized more uniformly.

[0090] Examples of the non-oxidizing atmosphere include an inert gas atmosphere such as nitrogen gas, argon gas, helium gas, or neon gas, a reducing gas atmosphere, hydrogen gas, reduced pressure air, and vacuum.

[0091] In this way, the carbon fiber structure manufacturing apparatus 100 can easily manufacture the carbon fiber structure S by sequentially carrying out the defibration step, the deposition step, and the carbonization treatment step. In particular, for example, by appropriately setting the degree of defibration in the defibration step, it is possible to appropriately set the physical properties of the cellulose fibers, such as the average fiber length and the surface roughness of the cellulose fibers. Therefore, by carbonizing the cellulose fibers, it is possible to appropriately set the properties of the carbon fibers.

[0092] The carbon fiber structure manufacturing apparatus 100 includes a defibration unit 13 that defibrates a material containing cellulose fibers to produce a defibrated material M3, a deposition unit 19 that deposits fine bodies M6 as the defibrated material to produce a second web M7 as a deposit, and a carbonization processing unit 3 that performs a heat treatment on the second web M7 to carbonize the cellulose fibers to produce a carbon fiber structure S. According to the carbon fiber structure manufacturing apparatus 100, the conditions in each unit of the apparatus, particularly the processing conditions in the carbonization processing unit 3, can be appropriately adjusted to easily manufacture a carbon fiber structure S having desired properties.

[0093] As shown in FIG. 1, a forming unit 20 is disposed downstream of the carbonization unit 3. The forming unit 20 is a unit that performs a forming process for forming the carbon fiber structures S into a desired shape, in this embodiment, into a sheet shape. The forming unit 20 has a pair of calendar rollers 201, 201, and can pressurize the carbon fiber structures S in the thickness direction by passing the carbon fiber structures S between the pair of calendar rollers 201, 201. This increases the density of the carbon fiber structures S. Although not shown, the forming unit 20 can also be configured to have a roller axis distance adjustment mechanism similar to the roller axis distance adjustment mechanism 238, and to adjust the axis distance (separation distance) of the pair of calendar rollers 201, 201 to adjust the density of the carbon fiber structures S.

[0094] The carbon fiber structure S, which has been pressurized by passing between the pair of calendar rollers 201 and adjusted in density, is transported toward the cutting section 21 where the next process is performed. One of the pair of calendar rollers 201 and 201 is a driven roller driven by the operation of a motor (not shown), and the other is a driven roller. The pair of calendar rollers 201 and 201 have both a function of transporting the carbon fiber structure S toward the downstream side and a function of adjusting the density by pressurization. The motor that drives the calendar roller 201 is electrically connected to a control device 28, and the rotation speed, rotation timing, etc. are controlled.

[0095] As described above, when the center distance between the pair of calendar rollers 201, 201 can be appropriately set, it is possible to adjust the thickness of the carbon fiber structures S sent to the next process and appropriately adjust the density of the carbon fiber structures S. The relationship between the center distance between the pair of calendar rollers 201, 201, the relationship between the thickness of the carbon fiber structures S sent to the cutting section 21, and the relationship between the density of the carbon fiber structures S correspond to each other.

[0096] The cutting unit 21 is disposed downstream of the forming unit 20. The cutting unit 21 is a section that performs a cutting process to cut the carbon fiber structure S into a desired planar shape and size. The cutting unit 21 has a first cutter 211 and a second cutter 212. The first cutter 211 and the second cutter 212 are each operated by a driving source such as a motor or a solenoid (not shown).

[0097] The first cutter 211 cuts the carbon fiber structures S in a direction intersecting the conveyance direction of the carbon fiber structures S, particularly in a direction perpendicular to the conveyance direction.

[0098] The second cutter 212 is disposed downstream of the first cutter 211 and cuts the carbon fiber structures S in a direction parallel to the conveying direction of the carbon fiber structures S. This cutting is performed to remove unnecessary portions from both ends in the width direction of the carbon fiber structures S to adjust the width of the carbon fiber structures S.

[0099] As shown in FIG. 3, the first cutter 211 and the second cutter 212 are each electrically connected to a control device 28, and the timing of cutting and the like are controlled by the operation of the control device 28.

[0100] The carbon fiber structures S having a desired planar shape and size can be obtained by cutting with the first cutter 211 and the second cutter 212. Examples of the desired planar shape of the carbon fiber structures S include a square, a rectangle, and a strip. The carbon fiber structures S may also have other shapes such as a circle, an ellipse, etc.

[0101] The carbon fiber structures S having the desired shape and size as described above are transported further downstream and accumulated in the stock section 22.

[0102] As described above, each of the components of the carbon fiber structure manufacturing apparatus 100 is electrically connected to the control device 28. The operation of each of these components is controlled by the control device 28.

[0103] As shown in FIG. 3, the control device 28 includes a control unit 281, a storage unit 282, and a communication unit 283.

[0104] The control unit 281 has at least one processor and executes various programs stored in the storage unit 282. As the processor, for example, a CPU (Central Processing Unit) can be used. The control unit 281 also has various functions, such as a function to control the driving of the heaters 32 and 33, the electromagnetic valve 343, and the suction pump 351 of the carbon fiber structure manufacturing apparatus 100.

[0105] The memory unit 282 stores various programs, such as a program related to the manufacturing of the carbon fiber structure S, a program related to the operation sequence of the defibrating unit 13, a program related to the operation sequence of the density adjustment unit 23, a program related to the operation sequence of the heater 32 and the heater 33, a program related to the operation sequence of the inert gas supply unit 34, a program related to the operation sequence of the pressure reduction unit 35, a program related to the operation sequence of the molding unit 20, and a program related to the operation sequence of the cutting unit 21.

[0106] The communication unit 283 is composed of, for example, an I / O interface, and communicates with each part of the carbon fiber structure manufacturing apparatus 100. In addition, the communication unit 283 has a function of communicating with a computer or a server (not shown) via, for example, a network.

[0107] The control device 28 may be built in the carbon fiber structure manufacturing apparatus 100, or may be provided in an external device such as an external computer. The control unit 281 and the storage unit 282 may be integrated into one unit, for example, or the control unit 281 may be built in the carbon fiber structure manufacturing apparatus 100 and the storage unit 282 may be provided in an external device such as an external computer, or the storage unit 282 may be built in the carbon fiber structure manufacturing apparatus 100 and the control unit 281 may be provided in an external device such as an external computer.

[0108] The control device 28 controls the operation of each part of the carbon fibrous structure manufacturing apparatus 100, whereby each step as described above is performed and the carbon fibrous structure S can be manufactured.

[0109] As described above, the method for producing carbon fiber structures includes a defibration step of defibrating a material containing cellulose fibers to produce a defibrated material M3, a deposition step of depositing the fine bodies M6 as the defibrated material to produce a deposited second web M7, and a carbonization step of heat treating the second web M7 to carbonize the cellulose fibers to produce carbon fiber structures S. Thus, by appropriately adjusting the conditions in each step, particularly the treatment conditions in the carbonization step, carbon fiber structures S having desired properties can be easily produced.

[0110] The heating temperature in the carbonization step is preferably 300° C. or higher, which allows the cellulose fibers to be carbonized quickly and uniformly.

[0111] As long as the cellulose fibers can be carbonized, the heating temperature in the carbonization process is not limited to the above-mentioned range.

[0112] The carbonization step is preferably carried out in a non-oxidizing atmosphere at a pressure of 500 kPa or less, which allows the cellulose fibers to be carbonized more uniformly.

[0113] As long as the cellulose fibers can be carbonized, the atmosphere in the carbonization process is not limited to the above.

[0114] The carbonization process is continuously performed on the second web M7 as a pile during transportation, whereby carbonization by heat treatment can be performed quickly and uniformly, and the productivity of the carbon fibrous structures S can be increased.

[0115] The carbonization process may be performed intermittently or discontinuously on the second web M7, for example, as a batch process.

[0116] The method for producing carbon fiber structures also includes a density adjusting step, which is performed between the depositing step and the carbonization step, for adjusting the density of the second web M7 as a deposit. By adjusting the density of the second web M7 before carbonizing the cellulose fibers, the density of the produced carbon fiber structures S can be easily adjusted. As described above, the same is true for the properties of the carbon fiber structures S other than the density.

[0117] Furthermore, by increasing the density of the second web M7 before performing the carbonization process, it is possible to prevent or suppress outside air from flowing into the chamber 31 through the second web M7 at the supply port 311. As a result, it is possible to more effectively ensure airtightness at the supply port 311, and the carbonization process can be more satisfactorily performed.

[0118] In the present invention, the density adjusting step may be omitted, that is, the density adjusting unit 23 may be omitted.

[0119] The method for producing the carbon fibrous structures also includes a forming step of forming the carbon fibrous structures S produced in the carbonization step into a sheet shape, which makes it possible to adjust the density of the carbon fibrous structures S or form them into a desired thickness, for example.

[0120] In the present invention, the molding step may be omitted, that is, the molding section 20 may be omitted.

[0121] The method for producing the carbon fiber structures also includes a cutting step of cutting the sheet-like carbon fiber structures S produced in the molding step into a desired planar shape or size. This allows the carbon fiber structures S to be processed into a desired planar shape or size.

[0122] In the present invention, the cutting step may be omitted. That is, the cutting unit 21 may be omitted. In this case, it is preferable that the stock unit 22 is configured to wind up the belt-shaped carbon fiber structure S in a roll shape.

[0123] Although the manufacturing method and the apparatus for manufacturing carbon fiber structures according to the present invention have been described above with reference to the illustrated embodiments, the present invention is not limited thereto.

[0124] Each step in the method for producing carbon fibrous structures can be replaced with any step that can exert a similar function. In addition, in the method for producing carbon fibrous structures, any step may be added before or after each of the steps.

[0125] Each part constituting the carbon fiber structure manufacturing apparatus can be replaced with any other part having a similar function. In addition, any other component may be added to the carbon fiber structure manufacturing apparatus.

[0126] Moreover, the carbon fibrous structure manufacturing apparatus may omit the raw material supply unit 11 and the coarse crushing unit 12. In this case, the carbon fibrous structure manufacturing apparatus includes a coarse crushed piece supply unit that supplies coarse crushed pieces, instead of the raw material supply unit 11 and the coarse crushing unit 12. [Explanation of symbols]

[0127] 3...carbonization processing section, 11...raw material supply section, 12...crushing section, 13...defibration section, 14...sorting section, 15...web formation section, 16...subdivision section, 18...dispersion section, 19...accumulation section, 20...molding section, 21...cutting section, 22...stock section, 23...density adjustment section, 27...recovery section, 28...control device, 31...chamber, 32...heater, 33...heater, 34...inert gas supply section, 35...pressure reduction section, 100...carbon fiber structure Manufacturing apparatus, 121...crushing blade, 122...chute, 141...drum section, 142...housing section, 151...mesh belt, 152...tension roller, 153...suction section, 161...propeller, 162...housing section, 172...pipe, 173...blower, 181...drum, 182...housing, 191...mesh belt, 192...tension roller, 193...suction section, 201...calendar roller, 2 11...first cutter, 212...second cutter, 230...calender roller, 231...humidifying section, 232...humidifying section, 233...humidifying section, 234...humidifying section, 235...humidifying section, 236...humidifying section, 238...roller axis distance adjustment mechanism, 241...pipe, 242...pipe, 243...pipe, 244...pipe, 245...pipe, 246...pipe, 261...blower, 262...blower, 263...blower, 281...control section, 2 82...storage unit, 283...communication unit, 311...supply port, 312...discharge port, 341...inert gas storage unit, 342...supply pipe, 343...electromagnetic valve, 351...suction pump, 352...suction pipe, G...inert gas, M1...raw material, M2...coarsely crushed pieces, M3...defibrated material, M4-1...first sorted material, M4-2...second sorted material, M5...first web, M6...fragmented body, M7...second web, S...carbon fiber structure, S0...internal space

Claims

1. A defibration process for defibrating a material containing cellulose fibers to produce a defibrated material; a depositing step of depositing the defibrated material to generate a deposit; and a carbonization step of subjecting the deposit to a heat treatment to carbonize the cellulose fibers to produce carbon fibrous structures.

2. The method for producing carbon fibrous structures according to claim 1 , wherein a heating temperature in the carbonization treatment step is 300° C. or higher.

3. The method for producing carbon fibrous structures according to claim 1 , wherein the carbonization step is carried out in a non-oxidizing atmosphere at a pressure of 500 kPa or less.

4. The method for producing carbon fibrous structures according to claim 1 , wherein the carbonization step is performed continuously on the deposit during transportation.

5. The method for producing carbon fibrous structures according to claim 1 , further comprising a density adjusting step, which is carried out between the depositing step and the carbonizing step, to adjust a density of the deposit.

6. The method for producing carbon fibrous structures according to claim 1 , further comprising a forming step of forming the carbon fibrous structures produced in the carbonization step into a sheet shape.

7. The method for producing carbon fibrous structures according to claim 6 , further comprising a cutting step of cutting the sheet-like carbon fibrous structures produced in the molding step into a desired planar shape or size.

8. The method for producing carbon fibrous structures according to claim 7 , wherein the carbon fibrous structures are used as a filter for adsorbing foreign matter.

9. a defibrator unit that defibrates a material containing cellulose fibers to generate a defibrated material; a depositing section that deposits the defibrated material to generate a deposit; a carbonization processing unit that performs a heat treatment on the deposit to carbonize the cellulose fibers and produce carbon fibrous structures.

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