WO2012133614A1

WO2012133614A1 - Carbon fiber bulk

Info

Publication number: WO2012133614A1
Application number: PCT/JP2012/058301
Authority: WO
Inventors: 清水　保雄; 充関野; 壮則早川; 芹澤　和泉
Original assignee: 株式会社オーク製作所; 国立大学法人信州大学
Priority date: 2011-03-31
Filing date: 2012-03-29
Publication date: 2012-10-04
Also published as: CN103459314B; CN103459314A; TW201238651A; KR20140014208A

Abstract

In this method for producing carbon fiber bulk, carbon fibers are aligned in the axial direction and packed into a cylindrical member and the cylindrical member packed with the carbon fibers is stretched and reduced in diameter. This carbon fiber bulk is a long fiber wherein anisotropic carbon fibers are formed integrally into a bundle shape and carbon is attached to the carbon fibers within the carbon fiber bundle, the packing rate of the carbon fibers within the carbon fiber bundle being 75% or higher.

Description

Carbon fiber bulk

The present invention relates to a carbon fiber bulk obtained by forming a long-fiber carbon material into a bundle, and a method for producing a carbon fiber-filled bulk.

Carbon fiber is light and high in strength, and has excellent functionality in terms of conductivity, thermal conductivity, adsorptivity, etc., and is used in various technical fields. For example, a continuous carbon fiber having a tensile strength can be provided on the conductor center line and covered to form a power transmission line (see Patent Document 1).

Moreover, a thin and thick carbon fiber reinforced resin (CFRP) in which light and high-strength carbon fibers are aligned in the longitudinal direction can be inserted into a hollow metal pipe to form a power transmission shaft (Patent Literature). 2).

On the other hand, it is also possible to use carbon fiber as an adsorbing material for an adsorption tank for gas separation, paying attention to the high adsorbability of carbon fiber. For example, a continuous carbon fiber for separating nitrogen and oxygen can be filled in an adsorption tank, and nitrogen gas can be separated with high purity (see Patent Document 3).

There, a method of press-fitting is described as a method of filling carbon fibers. First, carbon fibers having a predetermined length are arranged in the axial direction and filled in an inverted split jig to form a fiber bundle in the jig. Then, the fiber bundle is press-fitted along the axial direction from the jig toward the filling tank to fill the adsorption tank with the carbon fiber.

As a carbon fiber composite material (C / C composite) with improved thermal conductivity, a carbon fiber-boron carbide composite material in which carbon fibers are bundled and carbon is filled in the gaps is known (Patent Document 4). reference).

Therefore, in order to produce a highly conductive carbon fiber bundle, the bundled carbon fiber is immersed in a solution in which a phenol resin is dissolved, dried, and then fired at a high temperature. In the sintered body, the phenol resin is carbonized and adheres to the carbon fiber bundle, thereby preventing a decrease in thermal conductivity caused by the contact of boron carbide.

Japanese Patent No. 3475433 JP 2002-235726 A JP-A-6-190272 JP-A-8-81261

The present invention is directed to providing a carbon fiber bulk filled with carbon fibers at an unprecedented high density. In addition, the carbon fiber filling bulk which filled the cylindrical member with the carbon fiber shall also be contained in a carbon fiber bulk.

The carbon fiber bulk manufacturing method of the present invention is characterized in that a cylindrical member is filled with carbon fibers aligned in the axial direction, and the cylindrical member filled with the carbon fiber is stretched and reduced in diameter. For example, the diameter of the cylindrical member can be reduced by swaging. In addition, the tubular member can be filled with the carbon fiber bundle at a filling rate of 75% or more.

For example, in the manufacturing method, the cylindrical member can be stretched and reduced in diameter so that the cross-sectional shape is deformed in at least a part of the filled carbon fibers.

Further, in the manufacturing method, a carbon fiber in which one end side of the reduced cylindrical member is immersed in a solution containing a thermosetting resin and impregnated with the thermosetting resin along the fiber length direction. The bundle can be cured by heat treatment. After curing by heat treatment, the carbon fiber bundle can be carbonized.

For example, in the manufacturing method, it is possible to immerse one end of the cylindrical member in the solution. Further, it is possible to immerse the cylindrical member so that a portion of 70 to 80% of the remaining void portion of the carbon fiber bundle filled in the cylindrical member is impregnated with the thermosetting resin. Or it is also possible to take out a carbon fiber bundle from the said cylindrical member after a thermosetting process.

It is also possible to provide a discharge lamp in which a carbon fiber bulk manufactured by such a carbon fiber bulk manufacturing method is configured as a part of at least one electrode.

On the other hand, the carbon fiber bulk in another aspect of the present invention is formed by integrally forming a bundle of carbon fibers that are long fibers and having anisotropy, and carbon is converted into carbon fibers inside the carbon fiber bundle. It adheres and the filling rate of the carbon fiber in the said carbon fiber bundle is 75% or more, It is characterized by the above-mentioned. For example, the carbon contained in the carbon fiber bundle has no anisotropy.

As an example, the carbon content in the vicinity of one end face of the carbon fiber bundle is lower than the carbon content in the vicinity of the other end face. In addition, the occupation ratio of carbon in the region other than the carbon fiber bundle may be in the range of 40 to 90%. Furthermore, the thermal conductivity in the length direction of the carbon fiber bundle may be more than five times the thermal conductivity in the direction perpendicular to the length direction.

It is possible to provide a discharge lamp in which such a carbon fiber bulk is configured as a part of at least one electrode.

According to the present invention, it is possible to provide a molded body made of carbon fiber having excellent heat-related functionality.

It is process drawing which showed the manufacturing method of the carbon fiber filling bulk which is 1st Embodiment. It is typical sectional drawing of the electrode for discharge lamps incorporating the carbon fiber filling bulk. It is process drawing which showed the first half of the manufacturing method of the carbon fiber bulk which is 2nd Embodiment. It is process drawing which showed the second half of the manufacturing method of the carbon fiber bulk which is 2nd Embodiment. It is typical sectional drawing of the electrode for discharge lamps incorporating a carbon fiber bulk. It is the figure which showed the photograph which image | photographed the metal pipe filled with carbon fiber from the diagonal direction. It is the figure which showed the photograph which image | photographed the compaction filling state of the carbon fiber when a metal pipe was cut | disconnected using the optical microscope. It is the figure which cut | disconnected the carbon fiber filling bulk of the sample 1, and showed the photograph which image | photographed the high density filling state of the carbon fiber in a cut surface by SEM observation. It is the figure which cut | disconnected the carbon fiber filling bulk of the sample 2, and showed the photograph which image | photographed the high-density filling state of the carbon fiber in a cut surface by SEM observation. It is a figure which shows the photograph which image | photographed the cross section of the carbon fiber bundle impregnated with the phenol resin, and the carbon fiber bundle not impregnated with the phenol resin. It is a figure which shows the microscope picture inside the carbon fiber bundle after carbonizing. It is the graph which showed the anisotropy of thermal conductivity. It is the graph which showed the anisotropy of the thermal expansion coefficient. It is the graph which showed the relationship between the thermal conductivity in a carbon fiber filling bulk, and temperature.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a process diagram showing a carbon fiber-filled bulk manufacturing method according to the first embodiment.

As shown in FIG. 1, a carbon fiber 100 having a predetermined length and a hollow cylindrical member 200 are prepared as bulk materials. The carbon fiber 100 has a fiber structure in which a carbon fiber yarn composed of hundreds to thousands of carbon fiber filaments is a single body, and is composed of a plurality of carbon fiber yarns.

The cylindrical member 200 is made of a metal pipe such as tantalum or molybdenum. Here, the axial length is set shorter than that of the carbon fiber bundle 100. The cylindrical member 200 is formed from a plate-shaped metal member by welding. The weld joint 210 is formed in the axial direction here, but can also be formed in a spiral shape.

In the first filling step, the carbon fiber 100 is inserted into the cylindrical member 200 and filled. The carbon fiber 100 is prepared in an amount that fills up the internal space of the cylindrical member 200 to the maximum, and the carbon fiber 100 is accommodated in the cylindrical member 200 as a bundle. As a filling method, a method of pushing the carbon fiber 100 into the cylindrical member 200 by manual work can be applied, or press-fitting can be performed using a press machine or the like.

In the filling step, the carbon fiber bundle 100 is inserted into the cylindrical member 200 so that the cylindrical member 200 is not plastically deformed. At this time, the end face of the carbon fiber bundle 100 is filled so as to protrude from the cylindrical member 200. By the filling process, the filling rate of the cylindrical member 200 in a predetermined cross section reaches approximately 60 to 70 percent here. However, the filling rate represents the ratio of the cross-sectional area of the carbon fiber 100 to the internal space cross-sectional area of the tubular member 200. In addition, it is assumed that the filling rate of the carbon fibers 100 is substantially uniform along the axial direction.

The cylindrical member 200 filled with the carbon fiber bundle 100 is set in a swaging machine. Then, swaging is performed through the die 50 of the swaging machine. By the swaging process, the cylindrical member 200 is plastically deformed and extends along the axial direction, and the peripheral portion is narrowed to reduce the diameter. At this time, the diameter is reduced so that the filling rate of the carbon fibers 100 is 90% or more and so that the filling rate is uniform along the axial direction. Here, the diameter of the cylindrical member 200 is reduced so as to be approximately 2/3 of that before processing. By swaging, at least a part or the whole of the carbon fiber bundle 100, the carbon fiber having a circular cross section is elastically deformed by pressure welding. Thereafter, the end of the carbon fiber bundle 100 is cut to obtain a predetermined length. Here, cutting is performed using a cutting tool such as a fine cutter.

After manufacturing the cylindrical member 200 stretched in the axial direction by swaging and performing a cutting process, heat treatment is performed on the cylindrical member 200 under a temperature atmosphere of a predetermined temperature (eg, 1500 ° C. to 2000 ° C.). Do time. Through this heat treatment, the carbon fiber-filled bulk 400 is manufactured. The carbon fiber-filled bulk 400 is a molded body in which the filling density (bulk density) of carbon fibers is extremely increased, and is pressed against each other until the carbon fibers having a circular cross section are elastically deformed and are compactly filled. Also, the inner carbon fiber bundle has high convergence. By such high-density filling, the carbon fiber-filled bulk 400 is formed into a molded body having excellent thermal conductivity and thermal diffusibility. For example, as a heat transfer member for a discharge lamp electrode or a heat conductive member such as a heat pump. Can be used.

FIG. 2 is a schematic cross-sectional view of a discharge lamp electrode incorporating a carbon fiber filled bulk.

The anode 30 is a discharge electrode used in the short arc type discharge lamp 10 and is held in the vertical direction by the electrode support rod 40. The anode 30 has a cylindrical space 33 at the center of the electrode body 32, and a carbon fiber filled bulk 36 is accommodated in the cylindrical space 33.

A columnar electrode lid 39 that matches the size of the cylindrical space 33 is coupled to the electrode body 32 to seal the cylindrical space 33. The electrode support bar 40 is connected and fixed to the electrode lid 39 and holds the anode 30 via the electrode lid 39.

The electrode body 32, the electrode lid 39, and the electrode support rod 40 are made of tungsten (W). On the other hand, the carbon fiber-filled bulk 36 extending along the electrode axis inside the anode 30 is configured as a heat transfer body in which the carbon fibers 38 are filled in a hollow pipe 37 made of tantalum metal at a high density, and is manufactured as described above. Molded according to the method.

The end face of the carbon fiber 38 having high convergence properties protrudes from both ends of the hollow pipe 37, and both end faces are smooth. That is, when the end portions of the carbon fiber filaments are aligned along the axial direction, the entire end surface of the carbon fiber is smooth so as to define a flat surface without distortion, and a state in which the carbon fiber filament partially protrudes or is short in length. It does not occur substantially. Further, one end surface of the carbon fiber 38 is in close contact with the electrode lid 39 and the bottom surface of the cylindrical space 33 and is connected to the electrode tip portion 32S. Therefore, the heat generated by the collision with the electrons from the cathode (not shown) received by the electrode tip 32S during the discharge is caused by the high density filled carbon fibers 38 having excellent thermal conductivity and thermal responsiveness. Transported to the side.

Thereby, the temperature of the anode 30 is made uniform as a whole without locally heating the electrode tip 32S. As a result, it is possible to prevent devitrification due to melting and evaporation of the electrode tip portion 32S, and to reduce the light emission efficiency, and to suppress electrode consumption. Moreover, since it has suitable electroconductivity, even if input electric power becomes large and an electric current amount increases, it does not affect discharge.

As described above, according to the present embodiment, the carbon fiber 100 constituted by a plurality of yarns and the hollow cylindrical member 200 made of metal are prepared, and the carbon fiber 100 is aligned in the axial direction with respect to the hollow cylindrical member 200. Fill. After filling, the hollow cylindrical member 200 is subjected to swaging using a die 50. After swaging, the carbon fiber-filled bulk 400 is formed by cutting and heat treatment.

By stretching the carbon fiber after filling it, that is, reducing the diameter, there were relatively many gaps between the carbon fibers in the stage before the stretching, but the carbon fibers were substantially free of gaps as the carbon fibers were elastically deformed. The fibers are filled in a consolidated state. As a result, it has excellent thermal conductivity and thermal diffusivity along the entire axial length inside the bulk without impairing the thermal conductivity and thermal diffusibility of the carbon fiber itself. Moreover, the thermal conductivity and diffusibility are equal in any part of the bulk cross section, and the uniformity of the heat transport capability is maintained. In particular, by setting the filling rate to 90% or more, the carbon fibers can be brought into close contact with each other while being elastically deformed so that there is no gap, and can have better thermal conductivity.

The filling method and swaging process are not limited to the above carbon fiber filling method and swaging process. In order to stretch and reduce the diameter, other plastic working that reduces the diameter substantially uniformly along the axial direction may be used. Further, in the filling step, the carbon fiber may be packed as tightly as possible in the cylinder internal space without applying a force that plastically deforms the cylindrical member. Furthermore, the carbon fibers are not limited to filament-like carbon fibers in yarn units, and may have any cross-sectional shape and a structure in which a plurality of carbon fibers are filled in a bundle. The smoothing of the carbon fiber end face may be performed on at least one end face. Moreover, it is not necessary to smooth the carbon fiber end face.

Next, a method for manufacturing a carbon fiber-filled bulk according to the second embodiment will be described with reference to FIGS. In the second embodiment, a carbon fiber-filled bulk having excellent thermal conductivity is manufactured.

FIG. 3A and FIG. 3B are process diagrams showing a carbon fiber-filled bulk manufacturing method according to the second embodiment.

As shown in FIG. 3A, carbon fibers (CF) 100, which are long fibers arranged in a predetermined length, and a hollow cylindrical member 200 are prepared as bulk materials before production. The carbon fiber 100 has a fiber structure in which a carbon fiber yarn composed of hundreds to thousands of carbon fiber filaments is a single body, and is composed of a plurality of carbon fiber yarns.

The carbon fiber 100 has extremely high anisotropy with respect to thermal conductivity, and the thermal conductivity in the fiber length direction is extremely larger than that in the vertical direction. For example, mesophase pitch CF, which is a high-performance carbon fiber that realizes high thermal conductivity, is applicable.

The cylindrical member 200 is made of a metal pipe such as tantalum, molybdenum, or stainless steel (SUS), and has a shorter axial length than the carbon fiber 100 here. The cylindrical member 200 is formed from a plate-shaped metal member by welding. The weld joint 210 is formed in the axial direction here, but can also be formed in a spiral shape.

In the first filling step, the carbon fiber bundle 100 is bundled and inserted into the cylindrical member 200 for filling. At this time, the carbon fibers 100 are aligned in the axial direction of the cylindrical member 200 and filled so that the fibers do not intersect (hereinafter, the bundled carbon fibers 100 are also expressed as the carbon fiber bundle 100).

The carbon fiber 100 is prepared in an amount that fills the inner space of the cylindrical member 200 as much as possible. As a filling method, a method of pushing the carbon fiber 100 into the cylindrical member 200 by manual work can be applied, or press-fitting can be performed using a press machine or the like.

In the filling step, the carbon fiber bundle 100 is inserted into the cylindrical member 200 so that the cylindrical member 200 is not plastically deformed. Moreover, it is filled so that the end surface of the carbon fiber bundle 100 may protrude from the cylindrical member 200.

In the filling step, the filling rate of the cylindrical member 200 in a predetermined cross section reaches approximately 60 to 70% here. However, the filling rate represents the ratio of the cross-sectional area occupied by the carbon fiber bundle 100 to the arbitrary internal space cross-sectional area of the tubular member 200. Moreover, the filling rate of the carbon fiber bundle 100 along the axial direction is assumed to be substantially uniform.

The cylindrical member 200 filled with the carbon fiber bundle 100 is set in a swaging machine including a die 150. After setting, swaging is performed through the die 150. The tubular member 200 is plastically deformed by swaging and extends along the axial direction, and the peripheral portion is narrowed down to reduce the diameter.

At this time, the diameter of the carbon fiber 100 is reduced to 75% or more (preferably 80% or more). Further, the diameter is reduced so that the filling rate is substantially uniform along the axial direction.

However, regarding the diameter reduction, the ideal filling rate at which the highest density is obtained is theoretically about 91% at maximum, and it is preferable to suppress the carbon fiber to the above-mentioned maximum filling rate at which the carbon fibers are not elastically deformed by contact between the fibers. After reducing the diameter, one end of the carbon fiber bundle 100 is cut to obtain a predetermined length. Here, it cuts using cutting tools, such as a fine cutter.

Next, the cylindrical member 300 extended in the axial direction by swaging is immersed in the solution 400 ′ contained in the container M from the end side (see FIG. 3B). The solution 400 ′ is a solution containing the thermosetting resin F. For example, a solution in which a resol type phenol resin is dissolved is used as the solution. A novolac type phenolic resin is also applicable, and in this case, an additive for thermosetting is added.

In the dipping process of the carbon fiber bundle 100, the entire tubular member 300 is not dipped in the solution 400 ′, but the end portion 100T of the carbon fiber bundle 100 is dipped in the solution 400 ′, and the other not shown is illustrated. The end is not soaked. When the carbon fiber bundle 100 is partially immersed in this way, the thermosetting resin F of the solution 400 ′ is sucked up into the carbon fiber bundle 100 by capillary action, and the liquid thermosetting resin F is inside the carbon fiber bundle 100. Impregnate into.

By impregnating the carbon fiber bundle 100 with the thermosetting resin F along one direction, the air inside the carbon fiber bundle 100 is not immersed in the carbon fiber bundle 100 according to the penetration of the thermosetting resin F. Discharged from the edge. As a result, a large amount of the thermosetting resin F is impregnated in the voids inside the carbon fiber bundle 100.

In the capillary phenomenon, since the suction height is determined by the surface tension of the liquid, the wettability of the material, and the density of the liquid, it is desirable that the thermosetting resin has a low viscosity and a low density. Moreover, it is desirable to use a thermosetting resin having a high residual carbon ratio as the thermosetting resin.

Once the carbon fiber bundle 100 is impregnated with the thermosetting resin F, a thermosetting process using the heating device 600 is then performed at a predetermined temperature (here, 140 ° C. or higher). Further, an impurity removal process is performed at a predetermined temperature (eg, 700 ° C. or higher) in a vacuum atmosphere. As a result, the liquid thermosetting resin F contained in the carbon fiber bundle 100 is cured.

The above-described immersion treatment in the solution 400 ', thermosetting treatment, and impurity removal treatment are repeated a plurality of times. Specifically, the process is repeated until the thermosetting resin F occupies 70 to 80% of the void portion of the carbon fiber bundle 100.

Then, the carbon fiber bulk 100 ′ is taken out from the tubular member 500. The carbon fiber bundle 100 ′ can be pulled out from the tubular member 500 by extrusion or the like due to a difference in thermal expansion coefficient between the tubular member 500 and the carbon fiber material.

The taken-out carbon fiber bulk 100 'forms a glossy lump molded body, and the thermosetting resin F is exposed to the bulk surface. The carbon fiber bulk 100 ′ is finally carbonized at a predetermined temperature (for example, 1000 to 2300 ° C.) using a vacuum furnace 700 (or a heating apparatus containing an inert gas).

As a result, in the carbon fiber bulk 100 ′, carbon having no anisotropy with respect to thermal conductivity adheres between the carbon fibers and partially fills the void portion. The carbon occupancy in the space region other than the carbon fiber bundle reaches 40 to 90%.

The carbon occupancy is substantially within the range of 40 to 90% along the fiber length direction of the carbon fiber bundle 100, but since the phenol resin is impregnated from one direction into the carbon fiber bundle, it is immersed in the solution. The occupying ratio of carbon at the other end portion of the carbon fiber bundle that is not is smaller than the occupying ratio of carbon at the end side immersed in the solution. In order to make the carbon occupying ratio of the other end as close as possible to the carbon occupying ratio of the impregnation side end as much as possible, the dipping is performed twice or more here.

The carbon fiber bulk 100 ′ is a molded body in which the packing density (bulk density) of the carbon fibers is extremely increased, and the inner carbon fiber bundle has high convergence. By such high-density filling, the carbon fiber bulk 100 ′ becomes a molded body having excellent thermal conductivity and thermal diffusivity.

Particularly, the carbon fiber bulk 100 ′ has excellent thermal conductivity along the fiber arrangement direction, and has large anisotropy with respect to thermal conductivity. Specifically, the thermal conductivity in the fiber length direction is 5 times or more, for example, 20 times or more compared to the vertical direction. Therefore, it can be used as a heat transfer member for a discharge lamp electrode or a heat conducting member such as a heat pump and a thermoelectric conversion element. Therefore, it can be used as a heat transfer member for a discharge lamp electrode or a heat conducting member such as a heat pump and a thermoelectric conversion element.

FIG. 4 is a schematic cross-sectional view of a discharge lamp electrode incorporating a carbon fiber bulk.

The anode 30 is a discharge electrode used in the short arc type discharge lamp 10 and is held in the vertical direction by the electrode support rod 40. The anode 30 has a cylindrical space 37 in the center of the electrode body 32, and the carbon fiber bulk 50 is accommodated in the cylindrical space 37. A similar configuration can be adopted for the cathode.

A columnar electrode lid 39 that matches the size of the cylindrical space 37 is coupled to the electrode body 32 to seal the internal space 37. The electrode support bar 40 is connected and fixed to the electrode lid 39 and holds the anode 30 via the electrode lid 39.

The electrode body 32, the electrode lid 39, and the electrode support rod 40 are made of tungsten (W). On the other hand, the carbon fiber bulk 50 extending along the electrode axis inside the anode 30 is a heat transfer body in which the carbon fibers 38 are bundled in a high density as described above, and according to the manufacturing method described above. Molded.

Both end surfaces of the carbon fiber bulk 50 are smooth, and both the electrode lid 39 and the bottom surface of the cylindrical space 37 are in close contact with each other and connected to the electrode tip portion 32S. Accordingly, heat generated by collision with electrons from the cathode (not shown) received by the electrode tip 32S during discharge is transported to the electrode support rod side by the carbon fiber bulk 50.

Thereby, the temperature of the anode 30 is made uniform as a whole without locally heating the electrode tip 32S. As a result, it is possible to prevent devitrification due to melting and evaporation of the electrode tip portion 32S, and to reduce the light emission efficiency, and to suppress electrode consumption. Moreover, since it has suitable electroconductivity, even if input electric power becomes large and an electric current amount increases, it does not affect discharge. Furthermore, since there is a gap between the carbon fiber bulk 50 and the electrode internal space, the structure has excellent heat dissipation even in the radial direction and the oblique direction.

Thus, according to the second embodiment, carbon fibers that are long fibers are bundled and filled in the axial direction in the tubular member to reduce the diameter of the tubular member. Then, one end portion 100 </ b> T of the carbon fiber bundle is immersed in a solution 400 ′ containing the thermosetting resin F, and the carbon fiber bundle 100 is impregnated with the thermosetting resin F. Then, after carbonizing, the carbon fiber bulk 100 'is produced.

The cylindrical member filled with the carbon fiber bundle is reduced in diameter to improve the filling rate, and the entire portion is impregnated with the thermosetting resin from one end side of the carbon fiber bundle, so that a slight carbon fiber gap is filled with carbon. As a result, a large amount of carbon adheres to the surface of the bundle. As a result, a high-density carbon fiber bundle is formed as a strong lump. And it can have very excellent thermal conductivity in the fiber length direction.

In particular, when the carbon fiber bundle is filled in the cylindrical member, the filling rate is 75% or more, so that the thermal conductivity anisotropy can be easily ensured when the thermosetting treatment is performed. In addition, the penetration of the thermosetting resin by capillary action is facilitated.

Further, by impregnating the thermosetting resin in a region of 70 to 80% with respect to the void portion between the carbon fibers in the cylindrical member, the proportion of carbon after the carbonization treatment becomes 40 to 90%, The carbon fiber bulk is more firmly integrated. When the carbon content is 90% or more, the carbon fiber bulk shrinks during the carbonization treatment, but at this time, distortion tends to occur and cracks may occur. This can be prevented by adjusting the degree of impregnation of the thermosetting resin.

In addition, when carbon fibers are filled and then stretched, that is, when the diameter is reduced, a relatively large number of gaps between carbon fibers are filled in a state in which carbon fibers are in close contact before stretching. As a result, it has excellent thermal conductivity and thermal diffusivity along the entire axial length inside the bulk without impairing the thermal conductivity and thermal diffusibility of the carbon fiber itself.

In addition, regarding the manufacturing method of the said carbon fiber bulk, you may impregnate the thermosetting resin in the carbon fiber bundle in a cylindrical member, without performing a swaging process. Furthermore, the carbon fiber bundle may not be filled into the cylindrical member, but the carbon fiber bundle may be integrally held with other configurations, and the thermosetting resin may be permeated from one end. Moreover, you may make it impregnate by methods other than immersing one edge part of a cylindrical member in a solution.

The first embodiment and the second embodiment have been described above, but the present invention is not limited to such an embodiment. The present invention described in the first embodiment and the second embodiment pays attention to the following problems and realizes an excellent carbon fiber-filled bulk by an unprecedented manufacturing method.

First, the present invention relating to the first embodiment will be described.

Conventionally, a molded body in which a cylindrical member is filled with carbon fiber is configured as a molded body in consideration of mechanical strength, adsorptivity, and the like. However, these carbon fiber-filled bulks are structured on the premise of products such as electric wires with direct external force, power transmission shafts, or adsorption devices that suck in outside air, and these products have good flexibility or Inflow of outside air is inevitable. Therefore, the carbon fiber is filled with a certain amount of gaps and gaps between the fibers.

On the other hand, carbon fiber is graphitized at a high temperature (about 3000 ° C), so it has excellent thermal conductivity and thermal diffusion (temperature diffusion) properties, and uses carbon fiber-filled bulk for products that reach high temperatures. It is possible. For example, in a short arc type discharge lamp, it is necessary to heat the electrode to a stable lighting state early in order to ensure good lamp startability, while heat is released from the electrode (particularly the electrode tip) that becomes hot during lamp lighting. Therefore, an electrode made of a material having excellent thermal conductivity is required.

However, even when trying to apply carbon fiber-filled bulk to such products, no bulk manufacturing method has been established so far that can fully exploit the thermal conductivity and thermal diffusivity of carbon fiber. It is not possible to mold a carbon fiber filled bulk with

The present invention is a method for producing a carbon fiber-filled bulk, which is a production method for providing a bulk filled with carbon fibers at an unprecedented high density, further comprising a filling step and further densifying the filled carbon fibers. Including a step of improving the filling rate. In the filling step, the cylindrical member is filled with carbon fibers aligned in the axial direction. In the densification (high filling rate) step, the cylindrical member filled with carbon fiber is stretched to reduce the diameter.

In the present invention, the tubular member whose inside is already filled with carbon fibers by the filling step is processed by stretching, which is a process that cannot be taken from the viewpoint of loss of functionality in the conventional bulk molding, so that the tubular member is Stretching in the direction to reduce the diameter, creating a higher density filling state inside the cylindrical member. Thereby, the internal density of the bulk approaches the carbon fiber to the limit, and there are almost no gaps between the carbon fibers.

Generally, thermal conductivity is determined by multiplying thermal diffusivity, specific heat capacity and specific gravity. According to the carbon fiber filling structure in a state of being pressed at high density (consolidation state) as in the present invention, even if the carbon fibers are packed in a bundle, the original thermal conductivity of the carbon fibers is not impaired in the bulk. Good heat transport capability works. In addition, by realizing higher density by stretching and shrinking the cylindrical member as in the present invention, the thermal conductivity along the axial direction as a single bulk is further increased, The heat transport capability along the axial direction is effectively utilized, and a bulk having excellent thermal conductivity can be formed.

Moreover, in order to reduce the diameter of the tubular member by stretching, the carbon fiber inside the tubular member is accommodated in a more integrated and close state than the conventional carbon fiber-filled bulk, and is compactly filled in the axial direction. The degree is uniform, and the filling rate is almost equal in any cross section.

Thus, by filling the carbon fiber with a high density and a high filling rate, which is not conventional, a bulk having excellent heat-related functionalities such as thermal conductivity, heat capacity, and thermal diffusion can be formed. On the other hand, conventional functions such as high strength and electrical conductivity as a carbon fiber are sufficiently provided, and can be incorporated into a complex structure, an assembly combining metal materials, and the like. In particular, since carbon fiber has a lower specific gravity than metals such as tungsten, it is possible to form a bulk having a high volumetric efficiency (with a smaller diameter) and a heat transport capability.

Carbon fiber filled bulk that realizes such high-density filling can be applied to various products, and it can be used for products in which heat-related functionality such as heat resistance and heat conductivity is important as well as electrical conductivity. Is possible. For example, the carbon fiber filled bulk can be configured as an electrode body of a discharge lamp such as a short arc type discharge lamp or a part thereof. In addition, the carbon fiber-filled bulk can be used for electric wires that supply a large current, and the influence of heat loss due to electric power can be suppressed. Alternatively, it can be used as a heat conducting member such as a heat pipe.

In the carbon fiber filling step, various filling methods can be applied. To the extent that the cylindrical member does not apply as much force as possible to plastically deform in the filling step, the carbon fiber is filled in the inner space of the cylindrical member with as little gap as possible. Insert it so that it fills up. The carbon fiber may be filled manually, or the carbon fiber may be filled using a machine such as a press. Further, in consideration of bonding with other members or the like, the filling process may be performed so that at least one end face of the carbon fiber protrudes from the tubular member.

In the step of expanding and reducing the diameter of the cylindrical member, it is desirable to perform swaging processing in consideration of stably reducing the diameter of the plastic cylindrical member made of metal or the like. By swaging, the cylindrical member can be reduced in diameter with a uniform thickness, and a bulk with a uniform carbon filling rate can be formed along the axial direction. Moreover, the functionality of the carbon fiber can be improved by heat treatment after swaging.

As the cylindrical member, for example, a hollow or tubular member such as a pipe can be applied, and in particular, a metal pipe that is stably plastically deformed during the swaging process is preferably applied. Carbon fibers can be filled with various forms of carbon fiber, and when manually filled, yarns composed of a certain number (thousands to tens of thousands) of long carbon fiber filaments are filled. You may let them.

When filling is performed manually or by machining such as a press-fitting press, the filling rate (volume ratio) at that time is limited, and the filling rate before the swaging step is, for example, approximately 75% or less. In order to achieve high density filling, it is preferable to stretch the carbon fiber so that the filling rate is at least 85 percent. Alternatively, the bulk having the same high heat transport capability can be obtained by stretching and reducing the diameter of the cylindrical member so that the cross-sectional shape of the plurality of filled carbon fibers is elastically deformed or plastically deformed. Can be molded. In particular, a high-density carbon fiber filling structure that eliminates gaps between carbon fibers as much as possible is realized with a filling rate of 90 percent or more.

In order to achieve high-density filling, it is preferable to reduce the diameter appropriately in the swaging process. The degree of diameter reduction is determined based on the material characteristics of the cylindrical member, the strength of the carbon fiber, the size, and the like. For example, high-density filling can be achieved by reducing the diameter of the cylindrical member within a range of 1/4 to 3/4. In particular, by reducing the diameter of the cylindrical member by about 3/4, it is possible to mold a bulk having a filling rate of nearly 95%. This is a density higher than the theoretical density of 78.6% when the cross-section circular carbon fibers are arranged in a square lattice.

When connecting a bulk between certain members and exerting a heat conduction function, it is desirable that the carbon fiber end faces are brought into total contact. For this reason, the carbon fiber is preferably filled so that at least one end face of the carbon fiber that has been compactly filled is smooth. However, the smoothness here means the smoothness required for a general fiber end face. For example, even by SEM observation, the ends of the carbon fibers are aligned in the axial direction, and the carbon fiber end face is Smooth enough to define the plane as a whole. The cutting process may be performed after the stretching process and before or after the heat treatment.

The carbon fiber-filled bulk of the present invention includes a cylindrical member that is stretched and reduced in diameter, and a carbon fiber that is densely filled inside the cylindrical member, and the carbon fibers are filled in the axial direction. ing. And carbon fiber is filled in the cylindrical member so that the cross-sectional shape may deform | transform in at least one part of carbon fiber, It is characterized by the above-mentioned. Thereby, the outstanding functionality regarding a heat | fever can be given. On the other hand, the carbon fiber-filled bulk of the present invention having the same heat-related functionality is characterized in that carbon fibers are filled in a cylindrical member so that the cross-sectional shape of at least a part of the carbon fibers is deformed. To do. This filling rate is a filling rate that can be realized by a cylindrical member that is stretched and reduced in diameter after filling with carbon fibers.

Next, the present invention relating to the second embodiment will be described.

The conventional carbon fiber bundle manufacturing method cannot manufacture a high-density carbon fiber bundle and does not provide a carbon fiber bundle with sufficient thermal conductivity. In particular, it is required to obtain a high-density carbon fiber bundle that does not depend on the carbon fiber material of the C / C composite.

The present invention is a manufacturing method for providing a single / bulk carbon fiber bulk having high density and excellent thermal conductivity along the fiber arrangement direction. The carbon fiber, which is a long fiber, is bundled to form a carbon fiber. One end side of the bundle is immersed in a solution containing a thermosetting resin, and the carbon fiber bundle impregnated with the thermosetting resin along the fiber length direction is cured by heat treatment. It is also possible to perform an impurity removal treatment after the thermosetting treatment. Impregnation and thermosetting treatment (or including impurity removal treatment) can be repeated a plurality of times.

In consideration of improving the convergence and high density of the carbon fiber bundle, it is possible to carbonize the carbon fiber bundle after curing by heat treatment. In this case, after the thermosetting treatment, the carbon fiber bundle may be taken out from the tubular member and carbonized. Further, in the dipping step, the carbon fiber bundle can be filled in the cylindrical member in the axial direction, and the end of the carbon fiber bulk can be dipped in the solution after filling.

In consideration of securing the anisotropy of the thermal conductivity along the fiber length direction, it is desirable to fill the cylindrical member with the carbon fiber bundle at a filling rate of 75% or more. Further, it is desirable that the content of the remaining void portion of the carbon having no anisotropy generated by the carbonization treatment be 40 to 90%. For this purpose, 70 to 80 of the remaining void portion of the filled carbon fiber bundle is preferable. It is preferable to immerse the carbon fiber bundle so that the thermosetting resin is impregnated in the% portion.

In order to impregnate the carbon fiber as much as possible by impregnating the thermosetting resin, it is preferable to stretch and reduce the diameter of the cylindrical member filled with the carbon fiber bundle.

The carbon fiber bulk in another aspect of the present invention is formed by integrally forming a bundle of carbon fibers having long fibers and anisotropy, and impregnated with a thermosetting resin containing carbon. For example, carbon adheres to the carbon fiber inside the carbon fiber bundle, and the filling rate of the carbon fiber in the carbon fiber bundle is 75% or more.

This creates a carbon fiber bulk with high density, strong convergence, and very large anisotropy with respect to thermal conductivity in the fiber direction. However, the filling rate here represents the cross-sectional area occupied by the carbon fiber with respect to the cross-sectional area defined by the carbon fiber periphery in the predetermined cross-section.

Particularly, by impregnating the thermosetting resin from one end of the carbon fiber bundle, a large amount of carbon adheres between the carbon fibers while maintaining a high density state. In this case, the carbon content in the vicinity of one end face of the carbon fiber bundle is lower than the carbon content in the vicinity of the other end face. As a configuration for improving the convergence of the carbon fiber bulk, for example, the occupation ratio of carbon in a region other than the carbon fiber bundle is preferably in the range of 40 to 90%.

Also, the thermal conductivity in the length direction of the carbon fiber bundle is 5 times or more of the thermal conductivity in the direction perpendicular to the length direction. Due to this anisotropic characteristic, excellent heat conduction can be realized.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. The first example corresponds to the first embodiment, and the second example corresponds to the second embodiment.

First, the first embodiment will be described with reference to FIGS.

In the first example, a high-density-filled carbon fiber-filled bulk was produced by the same production method as in the first embodiment, and the filling rate, thermal conductivity, and specific gravity were measured and compared with a reference metal. The physical quantities were measured before and after the heat treatment. Here, two high-density carbon fiber-filled bulks (hereinafter referred to as sample 1 and sample 2) were manufactured according to the type of carbon fiber.

For the cylindrical member, a tantalum (Ta) plate material was prepared as a metal material for Samples 1 and 2, and the tantalum plate material was rolled and welded to form a metal pipe. At this time, welding was performed so that the joint line was along the axial direction. The metal pipes prepared for Samples 1 and 2 were formed to have a diameter of 30 mm, a length of 200 mm, and a wall thickness of 1.0 mm.

As for carbon fiber (CF), GRANOC (registered trademark) XN-90-60S (manufactured by Nippon Graphite Fiber Co., Ltd.) was used for sample 1, and many yarn-like fibers composed of 6000 carbon fiber filaments were prepared. The yarn-like carbon fiber has a thermal conductivity of 500 W / m · K and a carbon fiber density of 2.19 g / cm ³ . In sample 2, DIALEAD (registered trademark) K13D2U (manufactured by Mitsubishi Plastics, Inc.) was used, and a large number of yarn-like fibers composed of 2000 carbon fiber filaments were prepared. The thermal conductivity is 800 W / m · K, and the carbon fiber density is 2.21 g / cm ³ .

First, in the filling process, carbon fiber yarns were inserted into metal pipes while being aligned in the axial direction by hand. The interior of the pipe was filled with about 530 carbon fiber yarns for sample 1 and about 1320 carbon fiber yarns for sample 2. In either case, the end face of the carbon fiber yarn is filled so as to protrude from the pipe.

FIG. 5 is a view showing a photograph of the metal pipe filled with the carbon fiber yarn of Sample 1 taken from an oblique direction. FIG. 6 is a view showing a photograph of a state in which the carbon fibers of Sample 1 are aligned in the axial direction when a metal pipe is cut in the carbon fiber axial direction using an optical microscope. As is apparent from FIGS. 5 and 6, the carbon fibers are filled inside the metal pipe and aligned along the axial direction. Sample 2 is similarly filled with carbon fibers.

Next, swaging was applied to the metal pipes for Samples 1 and 2 filled with carbon fiber. Here, the metal pipe was drawn out using a plurality of hammer die pairs arranged circumferentially, and the diameter was reduced to 20 mm. Then, after the swaging process, both end faces of the carbon fiber yarn were cut. For sample 1, the carbon fiber was cut using a lathe, and for sample 2, the carbon fiber was cut using a fine cutter to smooth the carbon fiber end face.

The volume of the carbon fibers in the carbon fiber filled bulk molding samples 1 35.354Cm ^3, and the carbon fiber density of 2.001g / cm ^3, the filling rate was 91.8 percent. On the other hand, next 35.354Cm ³ is the volume of the carbon fibers in the carbon fiber filled bulk molded samples 2, carbon fiber density of 2.064g / cm ^3, it was filling ratio 93.4 percent. It is shown in Table 1 below. Here, the carbon fiber density and the filling rate at the carbon fiber cut surface are measured. However, due to the high convergence of the carbon fibers inside the pipe, the filling state at any carbon fiber cross section is substantially the same as the carbon fiber cut surface. Can be considered equal.

The thermal conductivity was measured for the bulk in which the carbon fibers were densely filled in this way. In the thermal conductivity measurement, the thermal conductivity was measured at the center of the cut surface of the carbon fiber by the flash method, specifically, the nano flash method, and the specific gravity was obtained. The thermal conductivity was calculated based on the formula of thermal diffusivity × density × specific heat capacity. The specific gravity was determined by the Archimedes method.

In addition, the specific heat capacity used in calculating the thermal conductivity was obtained by calculation based on a comparative method. As a standard sample to be compared at this time, Poco Graphite made of the same carbon element was used. As a result, the specific heat capacity was 0.49 J · K / g for both samples 1 and 2. Further, the thermal diffusivity (temperature diffusivity) used for calculating the thermal conductivity is determined by irradiating the cut surface of the cylinder with infrared rays and measuring the temperature change of the infrared rays with respect to samples 1 and 2, respectively. Calculated.

α = 0.1388 × D ² / T (1)

However, (alpha) is a thermal diffusivity (m < ² > / s) and D represents the cross-sectional diameter (mm) of a filling carbon fiber. T represents time (s) required to reach a half of the maximum temperature value.

As a result of thermal conductivity measurement, Sample 1 has a thermal conductivity of 350.2 W / m · K. On the other hand, Sample 2 with a smooth end surface of carbon fiber had a thermal conductivity of 678.8 W / m · K (see Table 1).

Next, heat treatment was performed on the high-density carbon fiber-filled bulks of Samples 1 and 2, and the density, filling rate, and thermal conductivity after the heat treatment were measured. In the heat treatment step, heating was performed at 1800 ° C. for 1 hour. As a result, Sample 1 had a carbon fiber density of 1.868 g / cm ³ , a filling rate of 85.7%, and a thermal conductivity of 294.3 W / m · K. On the other hand, Sample 2 had a carbon fiber density of 1.990 g / cm ³ , a filling rate of 90.1%, and a thermal conductivity of 800.8 W / m · K (see Table 1).

The change in carbon fiber density and thermal conductivity before and after heating is estimated based on shrinkage due to heat treatment and the influence of sizing material contained in the yarn-like carbon fiber yarn. Moreover, the change also differs in the samples 1 and 2 by the difference in the kind of yarn-like carbon fiber, etc. However, a sufficient filling rate (85% or more) and thermal conductivity are maintained even after the heat treatment. In particular, in Sample 2, the thermal conductivity after the heat treatment was almost equal to the thermal conductivity of 800 W / m · K of the yarn-like carbon fiber.

FIG. 7 is a view showing a photograph obtained by SEM observation of a high density filling state of carbon fibers on the cut surface of Sample 1 after heat treatment. However, the edge part of the carbon fiber end face is observed here.

On the other hand, FIG. 8 is a view showing a photograph obtained by SEM observation of a high-density filling state of carbon fibers on the cut surface of Sample 2 after heat treatment. However, the part near the edge of the carbon fiber end face is observed here.

As is apparent from FIG. 8, the carbon fiber filaments in Sample 2 are packed in close contact with each other without any boundary (no gap). Further, the measured filling rate exceeds an ideal filling rate, that is, a filling rate of 90.65% when the carbon fibers having a circular cross section are arranged in a close-packed manner. This indicates that the cross-section circular carbon fiber is compactly packed while being elastically deformed.

Further, as apparent from comparison with FIG. 7, the carbon fiber filaments of the sample 2 are aligned in the axial direction on the carbon fiber end surface, and the end surface is smooth and compactly packed. It can be seen that the entire carbon fiber cut surface defines a single plane and is uneven or flat without distortion.

On the other hand, in the sample 1 shown in FIG. 7, the cutting device is different from the sample 2, so that the carbon fiber end faces are partially irregular. In the cutting process with a lathe, the carbon fiber is cut while being drawn. It is caused by that. However, the filling rate exceeds the ideal filling rate, and it is clear from FIG. 7 that the carbon fibers are closely packed with no gap while elastically deforming each other.

Next, the measured thermal conductivity and specific gravity were compared with high thermal conductivity metals. Here, copper (Cu), which is a high heat conductive metal, and tungsten (W), which is a high heat resistance metal, are used as high heat conductive metals to be compared. The results of comparing the thermal conductivity and specific gravity are also shown in Table 1.

As can be seen from Table 1, the thermal conductivity inside the metal pipe filled with high density is 2 to 7 times better than copper and W. Considering that the specific gravity of the carbon fiber bundle is 1/4 that of copper, it can be said that the heat conductivity is extremely high. Further, it has a thermal conductivity much higher than that of tungsten (W) (174 W / m · K), which is one of refractory metals used for electrodes of a discharge lamp. In particular, considering that the specific gravity of carbon fiber is about 1/9 that of tungsten, the volumetric efficiency is about 20 times.

From the above, it was confirmed that the carbon fiber filled bulk of the first example had excellent thermal conductivity and volumetric efficiency.

Next, a second embodiment will be described with reference to FIGS.

In this example, two high-density carbon fiber filled bulks (hereinafter referred to as Sample 1 and Sample 2) were manufactured by the same manufacturing method as in the second embodiment, and the thermal conductivity and its anisotropy were measured.

For the cylindrical member, a SUS plate material was prepared for sample 1 as a metal material, and a Ta plate material was prepared for sample 2, and a metal pipe was formed by rolling and welding the plate material. At this time, welding was performed so that the joint line was along the axial direction. The metal pipes prepared for Samples 1 and 2 were formed to have a diameter of 30 mm, a length of 200 mm, and a wall thickness of 1.0 mm.

For carbon fiber (CF), GRANOC (registered trademark) XN-90-60S (manufactured by Nippon Graphite Fiber Co., Ltd.) was used for sample 1, and a large number of yarn-like fibers composed of 6000 carbon fiber filaments were prepared.

This yarn-like carbon fiber has a thermal conductivity of 500 W / m · K and a carbon fiber density of 2.19 g / cm ³ . In sample 2, DIALEAD (registered trademark) K13D2U (manufactured by Mitsubishi Plastics, Inc.) was used, and a large number of yarn-like fibers composed of 2000 carbon fiber filaments were prepared. The thermal conductivity is 800 W / m · K, and the carbon fiber density is 2.21 g / cm ³ .

In the filling process, carbon fiber yarns were inserted into metal pipes while being aligned in the axial direction by hand. In either case, the end face of the carbon fiber yarn is filled so as to protrude from the pipe.

Next, swaging was applied to the metal pipes for Samples 1 and 2 filled with carbon fiber. Here, the metal pipe was drawn out using a plurality of hammer die pairs arranged circumferentially, and the diameter was reduced to 20 mm.

Then, after the swaging process, both end faces of the carbon fiber yarn were cut. Samples 1 and 2 were cut with a lathe, and each yarn on the surface immersed with phenol resin was unwound to efficiently impregnate the phenol resin by capillary action.

After that, a container containing a solution containing a novolac type phenolic resin was prepared, a metal pipe was set up in the container, and the end face side of the pipe was immersed in the solution. Then, thermosetting treatment at 140 ° C. and impurity removal treatment at 700 ° C. in a vacuum atmosphere were performed, and from impregnation to impurity removal treatment as one set, two or more sets were repeated.

Both Sample 1 and Sample 2 used IF-3300 from Dainippon Ink & Chemicals, Inc. as the phenol resin. The remaining coal rate is 63%.

FIG. 9 is a view showing a photograph of a cross section of the carbon fiber bundle after impregnation with the phenol resin, taken with an enlarged microscope. As shown in FIG. 9, it can be seen that the phenol resin is impregnated in the carbon fiber bundle. FIG. 9 shows a carbon fiber bundle not containing a phenol resin for comparison.

Then, carbonization treatment was performed by heat curing treatment (140 ° C.) and impurity removal treatment (1800 to 2000 ° C.). The molded carbon fiber bulk was examined for carbon adhesion and thermal conductivity.

FIG. 10 is a view showing a photograph of an axial cross section of the carbon fiber bundle after carbonization, taken with an electron microscope. As shown in FIG. 10, it can be seen that a carbon component generated by the carbonization treatment of the phenol resin is adhered to the surface of the carbon fiber.

FIG. 11A is a graph showing the anisotropy related to thermal conductivity in Sample 1. FIG. FIG. 11B is a graph showing the coefficient of thermal expansion in Sample 1. Here, the carbon fiber length direction is defined as a axis, and the vertical direction (cross-sectional direction) is defined as c axis.

As shown in FIG. 11A, the thermal conductivity changes with temperature. The thermal conductivity in the fiber direction is up to about 70 times that in the vertical direction. Even in a high temperature state such as when a discharge lamp is used, it is clear that the thermal conductivity in the fiber direction is 5 times or more and 20 times or more compared to the vertical direction.

FIG. 12 is a diagram showing the thermal conductivity of Samples 1 and 2. As can be seen from FIG. 12, a high thermal conductivity can be obtained by setting the filling rate of the carbon fiber bundle to 75% or more and 80% or more.

From the above, it was confirmed that the carbon fiber bulk of the second example had excellent thermal conductivity.

-Various changes, substitutions, and alternatives are possible with respect to the present invention without departing from the spirit and scope of the present invention as defined by the appended claims. Furthermore, the present invention is not intended to be limited to the specific embodiments of the processes, apparatus, manufacture, components, means, methods, and steps described in the specification. Those skilled in the art will appreciate from the disclosure of the present invention devices, means, and methods that perform substantially the same functions as those provided by the embodiments described herein, or that provide substantially the same operations and effects. You will recognize it. Accordingly, the appended claims are intended to be included within the scope of such devices, means, and methods.

This application is a Japanese application (Japanese Patent Application No. 2011-079922, filed on March 31, 2011), and a Japanese application (Japanese Patent Application No. 2011-279567, filed on December 21, 2011) as a basic application. The disclosure, including the specification, drawings and claims of the basic application, is hereby incorporated by reference in its entirety.

DESCRIPTION OF SYMBOLS 10 Short arc type discharge lamp 30 Anode 50 Dice 100 Carbon fiber, carbon fiber bundle 100 'Carbon fiber bulk 200 Hollow cylindrical member 300 Cylindrical member 400 Carbon fiber filling bulk 400' Solution F Thermosetting resin

Claims

Fill the cylindrical member with carbon fibers aligned in the axial direction,
A method for producing a carbon fiber bulk, wherein the cylindrical member filled with the carbon fiber is stretched to have a reduced diameter.
The method for producing a carbon fiber bulk according to claim 1, wherein the tubular member is stretched and contracted by swaging.
The carbon fiber bulk production according to any one of claims 1 to 2, wherein the cylindrical member is stretched and reduced in diameter so that a cross-sectional shape is deformed in at least a part of the filled carbon fibers. Method.
Immerse the reduced cylindrical member in a solution containing a thermosetting resin,
The method for producing a carbon fiber bulk according to any one of claims 1 to 2, wherein the carbon fiber bundle impregnated with the thermosetting resin along the fiber length direction is cured by heat treatment.
The method for producing a carbon fiber bulk according to claim 4, wherein the carbon fiber bundle is carbonized after being cured by heat treatment.
The method for producing a carbon fiber bulk according to claim 4, wherein one end of the cylindrical member is immersed in the solution.
The method for producing a carbon fiber bulk according to any one of claims 1 to 2, wherein the cylindrical member is filled with the carbon fiber bundle at a filling rate of 75% or more.
The cylindrical member is immersed in such a manner that a portion of 70 to 80% of the remaining void portion of the carbon fiber bundle filled in the cylindrical member is impregnated with a thermosetting resin. Carbon fiber bulk manufacturing method.
3. The method for producing a carbon fiber bulk according to claim 1, wherein the carbon fiber bundle is taken out of the cylindrical member after the thermosetting treatment.
3. A discharge lamp comprising a carbon fiber bulk produced by the carbon fiber bulk production method according to claim 1 as a part of at least one electrode.
Long fibers and anisotropic carbon fibers are bundled and formed integrally.
Carbon adheres to the carbon fiber inside the carbon fiber bundle,
A carbon fiber bulk, wherein a filling rate of carbon fibers in the carbon fiber bundle is 75% or more.
The carbon fiber bulk according to claim 11, wherein the carbon content in the vicinity of one end face of the carbon fiber bundle is lower than the carbon content in the vicinity of the other end face.
The carbon fiber bulk according to any one of claims 11 to 12, wherein an occupation ratio of carbon in a region other than the carbon fiber bundle is in a range of 40 to 90%.
The carbon fiber bulk according to any one of claims 11 to 12, wherein the thermal conductivity in the longitudinal direction of the carbon fiber bundle is 5 times or more of the thermal conductivity in the direction perpendicular to the longitudinal direction.
The carbon fiber bulk according to any one of claims 11 to 12, wherein carbon contained in the carbon fiber bundle has no anisotropy.
A discharge lamp comprising the carbon fiber bulk according to any one of claims 11 to 12 as a part of at least one electrode.