JPH11302008A - Graphite formed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a graphite formed body having enough shape holding property which can be easily handled for carrying and assembling by filling a case body comprising a carbon fiber-reinforced carbon composite material with an expanded graphite material. SOLUTION: The graphite formed body consists of a boxlike case body 1 as the outer form, and the case body 1 consists of a housing member 2 having an opening 2a at the top and a lid member 3 to be joined on the faces of all side walls of the housing member 2 to seal the opening 2a. The housing member 2 and the lid member 3 consist of a carbon fiber-reinforced carbon composite material having a high mechanical strength even at a high temp. so that the case body 1 has enough shape holding property, and the carbon fiber is 2D(two- dimensionally) arranged to give 5 to 300 MPa bending strength. In the case body 1, expanded graphite sheets each press-formed into a sheet and having the expansion direction along the thickness direction are stacked in the thickness direction. The graphite sheets are expanded again by about >=1.2 times bulk density magnification to obtain the expanded graphite material 4 having excellent heat insulating property which fills the case body and is sufficiently in contact with the case body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite molding used for a heat insulating wall, a sound absorbing wall and the like.

[0002]

2. Description of the Related Art Graphite compacts obtained by press-molding expanded graphite with a small pressure are difficult to handle due to low mechanical strength. Therefore, various measures have been taken to increase mechanical strength. I have.

That is, for example, Japanese Patent Application Laid-Open No. 2-88415 discloses a graphite molded body reinforced by joining a high-density expanded graphite material to a low-density expanded graphite material. Japanese Patent Application Laid-Open No. 3-65550 discloses a graphite molded body reinforced by impregnating a resin with low-density expanded graphite.

[0004]

However, simply reinforcing a low-density expanded graphite material with a high-density expanded graphite molded article or resin as in the above-mentioned conventional technique tends to result in insufficient mold retention, and particularly large-sized. When formed, the shape retention is significantly reduced. If the shape retention property is insufficient, deformation or breakage occurs due to its own weight or a slight load, so that there is a problem that it is difficult to handle during transportation or assembly. Also, in order to have sufficient shape retention, thickening the high-density expanded graphite molded body or increasing the amount of resin impregnated in the expanded graphite,
Since the weight of the graphite molded body increases, there is a problem that handling during transportation or assembly becomes difficult as a result.

Accordingly, an object of the present invention is to provide a graphite molded article which is lightweight and has a sufficient shape-retaining property so that it can be easily handled during transportation and assembly.

[0006]

Means for Solving the Problems In order to solve the above problems, a graphite molded body is characterized in that a case made of carbon fiber reinforced carbon composite material is filled with an expanded graphite material.

According to the above configuration, since the case body is filled with the expanded graphite material, the carbon fiber reinforced carbon composite material of the case body surrounds the expanded graphite material and is positioned on the surface layer of the graphite molded body. Become. Therefore, even if the mechanical strength of the expanded graphite material filled in the case body is small, the graphite molded body has sufficient shape retention due to the large mechanical strength of the case body made of carbon fiber reinforced carbon composite material. It is easy to handle during transportation and assembly.

Further, when the graphite molded body is formed only of the expanded graphite material, the expanded graphite material comes into direct contact with an operator during the handling of the graphite molded body, so that the short fibers of the expanded graphite material work. It adheres to the person and irritates the skin, making handling difficult. However, according to the above configuration, the case body surrounds the expanded graphite material, thereby preventing direct contact between the expanded graphite material and the worker. Thereby, the short fibers of the expanded graphite material do not adhere to the worker and irritate the skin, so that handling is also easy in this respect.

[0009] Further, since the carbon fiber reinforced carbon composite material originally has air permeability, it can be used even when the graphite molded article is used in a low-pressure or high-pressure environment or in an environment where the pressure fluctuates. The pressure inside the case body can be made equal by following the external pressure. Thereby, since the stress due to the pressure difference hardly occurs on the wall surface of the case body,
A sufficiently large shape retention can be obtained even in a device for operating pressure. Further, since the carbon fiber reinforced carbon composite material constituting the case body has a sufficiently large mechanical strength, even if the thickness of the case body is reduced to reduce the weight, the above-described sufficiently large shape retention property is achieved. Can be obtained.

Further, according to the above configuration, the carbon fiber reinforced carbon composite material is used only for the case body containing the expanded graphite material. When the costs of the expanded graphite material and the carbon fiber reinforced carbon composite material are simply compared, the cost of the expanded graphite material is about 1/6 to 1/3 of the cost of the carbon fiber reinforced carbon composite material. Thereby, the cost of the graphite molded body containing the expanded graphite material in the case body can be made sufficiently lower than the case where the felt-like carbon fiber reinforced carbon composite material is used.

Here, the carbon fiber reinforced carbon composite material is 1D
Although it can be formed by carbon fibers arranged in 2D, 3D or more, it is desirable to form by carbon fibers arranged in 2D. This is because the case body made of the carbon fiber reinforced carbon composite material constitutes the surface layer of the graphite molded body, and if the mechanical strength of this surface layer is to be increased by using the least amount of the carbon fiber reinforced carbon composite material, This is because a 2D carbon fiber reinforced carbon composite material is considered to be optimal.

The carbon fiber reinforced carbon composite material preferably has a bending strength of 5 to 300 MPa. this is,
If the bending strength is less than 5 MPa, sufficient shape retention cannot be obtained. On the other hand, if the bending strength exceeds 300 MPa, it becomes uneconomical because it has an unnecessarily strong strength.

The case body made of the carbon fiber reinforced carbon composite material is formed in an arbitrary external shape such as a flat plate, a curved plate, a column, or a rectangular shape. A circumferential reinforcing hole is formed. The case body includes a housing member having an opening formed on an upper surface, and a lid member that is joined to the housing member to close the opening. The joining between the housing member and the lid member is made of an organic material. This is performed by using an adhesive (a thermoplastic resin and a thermosetting resin) or an inorganic adhesive. In some applications, the housing member and the lid member can be mechanically joined using a fastening member such as a bolt or a nut.

Examples of the thermoplastic resin adhesive include polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl chloride resin, polyvinyl acetal resin, and acrylic resin. Also, natural rubber, synthetic rubber, or the like can be used as the adhesive. Examples of the thermosetting resin adhesive include phenol resin, resorcin resin, furan resin, epoxy resin, urea resin, melamine resin, and unsaturated polyester resin. Examples of the inorganic adhesive include water-soluble sodium silicate, aluminum phosphate, aluminum acetate, and sodium borate.
Note that the adhesive is not limited to those exemplified above.

[0015] The expanded graphite material filled in the case body is prepared by press-molding expanded graphite, or is prepared by pulverizing with a suitable pulverizer after preparation, and expanding the pulverized material. Have been. The expanded graphite is a known natural flaky graphite, kitchen graphite, artificial flaky graphite, graphite particles such as pyrolytic graphite, mixed acid of concentrated sulfuric acid and concentrated nitric acid or concentrated sulfuric acid and hydrogen peroxide solution, ammonium persulfate and the like. After immersion in a strong oxidizing solution with an oxidizing agent, wash with water,
It is manufactured by a method such as a chemical treatment method in which rapid heating is performed, or an electrolytic treatment method in which similar graphite particles are anodized in a sulfuric acid electrolytic solution, and then rapidly heated to about 800 to 1000 ° C.

The bulk density of the expanded graphite material is 0.05 to
Desirably, the range is 0.85 g / cm ³ . The reason why this range is desirable is that when the bulk density is less than 0.05 g / cm ³ , the mechanical strength becomes extremely low, and it becomes difficult to handle the expanded graphite material at the time of filling work or storage. If the density exceeds 0.85 g / cm ³ , the performance of the space, such as heat insulation, will be significantly reduced.

The above-mentioned expanded graphite material is formed into various shapes such as a sheet shape and a column shape, or is coarsely or finely pulverized by a suitable pulverizing means to be formed into a powdery shape. When the case body is filled with the expanded graphite material, if the expanded graphite material is formed in a predetermined shape, a different shape or the same shape is appropriately selected from various shapes of the expanded graphite material, and the outer surface of the expanded graphite material is selected. This is performed by laminating or arranging expanded graphite materials in parallel so as to contact the entire inner surface of the case body. On the other hand, when the expanded graphite material is formed in a powder form, the filling is performed by charging the expanded graphite material into the case body. When filling the case body with the expanded graphite material, dust of the expanded graphite material may be scattered to deteriorate the working environment. Therefore, the expanded graphite material is impregnated with a liquid such as a resin to perform a dustproof treatment. It is desirable to keep. In addition, when the expanded graphite material is impregnated with a liquid such as a resin, the adhesion between the expanded graphite material and the case body is improved.

It is desirable that the above-mentioned expanded graphite material be closely adhered to the case body by being re-expanded after filling the case body. This is because, when the expanded graphite material is re-expanded in the case body and brought into close contact with the case body, the expanded graphite material is kept in the case even when external force such as impact or vibration is applied during storage or assembly of the graphite molded body. This is because the properties such as the heat insulating property of the expanded graphite material can always be obtained in a state in which the properties are not biased to a specific part in the body. still,
“Re-expand” means a process of filling the case body with the expanded graphite material and then expanding the case body further.

Reexpansion of the expanded graphite material in the case body is performed by impregnating the expanded graphite material with an expansion liquid and heating. The impregnation of the liquid for expansion may be performed on the entire expanded graphite material, or may be performed on a part of the expanded graphite material from the viewpoint of the shape of the case body and the strength distribution. The timing of impregnating the expandable graphite material with the expansion liquid may be before filling the case body or after filling the case body. If the expansion liquid is impregnated before filling the case body, the expanded graphite material can be subjected to dustproof treatment.

As the above-mentioned liquid for expansion, a wide variety of liquids can be used as long as they impregnate the pores of the expanded graphite material, but they exert an action such as oxidation on the graphite in a heated state. Liquids are undesirable. That is, specific examples of the expansion liquid include water, organic solvents such as methyl alcohol and ethyl alcohol, ethylene glycol, glycerol, benzene, toluene, and acetone, kerosene, light oil, machine oil, and oil-derived products such as liquid paraffin. And oils such as soybean oil, olive oil and whale oil. In addition, since a substance which becomes liquid by heating even if solid at normal temperature, such as paraffin or tallow, can be impregnated in a molten state, it can be used as a liquid for expansion. These inflation liquids can be used alone, or can be used as a mixture if necessary. In addition, in order to reduce impregnation unevenness and shorten the impregnation time, it is preferable to use, for example, water obtained by adding a surfactant to water.

When the graphite molded article is used for semiconductor applications, the reexpanded expanded graphite material is impregnated with full free alcohol or phenolic resin (dilute solution), and then the expanded graphite material is placed in a case body. 800 ℃ ～ 100
It is preferable to perform a heat treatment again at 0 ° C., perform a high-purity treatment at 2000 ° C. or the like, and impregnate high-purity glassy carbon. In this case, since the powder of the expanded graphite material can be prevented from leaking from the gap (communication hole) of the case body formed of the carbon fiber reinforced carbon composite material and scattered outside, for example, CZ In the apparatus, it is possible to prevent the powder of the expanded graphite material from being mixed as a contaminant during the pulling of the silicon single crystal. In addition, the above expanded graphite material,
Instead of the glassy impregnation, a pyro treatment for impregnating with pyrolytic carbon may be performed. In this case as well, it is possible to prevent the powder of the expanded graphite material from leaking from the gap (communication hole) of the case body. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the graphite molded body according to the present embodiment has a case 1 having a box shape (rectangular shape).
have. As shown in FIG. 3, the case body 1 includes a housing member 2 having an opening 2 a formed on an upper surface thereof, and a housing member 2.
And a lid member 3 which is planarly joined to all the side walls to cover the opening 2a. These housing members 2
The lid member 3 is made of a carbon fiber reinforced carbon composite material having high mechanical strength even at high temperatures so that the case body 1 has a sufficient shape retaining property. In the carbon fiber reinforced carbon composite material, the fiber portions are arranged in 2D so that the desired strength can be obtained at the lowest cost. Then, as shown in FIG. 2, when the case body 1 formed of the housing member 2 and the lid member 3 is combined with each other to form, for example, a heat insulating wall of a high-temperature furnace, each case is formed into a cartridge. It is made replaceable.

As shown in FIG. 1, the case body 1 is filled with an expanded graphite material 4 having excellent heat insulating properties. As shown in FIG. 3, the expanded graphite material 4 is formed by laminating an expanded graphite sheet 5 in which the expansion direction is set in the thickness direction by pressing the expanded graphite into a sheet shape. Is formed by re-expanding at a bulk density ratio of 1.2 times or more. The reason why the bulk density ratio of the expanded graphite sheet 5 is set to 1.2 times or more is that if it is less than 1.2 times, sufficient adhesion to the case body 1 cannot be obtained.

In the above structure, when manufacturing a graphite molded body, first, the housing member 2 and the lid member 3 are formed of a carbon fiber reinforced carbon composite material so as to form the case body 1 having a predetermined shape. Then, the plurality of expanded graphite sheets 5 (expanded graphite material) are stacked while being placed in the housing member 2.
The number of layers is determined based on the volume of the case body 1 so that a desired bulk density is obtained when the expanded graphite sheet 5 is expanded again. Thereafter, the case member 1 filled with the expanded graphite sheet 5 is created by covering the housing member 2 with the cover member 3 and joining the cover member 3 with an adhesive.

Next, as shown in FIG. 4, the case body 1 is immersed in a water tank 6 containing an inflation liquid 7. At this time, the case body 1 formed of the carbon fiber reinforced carbon composite material has a large number of communication holes on the entire surface. Therefore, when the expansion liquid 7 enters the case body 1 through the communication hole, the expansion liquid 7 impregnates the pores of the expanded graphite sheet 5.

When the impregnation of the expansion liquid 7 is completed, the case body 1 is taken out of the water tank 6 and transported to a heating furnace. Then, the expanded graphite sheet 5 impregnated with the expansion liquid 7 is heated together with the case body 1 to a temperature equal to or higher than the boiling point of the expansion liquid 7 to evaporate the expansion liquid 7 impregnated in the pores of the expansion graphite sheet 5. The expanded graphite sheet 5 is re-expanded in the case body 1. As a result, the expanded graphite sheet 5 expands mainly in the laminating direction and adheres to the upper surface and the lower surface of the case body 1 without any gap, so that the expanded graphite material 4 is substantially uniformly filled in the entire case body 1. Become.

When the graphite molded body is prepared as described above, as shown in FIG. 2, the surfaces of the case body 1 are joined to each other to assemble a heat insulating wall of a high-temperature furnace, for example.
Then, when the renewal time comes, the graphite molded body is renewed by replacing the case body by unit. At this time, since the case body 1 is formed of the carbon fiber reinforced carbon composite material, the case body 1 itself has extremely large strength even when the mechanical strength of the expanded graphite material 4 existing inside is small. . Accordingly, even when assembling or updating the heat insulating wall is performed in units of the graphite molded body, the case body 1 located on the surface layer of the graphite molded body is not damaged. Therefore, it is possible to easily assemble and renew the heat insulating wall, and when the degree of wear differs depending on the portion of the heat insulating wall, the time of renewal can be optimized for each graphite molded body. Wall maintenance costs can be reduced.

Although the present invention has been described based on the preferred embodiments, the present invention can be modified without departing from the spirit thereof. For example, in this embodiment,
Although the rectangular case body 1 has been described so that the graphite molded body has a box shape, the present invention is not limited to this. For example, as shown in FIG. Hole 11
It may be a cylindrical case body 11 having a, or the upper and lower sides may be covered in the same manner as a rectangular body.

That is, as shown in FIGS. 6 and 7, the cylindrical case body 11 is composed of a housing member 12 and a lid member 13 formed of a carbon fiber reinforced carbon composite material.
One. The accommodating member 12 has a cylindrical outer peripheral wall 1.
2a, an inner peripheral wall 12b, and a bottom wall 12c connected to lower edges of both walls 12a and 12b. Further, the lid member 13 has a side wall 13a formed so as to be fitted to the outer peripheral wall 12a of the housing member 12, and a through hole 13b formed at the center of the upper surface of the side wall 13a. In the case body 11 formed by the housing member 12 and the lid member 13, an expanded graphite material 14 is housed.
The expanded graphite material 14 is wound around an expanded graphite sheet 15 so as to expand in the radial direction of the case body 11, and then housed between the outer peripheral wall 12a and the inner peripheral wall 12b of the housing member 12, and Is formed by covering the housing member 12 and expanding it.

In the present embodiment, the expanded graphite sheet 4 is formed by expanding the expanded graphite sheet 5. However, the present invention is not limited to this. The expanded graphite material 4 may be formed by re-expanding after filling the body. In this case, since the pulverized expanded graphite molded body expands in an unspecified direction in the case body 1, even if the case body 1 has a complicated shape, the expanded graphite material is applied to the entire case body 1. 4 can be filled.

The high-temperature furnace described in this embodiment includes various industrial furnaces such as a sintering furnace, a crystal growth furnace, a single crystal pulling furnace, a vacuum deposition furnace, a HIP furnace, and a brazing furnace. Further, the graphite molded body can be applied to a soundproof wall, an electromagnetic wave shielding wall, and the like, in addition to a heat insulating wall of a high-temperature furnace.

[0033]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. Example 1 A case body having a length of 1000 mm, a width of 1,000 mm, and a thickness of 150 mm was made of a 2D carbon fiber reinforced carbon composite material. And the thickness is 0.5 mm and the bulk density is 1.0 g
/ Cm ³ expanded graphite sheet (PF-
50) was cut out into a size corresponding to the case body, and 150 pieces were stacked and accommodated in the case body. Thereafter, the case body was immersed in an inflation liquid (a 0.1% aqueous solution of mama lemon solution manufactured by Lion Corporation) at room temperature for 24 hours.

Next, the case body is carried into an electric furnace, and 800
By holding at a heating temperature of 1 ° C. for 1 minute, the expanded graphite sheet was re-expanded in the case body to form an expanded graphite material, and was brought into close contact with the case body to prepare a graphite molded body. Then, as shown in FIG. 8, both ends of the graphite molded body 20 thus produced were supported by the support members 21 having a height of 30 mm. Thereafter, by placing a 10 kg weight 23 at the center of the upper surface of the graphite molded body 20, it was checked whether the graphite molded body 20 flexed and contacted the floor surface. As a result, it was found that the resin had sufficient shape retention properties without contact with 24.

COMPARATIVE EXAMPLE 1 As shown in FIG. 9, an expanded graphite material 30 having a bulk density of 0.5 g / cm ³ and a thickness of 149 mm was prepared by press-molding expanded graphite particles. Then, a bulk density of 1.0 g / cm ³ and a thickness of 0.5 g on the upper and lower surfaces of the expanded graphite material 30.
A graphite molded body 32 having the same size as that of Example 1 was produced by bonding the expanded graphite sheets 31 having a thickness of 1 mm. Thereafter, when the mold retention was examined in the same manner as in Example 1, a result was obtained that the graphite molded body 32 was inadequate in keeping the floor surface 24 in contact.

[0036]

As described above, according to the present invention, since the case body made of carbon fiber reinforced carbon composite material is filled with the expanded graphite material, the mechanical strength of the expanded graphite material filled in the case body is small. Even so, it is possible to obtain a graphite molded body having a large mechanical strength of the case body. Thereby, since it has a sufficient shape-retaining property, there is an effect that handling at the time of transportation or assembly is easy. In addition, the case body prevents direct contact between the expanded graphite material and the worker, and short fibers of the expanded graphite material do not adhere to the worker and irritate the skin. This has the effect of being easy. Further, since the inexpensive expanded graphite material is housed in the case body of the carbon fiber reinforced carbon composite material, there is an effect that the cost of the graphite molded body can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a graphite molded body.

FIG. 2 is an explanatory view showing a state where a graphite molded body is assembled.

FIG. 3 is an exploded perspective view of a graphite molded body.

FIG. 4 is an explanatory view showing a state in which a case body is impregnated with an inflation liquid.

FIG. 5 is a perspective view of a graphite molded body.

FIG. 6 is a partially cutaway perspective view showing a graphite molded body.

FIG. 7 is an exploded perspective view of a graphite molded body.

FIG. 8 is an explanatory diagram showing a method for measuring the shape retention.

FIG. 9 is a perspective view showing a part of a graphite molded body with the part omitted.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 case body 2 housing member 3 lid member 4 expanded graphite material 5 expanded graphite sheet 6 water tank 7 expansion liquid 11 case body 11a inner peripheral reinforcing hole 12 receiving member 12a outer peripheral wall 12b inner peripheral wall 12c bottom wall 13 lid member 13a side wall 13b Through-hole 14 Expanded graphite material 15 Expanded graphite sheet

Claims (4)

[Claims] 1. A graphite molded body characterized in that a case body made of carbon fiber reinforced carbon composite material is filled with an expanded graphite material. 2. The carbon fiber-reinforced carbon composite material has carbon fibers arranged in a 2D pattern and has a bending strength of 5 to 300 MPa.
2. The graphite molded body according to claim 1, wherein a. 3. The graphite molded body according to claim 1, wherein the expanded graphite material is re-expanded after filling the case body, so that the expanded graphite material is in close contact with the case body. 4. The expanded graphite material has a bulk density of 0.05 to 0.05.
Graphite molded article according to any one of claims 1, characterized in that in the range of 0.85g / cm ^{3 3.}