阅读说明：本技术 加热炉、以及石墨的制造方法 (Heating furnace and method for producing graphite ) 是由 片山觉嗣 木村俊彦 饭塚直人 小铁贵广 田口雅史 于 2020-01-20 设计创作，主要内容包括：提供能够连续进行碳化工序和石墨化工序的加热炉、以及石墨的制造方法。加热炉为由高分子材料制造石墨的加热炉,其具备对高分子材料进行热处理的加热炉主体(2),在上述加热炉主体(2)的内部具有容纳高分子材料的密闭容器(8),在上述密闭容器(8)上连接有气体排出管(11),所述气体排出管(11)将从高分子材料产生的热分解气体排出到加热炉主体(2)的外部。(Provided are a heating furnace capable of continuously performing a carbonization step and a graphitization step, and a method for producing graphite. The heating furnace is a heating furnace for manufacturing graphite from a polymer material, and is provided with a heating furnace main body (2) for performing heat treatment on the polymer material, wherein a closed container (8) for accommodating the polymer material is arranged inside the heating furnace main body (2), a gas discharge pipe (11) is connected to the closed container (8), and the gas discharge pipe (11) discharges thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body (2).)

1. A heating furnace is a heating furnace for manufacturing graphite by high polymer materials,

which comprises a heating furnace main body for performing heat treatment on a polymer material,

a closed container for containing a polymer material is provided in the heating furnace main body,

the sealed container is connected to a discharge pipe that discharges a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body.

2. The heating furnace according to claim 1, wherein the closed vessel is made of graphite.

3. The heating furnace according to claim 1 or 2, wherein the closed vessel is connected to an introduction pipe for introducing an inert gas into the closed vessel.

4. A method for producing graphite from a polymer material, the method comprising:

a lead-in step of leading the sealed container containing the polymer material into the heating furnace main body;

a carbonization step of carbonizing the polymer material contained in the closed container to obtain a carbonaceous thin film;

a graphitization step of graphitizing the carbonaceous thin film produced in the carbonization step to obtain graphite; and

a taking-out step of taking out the graphite produced in the graphitization step from the closed vessel,

at least in the carbonization step, a discharge step of discharging a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body is performed, and the carbonization step and the graphitization step are continuously performed.

5. The method for producing graphite according to claim 4, wherein in the introducing step, a discharge pipe attaching step of attaching a discharge pipe to the closed vessel is performed, the discharge pipe discharging a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body.

6. The method for producing graphite according to claim 4 or 5, wherein in the introducing step, an introducing pipe installing step of installing an introducing pipe for introducing an inert gas into the closed container is performed.

7. The method for producing graphite according to claim 6, wherein in the discharging step, an inert gas introduction step of introducing an inert gas into the closed container is performed.

Technical Field

The present invention relates to a heating furnace for producing graphite and a method for producing graphite.

Background

A heating furnace for producing graphite by firing a polymer material such as polyimide at a high temperature of 2500 ℃ or higher is generally known. Specifically, graphite is produced through the following steps: the method comprises a carbonization step of obtaining a carbonaceous film by subjecting a polymer material in the form of a film to heat treatment (preheating) at about 1000 ℃ and carbonizing the polymer material, and a graphitization step of performing graphitization (graphitization) by firing the carbonaceous film produced in the carbonization step at a high temperature of 2500 ℃ or higher. In patent document 1, since the temperatures at which the heat treatment is performed in the carbonization step and the graphitization step are different from each other, heating furnaces having different configurations are used.

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No. Hei 3-75211 "

Disclosure of Invention

Problems to be solved by the invention

In the carbonization step, a combustible thermal decomposition gas is generated from the polymer material by the heat treatment. Therefore, for example, when the same heating furnace is used for the carbonization step and the graphitization step in order to shorten the production time of graphite and to simplify the steps, the thermal decomposition gas generated in the carbonization step adversely affects the heater and the heat insulating material of the heating furnace in the graphitization step. Specifically, if the heater and the heat insulating material are contaminated by the thermal decomposition gas, various problems occur in the graphitization step, such as the temperature inside the heating furnace being not higher than 2500 ℃, the risk of ignition, and the shortened life of the heat insulating material and the heater. Namely, the present inventors have found that the following problems exist: the above problems occur if the same heating furnace is used for the carbonization step and the graphitization step.

An object of one embodiment of the present invention is to provide a heating furnace capable of continuously performing a carbonization step and a graphitization step, and a method for producing graphite.

Means for solving the problems

As a result of intensive studies to solve the above problems, the present inventors have found that a carbonization step and a graphitization step can be continuously performed by a heating furnace having a closed container for containing a polymer material in an inner portion of a heating furnace main body and having a discharge pipe for discharging a thermal decomposition gas generated from the polymer material to an outside of the heating furnace main body connected to the closed container, and have completed the present invention.

In order to solve the above problem, a heating furnace according to one aspect of the present invention is a heating furnace for producing graphite from a polymer material, the heating furnace including a heating furnace main body for heat-treating the polymer material, the heating furnace main body having a sealed container for containing the polymer material therein, the sealed container being connected to a discharge pipe for discharging a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body.

The sealed container is preferably made of graphite, for example, because it needs to be resistant to the graphitization step. In the above-described sealed container, it is preferable that an introduction pipe for introducing an inert gas into the sealed container is connected to expel (discharge to the outside) the thermally decomposed gas generated inside the sealed container.

In order to solve the above problem, a method for producing graphite according to one aspect of the present invention is a method for producing graphite from a polymer material, the method including: a lead-in step of leading the sealed container containing the polymer material into the heating furnace main body; a carbonization step of carbonizing the polymer material contained in the closed container to obtain a carbonaceous thin film; a graphitization step of graphitizing the carbonaceous thin film produced in the carbonization step to obtain graphite; and a step of taking out the graphite produced in the graphitization step from the closed container, wherein at least in the carbonization step, a discharge step of discharging a thermal decomposition gas generated from the polymer material to the outside of the furnace main body is performed, and the carbonization step and the graphitization step are continuously performed.

In the introducing step, it is preferable to perform a discharge pipe attaching step of attaching a discharge pipe for discharging the thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body to the closed container. In the introducing step, it is preferable to perform an introducing pipe installing step of installing an introducing pipe for introducing an inert gas into the closed container. In the discharging step, it is preferable that an inert gas introducing step of introducing an inert gas into the sealed container is performed.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one embodiment of the present invention, since the furnace materials such as the furnace wall, the heater, and the heat insulating material are not contaminated by the thermal decomposition gas generated in the carbonization step, it is possible to provide a heating furnace capable of continuously performing the carbonization step and the graphitization step, and a method for producing graphite. This heating furnace can continuously perform the carbonization step and the graphitization step, and therefore is excellent in convenience such as space saving and simplification of the steps. In addition, the production method does not require an operation of taking out the carbonaceous thin film between the carbonization step and the graphitization step. Therefore, the carbonaceous thin film does not need to be cooled temporarily, and thus, the production time can be shortened, energy can be saved, and graphite can be produced at low cost.

Drawings

Fig. 1 is a front view showing a schematic configuration of a heating furnace according to an embodiment of the present invention.

Fig. 2 is a front view showing the configuration of the main part of the above-described heating furnace.

Fig. 3 is a perspective view showing a configuration of a main part of the heating furnace.

Fig. 4 is a front view showing the configuration of the main part of a heating furnace according to another embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail below. However, the present invention is not limited to this, and various modifications can be made within the scope described, and embodiments obtained by appropriately combining technical means disclosed in the respective different embodiments are also included in the technical scope of the present invention. In the present specification, "a to B" indicating a numerical range means "a to B" unless otherwise specified. Additionally, "weight" and "mass" are considered synonyms.

[ heating furnace ]

A heating furnace according to an embodiment of the present invention is a heating furnace for producing graphite from a polymer material, and is configured as follows: the heating furnace comprises a heating furnace main body for performing heat treatment on a polymer material, wherein a closed container for accommodating the polymer material is arranged in the heating furnace main body, and a discharge pipe for discharging a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body is connected to the closed container.

As shown in fig. 1, the heating furnace includes a heating furnace body 2 formed by combining a plurality of plate-like heat insulating materials into a rectangular parallelepiped shape in a casing 1. The heating furnace main body 2 includes a pair of main heaters (heaters) 3 in a pair of side surface portions facing each other in the inside thereof. The heating furnace body 2 is provided with a door (not shown) for sealing the inside of the heating furnace body 2 on one of the other set of side surface parts not provided with the main heater 3. The heating furnace main body 2 includes a sealed container 8 for containing a polymer material 10 therein. The closed container 8 is accommodated in the heating furnace main body 2 through the door portion.

The heating furnace further includes a power supply unit 4 for supplying power to the main heater 3 in the heating furnace main body 2. The power supply unit 4 includes a graphite power supply rod 4a for direct connection to the main heater 3.

Further, as shown in fig. 1 to 3, the heating furnace further includes: a gas discharge pipe (discharge pipe) 11 for discharging a combustible pyrolysis gas (gas containing hydrogen, nitrogen, oxygen, or the like) generated from the polymer material 10 inside the closed vessel 8 to the outside of the heating furnace main body 2, and a gas introduction pipe (introduction pipe) 12 for introducing an inert gas into the closed vessel 8 as necessary. That is, the closed vessel 8 is connected to a gas discharge pipe 11 for discharging the combustible pyrolysis gas generated in the closed vessel to the outside of the heating furnace main body 2, and a gas introduction pipe 12 for introducing an inert gas into the closed vessel as needed.

The size of the closed container 8 is preferably one turn smaller than the heating furnace main body 2 so as to be able to contain a larger amount of the polymer material 10. The closed casing 8 is made of graphite or ceramic, and is more preferably made of graphite. The number of the closed containers 8 housed in the heating furnace main body 2 is not particularly limited.

The sealed container 8 is connected to the gas discharge pipe 11 and the gas introduction pipe 12 by joints (joints), as appropriate. That is, the gas discharge pipe 11 and the gas introduction pipe 12 are preferably connected to the sealed container 8 together when the sealed container 8 is accommodated in the heating furnace main body 2, and the connection portion is also sealed. The gas discharge pipe 11 and the gas introduction pipe 12 are preferably formed of a heat-resistant material. Further, the diameters (inner diameters) of the gas discharge pipe 11 and the gas introduction pipe 12 may be set according to the size of the closed vessel 8 and the amount of the thermal decomposition gas generated, and are not particularly limited.

When the thermally decomposed gas generated from the polymer material 10 by the heat treatment is heavier than the atmospheric gas, the connection portion of the gas discharge pipe 11 in the closed vessel 8 is preferably at a position below the closed vessel 8, and more preferably at the bottom surface, without being blocked by the polymer material 10 contained therein. It is preferable that the thermally decomposed gas is discharged more efficiently, and the connection portion of the gas discharge pipe 11 is illustrated as being located at the center portion of the bottom surface of the closed casing 8 without being blocked by the polymer material 10 contained therein, but may be located at the peripheral portion of the bottom surface. Further, the gas discharge pipe 11 may be connected at a plurality of points. A blower (not shown) such as a blower may be connected to the downstream side of the gas discharge pipe 11 to smoothly discharge the thermally decomposed gas.

The connecting portion of the gas introduction pipe 12 in the closed vessel 8 may be a position where the gas introduction pipe is not blocked by the polymer material 10 contained therein and where the discharge of the thermally decomposed gas is promoted by the introduction of the inert gas, and is preferably located below the closed vessel 8, more preferably located at the bottom. It is preferable that the thermally decomposed gas is discharged more efficiently, and the connection portion of the gas introduction pipe 12 is not blocked by the contained polymer material 10 and is located at the peripheral edge portion of the bottom surface of the closed casing 8, but may be located at the central portion of the bottom surface. Further, the gas introduction pipe 12 may be connected at a plurality of positions. In order to smoothly discharge the thermally decomposed gas by the inert gas, the connection position of the gas introduction pipe 12 in the closed casing 8 may be located above the closed casing 8. A gas tank for supplying inert gas is connected to the upstream side of the gas introduction pipe 12.

The number of gas discharge pipes 11 and the number of gas introduction pipes 12 may be set according to the shape and size of the closed vessel 8, and is not particularly limited, but the number of gas introduction pipes 12 may be larger than the number of gas discharge pipes 11 so that the discharge of the thermally decomposed gas is promoted from all directions by the introduction of the inert gas.

According to the above configuration, since the thermal decomposition gas is discharged to the outside of the heating furnace main body 2 through the gas discharge pipe 11, the heat insulating material forming the heating furnace main body 2 and the main heater 3 provided inside the heating furnace main body 2 hardly come into contact with the thermal decomposition gas generated in the carbonization step. That is, the heat insulating material and the main heater 3 are not contaminated by the thermal decomposition gas. Therefore, when the carbonization step and the graphitization step are continuously performed using the same heating furnace, various problems such as a high temperature of not less than 2500 ℃ in the heating furnace, a risk of ignition, and a shortened heater life are not caused in the graphitization step subsequent to the carbonization step. Therefore, the same heating furnace can be used for the carbonization step and the graphitization step.

Further, when the carbonization step and the graphitization step are continuously performed using the same heating furnace, an operation of taking out the carbonaceous thin film between the carbonization step and the graphitization step is not necessary. Therefore, the carbonaceous film does not need to be cooled temporarily, and thus the production time can be shortened and energy can be saved.

As shown in fig. 4, the closed casing 8 may contain a plurality of polymer materials 10 therein. At this time, the connection portion between the gas discharge pipe 11 and the gas introduction pipe 12 in the closed casing 8 is illustrated as being located between the polymer materials 10 accommodated therein, but may be connected to a portion through which the pyrolysis gas or the inert gas flows in one direction. In addition, a plurality of closed containers may be used. Further, the flow of the thermally decomposed gas and the inert gas may be controlled by providing a partition in the closed vessel.

[ method for producing graphite ]

Graphite has excellent heat dissipation characteristics, and therefore is used as a semiconductor element mounted in various electronic and electrical devices such as computers, or a heat dissipation member for dissipating heat generated by various electronic and electrical devices. One embodiment of the present invention includes a method for manufacturing graphite (a graphite thin film, a graphite sheet, or the like) using the above-described heating furnace.

Graphite is generally produced by a so-called polymer thermal decomposition method in which a polymer material such as polyimide is heat-treated in an inert gas atmosphere or under reduced pressure. Specifically, graphite can be produced through the following steps: the method for producing the carbon film comprises a carbonization step of obtaining a carbon film by subjecting a polymer material in the form of a film to heat treatment (preheating) and carbonization at about 1000 ℃, a graphitization step of firing the carbon film produced in the carbonization step at a high temperature of 2500 ℃ or higher to graphitize (graphitize), and a compression step of compressing the graphitized carbon film (graphite) as necessary.

A method for producing graphite according to an embodiment of the present invention is a method comprising: the method for producing graphite from a polymer material comprises: a lead-in step of leading the sealed container containing the polymer material into the heating furnace main body; a carbonization step of carbonizing the polymer material contained in the closed container to obtain a carbonaceous thin film; a graphitization step of graphitizing the carbonaceous thin film produced in the carbonization step to obtain graphite; and a step of taking out the graphite produced in the graphitization step from the closed container, wherein at least in the carbonization step, a discharge step of discharging a thermal decomposition gas generated from the polymer material to the outside of the furnace main body is performed, and the carbonization step and the graphitization step are continuously performed. That is, in the method for producing graphite according to one embodiment of the present invention, the carbonization step is performed in a discharge step of discharging a thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body, and the carbonization step and the graphitization step are continuously performed (without removing the polymer material from the heating furnace). The polymer material is preferably in the form of a film, but the shape thereof is not particularly limited. In the following description, a case where the polymer material is in a film form is exemplified.

(Polymer Material)

Examples of the film-like polymer material suitable for producing graphite include polyimide, polyamide, polyoxadiazole, polybenzothiazole, polybenzobithiazole, polybenzoxazole, polybenzobisoxazole, polyparaphenylene vinylene, polybenzimidazole, polybenzobisoxazole, and polythiazole. Particularly, polyimide is more preferable because it can produce graphite excellent in thermal diffusivity, thermal conductivity, and electrical conductivity. The polymer material may be appropriately selected depending on the physical properties required for the graphite to be produced.

(introduction step)

The introduction step is a step of introducing a closed container containing a polymer material (hereinafter referred to as a "polymer material film") in a film form (sheet), preferably in a roll form (long strip) into the heating furnace main body. The form of the polymer material film contained in the closed container is not particularly limited. The number of the polymer material films wound up in a roll shape to be accommodated in the closed casing is not particularly limited.

Further, in the introducing step, a discharge pipe installing step of installing a gas discharge pipe for discharging the thermal decomposition gas generated from the polymer material to the outside of the heating furnace main body to the closed container and an introducing pipe installing step of installing a gas introducing pipe for introducing the inert gas to the inside of the closed container are performed together.

(carbonization step)

The carbonization step is a step of obtaining a carbonaceous thin film by heat-treating and carbonizing a polymer thin film at about 1000 ℃. The maximum temperature at the time of the heat treatment is, for example, preferably 500 to 1800 ℃, more preferably 700 to 1600 ℃, still more preferably 900 to 1400 ℃, and particularly preferably 1000 ℃.

The temperature increase rate in the carbonization step is, for example, preferably 0.01 to 50 ℃/min, more preferably 0.1 to 25 ℃/min, still more preferably 0.2 to 10 ℃/min, and particularly preferably 0.5 to 5.0 ℃/min.

In the carbonization step, the polymer material film is carbonized while being contained in a closed container. The combustible thermally decomposed gas generated from the polymer material film by the heat treatment is discharged to the outside of the heating furnace main body through the gas discharge pipe. That is, in one embodiment of the present invention, at least in the carbonization step, a discharge step of discharging the combustible thermally decomposed gas generated from the polymer material film to the outside of the heating furnace main body is performed.

Further, when the thermal decomposition gas is discharged to the outside of the heating furnace main body through the gas discharge pipe, the discharge of the thermal decomposition gas can be promoted by introducing the inert gas into the inside of the closed container through the gas introduction pipe. That is, in one embodiment of the present invention, in the discharging step, an inert gas introducing step of introducing an inert gas into the closed container may be performed.

The holding time in the carbonization step, specifically, the holding time at the maximum temperature is preferably 2 hours or less, more preferably 5 minutes to 1 hour, and further preferably 8 minutes to 30 minutes. The carbonization step is terminated at a point in time when the thermal decomposition gas is not substantially discharged, and the process is continuously transferred to the graphitization step.

(graphitization step)

The graphitization step is a step of firing the carbonaceous thin film produced in the carbonization step at a high temperature of 2500 ℃ or higher to graphitize (graphitize). The maximum temperature at the time of firing is preferably 2500 ℃ or more, 2600 ℃ or more, 2700 ℃ or more, 2800 ℃ or more, 2900 ℃ or more, 3000 ℃ or more, 3100 ℃ or more, or 3200 ℃ or more. The graphitization step is performed in an inert gas atmosphere such as nitrogen, helium, or argon, or under reduced pressure.

The temperature increase rate in the graphitization step is, for example, preferably 0.01 to 50 ℃/min, more preferably 0.1 to 20 ℃/min, and still more preferably 0.3 to 10 ℃/min.

The holding time in the graphitization step, specifically, the holding time at the maximum temperature is preferably 2 hours or less, more preferably 5 minutes to 1 hour, and further preferably 8 minutes to 30 minutes.

In the graphitization step, the carbonaceous thin film is graphitized in a state of being housed in a closed container. In the case where a gas generated by gasifying an inorganic substance contained in the polymer material film, graphite sublimated from a sealed container, or the like is generated, the gas may be discharged from a gas discharge pipe. In this case, the inert gas may be introduced into the sealed container through the gas introduction pipe to promote the discharge of the inert gas.

(taking out step)

The taking-out step is a step of taking out the closed vessel from the furnace main body and taking out the graphite produced in the graphitization step from the closed vessel. In one embodiment of the present invention, since the carbonization step and the graphitization step are continuously performed, an operation of taking out the carbonaceous thin film between the carbonization step and the graphitization step is not required, and only a taking-out step of taking out the graphite produced in the graphitization step may be performed. Therefore, the carbonaceous film does not need to be cooled temporarily, and thus the production time can be shortened and energy can be saved.

(compression Process)

The compression step to be performed as needed is a step of compressing the graphite produced in the graphitization step. By performing the compression step, flexibility can be imparted to the obtained graphite. In the compression step, the graphite produced in the graphitization step may be compressed by a method of compressing the graphite into a sheet by a press or the like, a method of rolling the graphite with a metal roll or the like, or the like. The pressing force in the compression step is not particularly limited. The compression step is performed at room temperature, but the temperature is not particularly limited.

According to the above method, the operation of taking out the carbonaceous thin film between the carbonization step and the graphitization step is not required. Therefore, since the carbonaceous thin film does not need to be cooled temporarily, the production time can be shortened, energy can be saved, and graphite can be produced at low cost.

Industrial applicability

The present invention can be suitably used for the production of graphite.

Description of the reference numerals

1 casing

2 heating furnace body

3 Main heater (Heater)

4 power supply part

4a power supply rod

8 closed container

10 high molecular material

11 gas discharge pipe (discharge pipe)

12 gas inlet pipe (inlet pipe)