JP4600703B2 - Method for producing glassy carbon - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing glassy carbon suitable for a member for a semiconductor production apparatus, a member for a CVD apparatus, a hard disk substrate and the like having excellent corrosion resistance, and a glassy carbon obtained by the production method.
[0002]
[Prior art]
Glassy carbon has properties such as lightness, heat resistance, corrosion resistance, electrical conductivity, high purity, etc. that general carbon materials have, as well as gas impermeability, low dust generation, and hardness. Since it has a feature such as high mirror finishing, it is being used for a wide range of applications in various fields such as the electronics industry, the nuclear industry, and the aerospace industry.
[0003]
Glassy carbon is obtained from a thermosetting resin as a raw material, and after curing it, it is obtained by calcination carbonization in an inert atmosphere or vacuum, but in the manufacturing process from molding to graphitization as necessary. Since it reacts in a solid state, it is impermeable to gas or liquid.
[0004]
For this reason, in the curing process of the thermosetting resin, the condensed water and decomposition gas generated by the condensation polymerization reaction, and the volatile monomer contained in the raw material resin are not easily diffused, causing closed pores to be generated in the molded body. . In the prior art, measures such as curing the resin for a long time have been taken to prevent such problems.
[0005]
Further, in the firing process, if the decomposition gas and the tar component generated due to the thermal decomposition of the resin are insufficiently diffused, foaming and cracks occur in the molded body, and the glassy carbon having the desired shape cannot be obtained. Even if foaming and cracks do not occur, the tar component expands and large closed pores are easily generated in the molded body.
[0006]
Decomposition gas generated in the firing process refers to low molecular weight substances that are gases at normal temperature and pressure, such as carbon monoxide, carbon dioxide, hydrogen, methane, and ethane, and tar components are miscellaneous products generated by thermal decomposition of the resin. A medium molecular weight substance that is liquid at room temperature and pressure.
[0007]
In addition, in the firing process of converting the resin cured product to glassy carbon, the carbon atoms forming the resin skeleton are rearranged into a graphite structure at the same time as the decomposition gas and the tar component are released, and accompanying this, Shrinkage of the compact occurs. In particular, when firing thick molded products, the speed of heat propagation differs greatly between the molded body surface and the interior, resulting in a difference in the shrinkage speed between the molded body surface and the interior, resulting in the phenomenon that the molded body breaks. easy.
[0008]
Therefore, a method for significantly reducing the time required for curing, producing foam and cracks during firing, generating large closed pores, and preventing cracking, and producing glassy carbon of a desired shape in a short period of time with a high yield The development of was requested.
[0009]
[Problems to be solved by the invention]
The invention according to claim 1 efficiently removes the volatile component of the thermosetting resin used as a raw material or the volatile component generated during curing to produce a cured resin product having a desired thickness and shape, and firing. In the process, a method for producing glassy carbon which can prevent foaming, cracking, generation of large closed pores and cracking and obtain glassy carbon having good properties is provided.
[0010]
In the invention according to claim 2, the volatile component of the thermosetting resin used as a raw material or the volatile component generated during curing is efficiently removed to produce a cured resin product having a desired thickness and shape, and firing. In the process, a method for producing glassy carbon having good properties in which foaming, cracking, generation of large closed pores and cracking are prevented is provided.
[0011]
[Means for Solving the Problems]
The present invention uses a liquid furan resin , which is a liquid thermosetting resin having a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s and a nonvolatile component content of 30 to 70% by weight, once. After forming a resin layer having a coating thickness of 500 μm or less and repeating the heat curing step a plurality of times to obtain a resin molded body, the temperature is increased up to 700 ° C. at a rate of temperature increase of 1.5 ° C./hour or less. The present invention relates to a method for producing glassy carbon characterized by heating and firing. The present invention also relates to a method for producing glassy carbon obtained by the above production method and having a maximum closed pore diameter of 100 μm or less and a maximum thickness of 5 mm or more.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing glassy carbon of the present invention, a liquid thermosetting resin having a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s and a nonvolatile component content of 30 to 70 wt% is used as a raw material. However, if a thermosetting resin whose starting material is out of the above range is used, it can be used by adding a solvent to the thermosetting resin so as to fall within the above range.
[0013]
Examples of the thermosetting resin include furan resin, phenol resin, divinylbenzene resin, unsaturated polyester resin, polyimide resin, diallyl phthalate resin, vinyl ester resin, polyurethane resin, melamine resin, urea resin, and the like. A mixture of these resins can also be used. Of these, furan resin, phenol resin or a mixture thereof is preferable, and furan resin is more preferable in consideration of stretchability during molding, release rate of volatile components, carbonization yield, and the like.
[0014]
Preferred examples of the furan resin include an initial condensate of a resin such as a furfural resin, a furfural phenol resin, a furfural ketone resin, a furfuryl alcohol resin, and a furfuryl alcohol phenol resin.
The solvent to be added to the thermosetting resin is not particularly limited as long as it is an organic solvent that is liquid at normal temperature and pressure, and the monomer of the thermosetting resin can also be used. Preferable examples of the solvent include various alcohols such as ethanol, propanol, and butanol.
[0015]
As the liquid thermosetting resin, a curing agent for the resin can be used as necessary, and examples thereof include acids and alkalis. Preferred acids include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, phenolsulfonic acid, toluenesulfonic acid, methanesulfonic acid, aniline sulfate, acetic acid, trichloroacetic acid, trifluoroacetic acid, and the like. Organic sulfonic acids such as acid, toluenesulfonic acid and methanesulfonic acid, and organic carboxylic acids such as acetic acid, trichloroacetic acid and trifluoroacetic acid are more preferred, and phenolsulfonic acid and toluene acid are more preferred. As the alkali, ammonia, amines, sodium hydroxide, potassium hydroxide and the like are preferable.
[0016]
The amount of curing agent used varies depending on the amount of thermosetting resin and solvent added as raw materials, but if it is too small, curing will be slow and insufficient, and if it is too large, a curing reaction will occur rapidly, causing foaming or ignition. It tends to be difficult to produce a beautiful molded body. Therefore, it is preferable to set it as the range of 0.01-20 weight% with respect to a thermosetting resin, and it is more preferable to set it as the range of 0.01-15 weight%.
The curing agent is added to the liquid thermosetting resin as it is or after being appropriately dissolved in a solvent. Examples of the solvent used here include lower alcohols such as methanol and ethanol, and organic solvents such as acetone and toluene.
[0017]
In the present invention, the non-volatile component refers to a low molecular polymer obtained by polymerizing 2 to 3 molecules of unreacted monomers and raw material monomers mainly contained in the thermosetting resin initial condensate. The amount of the non-volatile component was defined as a residual amount after taking a liquid thermosetting resin as a raw material or a liquid thermosetting resin prepared by adding a solvent to a thermosetting resin in an aluminum petri dish and leaving it at 120 ° C. for 3 hours. The viscosity was measured using a B-type viscometer at a rotor rotational speed of 60 min ⁻¹ . However, when a curing agent was used, viscosity measurement was performed on the resin before addition of the curing agent.
[0018]
The substrate used for applying the liquid thermosetting resin, that is, the substrate used as the base until the applied liquid thermosetting resin is heated and cured, and then baked to produce glassy carbon, is used as a raw material. Thermosetting resin has good stretchability and has sufficient heat resistance to prevent deformation, softening, etc. of the base material against the maximum temperature when curing the thermosetting resin. It is preferable to use a material having excellent releasability from the resin, and preferable examples include aluminum, glass, vinyl chloride, acrylic, Teflon, graphite material, ceramic material, and various metal materials. It is also possible to provide the substrate material with irregularities, curvature, etc. as required, and to add a desired shape to the resin molding. Examples of the application method include application using a brush or the like, and a dropping method, a spin coating method, a spraying method, and the like. However, there is no particular limitation as long as the resin is uniformly applied without any foreign matter mixed in the resin. Is not to be done.
[0019]
The liquid thermosetting resin has a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s, preferably 0.06 to 0.2 Pa · s, more preferably 0.06 to 0.17 Pa · s. However, when it is less than 0.05 Pa · s, particularly when applied by a spin coating method, the thickness that can be applied at one time is remarkably thin. On the other hand, if it exceeds 0.3 Pa · s, the fluidity of the thermosetting resin used as a raw material is remarkably lowered, and air entrained at the time of casting remains as it is, and it tends to be large closed pores.
[0020]
The content of the non-volatile component in the liquid thermosetting resin is in the range of 30 to 70% by weight, preferably 35 to 65% by weight, more preferably 40 to 60% by weight. It becomes difficult and air bubbles or the like are likely to remain in the molded body, and when it exceeds 70% by weight, there is a problem that uniform coating cannot be performed.
[0021]
The coating thickness of the liquid thermosetting resin at one time is 500 μm or less, preferably 300 μm or less, more preferably 280 to 180 μm, and if it exceeds 500 μm, it takes a long time to deviate from volatile components during curing. At the same time, volatile components remain in the cured body and cause voids. Also, the resin does not cure uniformly, and a large compression stress is applied to form a distorted resin molded product. Increases the amount of cracked gas generated and becomes a cause of foaming.
[0022]
The curing of the liquid thermosetting resin applied on the substrate is preferably 30 to 300 ° C., more preferably 50 to 250 ° C., because of easy reaction control. In addition, it is desirable to select an appropriate temperature from this temperature range, for example, 50 ° C., 100 ° C., 250 ° C., etc., in a stepwise curing process. However, the temperature is continuously raised and held at each selected temperature for the curing process. Can also be done. The curing treatment can be performed not only under normal pressure but also under reduced pressure or under pressure. As a heating furnace used for curing, any method such as a hot air method, a far infrared method, an electromagnetic wave method, or the like can be used, and two or more methods can be used in combination.
[0023]
The resin molded body obtained by the above method is then fired to form glassy carbon, but it can be processed into a desired shape by machining or the like before firing. At that time, it is necessary to set a processing dimension in consideration of dimensional shrinkage after firing. Calcination can be performed in an atmosphere containing no oxygen or an atmosphere composed of at least one or a mixture of two or more of an inert gas such as helium and argon and a non-oxidizing gas such as nitrogen, hydrogen and halogen. When firing is performed under reduced pressure, diffusion of cracked gas and tar components generated with thermal decomposition of the resin is facilitated, and a thicker glassy carbon material can be obtained. The degree of decompression is preferably 1 to 25 × 10 ⁵ Pa.
[0024]
The heating rate during firing is required to be up to 700 ° C. at 1.5 ° C./hour or less, preferably at 1 ° C./hour or less. The dimensional shrinkage rate becomes too high and cracking is likely to occur. Particularly, it becomes extremely difficult to obtain a thick glassy carbon having a maximum thickness of 5 mm or more, and the obtained glassy carbon has a compressive stress. To give glassy carbon with distortion.
[0025]
The glassy carbon that has been heated to 700 ° C. may be dehydrogenated by firing at a temperature of 700 to 1000 ° C., if necessary, and may be further graphitized to 3000 ° C. Graphitization is desirably performed in a non-oxidizing atmosphere such as argon gas or in a vacuum. In consideration of the characteristics of the glassy carbon material such as specific gravity, hardness and chemical resistance, the maximum temperature of the heat treatment is preferably 800 to 3000 ° C, particularly preferably 1100 to 2800 ° C.
[0026]
In addition, when glassy carbon is used in applications requiring high purity, after graphitization, a method used for high purity treatment of general carbon materials, for example, deashing treatment with halogen gas or the like is performed. High purity can also be achieved. In the firing and graphitization steps, it is preferable to use a highly purified jig, furnace or the like.
[0027]
The glassy carbon obtained by the present invention preferably has a maximum closed pore diameter of 100 μm or less, more preferably 50 μm or less, and more preferably 30 μm or less in terms of surface smoothness required for a hard disk substrate or the like. More preferably, it is most preferably 0 μm.
In the present invention, the maximum closed pore diameter is a value obtained by measuring the diameter when the shape of the maximum closed pore is substantially circular, and measuring the maximum width when the shape is elliptic.
Further, the thickness of the glassy carbon is preferably 5 mm or more, more preferably 6 mm or more, and in the range of 7 to 12 mm, for example, when used for a semiconductor manufacturing member. More preferably.
[0028]
In the present invention, the obtained glassy carbon material can be processed into the shape of the final product using wire cutting, electric discharge machining, ultrasonic machining, or the like, if necessary.
The glassy carbon of the present invention is useful as an electrode for plasma etching, a hard disk substrate, a phosphoric acid fuel cell separator, an acid-resistant container member, a member for semiconductor production, an electrode for chemical analysis, a carbon target for sputtering, and the like.
[0029]
【Example】
Hereinafter, the present invention will be described with reference to examples.
Example 1
A liquid furan resin (trade name VF-302, manufactured by Hitachi Chemical Co., Ltd.) having a viscosity of 0.12 Pa · s at 25 ° C. and a non-volatile component of 45% by weight is used as a raw material thermosetting resin. After adding 0.6 parts by weight of para-toluenesulfonic acid as a curing agent to 100 parts by weight and stirring and mixing, it was dropped and stretched to an aluminum petri dish so that the coating thickness at one time became 500 μm, and a hot air dryer And was cured by heating at 200 ° C. for 1 hour. The thickness of the cured resin after curing was 400 μm. This operation was repeated 25 times to obtain a resin molded body having a thickness of 10 mm.
[0030]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Furthermore, the temperature increase rate of 1000-2600 degreeC was 10 degreeC / hour, and it hold | maintained at 2600 degreeC for 5 hours, and obtained glassy carbon. The resulting glassy carbon had no foaming, cracking or cracking. Moreover, the maximum thickness of the obtained glassy carbon was 8 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 5 μm.
[0031]
Example 2
After adding 15 parts by weight of trichloroacetic acid as a curing agent to 100 parts by weight of the liquid furan resin used in Example 1, the mixture was stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 450 μm. Then, heat curing was performed at 50 ° C. for 5 hours with a hot air dryer, 10 minutes with a far infrared dryer, and then at 180 ° C. for 1 hour with a hot air dryer. The thickness of the cured resin after curing was 350 μm. This operation was repeated 40 times to obtain a resin molded body having a thickness of 14 mm.
[0032]
This resin molded body is held at 1000 ° C. for 5 hours under a reduced pressure of 1 × 10 ³ Pa with a temperature rising rate up to 900 ° C. being 1.0 ° C./hour and a temperature rising rate of 900 to 1000 ° C. being 10 ° C./hour Then, firing was performed to obtain glassy carbon. The resulting glassy carbon had no foaming, cracking or cracking. Further, the maximum thickness of the obtained glassy carbon was 11.2 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 10 μm.
[0033]
Example 3
After adding 0.6 parts by weight of paratoluenesulfonic acid as a curing agent to 100 parts by weight of the liquid furan resin used in Example 1 and stirring and mixing, the coating thickness at one time on an aluminum petri dish is 500 μm. The solution was dropped and stretched, and heat-cured with a hot air dryer at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour. The thickness of the cured resin after curing was 400 μm. This operation was repeated 20 times to obtain a resin molded body having a thickness of 8 mm.
[0034]
The resin molding was fired under a nitrogen atmosphere at a heating rate of up to 900 ° C. at 0.5 ° C./hour and a heating rate of 900-1000 ° C. at 5 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. Moreover, the maximum thickness of the obtained glassy carbon was 6.4 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 10 μm.
[0035]
Example 4
The liquid furan resin used in Example 1 was heat-treated at 50 ° C. for 10 hours to remove a part of the volatile components. The resin after the heat treatment had a viscosity at 25 ° C. of 0.28 Pa · s and a non-volatile component of 66% by weight. Next, with respect to 100 parts by weight of this liquid furan resin, 0.6 parts by weight of paratoluenesulfonic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 500 μm. Then, heat curing was performed with a hot air dryer at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour. The thickness of the cured resin after curing was 450 μm. This operation was repeated 23 times to obtain a resin molded body having a thickness of 10.35 mm.
[0036]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. Further, the maximum thickness of the obtained glassy carbon was 8.3 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 30 μm.
[0037]
Example 5
40 parts by weight of ethanol was added to 100 parts by weight of the liquid furan resin used in Example 1 and mixed with stirring. The liquid furan resin after stirring and mixing had a viscosity at 25 ° C. of 0.08 Pa · s and a non-volatile component of 32% by weight. Next, to 100 parts by weight of this liquid furan resin, 15 parts by weight of trichloroacetic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 400 μm. Heat curing was performed at 50 ° C. for 5 hours and then at 200 ° C. for 1 hour in a dryer. The thickness of the cured resin after curing was 250 μm. This operation was repeated 28 times to obtain a resin molded body having a thickness of 7 mm.
[0038]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. The maximum thickness of the obtained glassy carbon was 5.6 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 20 μm.
[0039]
Comparative Example 1
After adding 0.6 parts by weight of paratoluenesulfonic acid as a curing agent to 100 parts by weight of the liquid furan resin used in Example 1 and stirring and mixing, the coating thickness at one time on an aluminum petri dish is 500 μm. The solution was dropped and stretched, and heat-cured with a hot air dryer at 50 ° C. for 5 hours and then at 200 ° C. for 1 hour. The thickness of the cured resin after curing was 400 μm. This operation was repeated 25 times to obtain a resin molded body having a thickness of 10 mm.
[0040]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 2.0 ° C./hour and a heating rate of 700-1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. Cracks occurred in the obtained glassy carbon, and the desired shape was not obtained.
[0041]
Comparative Example 2
The liquid furan resin used in Example 1 was heat-treated at 90 ° C. for 5 hours to remove a part of the volatile components. The viscosity of the resin at 25 ° C. after the heat treatment was 0.34 Pa · s and the non-volatile component was 79% by weight. Next, with respect to 100 parts by weight of this liquid furan resin, 0.6 parts by weight of paratoluenesulfonic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 500 μm. Then, heat curing was performed with a hot air dryer at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour. The thickness of the cured resin after curing was 490 μm. This operation was repeated 21 times to obtain a resin molded body having a thickness of 10.29 mm.
[0042]
The resin molding was fired under a nitrogen atmosphere at a heating rate of up to 900 ° C. at 1.0 ° C./hour and a heating rate of 900-1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. The maximum thickness of the obtained glassy carbon was 8.2 mm.
However, as a result of rupturing the glassy carbon and observing the closed pores on the fracture surface, the maximum closed pore diameter was as large as 200 μm.
[0043]
Comparative Example 3
The liquid furan resin used in Example 1 was heat-treated at 50 ° C. for 10 hours to remove a part of the volatile components. The viscosity of the resin at 25 ° C. after the heat treatment was 0.28 Pa · s and the non-volatile component was 66% by weight. Next, with respect to 100 parts by weight of this liquid furan resin, 0.6 parts by weight of para-toluenesulfonic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 600 μm. Then, heat curing was performed with a hot air dryer at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour. The thickness of the cured resin after curing was 540 μm. This operation was repeated 19 times to obtain a resin molded body having a thickness of 10.26 mm.
[0044]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. Foaming occurred in the obtained glassy carbon, and the desired shape was not obtained.
[0045]
Comparative Example 4
After adding 0.6 parts by weight of paratoluenesulfonic acid as a curing agent to 100 parts by weight of the liquid furan resin used in Example 1 and stirring and mixing, the coating thickness at one time on an aluminum petri dish is 500 μm. The solution was dropped and stretched, and heat-cured with a hot air dryer at 50 ° C. for 5 hours, with a far-infrared dryer for 5 minutes, and then with a hot air dryer at 200 ° C. for 1 hour. The thickness of the cured resin after curing was 400 μm. This operation was repeated 25 times to obtain a resin molded body having a thickness of 10 mm.
[0046]
This resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 600 ° C. at 1.0 ° C./hour and a heating rate of 600 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. Cracks occurred in the obtained glassy carbon, and the desired shape was not obtained.
[0047]
Comparative Example 5
100 parts by weight of ethanol was added to 100 parts by weight of the liquid furan resin used in Example 1, and the mixture was stirred and mixed. The liquid furan resin after stirring and mixing had a viscosity at 25 ° C. of 0.06 Pa · s and a non-volatile component of 22.5% by weight. Next, with respect to 100 parts by weight of this liquid furan resin, 0.6 parts by weight of paratoluenesulfonic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 500 μm. Then, heat curing was performed with a hot air dryer at 50 ° C. for 5 hours, with a far infrared dryer for 5 minutes, and then with a hot air dryer at 200 ° C. for 1 hour. The thickness of the cured resin after curing was 200 μm. This operation was repeated 25 times to obtain a resin molded body having a thickness of 5 mm.
[0048]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. Moreover, the maximum thickness of the obtained glassy carbon was 4 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 200 μm.
[0049]
Comparative Example 6
300 parts by weight of acetone was added to 100 parts by weight of the liquid furan resin used in Example 1, and the mixture was stirred and mixed. The liquid furan resin after stirring and mixing had a viscosity at 25 ° C. of 0.04 Pa · s and a non-volatile component of 11.3 wt%. Next, with respect to 100 parts by weight of this liquid furan resin, 0.6 parts by weight of paratoluenesulfonic acid as a curing agent was added and stirred and mixed, and then dropped and stretched on an aluminum petri dish so that the coating thickness at one time became 500 μm. Then, heat curing was performed with a hot air dryer at 50 ° C. for 5 hours, with a far infrared dryer for 5 minutes, and then with a hot air dryer at 200 ° C. for 1 hour. The thickness of the cured resin after curing was 100 μm. This operation was repeated 100 times to obtain a resin molded body having a thickness of 10 mm.
[0050]
The resin molded body was fired under a nitrogen atmosphere at a heating rate of up to 700 ° C. at 1.0 ° C./hour and a heating rate of 700 to 1000 ° C. at 10 ° C./hour for 5 hours at 1000 ° C. Glassy carbon was obtained. The resulting glassy carbon had no foaming, cracking or cracking. Moreover, the maximum thickness of the obtained glassy carbon was 8 mm.
As a result of fracture of the glassy carbon and observation of the closed pores on the fracture surface, the maximum closed pore diameter was 150 μm.
[0051]
【The invention's effect】
The glassy carbon obtained by the method according to claim 1 efficiently removes the volatile component of the thermosetting resin used as a raw material or the volatile component generated during the curing to obtain a cured resin product having a desired thickness and shape. While producing, it is a glassy carbon with good properties, preventing foaming, cracking, generation of large closed pores and cracking in the firing process. The vitreous carbon according to claim 2 is obtained by efficiently removing a volatile component of a thermosetting resin as a raw material or a volatile component generated at the time of curing to produce a resin cured product having a desired thickness and shape, This is a method for producing glassy carbon having good properties, in which foaming, cracking, generation of large closed pores and cracking are prevented in the firing process.

Claims (2)

A liquid furan resin , which is a liquid thermosetting resin having a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s (0.5 to 3 poise) and a nonvolatile component content of 30 to 70% by weight , is used. After forming a resin layer having a coating thickness of 500 μm or less once and repeating the heat curing step a plurality of times to obtain a resin molded body, the temperature is increased to 700 ° C. by 1.5 ° C./hour or less. A method for producing glassy carbon, characterized by heating at a temperature rate and firing.   2. The method for producing glassy carbon according to claim 1, wherein the maximum closed pore diameter is 100 [mu] m or less and the maximum thickness is 5 mm or more.