JP2001122662A - Method for manufacturing glassy carbon and glassy carbon obtained by the manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing glassy carbon which manufactures the cured matter of a resin having a desired thickness and shape by efficiently removing the volatile component possessed by a thermosetting resin, i.e., a raw material or the volatile component formed during curing, prevents foaming, cracking, formation of large closed pores and crazing and yields the glassy carbon having good characteristics and the glassy carbon. SOLUTION: This method for manufacturing the glassy carbon consists in obtaining a resin molding by repeating, plural times, the stages of forming resin layers with which a coating application thickness of one time is <=500 μm, by using the liquid thermosetting resin having a viscosity at 25 deg.C of 0.05 to 0.3 Pa.s (0.5 to 3 poises) and a content of the volatile component of 3 to 70 wt.%, and then baking the resin molding by heating up to 700 deg.C at the temperature elevation rate of <=1.5 deg.C/hour. The glassy carbon is <=100 μm in the largest closed pore diameter and >=5 mm in the maximum thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing glassy carbon which is suitable for a member for a semiconductor manufacturing apparatus, a member for a CVD apparatus, a hard disk substrate, etc., having excellent corrosion resistance, and a glassy carbon obtained by the method. .

[0002]

2. Description of the Related Art Vitreous carbon has properties such as light weight, heat resistance, corrosion resistance, electric conductivity, and high purity that general carbon materials have, and gas impermeability and low emission. Due to its features such as high dustiness and high hardness, mirror finishing is possible, the electronics industry, nuclear power industry,
It is being used for a wide range of applications in various fields such as the aerospace industry.

[0003] Glassy carbon is made of thermosetting resin,
After this is cured, it is obtained by calcining in an inert atmosphere or in vacuum, but in the manufacturing process from molding to graphitization performed as necessary, it reacts in the solid state throughout, so gas or Impermeable to liquids.

[0004] Therefore, in the curing process of the thermosetting resin, condensed water and decomposed gas generated by the condensation polymerization reaction,
Volatile monomers contained in the raw material resin are not easily diffused,
This is a factor in forming closed pores in the molded body. In the prior art, measures have been taken to prevent such a problem, such as curing the resin for a long time.

[0005] Further, in the firing step, if the decomposition gas or tar component generated due to the thermal decomposition of the resin is insufficiently diffused, foaming and cracks are generated in the molded product, and the desired shape of glassy carbon is obtained. Can not be. Even if foaming or cracking does not occur, the tar component is likely to expand and generate large closed pores in the molded article.

[0006] The decomposition gas generated in the calcination process is a low molecular weight substance such as carbon monoxide, carbon dioxide, hydrogen, methane, ethane, etc., which is a gas at normal temperature and normal pressure. It is a miscellaneous substance that is produced and refers to a medium molecular weight substance that is liquid at normal temperature and pressure.

In the firing process for converting the cured resin to glassy carbon, the carbon atoms forming the skeleton of the resin are rearranged into a graphite structure simultaneously with the release of the decomposition gas and the tar component. Along with this, the compact shrinks. In particular, when firing thick molded products, the heat propagation speed differs greatly between the surface of the molded body and the inside, causing a difference in the shrinkage speed between the surface of the molded body and the inside, and the phenomenon of the molded body breaking. easy.

For this reason, the time required for curing is greatly reduced, and the occurrence of foaming and cracking during firing and the generation and cracking of large closed pores are prevented, and the yield of glassy carbon having the desired shape can be improved in a short period of time. Development of a manufacturing method was desired.

[0009]

According to the first aspect of the present invention, a volatile component contained in a thermosetting resin as a raw material or a volatile component generated during curing is efficiently removed to obtain a desired thickness and shape. In addition to producing a cured resin, foaming, cracking, and prevention of formation and cracking of large closed pores in the firing process, a method for producing glassy carbon capable of obtaining glassy carbon having good properties is provided. is there.

According to the second aspect of the present invention, a volatile resin contained in a thermosetting resin as a raw material or a volatile component generated during curing is efficiently removed, and a cured resin product having a desired thickness and shape is produced. In addition, the present invention provides good-quality glassy carbon in which foaming, cracking, generation of large closed pores and cracking are prevented in the firing step.

[0011]

The present invention uses a liquid thermosetting resin having a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s and a nonvolatile content of 30 to 70% by weight. After forming a resin layer having a coating thickness of 500 μm or less at one time and heating and curing the resin layer a plurality of times to obtain a resin molded body, the temperature is raised to 700 ° C. at a rate of 1.5 ° C./hour or less. The present invention relates to a method for producing glassy carbon, which comprises raising the temperature at a temperature rate and firing the same. The present invention also relates to a glassy carbon obtained by the above-mentioned production method, wherein the maximum closed pore diameter of the glassy carbon is 100 μm or less and the maximum thickness is 5 mm or more.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing glassy carbon of the present invention, the viscosity at 25 ° C. is 0.05 to 0.3 Pa · s, and the content of the non-volatile component is 30 to 70% by weight. Liquid thermosetting resin is used as the raw material, but if the starting raw material uses a thermosetting resin that is out of the above range, a solvent is added to the thermosetting resin and adjusted so as to fall within the above range. Can also be used.

As the thermosetting resin, 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 can be mentioned. Also, a mixture of these resins can be used. Among these,
In consideration of the stretchability during molding, the release rate of volatile components, the carbonization yield, and the like, a furan resin, a phenol resin, or a mixture thereof is preferable, and a furan resin is more preferable.

Preferred examples of the type of the furan resin include initial condensates of resins such as furfural resin, furfural phenol resin, furfural ketone resin, furfuryl alcohol resin, and 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 normal pressure, and it is also possible to use a monomer of the thermosetting resin. Preferred solvents are various alcohols such as ethanol, propanol and butanol.

As the liquid thermosetting resin, a curing agent for the resin can be used if necessary, and examples thereof include acids and alkalis. As the acid, sulfuric acid, hydrochloric acid,
Inorganic acids such as nitric acid and phosphoric acid, phenolsulfonic acid, toluenesulfonic acid, methanesulfonic acid, aniline sulfate, acetic acid, trichloroacetic acid, trifluoroacetic acid and the like are preferred, and among them, phenolsulfonic acid, toluenesulfonic acid, methane Organic sulfonic acids such as sulfonic acid, and organic carboxylic acids such as acetic acid, trichloroacetic acid, and trifluoroacetic acid are more preferable, and phenolsulfonic acid and toluene acid are more preferable. As the alkali, ammonia, amines, sodium hydroxide, potassium hydroxide and the like are preferable.

The amount of the curing agent used varies depending on the amounts of the thermosetting resin and the solvent used as the raw materials, but if the amount is too small, the curing is slow and inadequate. If the amount is too large, the curing reaction occurs rapidly, There is a risk of foaming or ignition, and it tends to be difficult to produce a clean molded article. Accordingly, the content is preferably in the range of 0.01 to 20% by weight, more preferably 0.01 to 15% by weight, based on the thermosetting resin. 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.

In the present invention, the non-volatile component mainly refers to a low molecular weight polymer obtained by polymerizing two to three molecules of unreacted monomers and raw material monomers contained in a thermosetting resin precondensate. The amount of the non-volatile component was defined as a residual amount after the liquid thermosetting resin as a raw material or the liquid thermosetting resin prepared by adding a solvent to the thermosetting resin was placed in an aluminum Petri dish and left at 120 ° C. for 3 hours. The viscosity was measured using a B-type viscometer at a rotor rotation speed of 60 min ^-1 . However, when a curing agent was used, the viscosity of the resin before the addition of the curing agent was measured.

The substrate used for applying the liquid thermosetting resin, that is, the substrate used as a base until the applied liquid thermosetting resin is heated and cured and then baked to produce glassy carbon, is used as a raw material. The stretchability of the thermosetting resin used is good, and the substrate has sufficient heat resistance to prevent deformation, softening, and the like with respect to the maximum temperature when the thermosetting resin is cured, and is further cured. It is preferable to use a material having excellent releasability from the thermosetting resin, and examples thereof include aluminum, glass, vinyl chloride, acryl, Teflon, graphite, ceramics, and various metal materials. The substrate material may be provided with irregularities, curvatures, and the like, as needed, to add a desired shape to the resin molded body. As a method of application, besides applying using a brush or the like, a dropping method, a spin coating method, a spraying method, and the like can be mentioned, without mixing foreign matter into the resin,
There is no particular limitation as long as the resin is uniformly applied.

The viscosity of the liquid thermosetting resin at 25 ° C. is as follows:
0.05 to 0.3 Pa · s, preferably 0.06 to 0.2 Pa
S, more preferably in the range of 0.06 to 0.17 Pa · s, and if less than 0.05 Pa · s, especially when applied by spin coating, the thickness that can be applied at one time is extremely thin. It is not practical because the number of times of application increases. On the other hand, 0.3
When the pressure exceeds Pa · s, the fluidity of the thermosetting resin used as a raw material is remarkably reduced, and air or the like entrained during casting remains as it is, and large closed pores are easily formed.

The content of the nonvolatile component in the liquid thermosetting resin is 30 to 70% by weight, preferably 35 to 65% by weight,
More preferably, the content is in the range of 40 to 60% by weight,
If the amount is less than 70% by weight, it is difficult to remove volatile components, and air bubbles and the like are likely to remain in the molded body.

The thickness of one application of the liquid thermosetting resin is 5
When the thickness exceeds 500 μm, it takes a long time for the volatile components to deviate during curing, and the volatile components remain in the cured body to generate voids. In addition, the curing of the resin does not proceed uniformly, and a large compressive stress is applied, so that it becomes easy to become a resin molded product with distortion, the amount of decomposition gas generated during firing increases, and the factor of foaming become.

The curing of the liquid thermosetting resin applied on the substrate is preferably 30 to 300 ° C., more preferably 50 to 250 ° C., from the viewpoint of easy control of the reaction. Further, an appropriate temperature is selected from this temperature range, for example, 50 ° C., 100 ° C., 25 ° C.
Although it is desirable to carry out the curing treatment stepwise at 0 ° C. or the like, it is also possible to carry out the curing treatment while continuously raising the temperature and holding at each selected temperature. The curing treatment can be performed not only under normal pressure but also under reduced pressure or increased pressure. As a heating furnace used for curing, any method such as a hot-air method, a far-infrared method, and an electromagnetic wave method can be used, and two or more methods can be used in combination.

The resin molded product obtained by the above method is
Then, it is fired to obtain glassy carbon, but it is also possible to process it into a desired shape by machining or the like before firing. At that time, it is necessary to set the processing dimensions in consideration of the dimensional shrinkage after firing. The calcination can be performed in an oxygen-free atmosphere or a reduced pressure comprising 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 baking is performed under reduced pressure, the decomposition gas and tar components generated due to the thermal decomposition of the resin are easily diffused, and a thicker glassy carbon material can be obtained. The degree of pressure reduction is desirably 1 to 25 × 10 ⁵ Pa.

The rate of temperature rise during firing is up to 700 ° C.
It is necessary to carry out at a temperature of 5 ° C./hour or less, preferably 1 ° C./hour or less. If the temperature is raised at a rate exceeding this, the dimensional shrinkage rate of the molded article becomes too large, and cracks easily occur, In particular, it becomes extremely difficult to obtain a thick glassy carbon having a maximum thickness of 5 mm or more of the molded product, and a compression stress is applied to the obtained glassy carbon, whereby the glassy carbon becomes strained.

The glassy carbon which has been heated to 700 ° C. may be subjected to firing at a temperature of 700 to 1000 ° C. for dehydrogenation if necessary, and further subjected to a graphitization treatment to 3000 ° C. The graphitization is desirably performed in a non-oxidizing atmosphere such as argon gas or in a vacuum. In consideration of the properties 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,
0 to 2800 ° C. is particularly preferred.

When the glassy carbon is used for applications requiring high purity, a method used for purifying general carbon materials after graphitization, such as a deashing treatment using a halogen gas or the like, is used. To perform high purification. In the firing and graphitizing steps, it is preferable to use a jig, a furnace, or the like purified to high purity.

The glassy carbon obtained by the present invention preferably has a maximum closed pore diameter of 100 μm or less from the viewpoint of surface smoothness required for a hard disk substrate or the like.
μm or less, more preferably 30 μm or less, and most preferably 0 μm. In the present invention, the maximum closed pore diameter indicates 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 elliptical. Further, the thickness of the glassy carbon is preferably 5 mm or more in terms of strength, for example, when used as a member for semiconductor production, and 6 mm.
More preferably, it is more preferably in the range of 7 to 12 mm.

In the present invention, the obtained glassy carbon material can be processed into a shape of a final product by 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 type 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]

The present invention will be described below with reference to examples. Example 1 A raw material thermosetting resin having a viscosity at 25 ° C. of 0.12 Pa · s
And a liquid furan resin having a nonvolatile component of 45% by weight (manufactured by Hitachi Chemical Co., Ltd., trade name: VF-302), and 0.6 parts by weight of paratoluenesulfonic acid as a curing agent with respect to 100 parts by weight of the liquid furan resin. After adding and mixing with stirring,
It was dropped and stretched on an aluminum Petri dish such that the thickness of one coating was 500 μm, and heat-cured at 50 ° C. for 5 hours and then at 200 ° C. for 1 hour using a hot-air dryer. 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.

The resin molded body was placed in a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
The temperature was raised at a rate of 10 ° C./hour at 1000 ° C. for 5 hours for baking, and the temperature was raised from 1000 to 2600 ° C. at a rate of 10 ° C./hour at 2600 ° C. for 5 hours. Obtained. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 8 mm. As a result of breaking the glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 5 μm.

Example 2 100 parts by weight of the liquid furan resin used in Example 1 was
After adding 15 parts by weight of trichloroacetic acid as a curing agent and stirring and mixing, a single application thickness of 450 μm was applied to an aluminum dish.
m, and cured by heating 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.

The resin molded body was heated under a reduced pressure of 1 × 10 ³ Pa to a temperature of 900 ° C. at a rate of 1.0 ° C./hour,
1000 ° C. with the temperature rising rate of 1000 ° C. being 10 ° C./hour
And firing for 5 hours to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 11.2.
mm. As a result of breaking the glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 10 μm.

Example 3 With respect to 100 parts by weight of the liquid furan resin used in Example 1,
After adding 0.6 parts by weight of p-toluenesulfonic acid as a curing agent and stirring and mixing, the mixture is dropped and stretched on an aluminum Petri dish so that the thickness of a single coating is 500 μm, and stretched at 50 ° C. for 5 hours using a hot-air dryer. Then, heat curing was performed 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.

This resin molded body was placed in a nitrogen atmosphere at 900
0.5 ° C./hour to 900 ° C.
Firing was performed while maintaining the temperature at 1000 ° C. for 5 hours at a temperature increasing rate of 5 ° C./hour, and glassy carbon was obtained. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 6.4 mm.
As a result of breaking the glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 10 μm.

Example 4 The liquid furan resin used in Example 1 was subjected to a heat treatment at 50 ° C. for 10 hours to remove a part of volatile components. The viscosity of the resin after heat treatment at 25 ° C. is 0.28 Pa · s and the non-volatile component is 6
It was 6% by weight. Next, with respect to 100 parts by weight of the liquid furan resin, 0.6 parts of
After adding the parts by weight and stirring and mixing, the mixture was dropped and stretched on an aluminum Petri dish so that the thickness of each coating was 500 μm, stretched, and heated and cured at 50 ° C. for 5 hours at 230 ° C. for 1 hour. went. The thickness of the cured resin after curing is 450
μm. This operation is repeated 23 times and the thickness becomes 1
A 0.35 mm resin molded body was obtained.

This resin molded body was placed under a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 8.3 mm. As a result of breaking the above glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 30 μm.

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 the mixture was stirred and mixed. The viscosity at 25 ° C. of the liquid furan resin after stirring and mixing is 0.08.
Pa · s and nonvolatile components were 32% by weight. Next, 15 parts by weight of trichloroacetic acid as a curing agent was added to 100 parts by weight of this liquid furan resin, and the mixture was stirred and mixed. 5 hours at 50 ° C in a dryer, then 2
Heat curing was performed at 00 ° C. for 1 hour. 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.

This resin molded body was placed under a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 5.6 mm. As a result of breaking the glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 20 μm.

Comparative Example 1 100 parts by weight of the liquid furan resin used in Example 1 was
After adding 0.6 parts by weight of p-toluenesulfonic acid as a curing agent and stirring and mixing, the mixture is dropped and stretched on an aluminum Petri dish so that the thickness of a single coating is 500 μm, and stretched at 50 ° C. for 5 hours using a hot-air dryer. Then, heat curing was performed 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.

This resin molded body was placed under a nitrogen atmosphere at 700
At a rate of 2.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. Cracks occurred in the obtained glassy carbon, and the desired shape could not be obtained.

Comparative Example 2 The liquid furan resin used in Example 1 was heated at 90 ° C. for 5 hours to remove a part of volatile components. 25 after heat treatment
The resin has a viscosity of 0.34 Pa · s at 70 ° C. and a non-volatile component of 79
% By weight. Next, 0.6 parts by weight of p-toluenesulfonic acid as a curing agent was added to 100 parts by weight of the liquid furan resin, and the mixture was stirred and mixed. Then, the mixture was dropped and stretched on an aluminum Petri dish so that the thickness of one application was 500 μm. Then, heat curing was performed at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour using a hot-air dryer. The thickness of the cured resin after curing is 490μ
m. This operation was repeated 21 times to obtain a thickness of 10.
A 29 mm resin molded body was obtained.

This resin molded body was placed under a nitrogen atmosphere at 900
Temperature rise rate to 1.0 ° C / hour, 900 to 1000
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 8.2 mm. However, as a result of observing the closed pores of the fracture surface by breaking the glassy carbon, the maximum closed pore diameter was 200 μm.
And it was a big one.

Comparative Example 3 The liquid furan resin used in Example 1 was heated at 50 ° C. for 10 hours to remove a part of volatile components. 2 after heat treatment
The resin has a viscosity of 0.28 Pa · s at 5 ° C. and a non-volatile component of 6
It was 6% by weight. Next, with respect to 100 parts by weight of the liquid furan resin, 0.6 parts of paratoluenesulfonic acid was used as a curing agent.
After adding the parts by weight and stirring and mixing, the mixture was dropped and stretched on an aluminum Petri dish so that the thickness of each coating was 600 μm, and the mixture was cured by heating with a hot air dryer at 50 ° C. for 5 hours and then at 230 ° C. for 1 hour. went. The thickness of the cured resin after curing is 540
μm. This operation is repeated 19 times and the thickness becomes 1
A 0.26 mm resin molded body was obtained.

This resin molded body was placed in a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. Foaming occurred in the obtained glassy carbon, and the desired shape could not be obtained.

Comparative Example 4 With respect to 100 parts by weight of the liquid furan resin used in Example 1,
After adding 0.6 parts by weight of p-toluenesulfonic acid as a curing agent and stirring and mixing, the mixture is dropped and stretched on an aluminum Petri dish so that the thickness of a single coating is 500 μm, and stretched at 50 ° C. for 5 hours using a hot-air dryer. Then, heat curing was performed for 5 minutes with a far-infrared dryer and then at 200 ° C. for 1 hour with a hot-air dryer. 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.

The resin molded body was placed in a nitrogen atmosphere at 600
At a rate of 1.0 ° C./hour, 600 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. Cracks occurred in the obtained glassy carbon, and the desired shape could not be obtained.

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. After stirring and mixing, the liquid furan resin has a viscosity at 25 ° C of 0.0
6 Pa · s and the non-volatile component were 22.5% by weight. Next, 0.6 parts by weight of paratoluenesulfonic acid as a curing agent was added to 100 parts by weight of the liquid furan resin, and the mixture was stirred and mixed.
And stretched at 50 ° C. with a hot air drier.
Heat curing was performed for 5 minutes with a far-infrared dryer and then at 200 ° C. for 1 hour with a hot-air dryer. 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.

The resin molded body was placed under a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 4 mm. As a result of breaking the above glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 200 μm.

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 viscosity at 25 ° C. of the liquid furan resin after stirring and mixing is 0.04.
Pa · s and the nonvolatile component were 11.3% by weight. Next, 0.6 parts by weight of p-toluenesulfonic acid as a curing agent was added to 100 parts by weight of the liquid furan resin, and the mixture was stirred and mixed. 5 hours at 50 ° C. in a hot-air dryer, 5 minutes in a far-infrared dryer, and 2 hours in a hot-air dryer.
Heat curing was performed at 00 ° 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.

This resin molded body was placed in a nitrogen atmosphere at 700
At a heating rate of 1.0 ° C./hour, 700 to 1000 ° C.
Firing was performed at 1000 ° C. for 5 hours at a temperature increasing rate of 10 ° C./hour at a temperature of 10 ° C. to obtain glassy carbon. There was no foaming, cracking or cracking in the obtained glassy carbon. The maximum thickness of the obtained glassy carbon was 8 mm. As a result of breaking the glassy carbon and observing closed pores on the fracture surface, the maximum closed pore diameter was 150 μm.

[0051]

The glassy carbon obtained by the method according to claim 1 has a desired thickness and shape by efficiently removing volatile components of the thermosetting resin as a raw material or volatile components generated during curing. While preparing a resin cured product of
It is a vitreous carbon having good properties by preventing foaming, cracking, formation and cracking of large closed pores in the firing process. The glassy carbon according to claim 2 is a volatile resin having a thermosetting resin as a raw material or a volatile component generated during curing is efficiently removed to produce a resin cured product having a desired thickness and shape, It is a glassy carbon of good properties, in which foaming, cracking, formation of large closed pores and cracking are prevented in the firing process.

Claims (2)

[Claims] 1. A composition having a viscosity at 25 ° C. of 0.05 to 0.3 Pa · s.
(0.5-3 poises) and the content of non-volatile components is 3
Using a liquid thermosetting resin of 0 to 70% by weight to form a resin layer having a coating thickness of 500 μm or less at one time, and repeating the step of heating and curing a plurality of times to obtain a resin molded body, A method for producing glassy carbon, comprising raising the temperature up to 700 ° C. at a rate of 1.5 ° C./hour or less and firing. 2. A glassy carbon obtained by the production method according to claim 1, wherein the maximum closed pore diameter of the glassy carbon is 100 μm or less and the maximum thickness is 5 mm or more.