Method for manufacturing carbon-coated carbon molded bodies and method for manufacturing activated carbon molded bodies

Abstract

To provide a method for manufacturing carbon-coated carbon molded bodies and a method for manufacturing activated carbon molded bodies that can easily produce carbon-coated carbon molded bodies that are less prone to liquid leakage. [Solution] A method for producing a carbon-coated carbon molded body, comprising the steps of: (a) forming a thin layer of a raw material mixture containing a molding resin composition containing a phenolic resin and a curing agent and spherical aggregate (A), irradiating a desired area with a laser to sinter it and form a sintered thin layer; (b) performing step (a) multiple times to obtain a primary molded body in which multiple sintered thin layers are stacked; (c) curing the molding resin composition contained in the primary molded body to obtain a secondary molded body; (e) applying a coating material to the secondary molded body, which contains a binder resin and aggregate (B) with an average particle diameter of 10 to 30 μm and has a solid content concentration of 75% by mass or more and less than 85% by mass; (f) curing the binder resin contained in the applied coating material to obtain a coated molded body; and (g) carbonizing the organic components contained in the coated molded body to obtain a carbon-coated carbon molded body.

Description

Technical Field

[0001] The present invention relates to a method for producing a carbon-coated carbon molded body and a method for producing an activated carbon molded body. Background Art

[0002] Carbon materials are excellent in properties such as heat resistance, electrical conductivity, thermal conductivity and chemical stability, so carbon molded bodies formed of carbon materials are widely used in a wide range of fields such as electricity, electronics, machinery, metallurgy and chemistry. A carbon molded body is obtained by using carbon powder such as coke powder as an aggregate, blending a binder such as pitch or tar to form a preliminary molded body, firing and carbonizing the same, and graphitizing as necessary. However, in order to obtain a carbon molded body of a desired shape, it is necessary to machine it into the desired shape after carbonization or graphitization, and it is difficult to process it into a complicated shape.

[0003] Accordingly, a method for producing a carbon molded body using an additive manufacturing method has been proposed. For example, Patent Document 1 discloses a method for producing a carbon molded body in which the steps of depositing a layer of carbon powder, inkjetting a binder to a desired area are repeated, then heating to cure the binder, and carbonizing the obtained cured product to produce the carbon molded body.

[0004] However, when a container made of a carbon molded body (for example, a heat-resistant container such as a crucible) is produced by an additive manufacturing method, liquid leakage may occur when a liquid such as water is injected into the obtained container. In order to prevent liquid leakage, for example, the surface of the carbon molded body may be coated. As a carbon molded body with a coated surface, for example, Patent Document 2 discloses a glassy carbon-coated carbon material having a glassy carbon layer on a surface layer of a base body made of a carbon material. Prior Art Documents Patent Documents

[0005] Patent Document 1 Special Publication No. 2017-535445 [Patent Document 2] Japanese Patent Publication No. 2006-143587 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in order to obtain the glassy carbon-coated carbon material described in Patent Document 2, it is necessary to heat-treat the substrate made of carbon material. The heat treatment temperature and the heating rate are inextricably linked, and these conditions are factors that govern the properties of the glassy carbon layer. Therefore, in order to manufacture a glassy carbon-coated carbon material with stable quality, it is necessary to precisely determine the heat treatment temperature and the heating rate, which complicates the manufacturing process.

[0007] The present invention aims to provide a method for manufacturing a carbon-coated carbon molded body and a method for manufacturing an activated carbon molded body, which enable the easy production of carbon-coated carbon molded bodies that are less prone to liquid leakage. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] A method for manufacturing a carbon-coated carbon molded body, Step (a) involves forming a thin layer of a raw material mixture containing a molding resin composition and spherical aggregate (A), irradiating a desired area of ​​the thin layer with a laser, and sintering the thin layer to form a sintered thin layer. Step (a) is performed multiple times to obtain a primary molded body in which multiple sintered thin layers are stacked (b), (c) A step of curing the molding resin composition contained in the primary molded body to obtain a secondary molded body, The steps include (e) applying a coating material containing a binder resin and aggregate (B) to the secondary molded body, (f) A step of curing the binder resin contained in the coated coating material to obtain a coated molded body, (g) A step of carbonizing the organic components contained in the coated molded body to obtain a carbon-coated carbon molded body, Includes, The aforementioned molding resin composition comprises a phenolic resin and a curing agent. The average particle size of the aggregate (B) is 10 to 30 μm. A method for producing a carbon-coated carbon molded article, wherein the solid content concentration of the coating material is 75% by mass or more and less than 85% by mass of the total mass of the coating material. [2] A method for producing the carbon-coated carbon molded article according to [1], wherein the spherical aggregate (A) contains spherical carbon. [3] A method for producing the carbon-coated carbon molded article according to [1] or [2], wherein the aggregate (B) contains carbon. [4] A method for producing a carbon-coated carbon molded article according to any of [1] to [3], further comprising the steps of: (α) impregnating one or more selected from the secondary molded article and the carbon-coated carbon molded article with a thermosetting resin; and (β) curing the impregnated thermosetting resin. [5] A method for producing a carbon-coated carbon molded article according to [4], further comprising between step (c) and step (e) a step (α1) of impregnating the secondary molded article obtained in step (c) with a thermosetting resin, and a step (β1) of curing the thermosetting resin impregnated in the secondary molded article. [6] A method for producing a carbon-coated carbon molded body according to [4], further comprising: a step (α2) of impregnating the carbon-coated carbon molded body obtained in step (g) with a thermosetting resin after step (g); a step (β2) of curing the thermosetting resin impregnated in the carbon-coated carbon molded body to obtain a tertiary molded body; a step (h) of applying a coating material containing a binder resin and aggregate (B) to the tertiary molded body; a step (i) of curing the binder resin contained in the coating material applied to the tertiary molded body to obtain a coated molded body; and a step (j) of carbonizing the organic components contained in the coated molded body obtained in step (i) to obtain a carbon-coated carbon molded body. [7] A method for producing a carbon-coated carbon molded article according to any of [1] to [6], further comprising a step (d) between step (c) and step (e) of carbonizing the organic components contained in the secondary molded article obtained in step (c). [8] A method for producing an activated carbon molded body, comprising obtaining a carbon-coated carbon molded body by the method for producing a carbon-coated carbon molded body according to any one of [1] to [7], and activating the obtained carbon-coated carbon molded body.

Effects of the Invention

[0009] According to the present invention, there can be provided a method for producing a carbon-coated carbon molded body and a method for producing an activated carbon molded body, which can easily produce a carbon-coated carbon molded body that is less prone to liquid leakage.

Brief Description of Drawings

[0010] [Figure 1] It is a flowchart showing an example of the method for producing a carbon-coated carbon molded body of the present invention. [Figure 2] It is a flowchart showing another example of the method for producing a carbon-coated carbon molded body of the present invention. [Figure 3] It is a flowchart showing another example of the method for producing a carbon-coated carbon molded body of the present invention. [Figure 4] It is a flowchart showing another example of the method for producing a carbon-coated carbon molded body of the present invention.

Mode for Carrying Out the Invention

[0011] Hereinafter, modes for carrying out the present invention will be described in detail. However, the present invention is not limited to the embodiments described later, and various modifications can be made without departing from the gist of the present invention. In the present specification and claims, a numerical range represented by "~" means a numerical range including the numerical values before and after ~ as the lower limit and the upper limit. For example, A~B is synonymous with A or more and B or less. Numerical ranges of the contents, various physical property values, and property values disclosed in the present specification can be used to form new numerical ranges by arbitrarily combining the lower limit values and the upper limit values thereof.

[0012] [Method for Producing Carbon-Coated Carbon Molded Body] Hereinafter, an example of the method for producing a carbon-coated carbon molded body of the present invention will be described in detail along the flowcharts shown in FIGS. 1 to 9.

[0013] "First aspect" As shown in Figure 1, the method for producing a carbon-coated carbon molded product of the present embodiment includes step (a), step (b), step (c), step (e), step (f), and step (g) shown below.

[0014] <Step (a)> Step (a) is a step (sintering step) of forming a thin layer of a raw material mixture containing a molding resin composition and a spherical aggregate (A), irradiating a desired region of the thin layer with a laser, and sintering the thin layer to form a sintered thin layer (step S1-1 in Figure 1). By irradiating a desired region of the thin layer with a laser, the molding resin composition is cured. In the present specification, the curing of the molding resin composition in step (a) is also referred to as "primary curing of the molding resin composition" or simply "primary curing". The raw material mixture used in step (a) contains a molding resin composition and a spherical aggregate (A). As long as the effects of the present invention are not impaired, the raw material mixture may optionally further contain, in addition to the molding resin composition and the spherical aggregate (A), components other than these (hereinafter also referred to as "optional components (b)").

[0015] (Molding Resin Composition) The molding resin composition contains a phenol resin and a curing agent. It is preferable that the molding resin composition further contains a curing accelerator. The molding resin composition may optionally further contain components other than the phenol resin, the curing agent, and the curing accelerator (hereinafter also referred to as "optional components (a)").

[0016] <<Phenol Resin>> Examples of the phenol resin include novolac-type phenol resins, resol-type phenol resins, various modified phenol resins, and mixtures of these. One type of phenol resin may be used alone, or two or more types may be mixed and used at any ratio.

[0017] Novolac-type phenolic resins are resins obtained by reacting at least one of phenols and bisphenols with aldehydes in the presence of an acid catalyst. Examples of phenols include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 3,5-xylenol, m-ethylphenol, m-propylphenol, m-butylphenol, p-butylphenol, o-butylphenol, resorcinol, hydroquinone, catechol, 3-methoxyphenol, 4-methoxyphenol, 3-methylcatechol, 4-methylcatechol, methylhydroquinone, 2-methylresorcinol, 2,3-dimethylhydroquinone, 2,5-dimethylresorcinol, 2-ethoxyphenol, 4-ethoxyphenol, 4-ethylresorcinol, 3-ethoxy-4-methoxyphenol, 2-propenylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 3,4,5-trimethylphenol, 2-isopropoxyphenol, 4-pyropoxyphenol, 2-allylphenol, 3,4,5- Examples include dimethoxyphenol, 4-isopropyl-3-methylphenol, pyrogallol, phloroglycinol, 1,2,4-benzenetriol, 5-isopropyl-3-methylphenol, 4-butoxyphenol, 4-t-butylcatechol, t-butylhydroquinone, 4-t-pentylphenol, 2-t-butyl-5-methylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3-phenoxyphenol, 4-phenoxyphenol, 4-hexyloxyphenol, 4-hexanoylresorcinol, 3,5-diisopropylcatechol, 4-hexylresorcinol, 4-heptyloxyphenol, 3,5-di-t-butylphenol, 3,5-di-t-butylcatechol, 2,5-di-t-butylhydroquinone, di-sec-butylphenol, 4-cumylphenol, nonylphenol, 2-cyclopentylphenol, and 4-cyclopentylphenol. These phenols may be used individually or in combination of two or more. Examples of bisphenols include bisphenol A, bisphenol F, bisphenol C, bisphenol S, bisphenol E, and bisphenol Z. Bisphenols may be used individually or mixed in any proportion.

[0018] Examples of aldehydes include formaldehyde, trioxane, furfural, paraformaldehyde, benzaldehyde, methylhemiformal, ethylhemiformal, propylhemiformal, salicylaldehyde, butylhemiformal, phenylhemiformal, acetaldehyde, propylaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, and pn-butylbenzaldehyde. Aldehydes may be used individually or mixed in any proportion.

[0019] Examples of acid catalysts include hydrochloric acid, sulfuric acid, phosphoric acid, sulfonic acid, carboxylic acid, or salts with metals such as zinc chloride or zinc acetate. Examples of sulfonic acids include p-toluenesulfonic acid, xylenesulfonic acid, benzenesulfonic acid, and methanesulfonic acid. Examples of carboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, malonic acid, succinic acid, maleic acid, oxalic acid, acetic acid, and benzoic acid. The acid catalyst may be used alone, or two or more types may be mixed in any proportion.

[0020] The reaction between at least one of phenols and bisphenols and aldehydes can be carried out by known methods. For example, at least one of phenols and bisphenols, aldehydes, an acid catalyst, and water can be charged into a reaction vessel, and an arbitrary reaction temperature can be maintained for an arbitrary reaction time. After the reaction is complete, the reaction solution can be neutralized as needed, and the reaction solution can be further concentrated under reduced pressure to remove water and obtain a novolac-type phenol resin. A silane coupling agent may be added before or after neutralization of the reaction solution as needed. In this case, a mixture containing the novolac-type phenol resin and the silane coupling agent can be obtained. Examples of silane coupling agents include N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. The silane coupling agent may be used alone, or two or more may be mixed in any proportion.

[0021] The mass-average molecular weight of the novolac-type phenolic resin is preferably 2,000 to 20,000, more preferably 3,000 to 17,000, and even more preferably 4,000 to 15,000. If the mass-average molecular weight of the novolac-type phenolic resin is above the lower limit, the raw material mixture becomes less likely to block. As will be described in detail later, the primary molded product obtained in step (b) is removed by removing the raw material mixture from the area that has not been irradiated by the thin layer of laser (non-irradiated area). The less likely the raw material mixture is to block, the easier it is to remove the raw material mixture from the non-irradiated area, which shortens the time required to remove the primary molded product (removal work time) and improves removal workability. If the mass-average molecular weight of the novolac-type phenolic resin is below the upper limit, the novolac-type phenolic resin can be easily manufactured. The mass-average molecular weight of novolac-type phenolic resins was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0022] The average particle size of the novolac-type phenolic resin is preferably 5 to 100 μm, and more preferably 10 to 80 μm. If the average particle size of the novolac-type phenolic resin is above the lower limit, the fluidity of the raw material mixture increases, resulting in excellent recoating properties. If the average particle size of the novolac-type phenolic resin is below the upper limit, the thin layer of the raw material mixture can be easily made thin, the laser can be sufficiently irradiated into the interior of the thin layer, and the molding resin composition can be sufficiently primary cured. In addition, the surface smoothness of the sintered thin layer during laser irradiation is improved. The average particle size of novolac-type phenolic resin is the particle size (median diameter) corresponding to the 50% cumulative frequency of the volume distribution basis of novolac-type phenolic resin measured by laser diffraction.

[0023] Resol-type phenolic resins are resins obtained by reacting at least one of phenols and bisphenols with aldehydes in the presence of a basic catalyst. Examples of phenols and aldehydes include those previously exemplified in the description of novolac-type phenolic resins. Examples of basic catalysts include alkali metal hydroxides such as sodium hydroxide and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide; ammonium hydroxide; and amines such as diethylamine, triethylamine, triethanolamine, ethylenediamine, and hexamethylenetetramine. These basic catalysts may be used individually or mixed in any proportion.

[0024] Resol-type phenolic resins are usually obtained in a dispersed state in a solvent such as water (hereinafter, resol-type phenolic resins in this state will be referred to as "liquid resol-type phenolic resins"). The resol-type phenolic resin may be used in liquid form, or the liquid resol-type phenolic resin may be dehydrated to remove the solvent, dried at room temperature, and then used in a solid form. In addition, silane coupling agents may be added to resol-type phenolic resins during the manufacturing process to improve their strength. If silane coupling agents are not added during the manufacturing process, resol-type phenolic resins and silane coupling agents may be used in combination. Examples of silane coupling agents include those exemplified earlier in the description of novolac-type phenolic resins.

[0025] Various modified phenolic resins include novolac-type phenolic resins or resol-type phenolic resins modified by known techniques such as boron modification, silicon modification, heavy metal modification, nitrogen modification, sulfur modification, oil modification, and rosin modification.

[0026] Phenolic resins may be used individually or mixed in any proportion. Among those mentioned above, novolac-type phenolic resins and resol-type phenolic resins are preferred as phenolic resins. From the viewpoint of ease of layering powders, novolac-type phenolic resins and solid resol-type phenolic resins are more preferred, with novolac-type phenolic resins being particularly preferred. Novolac-type phenolic resins have superior thermal stability compared to resol-type phenolic resins, and unintended polymerization is less likely to occur during heating in the melting process. Therefore, they can be stably molded into various shapes.

[0027] <<Hardening agent>> Examples of curing agents include hexamethylenetetramine, hexaethylenetetramine, and hexamethoxymethylolmelamine. Among these, hexaethylenetetramine is preferred from the viewpoint of storage stability and cost. The hardening agent may be used alone, or two or more types may be mixed in any proportion.

[0028] <<Curing accelerator>> Examples of hardening accelerators include benzoic acid, salicylic acid, and resorcinol. The curing accelerator may be used alone or by mixing two or more types in any proportion.

[0029] <<Optional component (a)>> Examples of optional components (a) include fluidizing agents, boron carbide, and silane coupling agents. Optional component (a) may be used alone or as a mixture of two or more components in any proportion.

[0030] (Spherical aggregate (A)) Spherical aggregate (A) is a particulate material. The sphericity of the spherical aggregate (A) is preferably 0.7 to 1.0, more preferably 0.8 to 1.0, and even more preferably 0.95 to 1.0. If the sphericity of the spherical aggregate (A) is within the above range, the variation in strength between parts of the carbon-coated carbon molded body will be reduced. In particular, if the sphericity of the spherical aggregate (A) is above the lower limit, the raw material mixture can be uniformly laid when forming a thin layer. The sphericity of spherical aggregate (A) is determined by the index (diameter of the circle equal to the projected area of ​​the particle) / (diameter of the smallest circle circumscribing the projected image of the particle). The closer this index is to 1.0, the closer the particle is to a perfect sphere.

[0031] The average particle size of the spherical aggregate (A) is preferably 10 to 150 μm, more preferably 20 to 80 μm, and even more preferably 40 to 60 μm. If the average particle size of the spherical aggregate (A) is above the lower limit, the raw material mixture can be uniformly spread when forming a thin layer. If the average particle size of the spherical aggregate (A) is below the upper limit, even carbon-coated carbon molded bodies with complex and fine shapes can be easily manufactured. The average particle size of spherical aggregate (A) is the particle size (median diameter) corresponding to the 50% cumulative frequency based on the volume distribution of spherical aggregate (A) measured by laser diffraction. When using commercially available spherical aggregate (A), if a catalog value is available, the catalog value may be used as the average particle size.

[0032] Examples of spherical aggregate (A) include spherical thermosetting resin cured products and spherical carbon. As a spherical thermosetting resin cured product, for example, a spherical cured product of phenolic resin can be used. Spherical cured products of phenolic resin can be obtained by condensing phenols and aldehydes in an aqueous medium under high temperature and high pressure conditions in the presence of a condensation reaction catalyst and an emulsifying dispersant. Specifically, fully curable spherical phenolic resins are used, and more specifically, the HF series manufactured by Gun-ei Chemical Industry Co., Ltd. is preferred. Spherical carbon can be obtained, for example, by carbonizing the aforementioned spherical thermosetting resin cured product at a temperature of 400 to 1000°C under a nitrogen atmosphere. Specifically, the GC series manufactured by Gun-ei Chemical Industry Co., Ltd. is preferred.

[0033] The spherical aggregate (A) may be used alone or mixed in any proportion of two or more types. Among the above, spherical carbon is preferred as the spherical aggregate (A).

[0034] Furthermore, spherical aggregate (A) may be surface-treated with a coupling agent or the like. Surface treatment of the spherical aggregate (A) can improve the adhesion between the spherical aggregate (A) and the molding resin composition. Examples of such coupling agents include silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents. Examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-aminopropyltriethoxysilane, N,N-bis[3-(trimethoxysilyl)propyl]amine, N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, N,N-bis[3-(trimethoxysilyl)propyl]methacrylamide, N-glycidyl-N,N-bis[3-(trimethoxysilyl)propyl]amine, γ-aminopropyltetraethoxydisiloxane, N,N-bis[3-(methyldimethoxysilyl)propyl]amine, N,N-bis[3-(methyldimethoxysilyl)propyl]ethylenediamine, N,N-bis[3-(methyldimethoxysilyl)propyl]methacrylamide, and N-glycidyl-N,N-bis[3-(methyldimethoxysilyl)propyl]amine. Examples of titanate-based coupling agents include isopropyl triisostearoyl titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, and bis(dioctyl pyrophosphate) ethylene titanate. Examples of aluminum-based coupling agents include acetalkoxyaluminum diisopropylate, diisopropoxyaluminum ethyl acetacetate, diisopropoxyaluminum alkyl acetacetate, isopropoxyaluminum alkyl acetacetate mono(dioctyl phosphate), diisopropoxyaluminum monomethacrylate, aluminum-2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkyl acetacetate aluminum oxide trimer. The coupling agent may be used alone, or two or more types may be mixed in any proportion.

[0035] (Optional component (b)) Optional components (b) include, for example, graphite, glassy carbon, carbon fiber, carbon black, graphene, fullerene, carbon nanotubes, carbon nanohorns, acetylene black, and Ketjenblack. Optional component (b) may be used alone or as a mixture of two or more components in any proportion.

[0036] (Content) The proportion of phenolic resin is preferably 5 to 50 parts by mass, more preferably 15 to 40 parts by mass, and even more preferably 20 to 30 parts by mass, when the total amount of phenolic resin and spherical aggregate (A) is 100 parts by mass. If the proportion of phenolic resin is above the lower limit, a carbon-coated carbon molded body with sufficient strength and density can be obtained. If the proportion of phenolic resin is below the upper limit, the laser-irradiated portion is more likely to sinter uniformly (primary harden), and the surface smoothness of the sintered thin layer is improved. Therefore, the next thin layer can be laid uniformly on top of the sintered thin layer, and the primary molded body is less likely to become brittle. If the proportion of phenolic resin exceeds the upper limit, the phenolic resin in the laser-irradiated portion may aggregate, forming a sintered thin layer with a sea-island structure. Since the surface smoothness of a sintered thin layer with a sea-island structure is poor, it becomes difficult to lay the next thin layer uniformly, and the primary molded body may become brittle.

[0037] The proportion of spherical aggregate (A) is preferably 50 to 95 parts by mass, more preferably 60 to 85 parts by mass, and even more preferably 70 to 80 parts by mass, when the total of phenolic resin and spherical aggregate (A) is 100 parts by mass. If the proportion of spherical aggregate (A) is above the lower limit, the laser-irradiated portion is more likely to sinter (primary harden) uniformly, and the surface smoothness of the sintered thin layer is improved. Therefore, the next thin layer can be uniformly laid on top of the sintered thin layer, and the primary molded body is less likely to become brittle. If the proportion of spherical aggregate (A) is below the upper limit, a carbon-coated carbon molded body with sufficient strength and density can be obtained.

[0038] The proportion of the curing agent is preferably 3 to 25 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 7 to 18 parts by mass, per 100 parts by mass of phenolic resin. If the proportion of the curing agent is above the lower limit, the phenolic resin will cure sufficiently. If the proportion of the curing agent is below the upper limit, the generation of gases such as ammonia can be reduced.

[0039] The proportion of the curing accelerator is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 4.5 parts by mass, and even more preferably 1.5 to 4.5 parts by mass, per 100 parts by mass of phenolic resin. If the proportion of the curing accelerator is above the lower limit, the curing of the phenolic resin will be accelerated, and the gelation time of the molding resin composition will be shortened. If the proportion of the curing accelerator is below the upper limit, the decrease in strength due to excessive addition can be suppressed.

[0040] (Preparation of raw material mixture) The raw material mixture is obtained by mixing a molding resin composition with spherical aggregate (A).

[0041] (Formation of sintered thin layer) The formation of the sintered thin layer will be explained in step (b) below.

[0042] <Process (b)> Step (b) is a step (lamination step) in which step (a) is repeated multiple times to obtain a primary molded body in which multiple sintered thin layers are stacked (step S1-2 in Figure 1). The above-described steps (a) and (b) are carried out, for example, by three-dimensional additive manufacturing as follows. For three-dimensional additive manufacturing, selective laser sintering (SLS) is preferred.

[0043] First, three-dimensional data of the cross-sectional shape at regular intervals of the target carbon-coated carbon molded body is created in advance. Based on this three-dimensional data, a thin layer made of the raw material mixture is deposited on the bottom surface of the molding chamber installed in a three-dimensional additive manufacturing device such as a powder bed fusion machine. The thin layer is sintered by scanning and irradiating a desired area of ​​this thin layer with a laser to heat it, thereby forming a sintered thin layer (step (a)). The bottom of the build chamber serves as a build table, which can be moved up and down. After forming a sintered thin layer, the bottom of the build chamber (build table) is lowered by one layer, and another thin layer made of the raw material mixture is deposited on top of the sintered thin layer. A laser is then scanned and irradiated onto a desired area of ​​this thin layer. These deposition and irradiation operations are repeated until a carbon-coated carbon molded body is formed, thereby obtaining a primary molded body (step (b)). The thickness of each thin layer is preferably 30 to 200 μm, and more preferably 50 to 150 μm.

[0044] It is preferable to use a laser with an irradiation output (laser intensity) of 10W or more. This melts the molding resin composition contained in the raw material mixture, and the raw material mixture is stably sintered together (primary curing). The laser intensity is preferably 10 to 100W, and more preferably 30 to 60W. Examples of laser types include CO2 lasers, YAG lasers, and semiconductor lasers.

[0045] The laser diameter (spot diameter) is preferably 0.05 to 1.5 mm, more preferably 0.05 to 1.4 mm, even more preferably 0.1 to 1.0 mm, particularly preferably 0.15 to 0.5 mm, and most preferably 0.18 to 0.4 mm. If the laser diameter is above the lower limit, the primary molded body can be manufactured in a short time. If the laser diameter is below the upper limit, even carbon-coated carbon molded bodies with complex and fine shapes can be easily manufactured. Laser diameter is the diameter of the laser beam when it strikes a thin layer.

[0046] The laser scanning speed is preferably 1 to 20 m / sec, more preferably 3 to 15 m / sec, and even more preferably 5 to 15 m / sec. If the laser scanning speed is above the lower limit, primary molded bodies can be manufactured in a short time. In addition, molding defects are less likely to occur, and even carbon-coated carbon molded bodies with complex and fine shapes can be easily manufactured. Furthermore, smoke and gas are less likely to be generated, and the equipment does not wear out easily. If the laser scanning speed is below the upper limit, it becomes easier to obtain carbon-coated carbon molded bodies with higher strength.

[0047] The laser scan interval is preferably 0.005 to 0.6 mm, more preferably 0.01 to 0.5 mm, and even more preferably 0.1 to 0.2 mm. If the laser scan interval is above the lower limit, primary molded bodies can be manufactured in a short time. In addition, molding defects are less likely to occur, and even carbon-coated carbon molded bodies with complex and fine shapes can be easily manufactured. Furthermore, smoke and gas are less likely to be generated, and the equipment does not wear out easily. If the laser scan interval is below the upper limit, it is easier to obtain carbon-coated carbon molded bodies with higher strength.

[0048] <Process (c)> Step (c) is a step (curing step) in which the molding resin composition contained in the primary molded product is cured to obtain a secondary molded product (step S1-3 in Figure 1). In step (c), the molding resin composition contained in the primary molded body is cured by heat treatment. In this specification, the curing of the molding resin composition in step (c) is also referred to as "secondary curing of the molding resin composition" or simply "secondary curing".

[0049] The primary molded body is formed while embedded in the powder of the raw material mixture. Therefore, prior to the secondary curing of the molding resin composition, the raw material mixture in the areas not irradiated by the thin layer of laser (non-irradiated areas), i.e., the raw material mixture in which the molding resin composition has not undergone primary curing, is removed using a brush or vacuum cleaner, and the primary molded body is extracted. Then, the extracted primary molded body is moved to, for example, a constant temperature oven and subjected to heat treatment to secondary curing of the molding resin composition. The molding resin composition in the area irradiated with a thin layer of laser has undergone primary curing and therefore possesses appropriate strength. Consequently, when removing the raw material mixture from the non-irradiated area to extract the primary molded body, the primary molded body is less likely to collapse, making it easy to remove and move.

[0050] The curing temperature and curing time for the secondary curing of the molding resin composition should be adjusted as appropriate, taking into account the size, shape, etc., of the carbon-coated carbon molded article to be obtained. Typically, the curing temperature is around 130 to 300°C, with 150 to 250°C being preferred. The curing time is around 1 to 120 minutes, with 10 to 90 minutes being preferred, and 30 to 60 minutes being more preferred. The secondary curing of the molding resin composition may be carried out under normal pressure or under pressure.

[0051] <Process (e)> Step (e) is a step (coating step) in which a coating material containing a binder resin and aggregate (B) is applied to the secondary molded body (steps S1-4 in Figure 1). By applying a coating material to the secondary molded body, a coating film of the coating material is formed on the surface of the secondary molded body.

[0052] (covering material) The covering material includes a binder resin and aggregate (B). The coating material preferably further contains a solvent. The coating material may, if necessary, further contain components other than the binder resin, aggregate (B), and solvent (hereinafter also referred to as "optional component (c)").

[0053] <<Binder resin>> Examples of binder resins include thermosetting resins. Examples of thermosetting resins include phenolic resins, epoxy resins, furan resins, melamine resins, unsaturated polyester resins, polyurethane resins, polyimide resins, and pitch. Examples of phenolic resins include those previously exemplified in the description of the molding resin composition used in step (a).

[0054] Examples of epoxy resins include phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenol type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, naphthol type epoxy resins, xylylene type epoxy resins, biphenyl aralkyl type epoxy resins, triphenylmethane type epoxy resins, dicyclopentadiene type epoxy resins, stilbene type epoxy resins, sulfur atom-containing epoxy resins, and phosphorus atom-containing epoxy resins.

[0055] Furan resin is a resin whose main raw materials are furfuryl alcohol, urea, formaldehyde, etc., and it hardens through polycondensation while undergoing a dehydration reaction with an acid catalyst. Preferably, the furan resin used is one or more condensates or co-condensates of furfuryl alcohol, furfuryl alcohol, urea, or aldehydes, and a mixture of furfuryl alcohol as the main component, and optionally contains at least one of phenols and bisphenols. Examples of phenols and aldehydes include those previously exemplified in the description of the phenolic resin of the first embodiment.

[0056] Alternatively, a condensate of furfuryl alcohol obtained by condensing furfuryl alcohol alone in the presence of an acid catalyst may be used as the furan resin. Examples of acid catalysts include those previously exemplified in the description of the molding resin composition used in step (a). Carboxylic acids are particularly preferred, and citric acid is more preferred.

[0057] Thermosetting resins may be used individually or mixed in any proportion. Among those mentioned above, from the viewpoint of easily resulting in a high carbon residue rate, phenolic resins, epoxy resins, furan resins, and pitch are preferred as thermosetting resins, with phenolic resins being more preferred, and resol-type phenolic resins being even more preferred. The thermosetting resin may be liquid or solid at, for example, 25°C.

[0058] <<Aggregate (B)>> Examples of aggregate (B) include cured products of thermosetting resins such as phenolic resin and carbon. Aggregate (B) may be used alone or mixed in any proportion of two or more types.

[0059] Examples of carbon include graphite, glassy carbon, carbon fibers, carbon black, graphene, fullerene, carbon nanotubes, carbon nanohorns, acetylene black, and Ketjenblack. Among these, graphite is preferred from the viewpoint of cost and workability. Carbon may be used alone, or two or more types may be mixed in any proportion.

[0060] The average particle size of aggregate (B) is 10 to 30 μm, preferably 10 to 25 μm, more preferably 10 to 20 μm, and even more preferably 15 to 20 μm. If the average particle size of aggregate (B) is above the lower limit, the amount of solvent added to the coating material can be reduced, thus maintaining a high residual carbon ratio. If the average particle size of aggregate (B) is below the upper limit, the gaps in the carbon coating layer covering the carbon molded body obtained by step (g) described later are less likely to become large, thus suppressing liquid leakage. The average particle size of aggregate (B) is the particle size (median diameter) corresponding to the 50% cumulative frequency based on the volume distribution of aggregate (B) measured by laser diffraction. When using commercially available aggregate (B), if a catalog value is available, the catalog value may be used as the average particle size.

[0061] Aggregate (B) may or may not be spherical. Spherical aggregate (B) is also called "spherical aggregate (B)". The sphericity of the spherical aggregate (B) is preferably 0.7 to 1.0, more preferably 0.8 to 1.0, and even more preferably 0.95 to 1.0. The spherical aggregate (B) may be the same type of aggregate as the spherical aggregate (A) used in process (a), or it may be a different type of aggregate.

[0062] Aggregate (B) may be surface-treated with a coupling agent or the like. Surface treatment of aggregate (B) can improve the adhesion between aggregate (B) and the binder resin. Examples of coupling agents include those previously exemplified in the description of the spherical aggregate (A) used in process (a).

[0063] <<Solvent>> Examples of solvents include water, organic solvents, and mixtures of water and organic solvents. Examples of organic solvents include alcohols such as methanol and ketone solvents such as acetone. The solvent may be one introduced from the binder resin. For example, when a resol-type phenolic resin is used as the binder resin, as mentioned above, the resol-type phenolic resin is obtained in a dispersed state in a solvent such as water (liquid resol-type phenolic resin). Therefore, a coating material containing liquid resol-type phenolic resin contains a solvent derived from this liquid resol-type phenolic resin as the solvent. The solvent may be used individually or as a mixture of two or more solvents in any proportion.

[0064] <<Optional component (c)>> Optional components (c) include, for example, hardening agents, hardening accelerators, fluidizing agents, boron carbide, and silane coupling agents. Examples of curing agents and curing accelerators include those previously exemplified in the description of the molding resin composition used in step (a), respectively. Optional component (c) may be used alone or as a mixture of two or more components in any proportion.

[0065] <<Content>> The proportion of binder resin, in terms of pure content, is preferably 10 to 70% by mass, and more preferably 10 to 50% by mass, relative to the total mass of solids in the coating material. If the proportion of binder resin is above the lower limit, the coating properties of the coating material will improve. If the proportion of binder resin is below the upper limit, the carbon residue rate of the coating material will increase. Here, "solid content of the coating material" refers to components other than the solvent contained in the coating material, i.e., the film-forming components.

[0066] The proportion of aggregate (B) is preferably 30 to 90% by mass, and more preferably 50 to 90% by mass, relative to the total mass of solids in the coating material. If the proportion of aggregate (B) is above the lower limit, the carbon residue rate of the coating material will increase. If the proportion of aggregate (B) is below the upper limit, the applicability of the coating material will improve.

[0067] The solid content concentration of the coating material is 75% by mass or more and less than 85% by mass relative to the total mass of the coating material, more preferably 76-84% by mass, and even more preferably 77-83% by mass. If the solid content concentration of the coating material is above the lower limit, defects are less likely to occur when the solvent evaporates in step (f) described later, and liquid leakage can be suppressed. If the solid content concentration of the coating material is below the upper limit, the coating material can be easily applied to the secondary molded body, and a coating film of the coating material can be easily formed on the surface of the secondary molded body. Here, "solid content concentration of the coating material" refers to the total content of components other than the solvent contained in the coating material, i.e., the film-forming components. In other words, the sum of the solid content concentration and the proportion of solvent is 100% by mass.

[0068] <<Preparation method>> The coating material is obtained by mixing a binder resin and aggregate (B) with an optional component (c) as needed. The resulting mixture may be used as is as the coating material, or a solvent may be added to the mixture as needed so that the solid content concentration of the coating material is within the range described above.

[0069] (Application method) There are no particular restrictions on the method of applying the coating material to the secondary molded body, but examples include pouring, spraying, and brushing. The amount of coating material to be applied is not particularly limited, but it is preferable to apply the coating material to the secondary molded body such that the thickness of the coating film (corresponding to the carbon coating layer described later) after curing and carbonization is, for example, about 10 to 1000 μm.

[0070] <Process (f)> Step (f) is a step (curing step) in which the binder resin contained in the coating material applied to the secondary molded body (i.e., the coating film of the coating material) is cured to obtain a coated molded body (steps S1-5 in Figure 1). In step (f), the secondary molded body coated with the coating material (hereinafter also referred to as the "coated secondary molded body") is heat-treated to harden the binder resin contained in the coating.

[0071] The curing temperature and curing time of the binder resin should be adjusted as appropriate, taking into account the size, shape, etc., of the carbon-coated carbon molded body to be obtained. Typically, the curing temperature is around 130 to 300°C, with 150 to 250°C being preferred. Typically, the curing time is around 1 to 120 minutes, with 10 to 90 minutes being preferred, and 30 to 60 minutes being more preferred. The binder resin may be cured under normal pressure or under pressure.

[0072] <Process (g)> Step (g) is a step (carbonization step) in which organic components contained in the coated molded body are carbonized to obtain a carbon-coated carbon molded body (steps S1-6 in Figure 1). In the first embodiment, the organic components contained in the coated molded article are derived from organic compounds in the molding resin composition contained in the raw material mixture, and from organic compounds contained in the coating material. Specific examples of organic compounds in molding resin compositions include cured phenolic resins, uncured phenolic resins, curing agents, and curing accelerators. Specific examples of organic compounds in coating materials include cured binder resins and uncured binder resins. Furthermore, when spherical thermosetting resin cured products are used as spherical aggregate (A), or when thermosetting resin cured products are used as aggregate (B), these cured products are also included in the organic components. Step (g) of the first embodiment combines the steps of carbonizing the organic components contained in the secondary molded body and carbonizing the organic components contained in the cured product of the coating applied to the surface of the secondary molded body.

[0073] The carbonization treatment for carbonizing the coated molded body may be carried out under normal pressure or under reduced pressure (vacuum). Furthermore, the carbonization treatment may be carried out under an oxidizing atmosphere or an inert atmosphere. In particular, it is preferable to carry out the carbonization treatment under reduced pressure and an inert atmosphere. Here, "oxidizing atmosphere" refers to an air atmosphere or an atmosphere containing known oxidizing substances such as oxygen. To create an inert atmosphere, you can use an inert gas such as helium, argon, or nitrogen.

[0074] The carbonization temperature and carbonization time for the carbonization treatment should be adjusted as appropriate, taking into account the type of phenolic resin and binder resin contained in the raw material mixture, as well as the size and shape of the carbon-coated carbon molded body to be obtained. Typically, the carbonization temperature is preferably 300 to 1200°C, and more preferably 500 to 1000°C. The carbonization time is preferably 10 minutes to 25 hours, more preferably 30 minutes to 10 hours, and even more preferably 30 minutes to 5 hours.

[0075] The carbon-coated carbon molded body obtained by step (g) is a molded body in which the surface of the carbon molded body, which is formed by the carbonization of organic components contained in the secondary molded body, is covered with a carbon coating layer formed by the carbonization of organic components contained in the coating film of the coating material. That is, the carbon-coated carbon molded body comprises a carbon molded body and a carbon coating layer that covers the surface of the carbon molded body. The thickness of the carbon coating layer is not particularly limited, but is preferably 10 to 1000 μm, more preferably 100 to 1000 μm, and even more preferably 100 to 500 μm.

[0076] Steps (f) and (g) may be carried out in separate devices, or they may be carried out in the same device, provided that the desired temperature can be adjusted. If steps (f) and (g) are performed in separate devices, after step (f), the coated molded body is cooled to a temperature at which it can be removed from the device such as a constant temperature oven, and then moved to another device such as a constant temperature oven or carbonization furnace to perform step (g). When steps (f) and (g) are performed using the same apparatus, the apparatus such as a constant temperature incubator is set to the desired temperature and the coated secondary molded body is heat-treated to become a coated molded body (step (f)). Subsequently, the temperature of the same apparatus is raised to the desired temperature and the coated molded body is further heat-treated to obtain a carbon-coated carbon molded body (step (g)). Furthermore, if necessary, the carbon-coated carbon molded body may be graphitized after step (g). For example, a graphitized carbon-coated carbon molded body can be obtained by heating the carbon-coated carbon molded body in an inert atmosphere at a maximum temperature exceeding 1200°C but not exceeding 3000°C.

[0077] <Effects and Effects> According to the method for manufacturing a carbon-coated carbon molded body of this embodiment described above, a carbon-coated carbon molded body is obtained in which the surface of the carbon molded body is covered with a carbon coating layer. The carbon coating layer is a carbide obtained by curing and carbonizing a coating film of a coating material with a specific solid content concentration, which contains a binder resin and aggregate (B) of a specific average particle size, and exhibits excellent impermeability to liquids and gases. Therefore, the carbon-coated carbon molded body obtained by this embodiment is less prone to liquid leakage. Moreover, since the surface of the carbon molded body can be covered with a carbon coating layer by a simple operation of applying a specific coating material to a secondary molded body, curing it, and then carbonizing it, a carbon-coated carbon molded body that is less prone to liquid leakage can be easily manufactured.

[0078] Furthermore, because the molding resin composition of the primary molded body has undergone primary curing, it possesses adequate strength even before step (c). Therefore, the primary molded body can be easily removed from the non-irradiated area and is easy to handle. In addition, since the non-irradiated area is removed at step (c), the equipment such as the incubator used for secondary curing can be miniaturized. Furthermore, since the molding resin composition is sufficiently cured in the primary molded product, even if a secondary curing treatment is applied to the primary molded product, the secondary molded product is less likely to bend or shrink compared to the primary molded product.

[0079] <Application> The carbon-coated carbon molded articles obtained by the present invention are suitable as components where lightweight, high strength, high rigidity, and heat resistance are required, and are widely used in various parts of aircraft, automobiles, ships and other transportation equipment, heat-resistant containers such as crucibles, semiconductor manufacturing equipment, medical equipment, batteries, sporting goods, leisure goods, and more.

[0080] <Other forms> The method for manufacturing the carbon-coated carbon molded article of this embodiment is not limited to the method described above. For example, if the process from process (e) to process (g) is considered one cycle (hereinafter also referred to as "cycle (i-1)"), then cycle (i-1) may be performed two or more times. That is, after process (g), processes (e), (f), and (g) may be repeated one or more times. When cycle (i-1) is performed two or more times, process (f) may be omitted in cycles other than the final cycle (that is, after repeating process (e) two or more times, processes (f) and (g) may be performed), but it is preferable to perform process (f) after process (e) each time. Also, in cycles other than the final cycle, process (g) may be omitted (that is, after repeating processes (e) and (f) alternately two or more times, process (g) may be performed), but it is preferable to perform process (g) after process (f) each time.

[0081] Furthermore, the method for manufacturing a carbon-coated carbon molded article according to this embodiment may further include the following step (d) between step (c) and step (e).

[0082] <Process (d)> Step (d) is a step (carbonization step) in which organic components contained in the secondary molded body are carbonized to obtain a carbonized secondary molded body (hereinafter also referred to as the "carbon molded body"). In this specification, if the method for producing a carbon-coated carbon molded article includes step (d), step (d) will also be referred to as the "first carbonization step," and step (g) will also be referred to as the "second carbonization step." In step (e), which is performed after step (d), the above-mentioned coating material is applied to the carbonized secondary molded body obtained in step (d).

[0083] The organic components contained in the secondary molded product are those derived from organic compounds in the molding resin composition contained in the raw material mixture, specifically cured phenolic resin, uncured phenolic resin, curing agents, curing accelerators, etc. Furthermore, if spherical thermosetting resin cured material is used as spherical aggregate (A), the spherical thermosetting resin cured material is also included in the organic components.

[0084] The carbonization treatment for the secondary molded body may be carried out under atmospheric pressure or under reduced pressure (vacuum). Furthermore, the carbonization treatment may be carried out under an oxidizing atmosphere or an inert atmosphere. In particular, it is preferable to carry out the carbonization treatment under reduced pressure and an inert atmosphere. Here, "oxidizing atmosphere" refers to an air atmosphere or an atmosphere containing known oxidizing substances such as oxygen. To create an inert atmosphere, you can use an inert gas such as helium, argon, or nitrogen.

[0085] The carbonization temperature and carbonization time for the carbonization treatment should be adjusted as appropriate, taking into consideration the type of phenolic resin contained in the raw material mixture, the size and shape of the carbon-coated carbon molded body to be obtained, etc. Typically, the carbonization temperature is preferably 300 to 1200°C, and more preferably 500 to 1000°C. The carbonization time is preferably 10 minutes to 25 hours, more preferably 30 minutes to 10 hours, and even more preferably 30 minutes to 5 hours.

[0086] Steps (c) and (d) may be carried out in separate devices, or they may be carried out in the same device, provided that the desired temperature can be adjusted. If processes (c) and (d) are carried out in separate devices, after process (c), the secondary molded body is cooled to a temperature at which it can be removed from the device such as a constant temperature oven, and then moved to another device such as a constant temperature oven or carbonization furnace to carry out process (d). When steps (c) and (d) are performed using the same apparatus, the primary molded body is heat-treated to a desired temperature using an apparatus such as a constant temperature incubator to obtain a secondary molded body (step (c)), and then the temperature of the same apparatus is raised to a desired temperature to further heat-treat the secondary molded body to obtain a carbon molded body (step (d)).

[0087] Furthermore, the method for producing the carbon-coated carbon molded article of this embodiment preferably further includes a step (α) of impregnating one or more of the secondary molded articles obtained in step (c) and the carbon-coated carbon molded articles obtained in step (f) with a thermosetting resin, and a step (β) of curing the impregnated thermosetting resin. By impregnating with a thermosetting resin, the thermosetting resin penetrates into the gaps between the spherical aggregate (A) and the cured resin composition, as well as the gaps between the aggregate (B) and the cured binder resin, increasing the amount of resin and thus resulting in a carbon-coated carbon molded article with higher strength. In addition, in step (α), a curing agent or curing accelerator may be used in combination with the thermosetting resin.

[0088] Examples of thermosetting resins used in process (α) include those previously exemplified in the description of the coating material used in process (e). Examples of curing agents and curing accelerators include those previously exemplified in the description of the molding resin composition used in step (a), respectively. In this invention, the thermosetting resin used to impregnate one or more of the secondary molded articles and carbon-coated carbon molded articles is also referred to as the "impregnation resin" or "thermosetting resin (G)". Furthermore, if the coating material contains a thermosetting resin, the thermosetting resin in the coating material is also referred to as the "coating resin" or "thermosetting resin (T)".

[0089] The thermosetting resin (G) may be used alone or by mixing two or more types in any proportion. From the viewpoint of easily resulting in a high carbon residue rate, the thermosetting resin (G) is preferably a phenolic resin, epoxy resin, furan resin, or pitch, more preferably a phenolic resin, and even more preferably a resol-type phenolic resin. The thermosetting resin (G) may be the same type of resin as the thermosetting resin (T), or it may be a different type of resin.

[0090] The thermosetting resin (G) may be liquid or solid at 25°C, for example. However, if it is solid, it is preferable to dissolve or disperse it in a solvent and impregnate one or more of the secondary molded articles and carbon-coated carbon molded articles in a liquid state, i.e., resin solution state. Examples of solvents include water, methanol, and acetone. The solvent may be used alone, or two or more solvents may be mixed in any proportion.

[0091] The ratio of thermosetting resin (G) to the total mass of the resin solution is preferably 30 to 99% by mass, more preferably 45 to 99% by mass, and even more preferably 60 to 99% by mass, on a pure content basis. If the ratio of thermosetting resin (G) is above the lower limit of the above, the strength of the carbon-coated carbon molded article will be further increased.

[0092] The viscosity of the resin solution at 25°C is preferably 10 to 1000 mPa·s, more preferably 10 to 500 mPa·s, and even more preferably 10 to 100 mPa·s. If the viscosity of the resin solution is below the above upper limit, the impregnation of the resin solution increases, making it easier to obtain a carbon-coated carbon molded article with higher strength. The viscosity of the resin solution is the value measured using a Type B viscometer at 25°C.

[0093] If the thermosetting resin (G) is liquid at 25°C, it may be used to impregnate one or more of the secondary molded articles and carbon-coated carbon molded articles as is, or it may be diluted with a solvent as needed until it reaches the desired concentration or viscosity. Examples of solvents include those previously exemplified in the description of the resin solution.

[0094] Process (α) may be performed between processes (c) and (e), or after process (g). In the present invention, step (α) performed between step (c) and step (e) is also referred to as "step (α1)", and step (α) performed after step (g) is also referred to as "step (α2)". Furthermore, process (β) performed after process (α1) is also specifically called "process (β1)," and process (β) performed after process (α2) is also specifically called "process (β2)."

[0095] The method for producing a carbon-coated carbon molded article preferably includes one or more of steps (α1) and (α2). That is, the method for producing a carbon-coated carbon molded article may include at least one of steps (α1) and (α2), or it may include steps (α1) and (α2). Furthermore, each of the processes (α1) and (α2) may be performed once or two or more times. Furthermore, if the method for manufacturing a carbon-coated carbon molded body includes step (α2), then steps (h), (i), and (j), described later, are carried out after step (β2). The following describes one embodiment of a method for manufacturing a carbon-coated carbon molded article, including steps (α) and (β).

[0096] "Second form" The method for manufacturing a carbon-coated carbon molded article according to this embodiment, as shown in Figure 2, includes steps (a), (b), (c), (e), (f), and (g) described in the first embodiment, and further includes steps (α1) and (β1) shown below between steps (c) and (e). In Figure 2, step S2-1 is process (a), step S2-2 is process (b), step S2-3 is process (c), step S2-6 is process (e), step S2-7 is process (f), and step S2-8 is process (g). Since steps (a), (b), (c), (e), (f), and (g) are the same as in the first embodiment, their descriptions are omitted.

[0097] <Process (α1)> Step (α1) is a step (α) that takes place between steps (c) and (e), and specifically, it is a step (impregnation step) in which a thermosetting resin (G) is impregnated into the secondary molded body (step S2-4 in Figure 2). By impregnating the secondary molded body with a thermosetting resin (G), the thermosetting resin (G) penetrates into the gaps between the spherical aggregate (A) and the cured resin composition for molding, increasing the amount of resin, and thus a carbon-coated carbon molded body with higher strength can be obtained.

[0098] There are no particular limitations on the method of impregnating the secondary molded body with the thermosetting resin (G), but examples include immersion in the thermosetting resin (dip method); and application of the thermosetting resin (G) to the secondary molded body by pouring, spraying, brushing, etc. Impregnation with thermosetting resin (G) may be carried out under normal pressure, or under pressure or reduced pressure. The amount of thermosetting resin (G) impregnated is not particularly limited, but it is preferable to impregnate the secondary molded body with at least 5 parts by mass of thermosetting resin (G) in terms of pure content per 100 parts by mass of the secondary molded body before impregnation.

[0099] <Process (β1)> Step (β1) is a step (β) that is performed after step (α1), and specifically, it is a step (curing step) in which the thermosetting resin (G) impregnated into the secondary molded body is cured (step S2-5 in Figure 2). The curing temperature and curing time of the thermosetting resin (G) should be adjusted as appropriate, taking into consideration the size and shape of the secondary molded product. Typically, the curing temperature is around 130 to 300°C, with 150 to 250°C being preferred. The curing time is around 1 to 120 minutes, with 10 to 90 minutes being preferred, and 30 to 60 minutes being more preferred. The curing of the thermosetting resin (G) may be carried out under normal pressure or under pressure.

[0100] In this specification, the secondary molded article obtained in step (c) is also referred to as "secondary molded article (I)," and the secondary molded article obtained after curing the thermosetting resin (G) impregnated into the secondary molded article (I) (however, as will be described in detail later, if step (β1) is performed two or more times, the secondary molded article obtained in the last step (β1)) is also referred to as "secondary molded article (II)." The secondary molded article (II) is a cured product obtained by curing the molding resin composition and the thermosetting resin (G).

[0101] In step (e), which is performed after step (β1), the above-mentioned coating material is applied to the secondary molded body (II) obtained in step (β1).

[0102] In step (g), the organic components contained in the coated molded body are carbonized. In the second embodiment, the organic components contained in the coated molded body are those derived from organic compounds in the molding resin composition contained in the raw material mixture, those derived from the thermosetting resin (G), and those derived from organic compounds contained in the coating material. Specific examples of substances derived from thermosetting resin (G) include cured products of thermosetting resin (G) and uncured thermosetting resin (G). Furthermore, when spherical thermosetting resin cured products are used as spherical aggregate (A), or when thermosetting resin cured products are used as aggregate (B), these cured products are also included in the organic components.

[0103] <Other forms> The method for manufacturing the carbon-coated carbon molded article of this embodiment is not limited to the method described above. For example, if the process from process (α1) to process (β1) is considered one cycle (hereinafter also referred to as "cycle (ii-1)"), then cycle (ii-1) may be performed two or more times. That is, after process (β1), processes (α1) and (β1) may be repeated one or more times. When cycle (ii-1) is performed two or more times, process (β1) may be omitted in cycles other than the final cycle (that is, process (α1) may be repeated two or more times before process (β1) is performed), or processes (α1) and (β1) may be repeated alternately.

[0104] Furthermore, for example, if the process from process (e) to process (g) is considered one cycle (hereinafter also referred to as "cycle (i-2)"), cycle (i-2) may be performed two or more times. That is, after process (g), processes (e), (f), and (g) may be repeated one or more times. When cycle (i-2) is performed two or more times, process (f) may be omitted in cycles other than the final cycle (that is, after repeating process (e) two or more times, processes (f) and (g) may be performed), but it is preferable to perform process (f) after process (e) each time. Also, in cycles other than the final cycle, process (g) may be omitted (that is, after repeating processes (e) and (f) alternately two or more times, process (g) may be performed), but it is preferable to perform process (g) after process (f) each time.

[0105] Furthermore, the method for producing the carbon-coated carbon molded article of this embodiment may further include a step (d) between step (c) and step (α1). In step (α1), which is performed after step (d), the carbonized secondary molded article (I) obtained in step (d) is impregnated with a thermoplastic resin (G). Furthermore, a step (d) may be included between step (β1) and step (e). If step (d) is performed between step (β1) and step (e), one or more cycles (ii-1) may be performed between step (d) and step (e). That is, the carbonized secondary molded body may be impregnated and cured with a thermosetting resin (G) one or more times. If two or more cycles (ii-1) are performed between step (d) and step (e), step (β1) may be omitted in cycles other than the final cycle, or steps (α1) and (β1) may be repeated alternately. Furthermore, step (d) may be performed after step (β1). In step (e) performed after step (d), a coating material (E) is applied to the carbonized secondary molded body (II) obtained in step (d). Since process (d) is the same as in the first embodiment, its explanation is omitted.

[0106] "The third aspect" The method for manufacturing a carbon-coated carbon molded article according to this embodiment, as shown in Figure 3, includes steps (a), (b), (c), (e), (f), and (g) described in the first embodiment, and further includes steps (α2), (β2), (h), (i), and (j) shown below after step (g). In Figure 3, step S3-1 is process (a), step S3-2 is process (b), step S3-3 is process (c), step S3-4 is process (e), step S3-5 is process (f), and step S3-6 is process (g). Since steps (a), (b), (c), (e), (f), and (g) are the same as in the first embodiment, their descriptions are omitted.

[0107] <Process (α2)> Step (α2) is step (α) performed after step (g), and specifically is the step of impregnating the carbon-coated carbon molded body with a thermosetting resin (G) (impregnation step) (step S3-7 in Figure 3). By impregnating the carbon-coated carbon molded body with a thermosetting resin (G), the thermosetting resin (G) penetrates into the gaps between the aggregate (B) and the carbides of the binder resin, increasing the resin content and thus resulting in a carbon-coated carbon molded body with higher strength. In addition, in step (α2), the graphitized carbon-coated carbon molded body may be impregnated with a thermosetting resin.

[0108] The method and amount of impregnation of the carbon-coated carbon molded body with thermosetting resin (G) are the same as those exemplified in step (α1) of the second embodiment. The impregnation of the thermosetting resin (G) may be carried out under normal pressure, or under pressure or reduced pressure. From the viewpoint of improving the impregnation of the thermosetting resin (G) into the carbon-coated carbon molded body, it is preferable to impregnate the carbon-coated carbon molded body with the thermosetting resin (G) under pressure or reduced pressure.

[0109] In this specification, the carbon-coated carbon molded body obtained in step (g) is also referred to as "carbon-coated carbon molded body (I)," and the carbon-coated carbon molded body obtained in step (j) (however, as will be described in detail later, if step (j) is performed two or more times, the last step (j)) is also referred to as "carbon-coated carbon molded body (II)."

[0110] <Process (β2)> Step (β2) is a step (β) that is performed after step (α2), and specifically, it is a step (curing step) in which a thermosetting resin (G) impregnated into a carbon-coated carbon molded body (I) is cured to obtain a tertiary molded body (step S3-8 in Figure 3). The curing temperature and curing time of the thermosetting resin (G) should be adjusted as appropriate, taking into consideration the size, shape, etc., of the carbon-coated carbon molded body (I) and the carbon-coated carbon molded body (II). Typically, the curing temperature is around 130 to 300°C, with 150 to 250°C being preferred. The curing time is around 1 to 120 minutes, with 10 to 90 minutes being preferred, and 30 to 60 minutes being more preferred. The curing of the thermosetting resin (G) may be carried out under normal pressure or under pressure.

[0111] <Process (h)> Step (h) is a step (coating step) in which a coating material containing a binder resin and aggregate (B) is applied to the tertiary molded body (step S3-9 in Figure 3). By applying a coating material to the tertiary molded body, a coating film of the coating material is formed on the surface of the tertiary molded body. The binder resin and aggregate (B) included in the coating material used in step (h) are the binder resin and aggregate (B) that were previously exemplified in the description of step (e) of the first embodiment.

[0112] In this specification, the coating material used in step (e) is also referred to as the "first coating material (E)" or simply as the "coating material (E)," and the coating material used in step (h) is also referred to as the "second coating material (H)" or simply as the "coating material (H)." Furthermore, the binder resin contained in the coating material (E) is also called "binder resin (E)," and the aggregate (B) contained in the coating material (E) is also called "aggregate (BE)." The binder resin contained in the coating material (H) is also called "binder resin (H)," and the aggregate (B) contained in the coating material (H) is also called "aggregate (BH)." The coating material (H) may have the same composition as the coating material (E), or it may have a different composition. The method for preparing coating material (H) is the same as the method for preparing coating material (E). The method and amount of coating material (H) applied to the tertiary molded body are the same as those of coating material (E).

[0113] <Process (i)> Step (i) is a step (curing step) in which the binder resin contained in the coating material (H) applied to the tertiary molded body (i.e., the coating film of the coating material (H)) is cured to obtain a coated molded body (step S3-10 in Figure 1). In this specification, the coated molded article obtained in step (f) is also referred to as "coated molded article (I)," and the coated molded article obtained in step (i) (however, as will be described in detail later, if step (i) is performed two or more times, the last step (i)) is also referred to as "coated molded article (II)."

[0114] In step (i), the tertiary molded body coated with the coating material (H) (hereinafter also referred to as the "coated tertiary molded body") is heat-treated to harden the binder resin (H) contained in the coating of the coating material (H). The curing temperature and curing time of the binder resin (H) should be adjusted as appropriate, taking into consideration the size, shape, etc., of the carbon-coated carbon molded body to be obtained. Typically, the curing temperature is around 130 to 300°C, with 150 to 250°C being preferred. Typically, the curing time is around 1 to 120 minutes, with 10 to 90 minutes being preferred, and 30 to 60 minutes being more preferred. The binder resin (H) may be cured under normal pressure or under pressure.

[0115] <Process (j)> Step (j) is a step (carbonization step) in which organic components contained in the coated molded body (II) are carbonized to obtain a carbon-coated carbon molded body (II) (Step S3-11 in Figure 1). In a third embodiment, the organic components contained in the coated molded body (II) are derived from the thermosetting resin (G) and from the organic compounds contained in the coating material (H). Specific examples of substances derived from thermosetting resin (G) include cured products of thermosetting resin (G) and uncured thermosetting resin (G). Specific examples of organic compounds among the coating material (H) include cured binder resin (H) and uncured binder resin (H). Furthermore, when cured thermosetting resins are used as aggregate (BH), these cured products are also included in the organic components.

[0116] The carbonization treatment of the coated molded body (II) may be carried out under normal pressure or under reduced pressure (vacuum). Furthermore, the carbonization treatment may be carried out under an oxidizing atmosphere or an inert atmosphere. In particular, it is preferable to carry out the carbonization treatment under reduced pressure and an inert atmosphere. Here, "oxidizing atmosphere" refers to an air atmosphere or an atmosphere containing known oxidizing substances such as oxygen. To create an inert atmosphere, you can use an inert gas such as helium, argon, or nitrogen.

[0117] The carbonization temperature and carbonization time for the carbonization treatment should be adjusted as appropriate, taking into consideration the type of thermosetting resin (G) and binder resin (H) contained in the coating material (H), as well as the size and shape of the carbon-coated carbon molded body (II) to be obtained. Typically, the carbonization temperature is preferably 300 to 1200°C, and more preferably 500 to 1000°C. The carbonization time is preferably 10 minutes to 25 hours, more preferably 30 minutes to 10 hours, and even more preferably 30 minutes to 5 hours.

[0118] Steps (i) and (j) may be carried out in separate devices, or they may be carried out in the same device, provided that the desired temperature can be adjusted. If steps (i) and (j) are performed in separate devices, after step (i), the coated molded body (II) is cooled to a temperature at which it can be removed from the device such as a constant temperature oven, and then moved to another device such as a constant temperature oven or carbonization furnace to perform step (j). When steps (i) and (j) are performed using the same apparatus, the apparatus such as a constant temperature oven is set to the desired temperature and the coated tertiary molded body is heat-treated to obtain a coated molded body (II) (step (i)). Subsequently, the temperature of the same apparatus is raised to the desired temperature and the coated molded body (II) is further heat-treated to obtain a carbon-coated carbon molded body (II) (step (j)). Furthermore, if necessary, the carbon-coated carbon molded body (II) may be graphitized after step (j). For example, a graphitized carbon-coated carbon molded body (II) can be obtained by heating the carbon-coated carbon molded body (II) in an inert atmosphere at a maximum temperature exceeding 1200°C but not exceeding 3000°C.

[0119] <Other forms> The method for manufacturing the carbon-coated carbon molded article of this embodiment is not limited to the method described above. For example, if the process from process (e) to process (g) constitutes one cycle (hereinafter also referred to as "cycle (i-3)"), then cycle (i-3) may be performed two or more times. That is, after process (g), processes (e), (f), and (g) may be repeated one or more times. When cycle (i-3) is performed two or more times, process (f) may be omitted in cycles other than the final cycle (i.e., after repeating process (e) two or more times, processes (f) and (g) may be performed), but it is preferable to perform process (f) after process (e) each time. Also, in cycles other than the final cycle, process (g) may be omitted (i.e., after repeating processes (e) and (f) alternately two or more times, process (g) may be performed), but it is preferable to perform process (g) after process (f) each time.

[0120] Furthermore, for example, if the process from process (α2) to process (β2) is considered one cycle (hereinafter also referred to as "cycle (iii-1)"), cycle (iii-1) may be performed two or more times. That is, after process (β2), processes (α2) and (β2) may be repeated one or more times. When cycle (iii-1) is performed two or more times, process (β2) may be omitted in cycles other than the final cycle (that is, process (β2) may be performed after repeating process (α2) two or more times), or processes (α2) and (β2) may be repeated alternately.

[0121] Furthermore, for example, if the process from process (h) to process (j) is considered one cycle (hereinafter also referred to as "cycle (iv-1)"), cycle (iv-1) may be performed two or more times. That is, after process (j), processes (h), (i), and (j) may be repeated one or more times. When cycle (iv-1) is performed two or more times, process (i) may be omitted in cycles other than the final cycle (that is, after repeating process (h) two or more times, processes (i) and (j) may be performed), but it is preferable to perform process (i) after process (h) each time. Also, in cycles other than the final cycle, process (j) may be omitted (that is, after repeating processes (h) and (i) alternately two or more times, process (j) may be performed), but it is preferable to perform process (j) after process (i) each time. Additionally, cycle (iii-1) and cycle (iv-1) may be performed one or more times after cycle (iv-1).

[0122] Furthermore, the method for manufacturing a carbon-coated carbon molded body according to this embodiment may further include a step (d) between steps (c) and (e). In step (e), which is performed after step (d), a coating material (E) is applied to the carbonized secondary molded body obtained in step (d). Step (d) is the same as in the first embodiment, so its description is omitted. Furthermore, the method for producing the carbon-coated carbon molded article of this embodiment may further include the following step (γ) between step (β2) and step (h).

[0123] <Process (γ)> Process (γ) is a process that takes place after process (β2), and involves carbonizing the organic components contained in the tertiary molded body to obtain a carbonized tertiary molded body (carbonization process). In this specification, if the method for producing a carbon-coated carbon molded article includes steps (d) and (γ), step (d) will also be referred to as the "first carbonization step," step (g) as the "second carbonization step," step (γ) as the "third carbonization step," and step (j) as the "fourth carbonization step." In step (h), which is performed after step (γ), a coating material (H) is applied to the carbonized tertiary molded body obtained in step (γ).

[0124] The organic components contained in the tertiary molded product are those derived from the thermosetting resin (G), specifically the cured product of the thermosetting resin (G), the uncured thermosetting resin (G), etc.

[0125] The carbonization treatment for carbonizing the tertiary molded body may be carried out under atmospheric pressure or under reduced pressure (vacuum). Furthermore, the carbonization treatment may be carried out under an oxidizing atmosphere or an inert atmosphere. In particular, it is preferable to carry out the carbonization treatment under reduced pressure and an inert atmosphere. Here, "oxidizing atmosphere" refers to an air atmosphere or an atmosphere containing known oxidizing substances such as oxygen. To create an inert atmosphere, you can use an inert gas such as helium, argon, or nitrogen.

[0126] The carbonization temperature and carbonization time for the carbonization treatment should be adjusted as appropriate, taking into consideration the type of phenolic resin contained in the raw material mixture, the size and shape of the carbon-coated carbon molded body (II) to be obtained, etc. Typically, the carbonization temperature is preferably 300 to 1200°C, and more preferably 500 to 1000°C. The carbonization time is preferably 10 minutes to 25 hours, more preferably 30 minutes to 10 hours, and even more preferably 30 minutes to 5 hours.

[0127] Furthermore, processes (β2) and (γ) may be carried out in separate devices, or they may be carried out in the same device if the desired temperature can be adjusted. If processes (β2) and (γ) are carried out in separate devices, after process (β2), the tertiary molded body is cooled to a temperature at which it can be removed from the device such as a constant temperature oven, and then moved to another device such as a constant temperature oven or carbonization furnace to carry out process (γ). When steps (β2) and (γ) are performed using the same apparatus, the apparatus such as a constant temperature incubator is set to the desired temperature and the carbon-coated carbon molded body (I) impregnated with thermosetting resin (G) is heat-treated to form a tertiary molded body (step (β2)). Subsequently, the temperature of the same apparatus is raised to the desired temperature and the tertiary molded body is further heat-treated to obtain a carbon molded body (step (γ)).

[0128] Furthermore, when performing step (γ), one or more cycles (iii-1) may be performed between step (γ) and step (h). That is, the carbon-coated carbon molded body (I), which has been impregnated with thermoplastic resin (G) and in which the impregnated thermosetting resin (G) has been cured and carbonized, may be further impregnated with thermosetting resin (G) and cured one or more times. When two or more cycles (iii-1) are performed between step (γ) and step (h), step (β2) may be omitted in cycles other than the final cycle, or steps (α2) and (β2) may be repeated alternately. Also, step (γ) may be performed after step (β2).

[0129] "The fourth aspect" The method for manufacturing a carbon-coated carbon molded article according to this embodiment, as shown in Figure 4, includes steps (a), (b), (c), (e), (f), and (g) described in the first embodiment, and further includes steps (α1) and (β1) between steps (c) and (e), and further includes steps (α2), (β2), (h), (i), and (j) after step (g). In Figure 4, step S4-1 is process (a), step S4-2 is process (b), step S4-3 is process (c), step S4-4 is process (α1), step S4-5 is process (β1), step S4-6 is process (e), step S4-7 is process (f), step S4-8 is process (g), step S4-9 is process (α2), step S4-10 is process (β2), step S4-11 is process (h), step S4-12 is process (i), and step S4-13 is process (j). Since steps (a), (b), (c), (e), (f), and (g) are the same as in the first embodiment, their descriptions are omitted. Since steps (α1) and (β1) are the same as in the second embodiment, their descriptions are omitted. Since processes (α2), (β2), (h), (i), and (j) are the same as in the third embodiment, their descriptions are omitted.

[0130] <Other forms> The method for manufacturing the carbon-coated carbon molded article of this embodiment is not limited to the method described above. For example, if the process from process (α1) to process (β1) is considered one cycle (hereinafter also referred to as "cycle (ii-2)"), then cycle (ii-2) may be performed two or more times. That is, after process (β1), processes (α1) and (β1) may be repeated one or more times. When cycle (ii-2) is performed two or more times, process (β1) may be omitted in cycles other than the final cycle (that is, process (α1) may be repeated two or more times before process (β1) is performed), or processes (α1) and (β1) may be repeated alternately.

[0131] Furthermore, for example, if the process from process (e) to process (g) is considered one cycle (hereinafter also referred to as "cycle (i-4)"), cycle (i-4) may be performed two or more times. That is, after process (g), processes (e), (f), and (g) may be repeated one or more times. When cycle (i-4) is performed two or more times, process (f) may be omitted in cycles other than the final cycle (i.e., after repeating process (e) two or more times, processes (f) and (g) may be performed), but it is preferable to perform process (f) after process (e) each time. Also, in cycles other than the final cycle, process (g) may be omitted (i.e., after repeating processes (e) and (f) alternately two or more times, process (g) may be performed), but it is preferable to perform process (g) after process (f) each time.

[0132] Furthermore, for example, if the process from process (α2) to process (β2) is considered one cycle (hereinafter also referred to as "cycle (iii-2)"), cycle (iii-2) may be performed two or more times. That is, after process (β2), processes (α2) and (β2) may be repeated one or more times. When cycle (iii-2) is performed two or more times, process (β2) may be omitted in cycles other than the final cycle (that is, process (α2) may be repeated two or more times before process (β2) is performed), or processes (α2) and (β2) may be repeated alternately.

[0133] Furthermore, for example, if the process from process (h) to process (j) is considered one cycle (hereinafter also referred to as "cycle (iv-2)"), cycle (iv-2) may be performed two or more times. That is, after process (j), processes (h), (i), and (j) may be repeated one or more times. When cycle (iv-2) is performed two or more times, process (i) may be omitted in cycles other than the final cycle (that is, after repeating process (h) two or more times, processes (i) and (j) may be performed), but it is preferable to perform process (i) after process (h) each time. Also, in cycles other than the final cycle, process (j) may be omitted (that is, after repeating processes (h) and (i) alternately two or more times, process (j) may be performed), but it is preferable to perform process (j) after process (i) each time. Additionally, cycle (iii-2) and cycle (iv-2) may be performed one or more times after cycle (iv-2).

[0134] Furthermore, the method for producing the carbon-coated carbon molded article of this embodiment may further include a step (d) between step (c) and step (α1). In step (α1), which is performed after step (d), the carbonized secondary molded article (I) obtained in step (d) is impregnated with a thermoplastic resin (G). Furthermore, a step (d) may be included between step (β1) and step (e). If step (d) is performed between step (β1) and step (e), one or more cycles (ii-2) may be performed between step (d) and step (e). That is, the carbonized secondary molded body may be impregnated and cured with a thermosetting resin (G) one or more times. If two or more cycles (ii-2) are performed between step (d) and step (e), step (β1) may be omitted in cycles other than the final cycle, or steps (α1) and (β1) may be repeated alternately. Furthermore, step (d) may be performed after step (β1). In step (e) performed after step (d), a coating material (E) is applied to the carbonized secondary molded body (II) obtained in step (d). Since process (d) is the same as in the first embodiment, its explanation is omitted.

[0135] Furthermore, the method for manufacturing a carbon-coated carbon molded article of this embodiment may further include step (γ) between step (β2) and step (h). When step (γ) is performed, cycle (iii-2) may be performed one or more times between step (γ) and step (h). That is, the carbon-coated carbon molded article, which has been impregnated with thermoplastic resin (G) and in which the impregnated thermosetting resin (G) has been cured and carbonized, may be further impregnated with thermosetting resin (G) and cured one or more times. When cycle (iii-2) is performed two or more times between step (γ) and step (h), step (β2) may be omitted in cycles other than the final cycle, or steps (α2) and (β2) may be repeated alternately. Also, step (γ) may be performed after step (β2). In step (h) performed after step (γ), a coating material (H) is applied to the carbonized tertiary molded article obtained in step (γ). Since process (γ) is the same as in the third embodiment, its explanation will be omitted.

[0136] [Method for manufacturing activated carbon molded bodies] The method for producing an activated carbon molded body in this embodiment is to obtain a carbon-coated carbon molded body (i.e., the carbon-coated carbon molded body (I) or the carbon-coated carbon molded body (II)) by the carbon-coated carbon molded body production method of the present invention described above, and then to obtain an activated carbon molded body by activating the obtained carbon-coated carbon molded body. By activating the carbon-coated carbon molded body obtained by the method for producing a carbon-coated carbon molded body of the present invention, three-dimensional activated carbon can be easily produced. Furthermore, the carbon-coated carbon molded body to be activated may be graphitized.

[0137] Conventional known activation methods such as gas activation methods and chemical activation methods can be used to activate carbon-coated carbon molded bodies. In the gas activation method, the carbon-coated carbon molded body is activated by bringing the activation gas into contact with it. Examples of activating gases include water vapor, air, carbon monoxide, carbon dioxide, hydrogen chloride, oxygen, or mixtures thereof.

[0138] In the chemical activation method, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide; inorganic acids such as boric acid, phosphoric acid, sulfuric acid, and hydrochloric acid; or inorganic salts such as zinc chloride are brought into contact with a carbon-coated carbon molded body to activate it. In the case of the drug activation method, after activation, the product and the chemicals used may be neutralized with an acid or alkali, or removed by washing with water or the like.

[0139] Among the activation methods described above, the gas activation method is preferred due to its simplicity of equipment and the fact that no special treatment is required after activation, and the gas activation method using water vapor is particularly preferred. Activation can be carried out using a multi-stage furnace, rotary kiln furnace, fluidized bed furnace, etc. [Examples]

[0140] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The materials used in each example are shown below. The various measurement methods are also described below.

[0141] [Materials used] As the phenolic resin, a novolac-type phenolic resin (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "Reditop PS-1299", mass-average molecular weight 13570) was used. Hexaethylenetetramine (manufactured by Mitsubishi Gas Chemical Company, Inc.) was used as the hardening agent. Benzoic acid (manufactured by EMERALD KALAMA CHEMICAL) and resorcinol (manufactured by Sumitomo Chemical Co., Ltd.) were used as curing accelerators. As spherical aggregate (A), spherical carbon (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "GC-050", sphericity 0.95, average particle size 50 μm) was used. The mass-average molecular weight of the novolac-type phenolic resin was measured using a GPC measuring instrument (HLC8320GPC, manufactured by Tosoh Corporation) and a column (TSKgel G3000HXL+G2000HXL+G2000HXL, manufactured by Tosoh Corporation), with polystyrene used as the standard substance.

[0142] As the thermosetting resin (G) (impregnation resin), a resol-type phenolic resin that is liquid at 25°C (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "Reditop PL-3261", resin content 60% by mass, viscosity 35 mPa·s) was used.

[0143] As the binder resin, a liquid resol-type phenolic resin at 25°C (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "Resitop PL-3261", resin content 60% by mass, viscosity 35 mPa·s) was used.

[0144] As aggregate (B), one of the following compounds was used. • Carbon: Graphite (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size (D50) 15 μm). • Carbon: Graphite (average particle size (D50) 37 μm). • Carbon: Graphite (average particle size (D50) 5μm).

[0145] [Evaluation Method] <Leak test> Leakage tests were conducted using fluorescent dyes in accordance with JIS Z 2330:2012, and the airtightness of the carbon-coated carbon molded body was evaluated according to the following evaluation criteria. ○: No leakage was observed. ×: Leakage is observed.

[0146] <Measurement of air permeability> The air permeability of the carbon-coated carbon molded body was measured using a Hatsunen electric air permeability tester manufactured by International Hatsunen Co., Ltd., in accordance with the foundry sand air permeability test method compliant with JIS Z 2601:1993.

[0147] [Example 1] <Preparation of raw material mixture> 20 parts by mass of novolac-type phenolic resin (PS-1299), 3.2 parts by mass of hexaethylenetetramine, 0.4 parts by mass of benzoic acid, and 0.4 parts by mass of resorcinol were pulverized in a pulverizer (manufactured by Hosokawa Micron Corporation, product name "ACM") to obtain a powdered molding resin composition. The entire amount of the molding resin composition (24.0 parts by mass) and 80 parts by mass of spherical carbon were mixed in a screw-type mixer for 5 minutes to obtain a raw material mixture.

[0148] <Preparation of covering material> 50 parts by mass of resol-type phenolic resin (PL-3261) and 50 parts by mass of graphite (average particle size (D50) 15 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 80% by mass.

[0149] <Manufacturing of carbon-coated carbon molded products> A carbon-coated carbon molded body was manufactured using a selective laser sintering method with a powder bed fusion fusion machine (manufactured by Aspect Co., Ltd., product name "RaFaElII HT300") as described below. First, three-dimensional data of the cross-sectional shapes at regular intervals of the target carbon-coated carbon molded body was created in advance. Using a powder bed fusion fusion machine, a 100 μm thick thin layer made of a raw material mixture was deposited on the bottom surface of the fusion chamber installed in the machine. A CO2 laser was scanned and irradiated onto a desired area of ​​this thin layer under the conditions of laser intensity 40 W, laser scanning speed 10 m / sec, laser diameter 0.32 mm, and laser scan interval 0.12 mm to heat and sinter the thin layer, thereby forming a sintered thin layer (step (a)). Next, the bottom surface of the build chamber (build table) was lowered by one layer, and another thin layer made of the raw material mixture was deposited on top of the sintered thin layer. A CO2 laser was then scanned and irradiated onto a desired area of ​​this thin layer under the same conditions as before. These deposition and irradiation operations were repeated until a carbon-coated carbon molded body was fabricated, resulting in a hollow, bottomed cylindrical primary molded body with an outer diameter of 50 mm, an inner diameter of 40 mm, a thickness of 5 mm, and a height of 25 mm (step (b)). Next, the raw material mixture in the thin, unirradiated region was removed to obtain the primary molded body.

[0150] The removed primary molded body was placed in a test incubator (manufactured by Yamato Scientific Co., Ltd., product name "Forced-Air Constant Temperature Incubator") and heat-treated at 170°C for 60 minutes to further cure the molding resin composition contained in the primary molded body and obtain a secondary molded body (I) (step (c)).

[0151] Next, the secondary molded body (I) was impregnated with resol-type phenolic resin (PL-3261) as the impregnation resin for 1 minute (step (α1)), then placed in a test incubator and heat-treated at 170°C for 60 minutes to further cure the resol-type phenolic resin (PL-3261) impregnated in the secondary molded body (I) to obtain the secondary molded body (II) (step (β1)). The amount of resol-type phenolic resin (PL-3261) impregnated was 32 parts by mass in terms of pure content per 100 parts by mass of the secondary molded body (I).

[0152] Next, the secondary molded body (II) was cooled to room temperature (25°C), a coating material was applied to the secondary molded body (II) (step (e)), and the body was placed in a test incubator and heat-treated at 170°C for 60 minutes to cure the resol-type phenolic resin (PL-3261) contained in the coating material applied to the secondary molded body (II) to obtain a coated molded body (step (f)). Next, the coated molded body was placed in a test carbonization furnace and carbonized at 800°C for 60 minutes in a nitrogen stream to carbonize the organic components contained in the coated molded body. The surface of the carbon molded body, which is the carbide of the secondary molded body, is the carbide of the coating film of the coating material, and a carbon-coated carbon molded body is obtained, which is coated with a carbon coating layer with a thickness of 200 μm (step (g)). Steps (e) through (g) described above constituted one cycle (cycle (i-2)), and cycle (i-2) was performed a total of three times. The total thickness of the carbon coating layer was 480 μm. After the obtained carbon-coated carbon molded body was cooled to room temperature (25°C), a leak test and air permeability measurement were performed. The results are shown in Table 1.

[0153] Furthermore, a carbon-coated carbon molded body was manufactured using a similar procedure. The obtained carbon-coated carbon molded body was placed in a horizontal tubular furnace and heated to 900°C at a heating rate of 5°C / min while flowing nitrogen gas through it. Next, the nitrogen gas, which had been passed through hot water pre-adjusted to 80°C, was introduced into the tubular furnace along with the nitrogen gas at a rate of 4.125 mL / min while heating at 900°C for 1 hour to activate the carbon. Subsequently, an activated carbon molded body was obtained by cooling while introducing only nitrogen gas.

[0154] [Comparative Example 1] 100 parts by mass of resol-type phenolic resin (PL-3261) and 50 parts by mass of graphite (average particle size (D50) 5 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 73% by mass. A carbon-coated carbon molded body was manufactured in the same manner as in Example 1, except that the obtained coating material was used, and a leak test and air permeability measurement were performed. The results are shown in Table 1.

[0155] [Comparative Example 2] Thirty parts by mass of resol-type phenolic resin (PL-3261) and fifty parts by mass of graphite (average particle size (D50) 37 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 85% by mass. Using the obtained coating material, a carbon-coated carbon molded body was manufactured in the same manner as in Example 1, except that cycle (i-2) was performed once. Leakage tests and air permeability measurements were then performed. The results are shown in Table 1.

[0156] [Comparative Example 3] 100 parts by mass of resol-type phenolic resin (PL-3261) and 50 parts by mass of graphite (average particle size (D50) 15 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 73% by mass. A carbon-coated carbon molded body was manufactured in the same manner as in Example 1, except that the obtained coating material was used, and a leak test and air permeability measurement were performed. The results are shown in Table 1.

[0157] [Comparative Example 4] Fifty parts by mass of resol-type phenolic resin (PL-3261) and fifty parts by mass of graphite (average particle size (D50) 37 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 80% by mass. A carbon-coated carbon molded body was manufactured in the same manner as in Example 1, except that the obtained coating material was used, and a leak test and air permeability measurement were performed. The results are shown in Table 1.

[0158] [Comparative Example 5] 50 parts by mass of resol-type phenolic resin (PL-3261) and 50 parts by mass of graphite (average particle size (D50) 5 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 80% by mass. An attempt was made to manufacture a carbon-coated carbon molded body in the same manner as in Example 1, except that the obtained coating material was used. However, the coating material was hard, and it was not possible to uniformly apply the coating material to the secondary molded body (II).

[0159] [Comparative Example 6] Thirty parts by mass of resol-type phenolic resin (PL-3261) and fifty parts by mass of graphite (average particle size (D50) 15 μm) were mixed to obtain a paste-like coating material with a solid content concentration of 85% by mass. An attempt was made to manufacture a carbon-coated carbon molded body in the same manner as in Example 1, except that the obtained coating material was used. However, the coating material was hard, and it was not possible to uniformly apply the coating material to the secondary molded body (II).

[0160] [Reference example A] The air permeability of a 5mm thick glass plate was measured. The results are shown in Table 1.

[0161] [Table 1]

[0162] As is clear from Table 1, the carbon-coated carbon molded body obtained in Example 1 was resistant to liquid leakage. Furthermore, it had a degree of air permeability comparable to that of a glass plate. In contrast, the carbon-coated carbon molded articles obtained in Comparative Examples 1-4 were easily permeable to liquids and gases, and prone to leakage.

Claims

1. A method for manufacturing a carbon-coated carbon molded body, Step (a) of forming a thin layer of a raw material mixture containing a molding resin composition and spherical aggregate (A), irradiating a desired area of ​​the thin layer with a laser, and sintering the thin layer to form a sintered thin layer, Step (a) is performed multiple times to obtain a primary molded body in which multiple sintered thin layers are stacked (b), (c) A step of curing the molding resin composition contained in the primary molded body to obtain a secondary molded body, Step (e) involves applying a coating material containing a binder resin and aggregate (B) to the secondary molded body, (f) A step of curing the binder resin contained in the applied coating material to obtain a coated molded body, (g) A step of carbonizing the organic components contained in the coated molded body to obtain a carbon-coated carbon molded body, Includes, The aforementioned molding resin composition comprises a phenolic resin and a curing agent. The average particle size of the aggregate (B) is 10 to 30 μm. A method for producing a carbon-coated carbon molded article, wherein the solid content concentration of the coating material is 75% by mass or more and less than 85% by mass of the total mass of the coating material.

2. The method for producing a carbon-coated carbon molded article according to claim 1, wherein the spherical aggregate (A) contains spherical carbon.

3. The method for producing a carbon-coated carbon molded article according to claim 1, wherein the aggregate (B) contains carbon.

4. A method for producing a carbon-coated carbon molded article according to claim 1, further comprising the steps of: impregnating one or more selected from the secondary molded article and the carbon-coated carbon molded article with a thermosetting resin (α); and curing the impregnated thermosetting resin (β).

5. A method for producing an activated carbon molded body, comprising obtaining a carbon-coated carbon molded body by the method for producing a carbon-coated carbon molded body described in any one of claims 1 to 4, and activating the obtained carbon-coated carbon molded body.

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