JPS63182208A - Production of raw material for forming novel carbon article by forming - Google Patents

Abstract

PURPOSE:To easily obtain the title material capable of providing a formed product having high dimensional accuracy, electric, thermal and chemical characteristics, unifrom and desired shape without impairing the shape of the formed product by mixing fine carbon powder and an org. compd. having low mol.wt. with a specified mixture of molten salts, and heating the mixture under stirring. CONSTITUTION:(A) A molten salt mixture contg. a large amt. of Lewis acid catalyst such as (a) an org. cationic molten salt which is liquid at room temp. obtd. by heating, mixing and melting AlCl3, etc. as Lewis acid catalyst added to alkyl pyridinium halide or dialkyl imidazolium halide, or (b) an inorg, molten salt contg. a large amt. of molten Lewis acid such as ternary molten salt comprising AlCl3+NaCl+KCl, etc., is mixed with (B) fine carbon powder such as fine granular natural graphite, etc., and (C) an org. compd. having a low mol.wt. such as naphthalene, etc., and the mixture is heated at <=300 deg.C under stirring. Thus, the title raw material comprising powdery material constituted of B component covered uniformly by dormant mesophase pitch and/or isotropic pitch as binder on the whole surface is obtd. After forming said raw material to a desired shape, the formed product is calcined and carbonized in inert atmosphere to thus obtain a novel formed carbon product having superior characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a raw material for forming new carbon products. Specifically, the present invention is extremely homogeneous, has high dimensional accuracy of the molded product, has excellent electrical, thermal, and chemical properties required as a new carbon material, and has the ability to design its performance in advance. Dormant mesophase pitch (Domant mesophase pitch) is a raw material for obtaining functional new carbon molded products.
MesophasePitch potential anisotropic pitch),
and/or relates to a method for producing a raw material for forming a new carbon product in which the entire surface is uniformly coated with isotropic pitch.

(Prior art) Currently, carbon molded bodies are generally produced using petroleum coke as a raw material.
It is made by using pitch coke, graphite, carbon black, etc. as an aggregate, pitch, tar, synthetic resin, etc. as a caking agent, and kneading, molding, and firing the two. Therefore, it is generally manufactured as a large block, and its structure is rough and the material does not exhibit sufficient properties, making it almost impossible to directly mold it into a desired shape. Since a large amount of caking material is used for the aggregate, it has the disadvantage that a large amount of distortion occurs due to shrinkage and stress deformation during firing.

Therefore, in order to improve dimensional accuracy or achieve densification, a large amount of aggregate should be bound with a very small amount of binder component, or
Alternatively, it can be manufactured by pulverizing the raw material aggregate to 10 μm or less, adding a caking agent thereto, and following the above procedure. Therefore, aggregate/
The larger the caking agent ratio or the finer the aggregate, the more difficult it becomes to mix the aggregate and the caking agent, and the more difficult it becomes to uniformly disperse the caking agent. In particular, carbon black has extremely fine particles and has a higher-order structure in which particles are bonded together, and the average particle size is 1μ.
Graphite powder has a large specific surface area, and when such powder is used as aggregate, it is difficult to mix, disperse, and knead with the second caking agent in one operation, and it is necessary to repeat the operation multiple times. are forced to do so. When using fine-grained carbon powder with a large specific surface area, or when covering a large amount of aggregate uniformly with a very small amount of binder component, in the past, styrene monomer or acrylonitrile was used on the surface of the carbon blank. There was knowledge about the production of grafted carbon by grafting low-molecular substances such as vinylbenzene, and the method of graft polymerizing methyl methacrylate monomer onto the surface of fine natural graphite powder.

However, styrene resin, polymethyl methacrylate, polyacrylonitrile, and vinylbenzene polymers have poor carbon yields, and the bonding between aggregate and binder by firing is insufficient, so that they cannot be used as carbonized binders. It's inappropriate.

Therefore, the final carbon molded product obtained in this way could not exhibit the desired properties, and in order to achieve further densification and higher crystallinity, the molded product was fired at a temperature of about 1000°C.
The process of impregnating tar, pitch, or synthetic resin under heat and pressure, and then firing it was repeated several times or heated to a high temperature of nearly 3000°C.

(Problems to be Solved by the Invention) The purpose of the present invention is to improve the shortcomings of the prior art by highly demonstrating the functional characteristics of carbon materials, avoiding complicated manufacturing steps, and, in particular, It is an object of the present invention to provide a method for producing an Arai blank molding material that can be fired without impairing its shape at the time of shaping and is used as a raw material for a new carbon molded body that can be expected to have high dimensional accuracy during firing.

(Means for Solving the Problems) In the process of researching low-temperature carbonization of hydrocarbons in room-temperature molten salts through an ionic mechanism, the inventors of the present application discovered that a mesophase is produced at a much lower temperature than that of a normal carbonization reaction. We discovered a phenomenon in which pitch precipitates uniformly on the surface of carbon particles already present in the reaction system, using them as nuclei. Here, the "mesophase pitch" referred to in this specification is - Although it appears to be isotropic, when external stress acts in one direction,
It is a pitch that can be easily arranged accordingly and has the property of providing an anisotropic structure. Therefore, in the presence of fine graphite powder as an aggregate in a molten salt solution, hydrocarbons were polymerized to form pitch, and we investigated whether pitch in a mesophase state would uniformly adhere to the entire surface of the fine graphite powder. As a result, it was confirmed that a good coating was obtained. Furthermore, using this mesophase pitch-coated carbon powder, the powder was pressure-molded and fired in a conventional manner without adding a binder, resulting in extremely homogeneous, highly crystalline and dense powder with the desired porosity. up to isotropic ones with
It was possible to design materials with different physical and chemical properties, and it was possible to freely produce new carbon molded bodies with excellent dimensional accuracy.

Here, the temperature used in the present invention is room temperature or 100%
A type of molten salt that becomes liquid at low temperatures below 0.degree. C. will be described.

First, as an organic cationic molten salt that is liquid at room temperature, one equivalent of alkylpyridinium halide or dialkylimidazolium halide synthesized from an alkyl halide and pyridine is added with one equivalent or more of aluminum chloride, etc. as a Lewis acid catalyst. It is obtained by heating, mixing and dissolving, and cooling to room temperature.

I8R,R”: Lower alkyl or aralkyl X:
Halogen n ≧ 1 As shown on the right side, this solution composition is characterized by being mostly ions and containing a large amount of dissolved aluminum chloride. When dichloroethane or trichloroethane is mixed with argon and blown into this molten salt, a de-HCI reaction occurs at 100 to 300°C, and in most cases, mesophase pitch containing 80% or more of BI acid component (benzene insoluble component) is obtained. It was done.

Examples of the inorganic molten salt include a ternary molten salt of aluminum chloride, sodium chloride, and potassium chloride (melting point: 95° C.) whose composition is shown in the following formula.

0.60 AlCl3 + 0.26 NaC1+
0.14 MCI −0,26Na ” + 0
0.14 K” +0.40 AlCl4.- +
0.20 AlCl:t In this molten salt, aromatic hydrocarbons are easily dehydrogenated and polycondensed at 200-300°C.
tar, pitch, or coke (RO) in high yield.
w coke). For example, from naphthalene,
After treatment at 300°C for 10 hours, black flake-like carbide was precipitated, but the Bl content was 92%, and the BE acid component H
/C atomic ratio was 0.42. In this case, the product is
By controlling the reaction temperature and time, it is possible to change the state from a coke state to a dormant mesophase pitch state, an isotropic pitch state, and a tar state.

By controlling the reaction temperature and time, it is possible to change the product from a coke state to a dormant mesophase pitch state to a tar state.

The order of reactivity of aromatic hydrocarbons was anthracene, naphthalene, phenanthrene, stilbene, biphenyl, benzene, and quinoline.

In addition, examples of inorganic molten salts suitable for the purpose of the present invention include:
In addition to the above, sodium chloride and iron chloride (melting point 156
℃), a mixed molten salt of sodium oxalide and aluminum chloride (melting point: 90°C), and the like.

(Example) Next, the present invention will be explained by giving examples.

Great Calamity - In the upper reaction vessel, under an argon atmosphere, add 2 moles of aluminum chloride to 1 mole of ethylpyridinium bromide synthesized from ethyl bromide and pyridine, heat it to 100°C to completely dissolve it, and then leave it at room temperature. A liquid molten salt was obtained at room temperature.

Into this reactor, 150 g of fine-grained natural graphite (manufactured by Nippon Graphite Co., Ltd., average particle size: 1 μm) was placed and stirred until the whole exhibited a uniform suspension state. Next, 15 g of naphthalene (manufactured by Tokyo Kagaku Co., Ltd.) was added with stirring, the temperature was slowly raised to 230°C, and after holding at this temperature for 5 hours, the heating was stopped and cooled, and the reactant was placed in ice water. After washing with water, the solution was filtered. Next, this was dried to produce 163.7 g of powder that uniformly coated the surface of fine graphite, which is the desired new coal molding material, with dormant mesophase pitch.
I got it.

A mixture of 2.40 moles of aluminum chloride, 0.16 moles of potassium chloride, and 1.04 moles of sodium chloride was melted (melting point: 95 DEG C.) in a cold flame reactor under an argon atmosphere. In this molten salt, 50% of expanded graphite (average particle size 10 μm) was added.
g and 50 g of naphthalene were added, the temperature was maintained at 100°C, and the mixture was stirred until the whole was homogeneous. Furthermore, the temperature was raised to 230° C., and this temperature was maintained for 5 hours to continue the reaction. After the reaction is complete, stop the heating, cool it down, take out the reactant, pour it into ice water, wash it,
It was filtered. Next, this was dried to obtain 98 g of powder in which the entire surface of expanded graphite, which was the intended new coal molding material, was uniformly coated with dormant mesophase pitch.

Testing Base-1 50 g of carbon blank having an average particle size of 0.07 μm was added to 500 g of the room temperature molten salt used in Example 1, and the mixture was stirred at room temperature to form a uniform suspension state. While heating and maintaining the entire system at 230°C, dichloroethane was mixed with argon gas to a raw material concentration of 200mg.
/l at a gas flow rate of 151/hour, and the reaction was continued for 5 hours. Thereafter, the reaction was stopped, cooled to room temperature, and the reactants were taken out and treated in the same manner as in Example 1, so that the entire surface of carbon black, which is the desired new carbon forming material, was uniformly coated with dormant mesophase pitch. 54 g of coated powder were obtained.

Claims (1)

[Scope of Claims] 1) A molding powder material to be used when producing a high-performance new carbon molded body by carbonizing and firing it in an inert gas phase after shaping it into a pre-designed arbitrary shape. In the manufacturing method, a mixed molten salt containing a large amount of Lewis acid catalyst is used as a solvent and catalyst, fine carbon powder and a low molecular weight organic compound are added to this liquid, and the carbon is heated under stirring. A method for producing a raw material for forming a new carbon product, which comprises coating the entire surface of fine powder with dormant mesophase pitch (potentially anisotropic pitch) and/or isotropic pitch as a binding agent. 2) The mixed molten salt containing a large amount of Lewis acid catalyst is characterized in that it is an organic cationic molten salt containing a large amount of Lewis acid dissolved therein, or an inorganic molten salt containing a large amount of Lewis acid dissolved therein. A method for producing a raw material for forming a new carbon product as described in paragraph 1. 3) The new carbon product according to item 1, wherein the heat treatment temperature (reaction temperature) when coating the surface of the carbon fine powder with mesophase pitch and/or isotropic pitch is 300°C or less. Method for manufacturing raw materials for molding.