JPS6355110A - Production of readily graphitizable high-density carbon and graphite material - Google Patents

Abstract

PURPOSE:To produce high-strength, readily graphitizable, high-density carbon and graphite material, by reacting a condensed polycyclic aromatic compound with a specific aromatic crosslinking agent by the use of an acid catalyst, subjecting the reaction product to thermosetting molding and molecular orientation, heating and calcining. CONSTITUTION:A mixture of condensed polycyclic aromatic compound mainly consisting of two or more rings, an aromatic crosslinking agent consisting of one or more rings containing two or more hydroxymethyl groups or halomethyl groups and an acid catalyst is reacted in an oxidizing or nonoxidizing atmosphere at 60-300 deg.C. A thermosetting intermediate reaction product substantially having thermoplasticity is subjected to thermosetting molding in an oxidizing or nonoxidizing atmosphere at 100-400 deg.C. Then the molded article is pressurized at 350-550 deg.C in a nonoxidizing atmosphere and the condensed polycyclic aromatic molecule is physically orientated. Then the molded article consisting of the orientated molecule is calcined in a nonoxidizing atmosphere at 800-3,000 deg.C to give readily graphitizable, high-density carbon and graphite material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing graphitizable high-density carbon and graphite materials using a thermosetting resin as a starting material.

(Prior art) Conventionally, phenol resin, furan resin, etc. are known as thermosetting resins, and after molding and curing these,
It is known that when carbonized or graphitized, a gas-impermeable carbon or graphite material called glassy carbon can be obtained. In addition, as a method for producing high-density carbon and graphite materials, carbon material raw materials are heated to 400 to 600°C under atmospheric pressure, and a hot press method is used to produce 50 to 400 kg/cm2.
A method of press forming at a pressure of
It is disclosed in Japanese Patent No. 1-122110.

(Problems to be Solved by the Invention) Conventionally known thermosetting resins such as phenolic resins and furan resins exhibit large carbonization shrinkage due to low carbonization yields, and therefore suffer from cracks, cracks, etc. during the carbonization process. The drawback is that it is difficult to obtain carbon and graphite materials without using special methods, and the resulting carbon is extremely difficult to graphitize, called glassy carbon. The problem was that the structure hardly changed even after graphitization treatment.

JP-A-61-122110 mentioned above, in which a carbon material raw material having self-sintering ability such as bulk mesophase, mesocarbon microbeads, petroleum-based or coal-based coke is heated under atmospheric pressure and pressure-molded by a hot press method. According to the method, at the heating temperature, the carbon material raw material is only physically bonded through the binder component contained therein that exhibits self-sintering ability, and the carbon material raw material is carbonized. Alternatively, carbon and graphite materials obtained by graphitization include
There are limits to its strength. Furthermore, when a graphite material is produced from the carbon material raw material by the above method, there is a drawback that graphitizability cannot be controlled.

(Means and operations for solving the problems) The present invention aims to eliminate and improve the drawbacks and problems of the conventional methods, and achieves the above objects by providing the method described in the claims. can do.

The present inventors mainly conducted a thermosetting intermediate reaction having thermoplasticity by heating a mixture of a fused polycyclic aromatic compound having two or more rings, an aromatic crosslinking agent, and an acid catalyst within a temperature range of 60 to 300°C. After obtaining the product, when it is thermally cured within a temperature range of 100 to 400°C, the methylene bonds are cleaved, noting that the obtained molded product is a crosslinked polymer molded product mainly composed of methylene bonds. Within the temperature range of 800-3000'C, after promoting molecular orientation by applying physical pressure by hot pressing to obtain a two-dimensional orientation more similar to graphite crystal structure, in the temperature range of 350-550'C. We have discovered a new method for producing easily graphitizable high-density carbon and graphite materials, which is characterized by heating and firing at a temperature of 100 mL.

Next, the condensed polycyclic aromatic compound, aromatic crosslinking agent, and acid catalyst that constitute the thermosetting intermediate reaction product of the present invention will be explained.

According to the present invention, the condensed polycyclic aromatic compounds include coal-based or petroleum-based heavy oil, tar, pinch, naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, acenatylene, perylene, coronene, and these as main skeletons. 1 selected from among the derivatives
A species or a mixture of two or more kinds can be used, and in particular, according to the present invention, it is preferable to select the fused polycyclic aromatic compound having a large molecular weight (and a low softening point).

According to the present invention, the aromatic crosslinking agent is an aromatic compound consisting of one or more aromatic rings having two or more of at least one of hydroxydimethyl and halomethyl groups, such as p-xylylene. Glycol, p-xylylene dichloride, dimethyl-p-xylylene glycol, dimethyl-m-xylylene glycol silylene glycol, etc. can be used.

According to the present invention, the acid catalyst is one or two selected from Lewis acids such as aluminum chloride and boron fluoride, protonic acids such as sulfuric acid, phosphoric acid, organic sulfonic acids, and carboxylic acids, and derivatives thereof. Mixtures of the above can be used.

In the present invention, coal-based or petroleum-based heavy oil, tar, pitch, etc. having a relatively large molecular weight among the fused polycyclic aromatic compounds are used, and foreign elements such as oxygen and sulfur are contained in the molecule. It is preferable to use a material that does not contain carbon to obtain a graphitizable carbon or graphite material, and it is particularly preferable to use a material with a softening point in the temperature range of 80 to 110°C. . When using the fused polycyclic aromatic compound having a softening point of 120° C. or higher, it is preferable to add a solvent and/or a plasticizer to lower the softening point, since it becomes difficult to control the reaction.

Next, the aromatic crosslinking agent and the acid catalyst for the fused polycyclic aromatic compound will be explained.

The aromatic crosslinking agent is 40 to 80 parts by weight based on 100 parts by weight of the condensed polycyclic aromatic compound, and the acid catalyst is based on a total of 100 parts by weight of the mixture of the aromatic crosslinking agent and the condensed polycyclic aromatic compound. A suitable range is 1 to 20 parts by weight. Moreover, the heating for reacting these needs to be in the temperature range of 60 to 300°C. If the heating temperature is lower than 60°C, the reaction will not occur, whereas if it is higher than 300°C, the reaction rate will be so fast that it will not be possible to react uniformly, so the heating temperature needs to be in the temperature range of 60 to 300°C. There is. Further, the temperature range must be at least equal to or higher than the softening point of the condensed polycyclic aromatic compound. By appropriately selecting the heating temperature and time, a thermosetting intermediate reaction product having thermoplasticity (so-called B-stage resin) can be obtained.

Next, the thermosetting molding will be explained.

The heating temperature for thermosetting and molding the thermosetting intermediate reaction product needs to be in the temperature range of 100 to 400°C. If the heating temperature is lower than 100°C, curing will not occur, whereas if it is higher than 400°C, methylene bonds will cleave, so the heating temperature needs to be in the temperature range of 100 to 400°C. The thermosetting intermediate reaction product is filled into a hot press mold, and by appropriately selecting the heating temperature and time under pre-pressure or non-pressure, thermosetting molding is performed to obtain a thermosetting resin composition molded article ( A so-called C-stage resin) can be obtained.

Next, the thermosetting resin composition molded body was heated to a temperature of 350 to 55
The action and effect of final pressurization within the temperature range of 0°C will be explained.

The temperature range is the temperature at which methylene bonds in the thermosetting resin composition are cleaved, and the present inventors have newly found that softening occurs, albeit slightly, within this temperature range.

Therefore, in the present invention, the methylene bond is cleaved by pressurizing at a pressure of 40 to 400 kg/cm2 in a non-oxidizing atmosphere within the above temperature range, and the fused polycyclic aromatic molecule containing radicals and ions is released. It is easy to undergo the initial process of carbonization, which involves the physical orientation of carbon atoms and the recombination of radicals and ions, which combines aromatization and the production of two-dimensional carbon precursor macromolecules similar to graphite crystal structures. I learned something new about scales.

Next, the firing will be explained.

Heating and baking is performed at 800 to 3000°C in a non-oxidizing atmosphere.
55 within the temperature range.
In the temperature range of 0 to 1500°C, carbonization progresses, and in the temperature range of 1500 to 3000°C, graphitization progresses. In the carbonization process, in the initial stage of carbonization, that is, within the temperature range of 350 to 550°C, the molecular orientation is more similar to the graphite crystal structure, so that it not only provides carbon that is easily graphitizable. ,
High density can be expected through pressurization.

In step a) of the method of the present invention, when mixing the fused polycyclic aromatic compound of (a), the aromatic crosslinking agent of (b), and the acid catalyst of (c) to form a mixture, natural graphite two artificial Graphite, coke mesocarbon microbeads, mesophase, carbon black.

A mixture of one or more selected from carbon fiber and charcoal is heated and reacted in an oxidizing or non-oxidizing atmosphere within a temperature range of 60 to 300°C to substantially It is also possible to obtain thermosetting intermediate reaction products with thermoplastic properties.

(Example) Next, the present invention will be explained with reference to examples.

Example 1 100 parts by weight of coal pitch with a softening point of 85°C, p-
A mixture was prepared by mixing 65 parts by weight of xylylene glycol, 9 parts by weight of p-toluenesulfonic acid was added to 100 parts by weight of this mixture, and the mixture was heated at 120° C. for 60 minutes to obtain a B-stage resin.

This B-stage resin was heated to 100 x at a mold temperature of 200°C.
After molding to a size of 100 x 5011, it was molded to 100 kg/cm at a temperature of 400°C in a non-oxidizing atmosphere.
This molded body was then heated at 20°C.
It was fired to 2800° C. at a temperature increase rate of /hr.

The electrical resistivity of the obtained fired body is 800 μΩcm in the direction perpendicular to the pressing axis when this fired body is really pressed.
On the other hand, in the direction parallel to the pressurizing axis, 4900μΩCl
It was 11. That is, it was found that the obtained fired body had extremely excellent two-dimensional orientation of graphite constituting it. The apparent specific gravity of this fired body is 1.85 g/cm
', and this fired body had extremely high density.

Example 2 65 parts by weight of p-xylene dichloride was mixed with 100 parts by weight of hydrogenated coal-based pitch having a softening point of 140°C to prepare a mixture.
10 parts by weight of t-toluenesulfonic acid was added and heated at 160°C for 30 minutes to obtain a B-stage resin. After thermosetting this B-stage resin at 200°C, it was hot pressed at a temperature of 450°C and a pressure of 250 kg/cm'' in a non-oxidizing atmosphere.Then, this molded body was heated at a rate of 10°C/hr. It was fired at a speed of up to 3000°C.

When the gas impermeability of the obtained fired body was investigated, it was found to be 10 cm/sec, cm Hg against helium gas in the direction parallel to the pressurizing axis during hot pressing of the molded body; 10-°C m”/sec in the direction perpendicular to the axis.

cmHg, and from this result it was found that gas impermeability was extremely excellent in the direction parallel to the pressurizing axis.

Example 3 70 parts by weight of coal-based pitch α-methylnaphthalene having a softening point of 220°C was added and mixed at 250°C in a non-oxidizing atmosphere to obtain a mixture having a softening point of 80°C. To 100 parts by weight of this mixture, 55 parts by weight of P-xylylene glycol was added and mixed, and to 100 parts by weight of the mixture, 9 parts by weight of p-+-luenesulfonic acid and 1 part of natural graphite pulverized to 44 μm or less were added.
00 parts by weight were added thereto and mixed and heated in a kneader at 120° C. for 40 minutes to obtain a B-stage resin. This B-stage resin was molded at a mold temperature of 250°C, and then hot pressed at a temperature of 450°C and a pressure of 250 Kg/cm 2 in a non-oxidizing atmosphere to obtain a molded body. This molded body is 1
It was heated and fired to 2800°C at a temperature increase rate of 0°C/hr.

When the bending strength and thermal conductivity of the obtained fired body were examined, the respective values in the direction perpendicular to the pressing axis during hot pressing were 1200 kg/cm" and 150 kcal/
m, hr, and °C, while the respective values in the direction parallel to the pressurizing axis are 300 kg/cm" and 40 kcal.
/m, hr, °C. That is, it was found that the obtained fired body had extremely excellent two-dimensional orientation of graphite constituting it.

(Effects of the Invention) As explained above, according to the present invention, by applying physical pressure to a thermosetting resin composition at a temperature at which methylene bonds are cleaved, molecules are oriented to form a structure more similar to a graphite crystal structure. Two-dimensional orientation can be obtained.

The carbon/graphite material obtained by the manufacturing method of the present invention has higher density and strength than conventional carbon/graphite materials, has high electrical conductivity and thermal conductivity, and is excellent in gas impermeability. It can be used advantageously as exchanger parts, chemical machine parts, etc. compared to conventional ones, and can be expected to make a significant contribution to industry.

Claims (5)

[Claims] 1. A method for producing easily graphitizable high-density carbon or graphite material using a thermosetting resin as a raw material, which consists of the following sequence of steps a) to d); (b) Aromatic crosslinking agent consisting of one or two or more aromatic rings having two or more of at least one of hydroxymethyl group and halomethyl group, (c) Acid catalyst, (a) and (b) above. ) and (c) in an oxidizing or non-oxidizing atmosphere within a temperature range of 60 to 300°C to obtain a thermosetting intermediate reaction product having substantially thermoplastic properties; b) a) step of thermosetting the intermediate reaction product obtained in step a) in an oxidizing or non-oxidizing atmosphere within a temperature range of 100 to 400°C to obtain a molded body; c) step b) a step of pressurizing the thermosetting composition molded article obtained in a non-oxidizing atmosphere within a temperature range of 350 to 550°C to physically orient the condensed polycyclic aromatic molecules; d) c) A step of heating and firing the molecularly oriented molded article obtained in the step within a temperature range of 800 to 3000° C. in a non-oxidizing atmosphere. 2. Patent claim No. 1, characterized in that the fused polycyclic aromatic compound described in step a) above is one or more selected from coal-based or petroleum-based heavy oil, tar, and pitch. The method described in Section 1. 3. The aromatic crosslinking agent described in step b) above is selected from p-xylylene glycol, p-xylylene dichloride, dimethyl-m-xylylene glycol, dimethyl-p-xylylene glycol, and derivatives thereof. 2. The method according to claim 1, characterized in that one or more of these are used. 4. The acid catalyst described in step c) of step a) is one or two selected from aluminum chloride, boron fluoride, phosphoric acid, organic sulfonic acids, carboxylic acids, and derivatives thereof.
The method according to claim 1, characterized in that the number of species is more than one species. 5. 2. The method according to claim 1, wherein the pressurization in step c) is a uniaxial hot press or an isostatic hot isostatic press.