JPS5832684A - Production of carbon material from pitch - Google Patents

Abstract

PURPOSE:A pitch for carbon material is formed and the resultant formed products ar heated under reduced pressure to effect preoxidation treatment then the carbonization treatment is conducted, thus keeping the original form, increasing the strength of the carbonized material, permitting the shortened preoxidation treatment and increasing productivity. CONSTITUTION:A pitch for carbon material is formed and the products are heated under high vacuum of less than 10Torr at the heating rate of several tens degrees/min. up to 500 deg.C to effect the preoxidation treatment. Then, they are subjected to carbonization and graphitization to produce objective pitch carbon materials such as carbon fiber or carbon films. EFFECT:No harmful gases are used to make the facilities for disposing the exhaust gas unnecessary an to simplify the preoxidation unit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing carbon materials (e.g., carbon fibers, carbon films, etc.) using five carbon-based and petroleum-based pitches, and a method for simplifying the process of immobilization of pitch molded bodies. The purpose is to improve the quality of flower products. ′ −□ Carbon materials such as carbon fibers and carbon films are produced by melting and molding the raw material coal-petroleum pi V′≠, and then carbonizing it.
It is manufactured by graphitizing it, but in this case, since the raw material pitch has thermoplasticity, it is necessary to perform a videte treatment before carbonizing or graphitizing.

As a method for making the pitch infusible, in many cases a method is used in which the pitch molded body is oxidized at a temperature that does not cause melting and deformation. That is, at a temperature around the softening point of the pitch, nitrogen oxides such as 'N*O=, NOs, No, SO,
Oxidize with a highly reactive oxidizing gas such as , halogen, Os, or a heated gas of a non-reducing gas such as fins, seeds, (Q*, At, air, etc.) as an acid agent. There are two ways to prevent melting, however, by this oxidation,
The scissors should be used in the following manner: Since the oxidation reaction is accompanied by heat generation, the molded body may be deformed due to the temperature rise due to local heat accumulation. There is a princess who needs attention. - Oxidation is a chemical reaction, and even if the oxidizing agent is a highly reactive oxidizing gas, the time required for infusibility is determined by the rate of the chemical reaction, and usually takes several hours.

■ Highly reactive oxidizing gases are highly corrosive and harmful to the human body, so special care must be taken when handling them and selecting equipment materials. It is necessary to implement some kind of body removal equipment.

In order to solve the problems of the conventional infusibility treatment due to oxidation reactions, the inventors investigated an infusibility method that does not rely on oxidation, and found that by heating the pitch molded body under reduced pressure under high vacuum, it became infusible. He discovered that this was possible and completed the invention.

The gist of this invention is to heat a molded body obtained by molding a pitch for carbon material to 500°C under a high vacuum with a degree of vacuum of 167 orr or less at a temperature increase rate of several 1017 minutes or less to make it infusible, and then carbonize it. At the point of being treated or graphitized.

In other words, this invention heats the beech molded body under high vacuum to evaporate and remove light components at a temperature below the softening point of the molded body to raise the softening point, thereby always keeping the softening point of the molded body below the heating temperature. This method is characterized in that the pitch is maintained at a high temperature, and the pitch ultimately undergoes a polycondensation reaction and is rendered infusible while maintaining its original shape. In addition, the softening point here means the softening point measured with a Koka type flow tester.

Normally, the pitch molded body begins to deform during the heating process at a temperature around the softening point of the molded body.

Although it is necessary to start at a temperature below the softening point of the molded body, the reason why the degree of vacuum during the heating process is limited to 10 TOrr or less in the method of this invention is as follows.

In other words, the degree of vacuum necessary to keep the softening point of the molded body higher than the heating temperature during the heating process varies depending on the properties of the raw pitch, but according to the results of studies on various coal-based pitches, It was confirmed that at a vacuum level exceeding 1Q70rr, it is difficult to make the pitch molded product infusible while retaining its original shape.

On the other hand, in order for the softening point of the molded product to rise, the rate of diffusion of light components in the molded product becomes rate-determining, and the softening point rises with respect to the heating temperature. It was found that there is a temperature increase rate of several 100 degrees Celsius per minute or more, where the rate of heating is determined by the softening diffusion rate of the mold, and that the above phenomenon is trivial at heating rates of several tens of degrees Celsius or less. . In addition, the temperature at which -pitch polycondenses and becomes sufficiently infusible is approximately 400 to 500°C, but the results of studies on various pitches show that all pitches can be sufficiently infusible after being heated to 500°C. There was found. Therefore,
In this invention, t'r? The fi type body has a vacuum level of 10 TOrr.
They adopted the following method of infusibility treatment by heating to 500° C. under high vacuum at a temperature increase rate of several 10° C. or less.

The infusible pitch molded body thus obtained is
The pitch molded body is immediately carbonized or lead-blended and manufactured into a product, but since the pitch molded body no longer undergoes softening and deformation, it is processed while retaining its original shape, resulting in poor quality. It will be excellent.

As described above, according to the method of the present invention, the softening point rises due to the evaporation of the light components in the pitch molded body to make it infusible, so the anti-dyeing is endothermic, the original shape is maintained, and the strength of the carbon material is increased. etc. The quality can be improved. Furthermore, several tens of degrees
Rise below C/min! Because it can be made infusible quickly, the time required for making it infusible is only a few minutes to several tens of minutes, which increases the productivity of carbon materials. There is no need for mountain pass exhaust gas treatment equipment that does not use harmful gases, and the infusibility treatment equipment can be simplified. , Next, an embodiment of the invention of B will be described.

[Example 1] After removal, vacuum distillation of 5 WHg was performed at a temperature of 280°C to obtain pitch for carbon fiber with a softening point of 150°C.

This pitch was melt-spun using a fixed nozzle roux spinning machine to obtain carbon fibers with an average diameter of 15 μm.

Next, this carbon fiber was subjected to infusibility treatment from room temperature to 500°C under the conditions shown in Table 1, and then heated at a heating rate of 2 in an Ar atmosphere.
The shape of the product obtained by firing at 0°C/min up to 800°C,
The strength is shown in Table 2.

As is clear from the results in Table 2, deformation occurred in the carbon fibers in Tests 1 and 4, which did not meet the infusibility treatment conditions of the present invention, whereas in Tests A2 and 3, which were based on the method of the present invention, the carbon fibers were deformed. The original shape was maintained and the strength of the product also showed good values.

Table 91 Infusibility treatment conditions Table 2 Results [Example 2] Petroleum pitch and coal corrugated pitch having the properties shown in Table 3 were melt-spun to obtain carbon fibers with an average diameter of 15 μm. This carbon fiber was subjected to infusibility treatment from room temperature to 500°C in an Ar atmosphere with a vacuum degree of 10 Torr at a heating rate of 20°C/min.
The shape and strength of the obtained carbon fibers are
Shown in the table.

As is clear from the results in Table 4, similar good results were obtained with petroleum pitch and coal liquefied pitch as with the coal tar pitch of Example 1.

Table 3 Pitch properties Table 4 Results [Example 3] Asphalt pitch having the properties shown in Table 5 was
After crushing 0 mesh insects, add 8% moisture and make this into a mold with an inner diameter of 4.
Fill the 0- cylinder and use the piston to 4 o o
A molding pressure of ke/d was applied to obtain a disc-shaped molded body of 40φ×10fi (height). This molded body is N-3111!
1 atmosphere, heating rate of 5°C/min, vacuum degree of 760 Torr
and 57 orr, respectively, to perform infusibility treatment by firing at room temperature to SOO°C at home.

As a result, when the vacuum degree was 71,107 Orr, the molded product was deformed and no longer maintained its original shape, whereas when the vacuum degree of this invention method was 570 rr, it did not deform and maintained its original shape.

Next, the molded body that retained its original shape was heated to 100% under NI air pressure.
As a result of firing to 0°C, a fired product that retained its original shape was obtained.

[Example 4] The petroleum pitch used in Example 3 was melted and spread on a 59al×5Q quartz glass plate to form a film-like molded product with an average thickness of 25 μm. This □ molded body was heated under an At atmosphere with a degree of vacuum of 10 TOrr from room temperature to 500'C1 at a heating rate of 10°C.
After being heated in a hot pot to make it infusible, it was heated to xooo'c at a heating rate of 16°C/min in an Ar atmosphere. As a result, a film-like carbonaceous molded body was obtained. On the other hand, a similar film-formed product was heated at a heating rate of 10°C/min under normal pressure.
When fired to 00℃, a large amount of foaming occurs on the surface,
No film-like substance was obtained.

As described above, the method of this invention aims to simplify the infusibility treatment of pitch molded bodies and improve quality, and its effects are significant.

Applicant Sumitomo Metal Industries Co., Ltd. 1.3゛Value Agent Press 1) Yoshihisa, (Voluntary procedure? City book September 131, 1982) Commissioner of Patents 1, Indication of the case 1982 Patent application No. 130898 ° No. 2, Name of the invention Method for manufacturing pitch-based carbon material 3, Relationship with the amended person's case "Detailed explanation of the invention J, Column 1 of applicant representative Norifumi Kumagai's specification, No. 2 of the specification of the present application Page lines 10-11 [...horse,
COl, Arm air, etc...'' is changed to ``...N8, CO
8, Ar etc...'' is corrected.・2 The same specification, page 5, line 1 to line s4 ``On the other hand, molded bodies...
...Cannot be made infusible. "On the other hand, the rate of increase in the softening point of a molded body is determined by the diffusion rate of light components in the molded body, and if the temperature increase rate is too high, the diffusion rate of light components per unit temperature will become smaller and the heating temperature will increase. "In contrast, the increase in softening point cannot keep up with the increase in temperature, and the molded product becomes soft and deformed, making it impossible to make it infusible."
In the row, ``The rate of temperature increase at which the diffusion rate is rate-determining is'' is changed to ``The rate of temperature increase at which it becomes difficult to achieve infusibility is'' and ±1, respectively. to correct. , 1 In Table 3 on page 8 of the specification, petroleum and pitch - Hebutane insoluble content (11) r40.5J is corrected to rllOJ, and Izene insoluble content (-) r46J is corrected to r3 & 2J. . .

ζ "Example 3" on page 1O, line 9 of the same specification is amended to "Example 2".

Claims (1)

[Claims] The molded body obtained by molding the pitch for carbon material is infusible-restored,
In a method for producing a pitch-based carbon material by carbonizing or graphitizing the after-squeezing molded body, the pitch molding is carried out under a high vacuum with a degree of vacuum IQ of 70 rr or less and at a heating rate of 10° C./min or less. A method for producing a pitch-based carbon material characterized by heating it to SOO° C. and making it infusible.