JPS61191508A - Production of carbonaceous material - Google Patents

Abstract

PURPOSE:To produce a carbonaneous material having a uniform structure while easily regulating the bulk density by molding a kneaded material consisting of a skeleton material and a binder, putting the molded body in a baking vessel at a specified space factor, and baking it. CONSTITUTION:A skeleton material is kneaded with a binder and molded. The molded body is put in a baking vessel at 1-50vol% space factor and baked. The baking vessel is made of ceramics such as SiC, Si3N4 or Al2O3, steel or the like.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing carbon materials.

(Prior art) Carbon materials are used for mechanical applications such as mechanical seals,
It has a wide range of uses, including electrical applications such as electrical brushes, and is made by extruding and molding a kneaded product made by kneading aggregates such as graphite powder, coke powder, and oil smoke with binders such as tar pinch and coal tar. Shape by molding etc., fire the molded body,
Manufactured by graphitization treatment if necessary.

Naturally, the various properties required of carbon materials differ depending on the use. For example, brushes for electrical machinery maintain sliding contact performance with commutators etc. by reducing the elastic modulus, but in order to do this, the bulk density, which has a correlation with the elastic modulus, must be reduced, and also for mechanical applications such as seals and bearings. The materials used for this purpose are generally made to have a high density to improve wear resistance and sealing properties. Conventionally, the bulk density of carbon materials has been adjusted by changing the molding pressure. This is because the bulk density of carbon material varies depending on the type of aggregate, the particle size of aggregate, the composition of aggregate and binder, etc., but it usually increases proportionally up to a molding pressure of about 1 ton/cm2. be.

(Problems to be Solved by the Invention) However, if the molding pressure is less than 1 ton/cm2, the structure of the carbon material obtained tends to be uneven, and the molding pressure is lower than 1 ton/cm2.
If the carbon material is increased to more than t/cm", the structure of the carbon material becomes uniform, but the rate of increase in bulk density becomes small, and the problem is that it becomes difficult to adjust the bulk density due to the influence of firing conditions such as firing temperature and heating rate. There is.

The inventor noticed that the bulk density changes depending on the volume occupied by the molded body filled into the firing container during firing, and after further study, the present invention was completed.

(Means for Solving the Problems) The present invention provides a method for producing a carbon material in which a molded body formed after kneading aggregate and a binder is fired, in which the volume occupancy of the molded body in a firing container is 1 to 1. The present invention relates to a method for manufacturing a carbon material, in which a firing container is filled with molded bodies to a size of 50 cm and fired.

In the present invention, the material of the firing container is ceramic.

There are no particular limitations as long as the material does not change or deform in the firing atmosphere, such as steel. SiC, 5isN4゜Aez
Ceramics such as Os are preferred because they are stable even at 1300° C. and have strong mechanical strength. There are no particular restrictions on the shape or dimensions of the firing container, but a rectangular one is usually used. There are no particular restrictions on the shape and dimensions of the molded body.

If the volume occupied by the molded body in the firing container is less than 1 inch, it is not economical, and volatile matter dissipates quickly and the structure may become non-uniform; if it exceeds 50%, blisters and cracks occur, which is undesirable. Known aggregates and binders are used, and kneading, molding, firing, and optionally graphitization are carried out by known methods without any particular limitations.

(Example) Next, an example will be described.

Example 1 10 parts by weight of homemade oil smoke and pitch coke (manufactured by Nippon Steel Chemical Co., Ltd.)
56 parts by weight of tar pitch (Yotetsu Kagaku, grade PK-L) was added to a mixed powder of 90 parts by weight of powder obtained by pulverizing LPC-A) to 100 μm or less, and the mixture was placed in a kneader and heated at 170°C. Average particle size after kneading for hours and cooling: 150μ
The molded powder is crushed into 1.m powder using a hydraulic press.
Thickness 30-9 width 55an due to molding pressure of 2 tons/Country 2,
A molded body having a length of 110 mm and a volume of 182 cm3 was prepared.

Next, the molded body is made of Si3N+ and has a height of 230 mm.
mm, width 220mm, length 270mm, internal volume 137mm
The number of sheets shown in Table 1 was placed in a 00cm" baking container, the space was filled with coke powder as a filler, the lid made of Si3N4 was covered, and the pieces were placed in an electric furnace and baked at 1100°C for 5 hours.

After cooling, the fired carbon material was taken out from the firing container and placed in a graphitization furnace, where it was graphitized at 2800°C.

Table 1 shows the bulk density of the obtained carbon material and the occupancy rate of the molded body in the firing container during firing.

Table 1 It can be seen from Table 1 that the bulk density can be adjusted by changing the volume occupancy of the molded body.

Furthermore, the structure of the obtained carbon material was also uniform.

Example 2 Using the same molding powder as in Example 1 and using the same molding pressure as in Example 1, a molded body with a thickness of 15 mm, 9 width, 60 cm, and a volume of 13.5 cm was obtained, and 345 pieces of this molded body were processed. Place in the same firing container as in Example 1 (volume occupancy 3t%).

Ivy. The structure of the carbon material was also uniform.

(Effects of the Invention) According to the present invention, the bulk density of the carbon material can be adjusted in the firing process without changing the molding pressure, and a carbon material with a uniform structure can be obtained.

Claims (1)

[Claims] 1. In a carbon material manufacturing method in which a molded body is fired after kneading aggregate and a binder, the molded body is placed in a firing vessel such that the volume occupancy of the molded body in the firing vessel is 1 to 50%. A method for producing a carbon material, characterized by filling and firing the carbon material.