JPH0388706A - Production of carbon material - Google Patents

Abstract

PURPOSE:To obtain the carbon material having a high fracture toughness value by mixing org. fibers into a carbon raw material, crushing forming and calcining the mixture. CONSTITUTION:Org. short fibers are added to the carbon raw material, and the mixture is kneaded, crushed, formed and calcined or further graphitized, as required, to obtain the desired carbon material. The carbon raw material contains a two-component material consisting of a carbon aggregate such as pitch coke powder and a binder such as tar pitch, mesocarbon microbeads, crude coke, etc., and the carbon material is obtained by mixing, forming and calcining the raw material. Viscose rayon and pulp fibers are preferably used as the org. fiber since they are available at a low cost and the diameters and lengths of the fibers are uniform. The diameter of the single fiber is preferably controlled to <=20mu, and the length to <= several mm. The amt. of the org. fiber to be added is preferable adjusted to 10-30wt.% based on the main aggregate in the carbon raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing carbon materials used for structural members.

(Conventional technology) As a carbon material that requires high fracture toughness.

There is a C/C composite using carbon fiber. C/C composite is made by impregnating a carbon fiber base material such as filament winding, woven fabric, or non-woven fabric with organic matter and carbonizing it.
It is made by depositing pyrolytic carbon using the CVD method.

On the other hand, short carbon fibers are blended into a two-component carbon material raw material consisting of a carbon aggregate such as pitch coke powder and a binder such as tar pitch, and the carbon material is mixed, formed, fired, or further graphitized. There is also.

(Problems to be Solved by the Invention) C/C composites using long carbon fibers have extremely high toughness in the fiber direction, but have low toughness in the direction perpendicular to the fiber direction, and have large anisotropy. Eight. For this reason, it has problems as a structural member, and also has the drawback of being long and expensive.

On the other hand, in the method of blending short carbon fibers into a two-component carbon material raw material, cross-firing, forming, and firing, the anisotropy can be improved if a rubber press molding method is adopted, but the carbon fibers immediately after forming The bulk density decreases due to springback, and the toughness is not improved by carbon fiber.

An object of the present invention is to provide a method for producing a carbon material having a high fracture aL of 75=91 toughness required as a structural member.

(Means for solving 11 problems) In the present invention, short organic fibers are added to the carbon raw material.

This invention relates to a method for producing a carbon material by mixing, pulverizing, molding and firing, and graphitizing if necessary.

In the present invention, the carbon raw material includes not only the above-mentioned two-component carbon material raw material consisting of a carbon aggregate such as pitch coke powder and a binder such as tar pitch, but also carbon microbeads, raw coke, and the like.

A carbon material that can be obtained by mixing, molding, and firing. Organic fibers are not particularly limited, such as PAN, viscose rayon, pulp fiber, pitch fiber, etc., but viscose rayon, viscose rayon, Pulp fibers are preferred. The diameter of the single fibers is preferably 20 μm or less, and the length of the fibers is preferably not more than 20 μm.

In addition, the amount of organic fiber added is 1% to the main aggregate in the carbon raw material.
It is preferable to set it as 0-30 weight excess.

Mixing, crushing, molding, firing and graphitization are carried out by known methods. It is best to use a rubber press for molding! Yes.

(Function) Organic fibers are soft like carbon fibers and have little springback immediately after molding.

(Example) Next, the present invention will be explained in detail.

Example 1 Valve fiber (manufactured by Sanyo Kokusaku Valve, KC flock.

(100 mesh or less) 10 parts by weight 7 Petroleum pitch P-cus powder (average particle size 20 μm) 90 parts by weight and tar pitch (Kawasaki Steel, softening point 130°C) 70 parts by weight were kneaded.
put in. The mixture was kneaded at 200°C.

The mixed wire was crushed to 100 mts or less to make a molding powder, put into a rubber mold, molded with a rubber press at a pressure of 1,000°C, and then fired at 1000°C in a nitrogen gas atmosphere in a box.Then, it was fired in an electric resistance furnace. and graphitized it at 2800℃.
010X10X20 (obtained a block.

Example 2 The pulp fibers applied in Example 1 were pulp flock W-1 (
A block of the same size was obtained in the same manner as in Example 1, except that the block was manufactured by Sanyo Kokusaku Pulp and had a mesh size of 100 or less.

Example 3 Instead of the pulp fiber in Example 1, viscose rayon (] [, 16 made of rayon, Raycot Y, 12 μmφ
A block of the same size was obtained in the same manner as in Example 1, except that 50 mm x 50 mm was used.

Comparative Example 1 A block having the same dimensions as in Example 1 was obtained in the same manner as in Example 1, except that chopped carbon fiber (manufactured by Osaka Gas, Dona Carbon) was used instead of the valve fiber in Example 1.

Comparative Example 2 100 parts by weight of petroleum pitch coke powder with an average particle size of 20 μm and 70 parts by weight of tar pitch (manufactured by Kawasaki Steel, softening point 130°C). Place part i into a kneader.

The mixture was kneaded at 200°C. The kneaded material was pulverized to 100 mesh particles or less, and then molded, fired, and graphitized in the same manner as in Example 1 to obtain a block with the same dimensions as in Example 1.

Test pieces were made from the blocks obtained in the above Examples and Comparative Examples, and their physical properties were measured. The results are shown in Table 1. In the table, the fracture toughness values were measured using 5END specimens.

Table 1 shows that the organic fiber-containing graphite blocks of the examples have clearly superior bending strength and fracture toughness values than the comparative examples containing carbon fiber or coke powder alone.

(Effects of the Invention) According to the present invention, a carbon material that does not cause springback during molding and has a high fracture toughness value can be obtained.

Claims (1)

[Claims] 1. Add short organic fibers to the carbon raw material, knead, crush,
A method for producing a carbon material, which is characterized by forming and firing, and graphitizing if necessary.