JPS61194223A - Production of carbon fiber by gaseous phase method - Google Patents

Abstract

PURPOSE:To improve dispersibility and activity of metallic fine powder, and to improve productivity of carbon fiber, by producing metallic fine powder by arcing, and making it exist in a productin zone of carbon fiber. CONSTITUTION:Arcing is produced between the graphite 4 and the metallic (Fe, Co, Ni, etc.) wire 5, the fine powder 10 is produced, and dispersed into the reaction layer 1 at 800-1,500 deg.C. The reaction tank 1 is sufficiently long and retension time of the fine powder is long. A hydrocarbon gas is fed from the gas inlet 3, and formed fibers are collected by the collector 8. The collector 8 has a built-in filter, the fibers are separated from the gas, and the gas is exhausted by the pump 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing vapor-grown carbon fibers, and more particularly to a method for obtaining carbon M&M in good yield.

Conventional technology The conventional method for manufacturing vapor-grown carbon fiber involves the presence of fine powder (seed) such as iron on the surface of a ceramic substrate such as mullite, and the addition of hydrocarbon such as benzene diluted with hydrogen to
It was manufactured over a long period of time by slowly flowing in an atmosphere of 1300°C. Gas phase method? 7 award #am+711 #shankhatto1stg-hangingcandyrodsice-male-nine-carbon-melted-in, II
The mechanism is explained by the mechanism of supersaturation and precipitation of solid carbon. Through repeated experiments, we have certainly obtained results that follow this mechanism. However, as long as this mechanism is followed in the conventional method, only a low productivity is achieved because only the surface substrate portion of the furnace can be utilized.

The fibers obtained by the conventional method have a diameter of 10 to 20 #L and a length of 3 to 10 cm, and are clearly fibrous even by visual inspection, and can be made into well-oriented graphite fibers by heat treatment. However, in the case of vapor-grown carbon fibers, thinner fibers have better properties such as strength, making them more difficult to use than other PANs.

Since it is expected to have properties not found in pitch-based fibers, fibers that are much shorter and thinner than conventional ones may be used as long as productivity is improved.

In addition, in the conventional method, the dispersion of the metal fine powder was not sufficient and the activity of the fine particles was not high, which was one of the causes of poor productivity.

Problems to be Solved by the Invention The object of the present invention is to improve the dispersibility and activity of fine metal powder, which has been a problem in the past, and to improve the productivity of carbon fibers.

Means for Solving the Problems In the present invention, in order to improve the dispersibility of metal fine particles, metal fine particles are generated by arc discharge, and the metal particles are immediately made to coexist in the carbon fiber production zone to maintain a high level of activity.

In addition, in order to increase the yield of carbon fibers, it is necessary to use a wide space and maintain a high carbon concentration in the gas.In the present invention, the generated fine particles are suspended in the space and the carbon fibers are precipitated. is desirable.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing one example of the apparatus used in the present invention, in which 1 is a reaction layer whose interior is maintained at a predetermined temperature, for example 800 to 1500 DEG C., by a heating device 2. The metal fine particles are made of, for example, graphite 4 and a metal wire 5, both of which are stiffened 6, 7 to generate an arc to obtain fine powder 10, which is dispersed within the reaction layer 1. The metals selected are Fe, Go, Ni, etc., which are known in the production of vapor-grown carbon fibers. May be done at the top of the layer0
The reaction layer should be sufficiently long to increase the residence time of the fine particles. Hydrocarbon gas is introduced from the gas supply port 3. For this, Hz
are usually mixed together, and At can also be used in combination. The generated fibers are collected by a collector 8. 8 has a built-in filter such as a fine mesh to separate the fibers from the gas, and the gas is discharged from the pump 9.

As the hydrocarbon gas, benzene, methane, ethane, propane, etc., which are generally used in gas phase hydrocarbon production, are used.

Example I Fine particles of Fe were generated using an apparatus shown in FIG. 1 using a Fe wire (diameter 0.3 sus). The wire feed rate was 1 cta/min, and the arc was generated in pulses for 1 to 2 seconds at approximately 5 second intervals. The reaction vessel has an inner diameter of 1OC11,
A ceramic pipe with a length of 100 cm was used. Gas is C3H, 11/min, Ar 100cc/min, )111
The inside of the reaction vessel was maintained at 800 to 1000°C by feeding from the supply port 3 in FIG. 1 at a rate of 17 minutes. As a result, a fibrous material having a diameter of 0.1 to 0.3 grs and a length of 50 to 1100 IL was obtained at a rate of 1.1 g/min.

Example 2 The same procedure was carried out except that the c5 H9 was changed to 2 sentences/min in the above example.
2.0 g/min was obtained.

On both sides, few of the fibers were straight, and many were curved or branched.

Effects According to the present invention, the fibers are thin and short, but the amount is considerably larger than in the conventional method of depositing on a substrate, for example.
For example, RA is dispersed in epoxy resin and injection molded,
It is a highly elastic body and can be used for sporting goods, etc.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one example of an apparatus used to carry out the method of the present invention. 10...Fine powder.

Claims (1)

[Claims] A method for producing vapor-grown carbon fiber by thermal decomposition of hydrocarbons, which is characterized in that metal fine powder is generated by metal arc discharge, and the fine powder is present in a carbon fiber production zone. Manufacturing method.