JPH04154662A - Production of carbon fiber reinforced carbon composition material - Google Patents

Abstract

PURPOSE:To improve accuracy of outer form during burning by adsorbing a carrier capable of ionizing in a liquid on carbonaceous fine powder to give an adsorbed material and coating a carbon fiber substrate with the adsorbed material in a dispersion of the adsorbed material by electrodeposition. CONSTITUTION:A carrier capable of ionizing in a liquid is adsorbed on carbonaceous fine powder, dispersed into a liquid, and to the liquid, DC voltage is impressed between a carbon fiber substrate and an opposing electrode. The carbonaceous powder and the carrier are precipitated on the carbon fiber substrate to give a coated material, which is impregnated with a resin, heated, molded, heat-treated and carbonized and burnt. A ribbonlike material prepared by bundling short fibers of carbon, woven fabric, paper and nonwoven fabric can be used as the carbon fiber substrate. A carrier which is obtained by modifying a polyacrylonitrile resin-based derivative or a thermosetting resin derivative and making the derivative into a resin to be subjected to electrodeposition is preferable as the carrier. A thermosetting resin is preferable as the resin to be impregnated.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for producing carbon fiber reinforced carbon composite materials.

``Prior art'' It has been known that carbon fiber reinforced carbon composite materials (hereinafter referred to as CFRC) have characteristics such as high temperature strength and chemical stability (excluding oxidation), and their production is based on carbon fibers. Carbon is attached to carbon fibers of base materials such as woven fabrics, strings, papers, mats, and nonwoven fabrics made of fibers by CVD or liquid phase impregnation, and then heated and fired.

The CVD method is a method in which hydrocarbon gas is brought into contact with the surface of a high-temperature carbon fiber base material under reduced pressure to decompose it, and carbon atoms are deposited on the fiber base material.The liquid phase impregnation method is a method in which a liquid resin is applied to the carbon fiber base material. Alternatively, there is a method in which a matrix material such as molten pitch is impregnated and then carbonized and fired. In the case of the liquid phase impregnation method (in this case, the volatile components of the matrix material escape during firing, creating fine pores, so it is necessary to repeat the impregnation firing to increase the material strength).

In any case, both the CVD method and the liquid phase impregnation method require complicated and long-term processes, which makes CFRC expensive despite its advantages, and limits the field of practical application.

Recently, in the case of ordinary carbon materials that are not reinforced with fibers, it has become possible to easily manufacture carbon materials by directly carbonizing and firing carbonaceous powder without using a liquid matrix material. Since this method uses a matrix material that has already undergone heat treatment, it is possible to obtain a high-density carbon material with less volatile content in the matrix and in a short firing time.

Therefore, by mixing such carbonaceous fine powder into a carbon fiber base material and firing it, it is possible to create Dadachi (a simple CFRC).
Although everyone hopes that the material can be manufactured, in reality it is extremely difficult to uniformly mix carbonaceous powder into a carbon fiber base material, and in the end it is not possible to manufacture CFRC with good properties.

In response to this situation, the present applicant has previously applied
No. 4974 and Japanese Patent Application Laid-Open No. 61-21973. In the former method, instead of the conventional CVD method, an ionizable organic carrier is attached to carbonaceous powder and dispersed in a liquid, and a DC voltage is applied between the carbon fiber base material immersed in the liquid and a counter electrode. electrophoretic deposition (
In this method, carbonaceous fine powder is deposited on a carbon fiber base material by an electrodeposition method, the obtained carbon fiber base material-carbon powder mixture is heated to decompose or volatilize the carrier, and then fired. The latter method is characterized in that a thermosetting resin is used as a carrier in the above method.

In order to manufacture CFRC in these inventions, a carbon fiber base material-carbon powder mixture manufactured by an electrophoretic deposition method is dried, laminated, and molded by filament winding, etc., while being heated at a low temperature (ripening form). Thereafter, heat treatment is performed to harden, decompose, and volatilize the carrier by further heating, and further pressurization and high-temperature heating firing (heating firing) are performed to obtain a CFRC molded body.

``Problems to be Solved by the Invention'' However, the carbon fiber base material-carbon powder mixture produced by the above method has carbon powder and resin uniformly dispersed on the carbon fiber base material, and naturally As such, a mixture of carbon powder and resin exists between the layers of carbon fibers. Although heat treatment is performed after thermoforming to harden or make the resin infusible, the carbon powder is heat treated under conditions that do not make it very infusible (this may cause misalignment between the carbon fiber layers during pressure firing). There are challenges.

"Means for Solving the Problems" This invention provides a method for manufacturing a carbon fiber reinforced carbon composite material (
In this process, a carrier that can be ionized in a liquid is adsorbed onto fine carbonaceous powder, and then dispersed in the liquid. In this method, a coating is obtained by depositing a fine powder and a carrier on a base material, which is impregnated with a resin, and then subjected to thermoforming, heat treatment, and carbonization firing to obtain a carbon fiber-reinforced carbon composite material.

In this case, as the carbon fiber base material, a string-like material made by bundling short carbon fibers, woven fabric, paper, non-woven fabric, etc. can be used. As the carrier, it is preferable to use an acrylonitrile resin derivative or another thermosetting resin derivative modified to form a resin that can be electrodeposited.

The resin to be impregnated is preferably a thermosetting resin, such as melamine resin, epoxy resin, furan resin, phenol resin, polyimide resin, polyamideimide resin, bismaleimide resin, etc., and a mixture of these resins is used. You can also do that.

"Function" According to the present invention, a resin-rich layer exists between the layers of carbon fibers, and the above-mentioned heat treatment can strengthen the bond between the eyebrows and prevent misalignment between the layers during subsequent pressure firing. It can be prevented.

The present invention will be explained below with reference to Examples.

Examples Example 1 (1) Self-sintering carbon powder was thoroughly kneaded with a polyacrylonitrile electrodepositing resin and a solvent, and then dispersed in water to form a so-called anionic paint dispersion state. In this state, the ratio of carbonaceous powder to resin was set to 3:2 by weight.

(2) Prepare a PAN-based carbon fiber woven fabric, use it as an anode, use a stainless steel plate as a counter electrode, and apply a voltage of about 50 V while stirring the solution well to determine the weight of the carbon fiber base material and coating. Electrodeposition was performed at a ratio of 10:12.

(3) The obtained electrodeposited body was impregnated with a phenol resin so that the weight ratio of the electrodeposited body and the resin was 10:2.

(4) Laminate 200 sheets of this electrodeposited body at a temperature of 150°C.
Thermoforming was carried out by heating and pressing at a single surface pressure cuff of 5 kg/cA for 50 minutes.

(5) Heat treatment was performed at 200°C for 9 hours while maintaining the thickness of the molded body.

(6) After this, the temperature was raised to 1000°C at a heating rate of 30'C/hr under a surface pressure of 600kq/d in an inert atmosphere, and then further raised to 2000°C at a rate of 100°C/hr. A carbon fiber-reinforced carbon composite material was obtained by carbonization and firing.

The obtained carbon fiber-reinforced carbon composite material exhibited good properties, with no misalignment between the carbon fiber base material layers.

Example 2 (1) Self-sintering carbon powder was thoroughly kneaded with a polyacrylonitrile electrodepositing resin and a solvent, and then dispersed in water to form a so-called anionic paint dispersion state. In this state, the weight ratio of carbonaceous powder to resin was set to 3=2.

(2) Prepare a PAN-based carbon fiber woven fabric, use it as an anode, use a stainless steel plate as a counter electrode, and apply a voltage of about 50μ while stirring the solution thoroughly to separate the carbon fiber base material and coating. Electrodeposition was performed so that the weight ratio was 10:12.

(3) The obtained electrodeposited body was impregnated with melamine resin so that the weight ratio of the electrodeposited body and the resin was 10:3.

(4) Laminate 200 sheets of this electrodeposited body at a temperature of 140°C.
1 surface pressure cuff 5kq/c! Thermoforming was carried out by heating and pressing for 50 minutes.

(5) Heat treatment was performed at 180°C for 12 hours while maintaining the thickness of the molded body.

(6) After this, the temperature was raised to 1000°C at a heating rate of 30°C/hr under a surface pressure of 600 kg/cA in an inert atmosphere, and then further raised to 2000°C at a rate of 100°C/hr. Then, carbonization and firing are performed to obtain a carbon fiber reinforced carbon composite material.

The obtained carbon fiber reinforced carbon covering material was also the same as in Example 1 (
There was no misalignment between the carbon fiber base material layers.

Example 3 The following experiment was conducted for comparison.

(1) Self-sintering carbon powder was thoroughly kneaded with a polyacrylonitrile electrodeposition resin and a solvent, and then dispersed in water to form a so-called anionic paint dispersion state. In this state, the ratio of carbonaceous powder to resin was set to 1:1 by weight.

(2) Prepare a PAN-based carbon fiber woven fabric, use it as an anode, use a stainless steel plate as a counter electrode, and apply a voltage of about 50 V while stirring the solution well to determine the weight of the carbon fiber base material and coating. Electrodeposition was performed at a ratio of 10:12.

(3) Laminate 200 sheets of this electrodeposited body at a temperature of 250°C.
The cuff 5 was heated and pressed at 9/Cd for 50 minutes to thermoform.

(4) Heat treatment was performed at 350°C for 9 hours while maintaining the thickness of the molded body.

(5) After this, the temperature was raised to 1000°C at a heating rate of 30°C/hr under a surface pressure of 600 kg/cl in an inert atmosphere, and then further raised to 2000°C at a rate of 100°C/hr. The mixture was heated and carbonized to obtain a carbon fiber-reinforced carbon composite material.

The obtained carbon fiber-reinforced carbon composite material had a deviation of about 5% in outer shape.

"Effects of the Invention" As explained in detail above, the method of the present invention (accordingly,
This method is effective because a carbon fiber-reinforced carbon composite material with high external shape accuracy during firing can be obtained by simply impregnating an electrodeposited base material with a resin.

Agent Patent attorney 1) Rio Naka

Claims (5)

[Claims] 1. After a carrier that can be ionized in a liquid is adsorbed onto a fine carbonaceous powder, the carrier is dispersed in a liquid, and a DC voltage is applied between a carbon fiber base material and a counter electrode in the liquid to form a carbonaceous powder and a carrier that can be ionized in a liquid. depositing a carrier on a carbon fiber substrate to obtain a coating;
A method for producing a carbon fiber-reinforced carbon composite material, which comprises impregnating the material with a resin, followed by heat molding, heat treatment, and carbonization firing. 2. String-like carbon fiber base material bundled with short carbon fibers,
The method for producing a carbon fiber-reinforced carbon composite material according to claim 1, wherein the carbon fiber-reinforced carbon composite material is made of any one of woven fabric, paper, and non-woven fabric. 3. 2. The method for producing a carbon fiber-reinforced carbon composite material according to claim 1, wherein the carrier is a resin that can be electrodeposited by modifying a polyacrylonitrile resin derivative or a thermosetting resin derivative. 4. 2. The method for producing a carbon fiber reinforced carbon composite material according to claim 1, wherein the resin to be impregnated is a thermosetting resin. 5. 2. The carbon fiber reinforced carbon composite material according to claim 1, wherein the resin to be impregnated contains at least one of melamine resin, epoxy resin, furan resin, phenol resin, polyimide resin, polyamideimide resin, and bismaleimide resin. Production method.