JPH02307816A - Production of carbon vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a carbon container, particularly a high-strength carbon material useful in applications that require heat resistance and corrosion resistance, such as reaction crucibles and heat treatment containers. The present invention relates to a method for manufacturing a container.

[Conventional technology]

Because carbon materials (including graphite) inherently have excellent heat resistance and corrosion resistance, they are widely used in containers for heat treatment of metals and ceramics, crucibles for melting metals, containers for storing various molten salts, etc.

These containers are generally manufactured by cutting a molded block of carbon material, or by molding and hardening a thermosetting resin into a container shape and then carbonizing it.

However, carbon containers processed from molded blocks require a certain thickness or more for strength reasons, resulting in high weight and disadvantages in that there is a lot of material loss due to cutting.

On the other hand, if a carbon container is obtained by molding and carbonizing a thermosetting resin, a gas-impermeable container made of glassy carbon can be obtained; There are some difficult issues.

In order to solve these problems, a carbon container manufacturing method (Japanese Patent Publication No. 53-433) was developed in which cellulose sheets impregnated with a thermosetting resin are laminated into a container shape and then carbonized.
No. 43) has been proposed.

[Problem to be solved by the invention]

According to the method described in the above publication, it is expected that large and lightweight carbon containers can be manufactured, but cellulose laminated sheets undergo large carbonization shrinkage during firing, making it difficult to control the thickness and dimensions of the container. Cellulose fibers have the disadvantage that their strength decreases due to carbonization.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a method for manufacturing a thin, lightweight carbon container with high strength.

[Means to solve the problem]

In order to achieve the above object, the method for manufacturing a carbon container according to the present invention includes prepregs formed by impregnating or coating carbon fibers with a thermosetting resin, which are laminated in a mold to form a container shape, and after curing. The structural feature is that firing is performed in a non-oxidizing atmosphere.

As the carbon fiber, plain weave, satin weave, etc. made of polyacrylonitrile, pitch, rayon, etc. are used, but thin ones with dense fibers are desirable due to their properties, and the use of the manufactured containers Depending on the temperature, select a high-strength type or a high-modulus type.

As the thermosetting resin, it is preferable to use a phenol resin or furan resin with a residual carbon content of 45% or more, and it is difficult to provide sufficient strength with a resin with a low carbonization yield and a residual carbon content below the above value. becomes.

These resins are diluted with a volatile solvent such as acetone or ethanol to have a viscosity of 50 cp or less at 20° C., preferably 10 to 20 cp, and are impregnated or applied onto the carbon fiber cloth in the form of a solution. The reason for using such a low viscosity resin solution is to smoothly fill even the minute voids with the resin to obtain a highly airtight composite.

Then, after air drying to remove the solvent component,
The resin is heated to a temperature of °C to semi-cure (prepreg) in the early stage of curing. This prepreg sheet is cut to match the molded shape of the container, and laminated and molded using a mold made of a suitable material such as metal, plastic, or wood. During molding, several layers (usually 2 to 3 layers) are laminated and pasted while pulling the prepreg into the mold to avoid wrinkles.
5 with pressure applied to 1 to 30 kg/alt using a presser plate.
It is desirable to set conditions for heat curing at a temperature of 0 to 100°C. In this way, by applying pressure and curing while applying tension to the carbon fibers in the prepreg in a semi-cured state, the carbon fibers are not disturbed and the interfacial adhesion between the fibers is improved, and at the same time, during curing The generation of bubbles in the pores is also suppressed, making it possible to obtain a structure free of complex defects.

The heat-cured molded product is released from the mold, fixed with a jig so that the side wall of the molded product does not deform, and heated at 150 to 300°C.
Further hardening treatment is performed by heating at a temperature increase rate of 5 to 20° C./hr.

The completely cured container molded body is fired and carbonized in a non-oxidizing atmosphere by a conventional method. The firing temperature should be in the range of 1000 to 2000°C, taking into account the temperature during use, and the rate of temperature increase up to this temperature range should preferably be set to 100°C/hr or less. [Function] According to the above process. During the molding stage, the volumetric content of carbon fibers in the molded object increases, so the thermal expansion and contraction of the molded object is dominated by the carbon fiber component. For this reason,
Deformation during firing is effectively suppressed and dimensional changes do not occur. Furthermore, since the surface layer of the container is substantially composed of glassy bar 1' carbon, there is no possibility of contaminating the contents unlike in graphite containers.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

Example 1 A solution prepared by diluting a phenol resin (manufactured by Dainippon Ink Industries, Ltd., P4O10) with acetone to adjust the viscosity to 20CP (20°C) was added to a polyacrylonitrile-based carbon fiber cloth (manufactured by Toho Rayon, W6101). Apply, 80
A prepreg was formed by curing at C for 1.5 hours.

This prepreg was cut into a container molding shape and pasted on a 200-square wooden mold while being stretched in two layers.
The resin component was cured by heating at 80° C. for 5 hours while applying pressure at g/Ci.

Next, the molded body was released from the wooden mold, and the temperature was raised to 250°C at a heating rate of 8°C/hr with the side wall fixed with an internal jig for further post-curing treatment, followed by a nitrogen gas atmosphere. Transferred to a furnace maintained at a temperature increase rate of 100℃/h
It was fired and carbonized by heating at 2000°C.

The characteristics of the carbon container thus obtained were measured and the results are shown in Table 1. For comparison, a graphite block [
Table 1 also shows the characteristics of the carbon container made by cutting G347 (manufactured by Tokai Carbon ■).

Table 1 From the comparison in Table 1, it can be seen that the carbon container according to the present invention is superior to the conventional product in all properties.

Example 2 Manufactured by the same process as Example 1, length and width 200mm, height 50I! Table 2 shows a comparison of the container performance of a lln carbon container and a graphite container having the same bending strength and thickness.

Table 2 [Effects of the Invention] According to the present invention, since the carbon container is substantially composed of carbon fiber-reinforced carbon composite material, it has high strength and can be made thin, and has high toughness and mechanical and thermal properties. It is possible to provide a lightweight container that is resistant to impact. Therefore, it is extremely useful as a processing vessel that involves high heat.

Claims (3)

[Claims] 1. Prepreg formed by impregnating or coating carbon fiber with thermosetting resin is laminated in a mold and formed into a container shape.
A method for manufacturing a carbon container, which comprises firing in a non-oxidizing atmosphere after hardening. 2. 2. The method for manufacturing a carbon container according to claim 1, wherein the carbon fiber is impregnated or coated with a solution of a thermosetting resin having a viscosity of 50 cp or less at 20° C. and a residual carbon content of 45% or more. 3. Molding is carried out by pasting the prepreg into the mold while pulling it and pressurizing it to 1 to 30 kg/cm^2.
Cured by heating at 100°C, and further heated to 150-300°C after release from the mold.
3. The method of manufacturing a carbon container according to claim 1, wherein the carbon container is hardened by a method of curing.