JP2762300B2 - Manufacturing method of carbon container - Google Patents

Description

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

[Prior art] Since carbon materials (including graphite) inherently have excellent heat resistance and corrosion resistance, they are used in heat treatment containers for metals and ceramics, crucibles for dissolving metals, containers for holding various molten salts, etc. It is widely used.

These containers are generally manufactured by cutting a molded block of a carbon material, or forming and curing a thermosetting resin into a container shape and then carbonizing the same.

However, a carbon container for processing a molded block has a drawback that it requires a certain thickness or more in terms of strength, is heavy, and has a large loss of material due to cutting.

On the other hand, in the case of a method in which a thermosetting resin is molded and carbonized to obtain a carbon container, a gas-impermeable one made of glassy carbon is obtained, but a box-shaped body such as a tray is made fragile. There are difficult issues.

In order to solve such problems, a cellulosic sheet impregnated with a thermosetting resin is laminated and formed into a container shape,
A method for producing a carbon container for carbonizing the carbon has been proposed (Japanese Patent Publication No. 53-43343).

[Problems to be solved by the invention]

According to the method described in the publication, it is expected to produce a large and lightweight carbon container, but it is difficult to control the thickness and dimensions of the container because the cellulosic laminated sheet causes large carbonization shrinkage during firing, and Cellulose fibers have a disadvantage in that strength is reduced by carbonization.

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

[Means for solving the problem]

In order to achieve the above object, a method for producing a carbon container according to the present invention comprises laminating and applying a prepreg formed by impregnating or applying a thermosetting resin to carbon fibers in a molding die, and bonding the prepreg with 1 to 30 kg / g. 50 to 100 ° C. in a pressurized state in cm ²
The composition is characterized in that the composition is heated and cured at a temperature of, formed into a container, released from the mold, cured at a temperature of 150 to 300 ° C., and then fired in a non-oxidizing atmosphere.

As the carbon fiber, a cloth such as a plain weave or a satin weave made of polyacrylonitrile, pitch, rayon or the like is used, but a thin fiber in which the fibers are densely present is desirable. Select and use a high-strength type or a high-modulus type according to the temperature.

As the thermosetting resin, it is preferable to use a phenol resin or a furan resin having a residual carbon ratio of 45% or more, and it is difficult to impart sufficient strength to a resin having a residual carbon ratio of less than the above value and a low carbonization yield. 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
Impregnate or apply to carbon fiber cloth in a solution state adjusted to 20 cp in 10. The reason for using such a low-viscosity resin solution is to obtain a highly airtight composite by smoothly filling the resin into the fine voids.

Then, after air drying to remove the solvent components, 70 ~ 90 ℃
To a semi-cured state (prepreg formation) in the initial stage of curing. The prepreg sheet is cut in accordance with the shape of the container in the form of a container, and is laminated and formed using a forming die made of an appropriate material such as metal, plastic, or wood. At the time of molding, several layers (usually 2 to 3 layers) are laminated and adhered while pulling the prepreg in the mold so as not to wrinkle, and the prepreg is pressed to 1 to 30 kg / cm ² by a pressing plate. The conditions for heating and curing at a temperature of ~ 100 ° C are set. 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. In this case, the generation of bubbles is also suppressed, and a structure free of compound defects can be obtained.

The heat-cured molded product is released from the molding die, fixed with a jig so that the side wall of the molded product is not deformed, and heated at 150 to 300 ° C at a heating rate of 5 to 20 ° C / hr to further cure. Perform

The completely cured container molded body is fired and carbonized in a non-oxidizing atmosphere by an ordinary method. The firing temperature is set in the range of 1000 to 2000 ° C. in consideration of the temperature at the time of use, and it is preferable to set the heating rate up to this temperature range to 100 ° C./hr or less. Since the volume content of the carbon fiber in the molded article increases in the molding step, the thermal expansion and contraction of the molded article is controlled by the carbon fiber component. For this reason, deformation during firing is effectively suppressed, and no dimensional change occurs. Further, since the surface layer of the container is substantially made of glassy hard carbon, there is no occurrence of development that contaminates the contained material unlike the graphite container.

〔Example〕

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

Example 1 A polyacrylonitrile-based carbon fiber cloth [W6101 manufactured by Toho Rayon Co., Ltd.] and a phenol resin [P5900 manufactured by Dainippon Ink Industries, Ltd.] were diluted with acetone to a viscosity of 20C.
A solution adjusted to P (20 ° C.) was applied and cured at 80 ° C. for one and a half hours to form a prepreg.

Cut this prepreg into the shape of a container, paste it on a 200mm square wooden mold while pulling two tanks, and use a holding plate to apply 15kg / c.
The resin component was cured by heating at 80 ° C. for 5 hours while applying a pressure of m ² .

Then, the molded body was released from the wooden mold, and the temperature was raised to 250 ° C. at a heating temperature of 8 ° C./hr while the side wall was fixed with an inner jig. Transferred to a furnace held at 2000 ℃ at a heating temperature of 100 ℃ / hr
Heating was performed and calcined.

The properties of the carbon container thus obtained were measured, and the results are shown in Table 1. For comparison, Table 1 also shows the characteristics of carbon containers prepared by cutting from a graphite block (G347, manufactured by Tokai Carbon Co., Ltd.).

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

Example 2 Length and width 200 mm, height 5 manufactured by the same process as in Example 1
Table 2 compares the performance of a 0 mm carbon container with that of a graphite container having a thickness of equivalent bending strength.

[Effects of the Invention] According to the present invention, since the carbon container is substantially made of carbon fiber reinforced carbon composite material, it can be thinned with high strength, and has high toughness and is resistant to mechanical and thermal shock. A container having a lightweight type performance can be provided. Therefore,
Very useful as a processing vessel with high heat.

Claims (1)

(57) [Claims] A prepreg formed by impregnating or coating a carbon fiber with a thermosetting resin is laminated and adhered to a molding die while being pulled, and is pressed under a pressure of ¹ to 30 kg / cm ² to 50 to 100 kg / cm ^2.
A method for producing a carbon container, comprising heating and curing at a temperature of ℃ to form a container, releasing from a mold, further curing in the range of 150 to 300 ℃, and then firing in a non-oxidizing atmosphere. .