JPS6033273A - Manufacture of porous body - 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] The present invention relates to a method for manufacturing a porous body.

Porous bodies, especially ceramic porous bodies, have traditionally been porous bodies with continuous pores, such as unglazed pottery or sintered ceramic particles with a certain roughness, or independent pores, such as foamed glass. Porous materials with . In addition, in recent years, open-pore ceramic porous materials such as ceramic foam, which utilizes the foaming of soft urethane foam, have been produced, and spongy ceramic porous materials in which the volume ratio of the ceramic part and the pore part are completely reversed have been produced. ing.

However, unglazed pottery, foam glass ceramics, and ceramic foams lack the hardness and fineness required by ceramics. In addition, when using the pores of ceramics to make electrolyte plates for fuel cells and air cells, the pores are filled with various organic and inorganic liquids. A ceramic sintered body with a certain roughness will lack ion permeability and electron conductivity.

Although glass foam and ceramic foam can be used satisfactorily in terms of ion permeability and electron conductivity, they have the disadvantage that various organic and inorganic substances filled in the pores flow out from the pores. Furthermore, it also has the disadvantage that the ceramic skeleton alone is not strong enough.

In the present invention, the material is dense, strong, has high porosity, and has continuous pores like a labyrinth, which is sufficient to eliminate or compensate for the flaw defects as described above. A method of manufacturing a porous body is provided.

Specifically, a sheet-like product obtained by wet-mixing powder of a sinterable inorganic substance, water pulp, natural fiber, and at least one organic fiber material selected from natural fibers and synthetic fibers, and coagulating the mixture to form a paper. When producing a thin and dense porous body by firing, the wood pulp, natural fibers or synthetic fibers used for papermaking are weighed against the total dry size of the sheet material before firing. It is characterized in that it is added in an amount of 51 to 70% and then fired. This is a method for producing a porous body with porous properties.

To explain in more detail below, when adding wood, natural fibers, or synthetic fibers to powder of sinterable inorganic substances such as metal oxides to obtain a base sheet for firing, conventionally thin ceramics were used. Wood pulp is mainly added as a reinforcing material. The amount added is usually 01 to 50% by weight based on the total dry weight. However, in the present invention, wood pulp is used for the purpose of increasing the porosity and function as a supplementary force.

The amount of natural fiber or synthetic fiber added is 51 to 70% by weight based on the total dry weight. That is, water of about 5 to 30 times the weight is added to the solid content consisting of this amount of organic fiber material and sinterable inorganic substance powder, wet mixing is performed to prepare an aqueous slurry suitable for papermaking, and then agglomeration is performed. An agent is added to cause agglomeration, and the material is formed into a sheet or plate using a paper-making machine. The sheet or plate is placed in a firing furnace and fired in an oxidizing atmosphere. The firing temperature is the temperature at which the organic fiber material made of wood pulp, natural fibers, or synthetic fibers is burned and vaporized to form a labyrinth of pores, that is, 800-1. Q: Baking at 00℃ for 1 hour or more. After that, the powder of the sinterable inorganic substance is sintered.
The temperature is raised to 1.800° C., and firing is performed until the sintering of the sinterable inorganic material powder is completed. As a result, a dense porous body with high porosity, labyrinth-like pores, and high strength is produced.

Specific examples of the present invention will be described below.

<Example 1> (A) Preparation of sample Put 1.000 parts of water and 25 parts of wood pulp into a container containing about 2 parts of fBl flocculant, stir for 20 minutes to fully disperse it in the water, and add it thereto. Add 20 parts of α-alumina and stir for 1 minute to form an aqueous slurry. Add 20 parts of sulfuric acid band (15% aqueous solution) prepared in advance to the solution and stir for 2 minutes.
After confirming that Pl-I was 4 or less using a PH test paper, we added a polyacrylamide polymer flocculant (02% aqueous solution of Sunpoly N-5oo), which had also been prepared in advance.
Add 20 parts of f- and stir for 1 minute to coagulate.

The sample agglomerated in the above manner is made into a paper using a paper making machine.
Formed into a sheet with 0 to 30 cTL angle and 1 to 5 centimeter thickness. After drying, it is placed in an electric furnace and heated in an oxidizing atmosphere, with air flowing if necessary, to a temperature of 300 to 100 mm. Calcination is performed to remove organic components by holding at o o o° C. for 1 hour or more. After that, the α-alumina is sintered to form a dense and strong porous ceramic at a temperature of i,3o o~1,600℃%2.
Increase the temperature at a rate of 00°C/H until the temperature of the electric furnace reaches 1.30°C.
D ~ 1. When it reaches 600℃.

The α-alumina was maintained at this temperature for 1 hour or more to sinter and produce a porous body.

<Example 2> (/V) Sample preparation (13) Flocculant A plate-shaped porous body was obtained by pressing in exactly the same manner as in Example 1 using the above composition (At (Bl). .

The porous body thus obtained has excellent performance as an electrolyte plate used in a fuel cell, and is also excellent in durability.

According to the present invention, a porous body is produced that is thin, dense, has high porosity, and has continuous pores like a maze.

It incorporates the advantages of both methods, and the porosity can be freely adjusted by changing the amount of wood pulp, natural fibers, or synthetic fibers added. Moreover, the complicated processing steps after foaming with polyurethane, which are a problem in the production of ceramic foam, are eliminated, so the production process is simplified. On top of that.

Because it produces a dense and strong porous plate, it could not be used in the past. It can be used in places that undergo repeated expansion and contraction due to heat or places that are subject to stress.

Furthermore, since papermaking technology is used to form sheets for firing, it is possible to continuously manufacture sheets of uniform thickness, and the thickness can also be varied within a variety of ranges. It is.

patent applicant Toppan Printing Co., Ltd. Representative Kazuo Suzuki

Claims (1)

[Claims] (11 Sinterable inorganic substance powder and wood pulp, natural fiber 1
At least one type of organic fiber material selected from synthetic fibers is wet-mixed to form an aqueous slurry, and a sheet material obtained by agglomerating and forming a sheet is fired to vaporize the fiber material and perform the sintering. When producing a thin, dense porous body by sintering powdered inorganic substances, the wood pulp, natural fibers, or synthetic fibers used for papermaking are added to the total dry weight of the sheet before firing. 51-70% per weight
A method for producing a porous body, the method comprising adding and firing the porous body.