JPS6126576A - Manufacture of ceramic porous moldings - 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 (Field of Industrial Application) The present invention relates to a method for manufacturing a porous ceramic molded body.

(Prior Art) In recent years, this type of ceramic porous molded body has been used as a filter material, a catalyst carrier, a radiation converter, and the like. As a manufacturing method for this ceramic porous molded body, a conventional method was disclosed in Japanese Patent Application Laid-open No. 5
8-84162 exists as an existing technique.

This existing method, as shown in Fig. 2, extrudes the material into a plastically deformable linear shape from a nozzle ('ioi) provided on an extrusion die (100), and then transfers the extrudate (102) to a molding die (102) of a predetermined shape. 103), the dice (
After forming an aggregate (104) according to the shape of the inside (103), this is dried and sintered.

However, this method has the following problems.

(1) Since the linear extrudate is unsintered, the aggregate shrinks during the drying and sintering stages, making it difficult to obtain a ceramic porous molded body with regular dimensions.

(2) Since the linear extrudate is directly filled into the molding die, it is not only difficult to mold products with complex shapes, but also requires skill when filling the die, resulting in partially uneven packing density.

(Problems to be Solved by the Present Invention) The problems to be solved by the present invention are to easily and reliably mold a porous molded body of a predetermined shape without producing dimensional errors due to shrinkage.

(Means for Solving the Problems) The technical means taken by the present invention is to form a straight or curved sintered body of a desired length, and to bond the fired short linear sintered bodies with each other through a slurry to form a manufacturing mold. After drying, demolding and firing, slurry is attached to the surface of the linear body after demolding or firing, and if the slurry is attached after firing, it is re-dried and fired. It is.

(Function) The function of the technical means of the present invention is that the linear objects after firing are bonded using slurry so that they do not shrink or deform even after firing.

<Example> The first step is to obtain a short linear sintered body (A>) with a desired length.

Short linear sintered body (A> has a wire diameter of 3IIIlφ or less and a length of 10 to 150 times the wire diameter, preferably 30 to 8
One or more types of linear or curved materials within the range of 0 times, and are made by adding water or an appropriate amount to powder or granules of non-porous inorganic materials such as alumina, cordierite, mullite, silicon nitride, silicon carbide, etc. A binder is added and extruded using a clay kneading machine to produce short linear extrudates, and after drying or firing, the long linear extrudates are cut and shaped.

The cross-sectional shape of this short linear sintered body (A) may be either circular or square.

In the second step, the short linear sintered bodies (A) are joined together using slurry <C> to form an aggregate (B).

The slurry (C) has the same composition as the short linear sintered body (A>) or a composition with a slightly lower ignition temperature. C) After a predetermined period of time, the accumulated material (C) is removed from the slurry layer (C).
Make B).

In addition, it goes without saying that the accumulated material <8> should be used to remove excess slurry (C) that is not related to bonding, and this accumulated material (B
) can be manufactured by using several short linear sintered bodies (A) with different lengths, diameters, and shapes without using the same type of short linear sintered bodies (A).
> may be prepared by mixing. Incidentally, the excess slurry may be removed by gravity, but in this case, it is preferable to remove it by centrifugation since it is likely to result in a plurality of short linear objects.

The third step is to mold the aggregate (B) into a predetermined shape, dry it, and then remove it! 1 and firing, and after demolding or after firing, a slurry (d) is deposited on the surface, and the deposit (B) is filled into a predetermined manufacturing mold (D) so as to be blended, and dried. After demolding, the slurry (C) is applied to the surface by spraying (1) or by hand-painting, redrying and baking to obtain a relamic porous molded body (F) having continuous pores (E) inside.

In addition, when spray painting or hand-painting the surface of the aggregate (B) after baking, dry and bake it again to create continuous pores (F).
Naturally, it is possible to obtain a ceramic porous molded body (F) having
The slurry is attached to the intersection points and the surface of the internal sintered body <A), and the excess slurry accumulated in the voids is removed by gravity or centrifugation, followed by drying and firing to form a porous ceramic. Obtaining the field (F) is also optional.

In this way, by preventing the slurry (C) from adhering to the surface of the aggregate (B), the sintered body (△
)...They are bonded to each other by the slurry (C), increasing the degree of bonding and reducing the resistance to force and flaking of the sintered body (A) on the surface.

In addition, in the above case where the fired aggregate (B) is immersed in the slurry, the slurry also adheres to the intersection of the internal sintered body <A).
It becomes even stronger. Incidentally, it is also possible to apply slurry to parts that are easily damaged, such as corners, for further reinforcement. In this case as well, it does not matter whether it is after drying or after firing.

In addition, to explain the experimental examples conducted in order to further ensure the understanding of the present invention, in the experimental example (I>, 35 parts of chloride, 30 parts of kaolin, 16 parts of feldspar, 13 parts of betalite, and 6 parts of alumina were used). 2 parts of water glass and 50 parts of water are mixed with the basic composition of Mix 1 part of the binder made by mixing 2 parts of the granules with 1 part of the granules. Make wires of .7φ and 0.5φ, and after drying,
Two types of short linear sintered bodies (A) are obtained by cutting into 0 to 80III11 pieces and firing at 1250°C. This short linear sintered body (A) was added to 100 parts of the slurry by CMG.
After being immersed in a slurry bath containing 20 parts by weight of a 1% solution, it was taken out and the excess slurry was cut off to form a mass (B), which was then put into a predetermined mold and formed into a predetermined shape. After temporary drying, the mold was removed. After main drying, slurry was sprayed on the surface and a part of the corner was coated with slurry, and after re-drying, it was fired at 1250°C. As a result, there was no shrinkage, and a porous molded article (F) having continuous pores with a porosity of 75 to 89% was obtained.

Experimental example (It) uses a slurry prepared by mixing 98 parts of alumina, 1 part of clay, and 1 part of MaCog with 67 parts of water as the composition of the short linear sintered body (A>), which is mixed with 4 parts of methylcellulose,
Mix 15 parts of water and 3 parts of glycerin with a binder using a mixer, extrude this using a clay kneader in the same manner as in Experimental Example (1) to make linear products of 0.7φ and 0.5φ, and after drying,
Two types of short linear sintered bodies (A) are obtained by cutting into pieces of ~80II1 m and firing at 1600°C.

This was immersed in a slurry bath in the same manner as in Experimental Example (I), and the slurry (C
) was applied, filled into a predetermined mold, dried, and fired.

The results showed that the manufactured porous molded body (F) had no shrinkage deformation and maintained a continuous porosity of 70 to 85%.

It goes without saying that this porosity can be freely changed in both Experimental Examples (I) and (n) depending on the shape, length, and wire diameter of the short linear sintered body (Δ).

(Effects of the Invention) Since the present invention employs the method described above, it is possible to easily and easily form a porous molded body with accurate dimensional accuracy without shrinkage deformation, and to obtain a predetermined shape, it is possible to easily and simply mold a porous molded body with accurate dimensional accuracy. There is no need to waste effort such as splitting or cutting after firing.

In addition, porous molded bodies with various continuous porosity can be formed depending on the length, shape, and wire diameter of the short wire sintered body, and porous molded bodies with continuous porosity of up to 95% can be formed. It is also possible to manufacture

Furthermore, since the slurry is applied as a bonding agent to the surface, it is possible to bond the sintered bodies that protrude like split ends on the surface and improve the degree of bonding, thereby preventing chipping and breakage due to external forces. A porous molded body with excellent durability can be obtained.

Further, after shaping and sintering, the linear body is immersed in slurry and further coated with slurry to further strengthen the bond.

Therefore, the intended purpose can be achieved.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an example of the method for manufacturing a ceramic porous molded body according to the present invention, and FIG. 1 is a process diagram, and FIG. 2 is a vertical cross-sectional view schematically showing the conventional manufacturing method. . In the figure, (A): short linear sintered body, (B): aggregate, (C): slurry, (D): production mold, (E): continuous pores (F): ceramic porous molded body (1 ) nisplay

Claims (1)

[Claims] Manufacture a predetermined shape by cutting an unfired linear object and firing it, or by cutting the fired linear object to make a large number of short linear sintered bodies, and then attaching slurry to the short linear sintered bodies. Fill the mold,
1. A method for producing a porous ceramic molded body, which comprises drying and demolding, attaching slurry to the surface and firing, or attaching slurry to the surface after firing and firing again.