JPS6030525B2 - Molding method for ceramic base material with honeycomb structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a ceramic body having a honeycomb structure that can be effectively used as a catalyst carrier for treating automobile exhaust gas.

The conventional method for forming this type of molded material is, for example, as known from the descriptions in Tokubatsu No. 52-10305 and Japanese Unexamined Patent Publication No. 49-174208, in which an extrusion die for extruding a molded material having a honeycomb structure is used. Attached to the extrusion port of the extruder, a ring-shaped press plate with an inner diameter slightly smaller than the flea of the extrusion die is attached to the front of the extrusion die, and the extrusion die and ring-shaped press plate are attached to the extrusion die. However, in this conventional method, the molded material extruded from the extrusion die is extruded to a large extent in the cross section perpendicular to the wisteria direction by the amount of drying shrinkage and firing shrinkage. At the same time, the outside and the same surface can be formed into a non-porous mantle, but the ceramic body with a honeycomb structure obtained by drying and firing this molded material has a thickness of 0.1 to 0.3, for example. If you are trying to obtain one with a wall thickness as thin as that of a willow tree,
Unlike when obtaining a ceramic body with a simple structure, the drying shrinkage and firing shrinkage in each direction in the cross section perpendicular to the axial direction are not uniform, so it is easy to cause distortion and deformation, and the distortion dimension is within the allowable limit. It was difficult to mass-produce high-quality products efficiently.

The present invention provides that in the above-mentioned subordinate honeycomb structure, shrinkage is restrained at the intersecting portions of the partition walls due to the orientation of clay particles, so when the lattice of the honeycomb structure is, for example, square, contraction in the diagonal direction is restrained. It was discovered that the shrinkage of the diameter in the diagonal direction of the lattice is smaller than the shrinkage of the diameter in the orthogonal direction, causing distortion. By making the ring-shaped presser plate attached to the honeycomb structure have a specific configuration in relation to the honeycomb structure, we succeeded in efficient mass production of good products, which was difficult with conventional methods. Attach the extrusion die that extrudes the material to the extrusion port of the Shifudo extruder, and attach a ring-shaped holding plate to the front of the extrusion die with the inner diameter of the green part slightly smaller than the diameter of the extrusion die. In a method for molding a ceramic body having a honeycomb structure in which a base is extruded through an extrusion die and a ring-shaped presser plate, the dimensions of the inner circumferential surface of the ring-shaped presser plate are determined by the molding extruded from the extrusion die. The base material is larger in cross section perpendicular to its axis by the amount of drying shrinkage and firing shrinkage. The present invention is characterized in that the dimension on the diagonal center line corresponding to the intersecting portion of the partition wall of the molded body having a honeycomb structure that is large in size and molded is set to be equal to or less than the dimension on the horizontal bisector.

The illustrated embodiment will be described in detail below.

In FIG. 1, an extrusion die 3 is attached to the extrusion port 1 of the extruder, as in the conventional method described above.
The cup soil is extruded through slits 2' for forming a honeycomb structure, which are connected to a large number of adjacent holes 2. 4
is a ring-shaped presser plate attached to the front surface of the extrusion die 3, and the dimension of the inner circumferential edge of the presser plate 4 is adjusted by the drying shrinkage and firing shrinkage of the molded material extruded from the extrusion die 3. A partition wall of a molded base material having a honeycomb-like structure that has a dimension that is largely extruded in a cross section perpendicular to all directions, and a dimension on a vertical bisector of the inner peripheral edge that is larger than a dimension on a horizontal bisector. The dimension on the center line in the diagonal direction corresponding to the intersection is set to be equal to or less than the dimension on the horizontal bisector.

That is, as shown in Fig. 2, if the diameter dimension burnt on the perpendicular bisector a is 100, the flea dimension burnt on the horizontal bisector b is 99.5, and the diameter dimension burnt on the perpendicular bisector a is 99.5. The length of the cover on the center line in the diagonal direction at an angle of 450 to the left and right is 99, respectively. Note that the inner peripheral edge 5 of the presser plate 4
The dimension of the molded material extruded from the extrusion die 3 is set to be a dimension in which the molded material extruded from the extrusion die 3 is extruded largely in a cross section perpendicular to its axial direction by the amount of drying shrinkage and firing shrinkage. It is calculated in the same way as when obtaining a normal ceramic body. Therefore, an extrusion die 3 with a honeycomb structure is attached from the extruder to the extrusion port 1.
If the cup is continuously extruded through a ring-shaped presser plate 4 attached to the front surface of the ring-shaped presser plate 4, the inner peripheral edge 5 of the ring-shaped presser plate 4 will have a dimension slightly smaller than the diameter of the extrusion die 3. The molded material extruded by the outer ear is formed into a non-porous outer mantle by being subjected to vertical folding action, and the inner part has a honeycomb structure as shown in Fig. 3. Although it is formed into a molded base,
The dimension on the perpendicular bisector of the inner circumference green 5 of the presser plate 4 is larger than the dimension on the horizontal bisector, and on the center line in the diagonal direction corresponding to the partition intersection of the molded base material of the honeycomb structure to be molded. By making the dimension of the clay particle smaller than the dimension on the horizontal bisector, the drying shrinkage and firing shrinkage at the partition intersection due to the orientation of the clay particles are not restricted, and therefore, after being extruded, the clay particles can be extruded to a specified length. The ceramic body with a honeycomb structure obtained by drying and firing the cut molded material has almost no distortion, about 1
It is possible to eliminate the occurrence of defective products by as much as 0%. As is clear from the above description, the present invention solves the problems of the conventional molding method of a ceramic body having a honeycomb structure, and is a method for forming a catalyst carrier for automobile exhaust gas treatment. This will greatly improve the productivity of ceramic bodies with a honeycomb structure useful in the chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS The drawings are explanatory diagrams for carrying out the present invention, in which Fig. 1 is a cross-sectional view of the extrusion port of the extruder, and Fig. 2 shows a presser plate and an extrusion die partially enlarged. FIG. 3 is a partially enlarged front view of the molded base.

1: Extrusion port, 2: Hole, 3: Extrusion die, 4: Ring-shaped press plate, 5: Inner peripheral edge of ring-shaped press plate.

Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An extrusion die for extruding a molded material having a honeycomb structure is attached to the extrusion port of a clay extruder, and a ring-shaped presser with an inner peripheral edge diameter slightly smaller than the diameter of the extrusion die is installed in front of the extrusion die. In a method for molding a ceramic body having a honeycomb structure in which a plate is attached and the clay is extruded through the extrusion die and a ring-shaped presser plate, the dimensions of the inner peripheral edge of the ring-shaped presser plate are measured from the extrusion die and the ring-shaped presser plate. The size of the extruded molded base material to be extruded in a cross section perpendicular to its axial direction by the amount of drying shrinkage and firing shrinkage, and the dimension on the perpendicular bisector of the inner peripheral edge as well as the dimension on the horizontal bisector and has a honeycomb-like structure characterized in that the dimension on the center line in the diagonal direction corresponding to the intersecting part of the partition wall of the molded base material of the honeycomb-like structure to be molded is equal to or less than the dimension on the horizontal bisector. A method for molding a ceramic base.