JP4946274B2 - Method for plugging ceramic honeycomb molded body - Google Patents

Description

  The present invention relates to a method for plugging a cell end of a ceramic honeycomb formed body in which a large number of cells are defined by porous cell walls.

  Ceramic honeycomb molded bodies are widely used as a carrier for automobile exhaust gas purification catalysts. The honeycomb formed body includes an outer skin, a cell wall disposed in a honeycomb shape in the outer skin, and a large number of cells that are partitioned in the cell wall and formed along the axial direction. As a method for forming a honeycomb formed body, extrusion molding or plunger molding is generally used.

  Further, the honeycomb formed body includes a plugged honeycomb formed body in which the opening end portions of the cells are plugged. The plugged honeycomb molded body can be manufactured, for example, by extruding the kneaded raw material using an extrusion mold, followed by drying, temporary firing, masking, plugging, and firing.

  Conventionally, plugged honeycomb molded bodies have had plugging material popped out from the end face of the honeycomb molded body immediately after plugging. Specifically, a masking material is formed on the end face of the honeycomb formed body at the time of masking in the step before plugging. During plugging, slurry adheres around the masking material. Therefore, only the masking material disappears at the time of firing in the subsequent process, and the slurry attached around the masking material at the time of plugging remains in a state of protruding from the end face of the honeycomb formed body.

  In this case, when the product is used as it is, there is a problem that the surface area exposed to the exhaust gas becomes large and extra particulates are easily attached. Further, when plugging is performed by simply immersing, there is a problem that a sufficient plugging density cannot be obtained and a gap is formed between the plugging material and the cell wall.

JP 2002-37672 A

  The present invention has been made in view of such conventional problems, and at least one of the end surfaces can suppress the plug portion from protruding from the end surface, and has a high plugging density with no gaps. An object of the present invention is to provide a plugging method for a ceramic honeycomb formed body.

In producing a ceramic honeycomb molded body in which a large number of cells are partitioned by a porous cell wall and the cell ends are plugged with a plugging material, the plugging material is formed on the end face of the ceramic honeycomb molded body. A method of plugging the cell end of the ceramic honeycomb molded body by immersing the end face of the ceramic honeycomb molded body in a plugging slurry in a state where the cell end not provided is covered with a masking material,
A first plugging step of immersing one end face of the ceramic honeycomb molded body in a plugging slurry;
A second plugging step of immersing the other end face of the ceramic honeycomb molded body in a plugging slurry,
In the second plugging step, the ceramic is formed using a holding device having a chuck portion for holding a side surface of the ceramic honeycomb formed body and a surface pressing portion for pressing an end face of the ceramic honeycomb formed body. By holding the honeycomb formed body by the chuck portion, providing an elastic member between the face pressing portion and the ceramic honeycomb formed body, and pressing the end face of the ceramic honeycomb formed body by the surface pressing portion, the first A plugging method for a ceramic honeycomb molded body is characterized in that the plugging slurry disposed in the plugging step is compressed inward by the elastic member (claim 1).

  In the plugging method of the ceramic honeycomb formed body of the present invention, the most notable point is that in the second plugging step, the gripping device is used, and an elastic member is provided between the face pressing portion and the ceramic honeycomb formed body. In this state, the end face of the ceramic honeycomb formed body is pressed using the face pressing portion. Thereby, at least one end surface (end surface plugged in the first plugging step) can prevent the plug portion from projecting from the end surface, and the plugging density is high, and the plug can be plugged without a gap.

In the second plugging step, the end surface immersed in the plugging slurry is plugged, and the protruding portion of the plugging slurry disposed in the first plugging step is placed in the ceramic honeycomb molded body (cell Middle).
By pressing the end face of the ceramic honeycomb molded body using a face pressing portion with an elastic member provided between the ceramic honeycomb molded body and the ceramic honeycomb molded body, the masking material is crushed and adhered to the periphery of the masking material. The plugging slurry thus formed can be compressed to the end face of the ceramic honeycomb formed body.

Originally, the overall shape of the end face of the ceramic honeycomb formed body is not necessarily flat. Therefore, it is effective to provide an elastic member that is deformed by pressing according to the shape and hardness of the end face of the ceramic honeycomb formed body. By deforming the elastic member at the time of pressing, the plugging slurry protruding from the end face of the ceramic honeycomb formed body can be compressed so as to be pushed into a soft cell, and the end face can be adjusted.
Thereby, even if it is a case where the whole shape of the end surface of a ceramic honeycomb molded object is not flat, it can suppress that a plug part protrudes in an end surface.

  Furthermore, as described above, the ceramic honeycomb formed body partitions a large number of cells by the porous cell walls. Therefore, when the end face of the ceramic honeycomb formed body is immersed in the plugging slurry, moisture in the plugging slurry is absorbed by the cell walls. The fluidity of the plugging slurry disposed in the cell is lowered due to a decrease in water content. Therefore, in the second plugging step, when the plugging slurry disposed in the first plugging step is compressed inward, the plug shape on the inner side of the plug portion is hardly changed. The plugging slurry can be compressed on the end face side (cell opening end side) of the portion. As a result, the plug portion expands in the lateral direction so that the end surface side portion of the plug portion is in close contact with the cell wall, and a plug portion having a high plugging density can be obtained without a gap.

  Thus, according to the present invention, it is possible to obtain a ceramic honeycomb molded body in which at least one end face is suppressed from protruding from the end face, the plug density is high, and the plug is filled without a gap. it can.

As described above, in the plugging method of the ceramic honeycomb formed body of the present invention, an elastic member is provided between the surface pressing portion and the ceramic honeycomb formed body in the second plugging step.
Examples of the elastic member include a rubber sheet, a sponge sheet, and a urethane foam sheet.
In particular, the elastic member is preferably a rubber sheet.
In this case, the ceramic honeycomb formed body can be particularly well plugged.
Examples of the material constituting the rubber sheet include CR, NR, NBR, urethane, and silicone.

The ceramic honeycomb formed body is preferably made of cordierite.
In this case, in particular, a ceramic honeycomb formed body having a small thermal expansion and strong against thermal shock can be obtained.

  In the first plugging step, the ceramic honeycomb formed body is gripped using the gripping device, an elastic member is provided between the face pressing portion and the ceramic honeycomb formed body, and the surface pressing portion is used to It is preferable to press the end face of the ceramic honeycomb formed body.

  In this case, the masking material formed on the end surface facing the surface pressing portion can be crushed. Thereby, in the end surface plugged in the second plugging step, the amount of the plugging material protruding from the end surface can be reduced in advance.

Example 1
In this example, an example according to the plugging method of the ceramic honeycomb formed body of the present invention will be described with reference to FIGS.
As shown in FIG. 1, this example was performed using the gripping device 3. The gripping device 3 includes a chuck portion 31 and a surface pressing portion 32 that comes into contact with the chuck portion 31.
The chuck portion 31 is for holding the side surface of the ceramic honeycomb formed body, and the surface pressing portion 32 is for pressing the end surface of the ceramic honeycomb formed body.
The surface pressing portion 32 is provided with an elastic member 4. As the elastic member 4, an NBR rubber sheet was used.

The ceramic honeycomb formed body 1 subjected to plugging in this example is made of cordierite, and the size is a diameter W of φ160 mm and a height H of 100 mm.
In the ceramic honeycomb formed body 1, the cell end portion where the plugging material is not provided on the end surface is covered with the masking material 5.

Next, the plugging method of this example will be described.
The plugging method of this example performed the 1st plugging process (illustration omitted), and performed the 2nd plugging process shown in FIG. 1 after that.
In the first plugging step, one end face 11 of the ceramic honeycomb formed body 1 is immersed in the plugging slurry using the gripping device 3.

  First, one end surface 11 of the ceramic honeycomb formed body 1 is set as the lower end, the side surface of the ceramic honeycomb formed body 1 is gripped by the chuck portion 31, and the elastic member 4 is interposed between the surface pressing portion 32 and the ceramic honeycomb formed body 1. It was in the state where it was provided. Thereafter, the other end face 12 of the ceramic honeycomb formed body 1 is pressed using the face pressing portion 32, and one end face 11 of the ceramic honeycomb formed body 1 is immersed in the liquid layer 22 containing the plugging slurry 1. Then, it was plugged by holding for 30 seconds.

Thereafter, the ceramic honeycomb formed body 1 was inverted and a second plugging process was performed.
In the second plugging step, as shown in FIGS. 1 and 2, one end surface 11 of the ceramic honeycomb formed body 1 is pressed using the holding device 3, and the other end surface 12 is used as a plugging slurry. Immerse.

  First, the side surface of the ceramic honeycomb formed body 1 was held by the chuck portion 31, and the elastic member 4 was provided between the surface pressing portion 32 and the ceramic honeycomb formed body 1. Thereafter, one end face 11 of the ceramic honeycomb formed body 1 is pressed using the face pressing portion 32 and the other end face 12 of the ceramic honeycomb formed body 1 is immersed in the liquid layer 22 containing the plugging slurry 2. Then, plugging was performed by holding for 30 seconds.

FIG. 1A shows a state in which the ceramic honeycomb formed body is gripped using the gripping device 3 in the second plugging step, and FIG. 1B shows the ceramic honeycomb forming in the second plugging step. The state where one end surface 11 of the body 1 is pressed and the other end surface 12 is immersed in the plugging slurry 2 is shown.
As can be seen from FIG. 1B, in this example, the ceramic honeycomb formed body 1 has one end face 11 pressed in a state where the other end face 12 is pressed against the bottom of the liquid layer 22.

Moreover, Fig.2 (a) shows the plugging part of the one end surface 11 before a press in a 2nd plugging process, FIG.2 (b) shows the plugging part of the one end surface 11 after a press. .
As can be seen from the figure, in the plugging portion before pressing, the plugging material 21 (the plugging slurry) arranged by the first plugging process exists up to the end face of the masking material 5. Thereafter, the masking material 5 is crushed by pressing through the elastic member, and the plugging slurry adhering to the periphery of the masking material 5 is compressed inward, and the end surface side of the plugging material 21 is pressed. It can be seen that this portion 23 spreads in the lateral direction so as to be in close contact with the cell wall, and is a plug portion having a high plugging density without gaps.

  Thereby, in this example, as shown in FIG. 3, it is possible to manufacture the ceramic honeycomb formed body 1 in which a large number of cells are partitioned by the porous cell walls 14 and the cell ends are plugged with the plugging material 21. did it.

(Comparative Example 1)
This comparative example is an example in which a conventional plugging method is performed.
Specifically, as shown in FIG. The gripping device 9 has a handling portion 91 that grips the side surface of the ceramic honeycomb formed body 8.
The ceramic honeycomb molded body 8 plugged in this comparative example was the same as that plugged in Example 1.
The plugging slurry 2 was the same as in Example 1.

The plugging method of this comparative example is performed by holding only the side surface 83 of the ceramic honeycomb molded body 8 and immersing it in the liquid layer 22 containing the slurry 2.
First, the ceramic honeycomb molded body 8 is dipped in the slurry 2 by holding and lowering the ceramic honeycomb molded body 1 by the handling portion 91 with one end surface 81 at the lower end and lowering the ceramic honeycomb molded body 8. And plugged.
Next, the same operation was performed on the other end face 82 to perform plugging.

Next, the ceramic honeycomb molded body plugged in Example 1 and Comparative Example 1 was fired to make the masking material 5 disappear.
Thereafter, the following evaluation test was performed on the ceramic honeycomb formed body.

<Gap evaluation test>
The evaluation of the gap was performed by conducting a light transmission test and confirming the presence or absence of the gap.
<Cross-section plug shape evaluation test>
The cross-sectional plug shape was evaluated by photographing and observing the cross-sectional shape of the plug member using CT.
<Capping density evaluation test>
The plugging density was evaluated by photographing and observing the cross-sectional shape of the plug member using SEM.

In the ceramic honeycomb formed body of Example 1, no gap was observed at least on the end face plugged in the first plugging step, the cross-sectional plug shape was good, and a sufficient plugging density was exhibited.
In the ceramic honeycomb molded body of Comparative Example 1, a gap was confirmed, and the slurry adhered around the masking material during plugging remained in a state of protruding from the end face of the honeycomb molded body, and sufficient plugging Density was not obtained.

Explanatory drawing which shows the 2nd plugging process in Example 1. FIG. The enlarged view which shows the plugging part in Example 1. FIG. FIG. 3 is an explanatory view showing a ceramic honeycomb formed body in Example 1. Explanatory drawing which shows the plugging process in the comparative example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic honeycomb molded object 11 One end surface 12 The other end surface 13 Side surface 2 Slurry for plugging 3 Gripping device 31 Chuck part 32 Face pressing part 4 Elastic member

Claims (4)

When manufacturing a ceramic honeycomb molded body in which a large number of cells are partitioned by a porous cell wall and the cell end is plugged with a plugging material, the cell edge without the plugging material provided on the end face of the ceramic honeycomb molded body In a state where the part is covered with a masking material, the end surface of the ceramic honeycomb formed body is immersed in a plugging slurry, and the cell end of the ceramic honeycomb formed body is plugged.
A first plugging step of immersing one end face of the ceramic honeycomb molded body in a plugging slurry;
A second plugging step of immersing the other end face of the ceramic honeycomb molded body in a plugging slurry,
In the second plugging step, the ceramic is formed using a holding device having a chuck portion for holding a side surface of the ceramic honeycomb formed body and a surface pressing portion for pressing an end face of the ceramic honeycomb formed body. By holding the honeycomb formed body by the chuck portion, providing an elastic member between the face pressing portion and the ceramic honeycomb formed body, and pressing the end face of the ceramic honeycomb formed body by the surface pressing portion, the first A plugging method for a ceramic honeycomb molded body, wherein the plugging slurry disposed in the plugging step is compressed inward by the elastic member.   2. The plugging method for a ceramic honeycomb molded body according to claim 1, wherein the elastic member is a rubber sheet.   3. The plugging method for a ceramic honeycomb molded body according to claim 1, wherein the ceramic honeycomb molded body is made of cordierite.   4. The elastic member according to claim 1, wherein in the first plugging step, the ceramic honeycomb formed body is gripped using the gripping device, and the elastic member is interposed between the face pressing portion and the ceramic honeycomb formed body. And plugging the ceramic honeycomb molded body, wherein the end face of the ceramic honeycomb molded body is pressed using a face pressing portion.

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