JP2006272183A - Production method of ceramic honeycomb filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a ceramic honeycomb filter capable of lowering a generation of a sink in an end part of a sealing part which forms the sealing part immersing an end side of a ceramic honeycomb structure having many cells divided by a partition wall in a slurry in a vessel to cast the slurry into the determined cells. <P>SOLUTION: The ceramic honeycomb structure, the determined cells of which receive the cast of the slurry to form the sealing part, is made to move to the nearly horizontal direction relatively to the vessel to be taken out. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a ceramic honeycomb filter, and more particularly to a method for manufacturing a ceramic honeycomb filter in which a sealing portion is formed by immersing an end face of a ceramic honeycomb structure in slurry in a container.

  Exhaust gas from diesel engines, etc. contains a large amount of particulate matter (particulate matter, hereinafter referred to as “PM”) mainly composed of carbon, and when released into the atmosphere, Adversely affected. For this reason, exhaust system parts, such as a diesel engine, are equipped with a filter for capturing PM. FIG. 2 shows an example of a ceramic honeycomb filter (hereinafter referred to as “honeycomb filter”) that collects and purifies PM in exhaust gas, (a) is a schematic front view thereof, and (b) is a diagram of (a). It is an EE cross-sectional schematic diagram. In the honeycomb filter 10 of FIG. 2, end faces 5a and 5b of a ceramic honeycomb structure (hereinafter referred to as “honeycomb structure”) 10a partitioned by partition walls 2 inside the outer peripheral wall 1 and having a large number of cells 3 are plugged 40a. 40b are alternately sealed.

  In the honeycomb filter 10 shown in FIG. 2, exhaust gas purification is performed as follows. Exhaust gas (indicated by a dotted arrow) flows from the cell 3 that is open to the end face 5a. The PM contained in the exhaust gas is collected by the partition wall 2 when passing through the partition wall 2, and the purified exhaust gas flows out from the cell 3 opened in the end face 5b and is released into the atmosphere. .

  Next, formation of the pluggings 40a and 40b on the end faces 5a and 5b of the conventional general honeycomb structure 10a will be described with reference to FIGS. As shown in FIG. 3 (a), one end face 5a of the honeycomb structure 10a is immersed in the slurry 6 containing the ceramic powder and the dispersion medium in the container 41 and pressed toward the inner bottom of the container (dotted line). Indicated by a down arrow). As a result, the slurry 6 enters the predetermined cell 3 from the opening of the sealing film (not shown) adhered to the honeycomb structure 10a. Thereafter, as shown in FIG. 3 (b), the honeycomb structure 10a is taken out from the container 41 (indicated by an arrow on the dotted line), whereby a sealing portion 4a is formed in a predetermined cell 3 among the many cells 3. The Similarly, as shown in FIG. 3C, the sealing portion 4b is formed also on the other end surface 5b. And the end face 5a, 5b is made into the honey-comb filter 10 by which the end parts 5a and 5b were alternately sealed by plugging 40a and 40b by baking the sealing parts 4a and 4b if desired.

  However, as shown in FIGS. 3B and 3C, sink marks 7 may occur in the sealing portions 4 a and 4 b at the sealing portion end portions 45 a and 45 b on the side of the end surfaces 5 a and 5 b. This will be described in detail with reference to FIGS. Originally, the sealing part 4 to be formed as shown in FIG. 4A is surrounded by a circle in FIG. In this case, as shown in FIG. 4C, the sink marks 7 may become the through holes 7a. When the sink mark 7 becomes the through hole 7a, there is a problem in that PM leaks from the through hole 7a when used as the honeycomb filter 10 of FIG. For this reason, conventionally, as shown in FIG. 4 (d), extra slurry is press-fitted into the cell 3 to lengthen the length 4d of the sealing portion 4 and avoid it. However, when the length 4d of the sealing portion 4 is increased, the surface area of the partition walls 2, that is, the area for capturing PM is reduced when used as the honeycomb filter 10 of FIG. There is no.

  In order to prevent the occurrence of sink marks when forming such a sealing portion, in Patent Document 1, as shown in FIG. 5A, after the slurry 6 in the container 41 is press-fitted into the cell 3, There has been a proposal in which an air layer 61 is formed between the slurry 6 and the inner bottom surface of the container 41 to separate them once, and then the honeycomb structure 10a is taken out from the container 41. According to this Patent Document 1, since the negative pressure acting on the sealing portion 4 when the slurry 6 is press-fitted is released by the air layer 61, the end portion of the sealing portion 4 as shown in FIG. The generation of sink marks 7 to 45 and the generation of through holes 7a to the sealing portion 4 as shown in FIG. 4C can be prevented.

  Further, in Patent Document 2, as shown in FIG. 5B, when the slurry 6 in a container (not shown) is press-fitted into the cell 3 to separate the honeycomb structure 10a from the container, the honeycomb structure Proposals have been made to remove the slurry 6a adhering to the end face 5 of the body 10a. According to Patent Document 2, generation of sink marks due to negative pressure and viscosity can be prevented by forcibly separating the slurry 6 in the cell 3 and the slurry outside the cell 3.

JP 2004-25098 A JP-A-2004-290766

  However, as a result of testing by the present inventors, the method shown in FIG. 5A proposed in Patent Document 1 has the following problems. When the air layer 61 is formed between the slurry 6 and the inner bottom surface of the container 41, the end surface 5 is inevitably pulled up from the container 41, so that sink marks 7 are generated at the end portion 45 of the sealing portion 4. There was a thing. Furthermore, since the moisture contained in the sealing portion can move only to the partition wall, the occurrence of sink marks 7 at the end of the sealing portion could not be suppressed. In the method shown in FIG. 5B proposed in Patent Document 2, when the slurry 6 in the cell 3 and the slurry outside the cell 3 are forcibly separated, a part of the slurry 6 on the end surface 5 is obtained. As a result, the sink marks 7 may be generated at the end portion 45 of the sealing portion.

  The present invention has been made in order to solve the above-described problems. The end face of a ceramic honeycomb structure having a large number of cells partitioned by partition walls is immersed in slurry in a container, and the slurry is introduced into predetermined cells. Thus, there is provided a method for manufacturing a honeycomb filter for forming a sealing portion, which is capable of reducing the occurrence of sink marks at the end of the sealing portion.

  In order to solve the above-mentioned problems, the present invention immerses the end face of a honeycomb structure having a large number of cells partitioned by partition walls in slurry in a container, introduces the slurry into the predetermined cells, and seals the sealing portion. A method for manufacturing a ceramic honeycomb filter to be formed is characterized in that the ceramic honeycomb structure having the sealing portion formed is moved in a substantially horizontal direction relative to the container and taken out.

  When the ceramic honeycomb structure is removed from the container by moving the ceramic honeycomb structure having the sealing portion formed in the above configuration in a substantially horizontal direction relative to the container, the end of the sealing portion is removed. This is because the occurrence of sink marks can be suppressed.

  In the present invention, the end face of the ceramic honeycomb structure taken out is brought into contact with a water absorbing member.

By bringing the end face of the ceramic honeycomb structure taken out into contact with the water absorbent member, moisture contained in the sealing portion not only moves to the partition wall, but also moves to the water absorbent member side. Solidification at the end portion is also performed, and the occurrence of sink marks at the end portion of the sealing portion can be suppressed.
Here, as the water absorbent member, for example, any cloth towel, paper towel, water absorbent sheet, water absorbent mat, sponge, leather, foam, porous body, etc. can be used as long as it can absorb moisture. be able to. Among them, the water absorption member is damaged due to water absorption and water absorption is not sufficiently performed, the end face of the ceramic honeycomb structure is difficult to be damaged when contacting, and the ceramic honeycomb structure when contacted That can be stably placed is preferable. From such a point, the material constituting the water-absorbing member is preferably an organic material, particularly including pulp, polypropylene nonwoven fabric, polystyrene, polyester, polyvinyl alcohol or the like, or one or two of these. What is combined in the above is preferable.

  In another invention of the present invention, an end surface of a ceramic honeycomb structure having a large number of cells partitioned by partition walls is immersed in a slurry in a container, and the slurry is introduced into the predetermined cells to form a sealing portion. A method for manufacturing a ceramic honeycomb filter, comprising: forming a sealing material layer on an end face of the ceramic honeycomb structure, and moving the ceramic honeycomb structure together with the sealing material layer in a substantially horizontal direction relative to the container. The water absorbing member is brought into contact with the sealing material layer formed on the end face of the ceramic honeycomb structure thus taken out.

In the above configuration, the sealing material layer is formed on the end face of the honeycomb structure for the following reason. Since sink marks are generated from the surface of the sealing material layer toward the internal sealing portion, even if sink marks are generated on the surface of the sealing material layer, if the depth of the sink marks is shallow, the sink marks may be sealed. This is because it is possible to prevent the sink marks from reaching the inner sealing portion only by the layer.

  In another invention of the present invention, it is preferable to remove the sealing material layer after contacting the water-absorbing member. The reason for this configuration is as follows. Sinking occurs from the surface of the encapsulant layer toward the internal sealing part, but when the depth of the sinking is deep, the sinking reaches not only the sealing material layer but also the internal sealing part. In such a case, when removing the sealing material layer, by embedding the sealing material layer in the sink part of the sealing part where the sink mark is generated, Because it can be done.

  In another invention of the present invention, the sealing material layer is preferably formed to have a thickness of 0.5 to 2 mm. This is because, when the thickness of the encapsulant layer is thin, sink marks easily reach not only the encapsulant layer but also the internal seal portion, and the sink portion of the seal portion where the sink marks are generated. This is because the sealing material for filling is insufficient, the sink part cannot be completely embedded, and the seal part without sink cannot be obtained. Therefore, the thickness of the sealing material layer is preferably 0.5 mm or more. On the other hand, when the sealing material layer is thick, when the dehydration is performed by bringing the water absorbent member into contact with the end face of the ceramic honeycomb structure taken out from the container, the sealing material layer is thick. It becomes difficult for moisture to move to the side of the water-absorbing member through the sealing material layer, and sink marks are easily generated in the sealing portion. From this, it is preferable that the thickness of the sealing material layer is 2 mm or less.

Hereinafter, although several examples of embodiment are described, the present invention is not limited to these.
(Embodiment 1)
First, a suitable amount of a molding aid and a pore-forming agent are added to the cordierite-producing raw material powder, and mixed and kneaded to produce a ceramic clay. Next, the kneaded material is extruded using an extrusion molding die, cut into a molded body having a diameter of 270 mm × length of 300 mm, and subsequently dried and fired to obtain a honeycomb structure. Grind the end face of the body. Next, after sticking the sealing film to both end faces of the honeycomb structure, the sealing film is perforated in accordance with the cells forming the sealing portion.

  Next, a sealing portion is formed in the cell on the end face of the honeycomb structure. FIG. 1 is an explanatory diagram for forming a sealing portion on an end face of a honeycomb structure according to Embodiment 1, and FIG. 1 (a) shows the honeycomb structure 10a in a container 11 (divided containers 11a and 11b). The state immersed in the slurry 6, (b) is the state where one of the divided containers 11b is displaced and then the honeycomb structure 10a is taken out from the divided container 11a, and (c) is the end face 5 of the removed honeycomb structure 10a. (D) is a state where the sealing material layer 9 is removed, (e) is a state where the sealing portion 4a is formed on the end face 5a of the honeycomb filter 10, f) is a schematic cross-sectional view of a state in which sealing portions 4a and 4b are formed on both end faces 5a and 5b of the honeycomb filter 10. FIG.

First, in FIG. 1A, the container 11 for storing the slurry 6 is integrated by combining the divided containers 11a and 11b. Further, the container 11 has an inner diameter 11d slightly larger than the outer peripheral wall 1 of the honeycomb structure 10a, and the gap between the inner diameter 11d of the container 11 and the outer peripheral wall 1 near the end face 5 of the honeycomb structure 10a is reduced. Then, one end face 5 a of the honeycomb structure 10 a is immersed in the slurry 6 in the container 11 and pressed with the pressing force P in the direction of the inner bottom surface 11 c of the container 11 to press-fit the slurry 6 into the cell 3. Then, by adjusting the pressing force P, the sealing portion 4a and the sealing material layer 9 are formed in the cells of the end surface 5a of the honeycomb structure 10a so that the thickness t is 0.5 to 2 mm. Next, as shown in FIG. 1B, after moving one divided container 11b forming the container 11 to the right in the figure (dotted line arrow A), the honeycomb structure 10a is moved to the other divided container 11a. And move along the inner bottom surface 11c, which is in a substantially horizontal direction (dotted arrow B). Next, as shown in FIG.1 (c), the water absorbing member 12 is made to contact the sealing material layer 9 formed in the end surface 5a of the honeycomb structure 10a taken out from the container 11, and it seals with the sealing part 4a. Moisture contained in the material layer 9 is moved to the water absorbing member 12 side. Further, as shown in FIG. 1D, after removing the sealing material layer 9 having a thickness t from the top of the sealing film (not shown) with a spatula 28 or the like, the sealing film is peeled off. Thereby, even if sink marks 7 are generated on the surface 91 of the sealing material layer 9 and reach the sealing portion 4a, the sealing material layer 9 is removed when the sealing material layer 9 is removed. 9 is filled with sink marks 7 reaching the sealing portion 4a, and as a result, the end portion 45a can be a sealing portion 4a with few sink marks 7.
Then, after the sealing portion 4b is similarly formed on the other end surface 5b (FIG. 1 (f)), the sealing portion is baked to reduce the occurrence of sink marks on the end portions 45a and 45b of the sealing portion. It can be a ceramic honeycomb filter.
In the embodiment of the present invention, a honeycomb structure dried and fired after extrusion molding is used, but an unfired honeycomb structure dried only after extrusion molding can also be used.

Specific examples will be described below.
Kaolin, talc, silica, by adjusting the powder such as alumina, in a mass _{ratio, SiO 2: 48~52%, Al} 2 O 3: 33~37%, MgO: cordierite generation such as those containing from 12 to 15% It was made into raw material powder, and graphite as a binder such as methylcellulose and hydroxypropylmethylcellulose, a lubricant, and a pore-forming material were added thereto. After thoroughly mixing in a dry process, a specified amount of water was added, and the mixture was sufficiently kneaded and plasticized. Made a ceramic clay. Next, the kneaded material was extruded using an extrusion molding die and cut into a molded body having a diameter of 270 mm and a length of 300 mm. Next, the formed body was dried and fired to obtain a cordierite honeycomb structure 10a having a cell wall 33 having a thickness of 0.3 mm, a porosity of 65%, an average pore diameter of 20 μm, and a cell pitch of 1.5 mm.

  Next, the end faces 5a and 5b of the honeycomb structure 10a were ground, a sealing film was stuck to the both end faces 5a and 5b, and the film portions corresponding to the cells to be sealed were opened in a checkered pattern. Next, the sealing part was formed by the method according to Embodiment 1. That is, as shown in FIG. 1, the honeycomb structure 10a is immersed in slurry 6 having a viscosity of 5 to 300 Pa · s by mixing methylcellulose and the like with the cordierite-producing raw material powder, and the pressing force P when pressing is 0. The sealing material layer 9 having a thickness t was formed together with the sealing portion 4a on one end face 5a of the honeycomb structure 10a. Here, the pressing force P indicates a load acting per unit area of the partition walls at the end faces 5a and 5b of the honeycomb structure. Then, the honeycomb structure 10a is moved and taken out along the inner bottom surface 11c, which is in a substantially horizontal direction relative to the container 11, and a Kim towel made by Crecia Co., Ltd. is used as a water absorbing member on the end surface 5a of the honeycomb structure 10a. The moisture contained in the sealing part 4a and the sealing material layer 9 was dehydrated by contacting. Then, after dehydration, the sealing material layer was removed as necessary, and the sealing film was peeled off to form a sealing portion. On the other hand, as a comparative example, the sealing part is formed by changing the method of taking out the honeycomb structure 10a from the container, whether the honeycomb structure end face is dehydrated, the thickness of the sealing material layer, and whether the sealing material layer is removed. did. The implementation conditions are shown in Table 1. In Table 1, (1) and (2) in the “How to take out” column are (1) is a method of removing the honeycomb structure by moving it in a substantially horizontal direction relative to the container, and (2) is a honeycomb structure. A method of lifting the body upward from the inner bottom surface of the container will be described. The sink rate (%) was defined as (number of cells in which sink marks were generated at the sealing portion end portions 45a and 45b) / (number of cells requiring total sealing).

  As shown in Table 1, in Examples 1-7, the honeycomb structure was moved out of the container by moving it relatively along the inner bottom surface that is substantially in the horizontal direction. The incidence of sink marks in the part was as small as 0.5 to 3.0%. In particular, Examples 2 to 7 are water-absorbing members that dehydrate moisture contained in the sealing portion 6 and the sealing material layer 9, so that the rate of occurrence of sink marks at the end portion of the sealing portion is 0. It was as small as 5 to 2.5%. Further, in Examples 3 to 5, since the thickness of the sealing material layer 9 was 0.5 to 2.0 mm, which was a preferable range of the present invention, the occurrence rate of sink marks at the end of the sealing portion was 0. .5 to 0.8%, which is even smaller. On the other hand, in Comparative Examples 1 to 3, when the honeycomb structure 10a was taken out from the container, the honeycomb structure was pulled up from the inner bottom surface of the container and taken out. It is as large as 40%.

An explanatory view for forming a sealing part in an end face of a honeycomb structure concerning Embodiment 1 is shown, (a) immersing honeycomb structure 10a in slurry 6 in container 11 (divided containers 11a and 11b) (B) is a state where one of the divided containers 11b is displaced and then the honeycomb structure 10a is taken out from the divided container 11a, and (c) is a water absorbing member on the end face 5 of the removed honeycomb structure 10a. 12 is a state in which the sealing material layer 9 is removed, FIG. 9E is a state in which the sealing portion 4 is formed on the honeycomb filter 10, and FIG. It is each cross-sectional schematic diagram of the state by which sealing part 4a, 4b was formed in the both end surfaces 5a, 5b. An example of the ceramic honeycomb filter which collects and purifies PM in exhaust gas is shown, (a) is the front schematic diagram, (b) is EE sectional drawing of (a). It is explanatory drawing about formation of the sealing parts 4a and 4b to the end surfaces 5a and 5b of the honeycomb structure 10a. FIG. 4 is a schematic diagram of occurrence of sink marks 7 on the sealing portion 4 of the honeycomb filter 10. (A) is the sealing method proposed in Patent Document 1, and (b) is the sealing method proposed in Patent Document 2.

Explanation of symbols

10: Honeycomb filter (ceramic honeycomb filter)
10a: Honeycomb structure (ceramic honeycomb structure)
1: outer peripheral wall 2: partition wall 3: cell 4, 4a, 4b: sealing part 45, 45a, 45b: end part of sealing part 5, 5a, 5b: end face 6: slurry 6a: slurry adhering to end face 7: Sink 7a: Through hole 9: Sealing material layer 91: Surface of sealing material layer 11: Container 11a, 11b: Divided container 11c: Inner bottom surface 11d: Inner diameter 21: Outside jig 21a, 21b: Outside division Jig 21d: Inner diameter 28: Spatula 40a, 40b: Plugging 61: Air layer P: Pressing force t: Thickness of sealing material layer

Claims (5)

This is a method for manufacturing a ceramic honeycomb filter, in which an end face of a ceramic honeycomb structure having a large number of cells partitioned by partition walls is immersed in slurry in a container, and the slurry is introduced into predetermined cells to form a sealing portion. Then, the method for manufacturing a ceramic honeycomb filter, wherein the ceramic honeycomb structure having the sealing portion formed is moved in a substantially horizontal direction relative to the container and taken out. The method for manufacturing a ceramic honeycomb filter according to claim 1, wherein the end face of the ceramic honeycomb structure taken out is brought into contact with a water absorbing member. This is a method for manufacturing a ceramic honeycomb filter, in which an end face of a ceramic honeycomb structure having a large number of cells partitioned by partition walls is immersed in slurry in a container, and the slurry is introduced into predetermined cells to form a sealing portion. Then, a sealing material layer is formed on the end face of the ceramic honeycomb structure, and the ceramic honeycomb structure is moved together with the sealing material layer in a substantially horizontal direction relative to the container and taken out. A method for producing a ceramic honeycomb filter, comprising bringing a water-absorbing member into contact with a sealing material layer formed on an end face of a structure. The method for manufacturing a ceramic honeycomb filter according to claim 3, wherein the sealing material layer is removed after contacting the water absorbent member. The method for manufacturing a ceramic honeycomb filter according to claim 3 or 4, wherein a thickness of the sealing material layer is 0.5 to 2 mm.

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