JP2020104054A - Manufacturing method for ceramic honeycomb filter - Google Patents

Abstract

To provide a manufacturing method for a ceramic honeycomb filter, capable of preventing occurrence of mesh-sealing defect when forming a mesh-sealing part by filling a mesh-sealing material in a process of forming a mesh-sealing part to a ceramic honeycomb structure and capable of recognizing a flow path position to be sealed by an imaging device when opening a through-hole on a film.SOLUTION: There is provided a method for manufacturing a ceramic honeycomb filter by forming a mesh-sealing part 5a to a prescribed flow path end part of a ceramic honeycomb structure comprising numerous flow paths partitioned by a porous barrier 2. The mesh-sealing part is formed by: sticking a film on the edge face of the above structure; deciding a flow path position for forming the mesh-sealing part by imaging of an imaging device; forming a through-hole on the film of the above flow path position; filling the flow path end part with a mesh-sealing slurry from the through-hole; and drying the filled slurry. The method is characterized in that the average transmittance of a light having a wave length of 480 to 590 nm measured using the integrating sphere of the film is 50% or more but 88% or less.SELECTED DRAWING: Figure 1(a)

Description

The present invention relates to a method for manufacturing a ceramic honeycomb filter used to purify exhaust gas containing particulate matter discharged from a diesel engine or the like.

Exhaust gas from diesel engine contains PM (Particulate Matter: particulate matter) whose main components are soot consisting of carbonaceous matter and SOF (Soluble Organic Fraction) consisting of high boiling point hydrocarbon components. However, if it is released into the atmosphere, it may adversely affect the human body and the environment. For this reason, it has been conventionally performed to install a ceramic honeycomb filter (hereinafter, abbreviated as "honeycomb filter" for short) on the exhaust pipe of a diesel engine to trap PM. An example of a honeycomb filter that collects and purifies PM in exhaust gas is shown in FIGS. 1(a) and 1(b). The honeycomb filter 10 is a ceramic honeycomb structure composed of a porous partition wall 2 that forms a number of outflow-side sealing channels 3 and an inflow-side sealing channel 4 and an outer peripheral wall 1, and an outflow-side sealing channel 3 and The exhaust gas inflow side end face 6 and the exhaust gas outflow side end face 7 of the inflow side sealing flow path 4 are composed of an upstream side sealing part 5a and a downstream side sealing part 5b which alternately seal the check pattern. The outer peripheral wall 1 of the honeycomb filter is gripped so as not to move during use by a gripping member (not shown) formed of a metal mesh or a mat made of ceramics, etc., in a metal storage container (not shown). It is arranged.

Exhaust gas is purified in the honeycomb filter 10 as follows. The exhaust gas flows in from the outflow side sealed flow path 3 that is open to the exhaust gas inflow side end face 6 as shown by the dotted arrow. Then, when passing through the partition wall 2, more specifically, when passing through the communication holes formed by the pores that communicate with each other on the surface and inside of the partition wall 2, PM contained in the exhaust gas is collected. The purified exhaust gas flows out from the inflow side sealed flow path 4 that is open to the exhaust gas outflow side end face 7 and is released into the atmosphere.

The honeycomb filter is manufactured by the following steps. First, for example, as a ceramic raw material, cordierite forming raw material powder, a molding aid, a pore-forming agent and water are mixed and kneaded to obtain a ceramic kneaded clay. This ceramic kneaded material is extruded into a honeycomb shape through a mold to obtain a formed body having a honeycomb structure having a large number of channels partitioned by partition walls. The molded body is placed in a drying oven to evaporate and dry the water content in the molded body, and further placed in a firing oven to remove the molding aid and the like in the molded body, and then fired. This makes it possible to obtain a fired body having a honeycomb structure having a predetermined shape and strength and having a large number of channels partitioned by porous partition walls. The predetermined flow path end of the obtained fired body having a honeycomb structure is filled with the plugging material slurry, dried, and fired to form the plugged portion, and the honeycomb filter 10 is obtained. An outer peripheral wall is formed on the outer periphery of the honeycomb filter for the purpose of further improving its mechanical strength.

As a method of forming a plugging portion at a predetermined flow path end portion of a honeycomb structure (fired body having a honeycomb structure), Japanese Patent Laid-Open No. 2003-320517 (Patent Document 1) discloses that a film is formed on the end surface of the honeycomb structure. A first sub-step of attaching, a second sub-step of making a hole with a high-density energy beam at a predetermined position of the film corresponding to a cell to be plugged, and a plugging material in the flow path to be plugged. And a third sub-step of filling, the film used in the first sub-step is transparent or translucent, includes a base material layer and an adhesive layer, and has an adhesive force of 3 to 15 N/25 mm. Disclosed is a method characterized by the above. In Patent Document 1, the film is preferably transparent or semi-transparent in order to facilitate the determination of the position to punch a hole in the film, that is, after the film is attached, image recognition means (imaging device such as a camera) It is described that it is preferable to have transparency that allows the position of the cell to be recognized.

However, in the method described in Patent Document 1, when a through hole is formed at a predetermined position of a transparent or semitransparent film by a high-density energy beam (second sub-step), a hole is formed at a position displaced from the predetermined position of the film. Poor hole punching may occur. When a defective hole is formed, a plugging part is not formed at a desired flow path position, a plugging part is formed only at a part of the flow path, and a plugging part is formed at an undesired flow path position. The part etc. which are to be generated. Then, after the third sub-step of filling the flow path to be plugged with the plugging material, if the above-mentioned site is found, the ceramic honeycomb structure is forced to be discarded due to plugging failure. ..

Further, the applicant of the present invention, as a method of suppressing the occurrence of a punching failure in which a through hole is formed at a position deviated from the predetermined position of the film when the through hole is formed at the predetermined position of the film, JP-A-2008-161765 ( In Patent Document 2), when perforating 45% or more of the cell area at a predetermined position of the film with laser light, the temperature of the galvanometer in the laser head is set to 36°C ± 5°C, and the film is perforated with laser light. Is disclosed. As a result, the laser light is less likely to shift due to temperature drift and the film can be perforated at an accurate position, so the undesired flow of the plugging material into the cell where the plugging portion should not be provided. Occurrence of defective plugging in which a plugged portion is formed at the road position can be suppressed. However, even if the technique described in Patent Document 2 is used, the plugging member is formed in the cell where the plugging portion should not be provided, and the plugging portion is formed at an undesired flow path position. It was not possible to completely suppress the occurrence of stoppage defects.

JP 2003-320517 JP Japanese Patent Laid-Open No. 2008-161765

Therefore, an object of the present invention is to form a plugging portion at a desired flow path position when filling the plugging material with a plugging material in the step of forming the plugging portion in the ceramic honeycomb structure. It is an object of the present invention to provide a method for manufacturing a ceramic honeycomb filter capable of suppressing the occurrence of defective plugging such that a plugging portion is not formed and/or a flow path position is not desired. At the same time, when a through hole is formed in a film, a method for manufacturing a ceramic honeycomb filter that can recognize the position of a channel to be plugged (to be opened) with an image pickup device such as a camera, as in the conventional method. Is to provide.

In view of the above object, the present inventors have attached a film to the end surface of the ceramic honeycomb structure, determine the flow path position with an imaging device, perforate the film at the flow path position to be plugged with a laser, and form In the step of forming the plugging portion in the ceramic honeycomb structure by filling the plugging material slurry through the holes, drying, and firing as necessary, the film and the manufacturing process are thoroughly studied. In addition, it is possible to suppress the occurrence of defective plugging when the plugging material is filled to form the plugged portion, and at the same time, when the through hole is formed in the film, as in the conventional method, the plugging is performed. The inventors have found a method for manufacturing a ceramic honeycomb filter in which an imaging device such as a camera can recognize the position of a flow path to be stopped (to open a hole), and conceived the present invention.

That is, the manufacturing method of the ceramic honeycomb filter of the present invention,
A method for producing a ceramic honeycomb filter by forming a plugging portion at a predetermined channel end portion of a ceramic honeycomb structure including a plurality of channels partitioned by porous partition walls,
The formation of the plugged portion includes a step of attaching a film to the end face of the ceramic honeycomb structure, a step of determining a flow path position where the plugged portion is to be formed by an imaging device, and the plugged portion is formed. Forming a through hole at the position of the film corresponding to the desired flow path, filling the plugging material slurry into the flow path end portion from the through hole, and drying the filled plugging material slurry Have
The average transmittance of light having a wavelength of 480 to 590 nm measured using the integrating sphere of the film (value obtained by measuring the transmittance of light of 480 to 590 nm every 10 nm and averaging) is 50 to 88%. It is characterized by

The average transmittance of light having a wavelength of 480 to 590 nm measured using the integrating sphere of the film is preferably 55 to 88%.

After the step of forming the through hole, it is preferable to have a step of visually inspecting the hole forming failure of the through hole formed on the film.

The film preferably has a film substrate having a thickness of 20 to 90 μm and an adhesive layer having a thickness of 10 to 40 μm.

According to the method of the present invention, in the step of forming the plugged portion in the ceramic honeycomb structure, when the plugged material is filled to form the plugged portion, the plugged portion is not formed at the desired flow path position. And/or it is possible to suppress the occurrence of defective plugging such that a plugged portion is formed at an undesired flow path position. At the same time, when a through hole is formed in the film attached to the end surface of the ceramic honeycomb structure, the flow path position to be plugged can be recognized by an imaging device such as a camera, as in the conventional method.

It is a front view which shows an example of a ceramic honeycomb filter typically. FIG. 3 is a cross-sectional view schematically showing an example of the ceramic honeycomb filter, which is parallel to the axial direction. 6 is a photograph of an end face of a film attached to the end face of a ceramic honeycomb structure after a through hole is formed at a position corresponding to a predetermined flow path, as viewed from a direction perpendicular to the end face. Is a photograph showing. It is a graph which shows the transmittance|permeability measured using the integrating sphere of the films AF used in the Example and the comparative example. It is a perspective view which shows typically the apparatus for forming a through-hole in the film stuck on the end surface of the ceramic honeycomb structure.

[1] Method for Manufacturing Ceramic Honeycomb Filter A ceramic honeycomb filter is a molded body having a honeycomb structure composed of a plurality of channels partitioned by porous partition walls, or a predetermined flow of a fired body formed by firing the molded body. After the plugging material slurry is filled in the road end portion, the plugging material slurry is dried, and if necessary, fired to form a plugged portion. That is, a method of firing the molded body having the honeycomb structure to prepare a fired body having the honeycomb structure, filling and drying the plugging material slurry, and firing the dried plugging material as necessary ( A first method), and a method (second method) in which the molded body having the honeycomb structure is filled with a plugging material slurry and dried, and then the molded body and the dried plugging material are simultaneously fired. There is. Since the method of the present invention is a method characterized by the film used for forming the plugged portions, even when the plugged portions are formed on the fired body having the honeycomb structure, the formed body having the honeycomb structure can be obtained. The same can be applied to the case where the plugged portion is formed. In the present application, the honeycomb structure includes both a molded body having a honeycomb structure and a fired body having a honeycomb structure. Hereinafter, the method for manufacturing the ceramic honeycomb filter of the present invention will be described in detail by taking the first method as an example.

In the first method, the plugged portion is formed by a step of attaching a film to the end surface of the fired body having the ceramic honeycomb structure, and the flow path position where the plugged portion is to be formed is determined by imaging with an imaging device. A step, a step of forming a through hole at a position of the film corresponding to a flow path in which the plugging portion is to be formed, a step of filling a flow path end portion with a plugging material slurry from the through hole, and the filling The plugging material slurry is dried and baked if necessary, and the average transmittance of light having a wavelength of 480 to 590 nm measured using an integrating sphere of the film (transmission of light of 480 to 590 nm is measured). The value is 50 to 88%, which is the average of the measured values for every 10 nm.

(1) Step of obtaining a molded body having a honeycomb structure A molded body having a honeycomb structure is formed by mixing and kneading molding raw materials to obtain a kneaded material, which is formed into a honeycomb shape using a molding die having a honeycomb structure molding groove. It is obtained by extrusion molding and drying. It is preferable that the forming raw material is obtained by mixing and kneading a ceramic raw material, a binder, water, and if necessary, a forming aid and a pore-forming material. The ceramic raw material is not particularly limited, but it is possible to use a cordierite-forming raw material composed of a silica source raw material, an alumina source raw material, a magnesia source raw material, or alumina, silica, silicon nitride, silicon carbide, aluminum titanate, LAS, or the like. it can. Above all, it is preferable to use a cordierite forming raw material. As the cordierite forming raw material, silica, talc, kaolin, alumina, aluminum hydroxide or the like can be used. Further, as the pore-forming material, a material such as foamed foamed resin or graphite can be used.

(2) Step of obtaining a fired body having a honeycomb structure The obtained formed body is put in a drying oven to evaporate and dry the moisture in the formed body, and then put in a firing oven to remove the forming aid etc. in the formed body After that, it is baked. As a result, a fired body having a honeycomb structure having a predetermined shape and strength and having fine pores in the partition walls can be obtained. In order to further improve the mechanical strength of the fired body having such a honeycomb structure, it is preferable to form an outer peripheral wall on the outer peripheral portion of the fired body after the outer edge is removed by processing. Firing of the molded body, for example, when using a cordierite forming raw material as the ceramic raw material, after heating to a firing temperature of 1350 ~ 1450 ℃ at a rate of 2 ~ 100 ℃ / hr, after holding for 5 to 30 hours at the maximum temperature , Cool to 1000℃ at a rate of less than 100℃/hr.

(3) Step of forming plugged portions With respect to the obtained fired body, as shown in FIGS. 1(a) and 1(b), the flow path ends of the ceramic honeycomb structure are in a checkered pattern. After filling the plugging material slurry so as to alternately plug, it is dried, and if necessary, the dried plugging material is fired to form plugging portions, and a ceramic honeycomb filter is obtained. .. The filling of the plugging material slurry into the flow path ends of the ceramic honeycomb structure is performed by (a) attaching a film to the end face of the ceramic honeycomb structure, and (b) forming a plugging part by imaging with an imaging device. To determine the flow path position to be formed, (c) forming a through hole at the position of the film corresponding to the flow path in which the plugged portion is to be formed, and (d) sealing the film attachment surface of the ceramic honeycomb structure. It is carried out by immersing in the stopping material slurry and introducing the plugging material slurry from the through hole to the end of the flow path. Here, after forming a through hole at a position of the film corresponding to a flow path in which the plugged portion is to be formed, it is preferable to perform a step of visually inspecting the through hole for defective opening. As a result, it is possible to prevent the plugging portion from being formed while the film has a hole punching defect, suppress the occurrence of a plugging defect, and discard the ceramic honeycomb structure as a plugging defect. Can be prevented. The plugged portions are preferably formed on both flow path ends of the ceramic honeycomb structure. The plugged portion can be formed, for example, by a known method as described in the cited document 1.

(a) Step of attaching film A film is attached to both end faces of the ceramic honeycomb structure. In the present invention, the film attached to the end surface of the ceramic honeycomb structure has an average transmittance of light having a wavelength of 480 to 590 nm measured using an integrating sphere (hereinafter, also simply referred to as “average transmittance”). ) Is 50 to 88%. Here, the average transmittance of light having a wavelength of 480 to 590 nm is the value obtained by measuring the transmittance of the wavelength of 480 to 590 nm every 10 nm (480, 490, 500... every 590 nm wavelength). It is the arithmetic average value. The transmittance in the present invention is a value measured using a spectrophotometer equipped with an integrating sphere (Integrating sphere spectrophotometer Ci7800 manufactured by X-Rite). When the average transmittance is less than 50%, when the end face of the ceramic honeycomb structure is imaged through the film by the imaging device, the accuracy of distinguishing between the flow path and the partition wall decreases, and plugging (should be opened) ) It becomes difficult to recognize the flow path position. On the other hand, when the average transmittance is more than 88%, it is difficult to distinguish the flow channel that can be recognized by passing through the film from the through hole formed in the film, so that the flow channel that should not be perforated is perforated. It may be easy to overlook the defective opening, and the plugging portion may be formed in the film in the state where the defective opening has occurred, and defective plugging may occur. The average transmittance is preferably 55 to 88%, more preferably 60 to 80%.

In the present invention, the film attached to the end surface of the ceramic honeycomb structure does not shift when the plugging material slurry is filled in the flow path, or the plugging material slurry does not flow into the flow path that should not be plugged. It has a pressure-sensitive adhesive layer on the surface of the film substrate, and preferably has a film substrate having a thickness of 20 to 90 μm and a pressure-sensitive adhesive layer having a thickness of 10 to 40 μm. A film having an average transmittance of light having a wavelength of 480 to 590 nm in a desired range can be selected from various commercially available films. The thickness of the film substrate is preferably 20 to 90 μm because it can be a major factor in the rigidity and strength of the film and the ease with which the through holes can be opened by the high-density energy beam. Further, when the thickness of the adhesive is less than 10 μm, the adhesive strength becomes insufficient, the pressure of the plugging material slurry when filling the plugging material slurry, the film is easily peeled off, plugging The stopping material slurry flows into a flow path that should not be plugged, resulting in plugging failure. On the other hand, when it exceeds 40 μm, when the film is peeled off after forming the plugged portions, the film is less likely to peel off, and the partition walls on the end faces of the honeycomb are likely to be chipped. The material of the film is preferably a polymer material selected from polypropylene, polyethylene, acryl, olefin and the like. Further, the adhesive layer is preferably a rubber-based material based on acrylic rubber, styrene-butadiene rubber or the like. The adhesive force of the film is preferably 4 to 15 N/25 mm so that the film can be easily peeled off when peeled off and the film is less likely to be peeled off by the pressure of the plugging slurry. More preferably, it is 5 to 13 N/25 mm.

(b) Step of Determining Flow Path Position In order to determine a predetermined flow path position to be plugged in the attached film, for example, a laser processing device 20 as shown in FIG. 4 is used. In FIG. 4, the ceramic honeycomb structure 11 having the films 31 attached to both end surfaces is set on the XY stage 22, and above the XY stage 22 is an imaging device that images the end surface of the ceramic honeycomb structure 11. A CCD camera 23 and a laser head 25 are arranged. The laser processing device 20 is installed in a temperature-controlled thermostatic chamber 21. The XY stage 22 has a stroke capable of moving between a position where the ceramic honeycomb structure 11 is set and taken out, a position where the CCD camera 23 captures an image, and a position where laser light is emitted. The control device 24 controls the position of the XY stage 22, and also takes in the image information from the CCD camera 23 at the time of imaging and the movement information of the XY stage 22 to determine the position of a predetermined flow path to be plugged. Control of laser light irradiation and position control of the XY stage 22. The CCD camera 23 has an image resolution sufficient to define the shape of the flow path. The CCD camera 23 images the flow path and the partition through the film 31.

The ceramic honeycomb structure 11 having the film 31 attached to both end faces is set on the XY stage 22, and image information obtained by imaging the end faces of the ceramic honeycomb structure 11 by the CCD camera 23 and movement information of the XY stage 22. Based on the above, the position of the predetermined flow path to be plugged is determined. In the method for manufacturing a ceramic honeycomb filter of the present invention, the average transmittance of light having a wavelength of 480 to 590 nm measured using an integrating sphere (the transmittance of light of 480 to 590 nm was measured every 10 nm and averaged). By using a film whose (value) is 50% or more, the flow path and partition walls in the imaging device can be distinguished easily, and it becomes difficult to misidentify the flow path position where the plugged portion should be formed, and the position is determined. The accuracy of is increased. It is preferable that the flow passage positions where the plugged portions are formed are determined so that the sealed flow passages are arranged in a checkered pattern, for example.

(c) Step of forming a through hole in the film When the position of a predetermined cell to be sealed is determined by the imaging of the imaging device, this position information and perforation shape information (for example, 30 to 70% of the flow channel area) Through holes having an opening area of 1), a through hole is formed at a predetermined position of the film by high-density energy beam processing such as laser processing. When the through hole formed in the film by laser processing or the like is shifted to the adjacent channel side due to the deviation of the laser beam due to temperature drift, etc., for example, as shown by A in FIG. 2, the through hole is formed. There is. If the plugging portion is formed in the state where these hole shifts occur, the plugging portion is not formed at the flow path position where the plugging portion should be formed, or the plugging portion is A defective product such as a case where the plugging portion is formed only partially or a plugging portion is formed at a flow path position where the plugging portion should not be formed is manufactured.

In the method for manufacturing a ceramic honeycomb filter of the present invention, the average transmittance of light having a wavelength of 480 to 590 nm measured using an integrating sphere (the transmittance of light of 480 to 590 nm was measured every 10 nm and averaged). Since a film with a (value) of 50 to 88% is used, it is easy to distinguish the flow path that can be recognized through the film from the through holes formed in the film, and even if it is visually observed, it is possible to open a hole. It is possible to easily determine a defective hole in which a flow path that should not be formed is formed. For this reason, it is possible to prevent the plugging slurry from being filled through the film in which the hole forming defect has occurred and the plugging defect from occurring. When a defective hole is formed in the film, it is preferable to peel off the film in which the defective hole has been formed, and then reattach the film to re-form the through hole. This is because the ceramic honeycomb structure can be reused, which leads to an improvement in manufacturing yield.

(d) Step of filling the flow path end portion with the plugging material slurry The end surface of the ceramic honeycomb structure is immersed in the plugging material slurry, and the other end surface of the ceramic honeycomb structure is pressed by a pressing means to form a film. The encapsulant slurry is introduced into the flow path end through the through hole. Alternatively, the plugging material slurry can be introduced into the end portion of the flow path by pressurizing the plugging material slurry into the end surface of the ceramic honeycomb structure.

As the plugging material slurry to be filled in the flow passage, use a slurry in which a ceramic raw material is mixed and kneaded with a binder, water, and if necessary, an additive such as a dispersant and a pore-forming material. You can As this ceramic raw material, those used in conventional honeycomb filters can be applied, for example, selected from the group consisting of cordierite, raw material for making cordierite, alumina, silica, silicon nitride, silicon carbide, LAS, and aluminum titanate. It is possible to use a ceramic material containing at least one selected from the main crystals. The material of the plugged portions is preferably the same as that of the honeycomb fired body (ceramic honeycomb structure). Particularly, when the fired body having the honeycomb structure is made of cordierite-based ceramic, it is most preferable because it is inexpensive, has excellent heat resistance and corrosion resistance, and has low thermal expansion. The plugging material slurry is cordierite powder or cordierite. It is preferable that the slurry contains an erythetic raw material. As the cordierite forming raw material, silica, talc, kaolin, alumina, aluminum hydroxide or the like can be used. It is preferable that the length of the plugged portion is appropriately set according to the cross-sectional area of the flow channel.

After filling the desired flow path with the plugging material slurry, the attached film is peeled off, and the plugging material slurry is dried and fired if necessary. When firing the plugging material, if the plugging material is made of a cordierite forming raw material, it is preferably performed at 1350 to 1450°C.

The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Examples 1-3
A fired body having a honeycomb structure (honeycomb fired body) was manufactured by a known method. First, by using powders of kaolin, talc, silica, alumina and aluminum hydroxide, the cordierite is made to have a chemical composition of 50 mass% SiO ₂ , 35 mass% Al ₂ O ₃ and 15 mass% MgO. yielding feedstock powder was adjusted (the content of these, SiO _2: 48 to 52 wt%, Al ₂ O _3: 33~37 wt% and MgO: is adjustable in a range of 12 to 15 wt%.). Methyl cellulose and hydroxypropyl methyl cellulose as a binder and a foaming resin as a pore-forming agent were added to this, and after thoroughly dry mixing, water was added and sufficient kneading was performed to prepare a plasticized ceramic kneaded material. This kneaded material was extruded, molded, and cut to obtain a molded body having a honeycomb structure. After this molded body was dried, it was fired at a maximum holding temperature of 1400° C. to obtain 150 cordierite ceramic honeycomb fired bodies having a honeycomb structure. The ceramic honeycomb fired body having this honeycomb structure had an outer diameter of 267 mm, a length of 305 mm, a partition wall thickness of 0.3 mm, a partition wall pitch of 1.5 mm, and a porosity of 61%.

After polishing both end faces of the obtained 150 ceramic honeycomb fired bodies (ceramic honeycomb structure) with a grindstone, the average transmittance shown in Table 2 on both end faces (wavelength measured using an integrating sphere 480 to 590 nm 50 pieces of ceramic honeycomb firing film A, B, C (thickness 70 μm, base material thickness 50 μm, base material: polypropylene, adhesive layer: thickness 20 μm, acrylic rubber) 50 ceramic honeycomb fired bodies of each of Examples 1 to 3 were prepared by sticking to a body.

In order to form through holes at predetermined positions of the film attached to the ceramic honeycomb fired bodies of Examples 1 to 3, the ceramic honeycomb fired bodies were set on the XY stage 22 of the laser processing apparatus 21 shown in FIG. Then, the end face of the ceramic honeycomb fired body is imaged with a CCD camera through a film to obtain image information of the flow channel, and then the position of the flow channel is calculated based on the image information and the movement information of the XY stage. The position of the flow path where the sealed portion should be formed was determined. The positions of the flow passages where the plugged portions are to be formed are, as shown in FIGS. 1(a) and 1(b), alternately arranged in a checkered pattern in the flow passages on both end faces of the honeycomb structure. Was set at the position where In all of the ceramic honeycomb fired bodies of Examples 1 to 3, it was possible to determine the flow channel position where the plugged portion should be formed. Therefore, based on the determined flow channel position data, laser light irradiation was performed. The position was determined and a laser beam was irradiated to form a through hole. The through hole was set at the center of the flow channel so as to be 60% of the flow channel area.

For each of the 50 ceramic honeycomb fired bodies of Examples 1 to 3 in which the through holes were formed in the film, the formation state of the through holes on the film surface was visually inspected, and the through holes were formed in the channels that should not be plugged. In the case where defective holes were formed, which were formed, plugging portions were formed on the remaining ceramic honeycomb fired bodies after removing them. As the plugging material slurry for forming the plugging portion, powders of kaolin, talc, silica, and alumina are adjusted to have a chemical composition of 50 mass% SiO ₂ , 35 mass% Al ₂ O ₃ and 15 Prepared by adding methyl cellulose and water to the cordierite-forming raw material powder so that the mass% of MgO becomes, and the end face of the ceramic honeycomb fired body (film that was not found to have defective holes in the film in this plugging slurry) (Pasting surface) is immersed, and the plugging slurry is filled from the through hole to the flow path end portion at a length of 3.0 to 8.0 mm, then the stuck film is peeled off, and the filled plugging slurry is dried. As a result, a ceramic honeycomb fired body having plugging portions alternately arranged in a checkered pattern on the end face of the flow path was produced. For the ceramic honeycomb fired body having the alternately plugged portions, the formation state of the plugged portions was visually observed, and the plugged portions were formed in the channels that should not be plugged. The existence was confirmed. Occurrence rate of defective holes in which through holes were formed in the channels that should not be plugged after forming through holes in the film, and flow that should not be plugged after forming plugged portions Table 1 shows the occurrence rates of defective plugging in which plugged portions were formed in the paths.

Examples 1-3, by using a film having an average transmittance of 53.1-87.0%, the position of the flow channel can be recognized by the CCD camera, and it is possible to determine the flow channel position to form the plugged portion. After the through holes were formed on the film surface, it was possible to confirm by visual inspection that the holes were not formed and the through holes were formed in the channels that should not be plugged. Then, as a result of forming the plugging portion by filling the plugging material slurry into the flow path end portion of the ceramic honeycomb fired body after excluding this poor opening, the plugging is performed in the flow paths that should not be plugged. There was no occurrence of defective plugging in which the stopper was formed.

Comparative Examples 1 and 2
After polishing both end faces of 100 ceramic honeycomb fired bodies produced in the same manner as in Example 1 with grindstones, both end faces had an average transmittance shown in Table 2 (wavelengths 480 to 590 measured using an integrating sphere). Films D and E (thickness 70 μm, substrate thickness 50 μm, substrate material: polypropylene, pressure-sensitive adhesive layer: thickness 20 μm, acrylic rubber) with 50 nm ceramic honeycomb firing 50 ceramic honeycomb fired bodies of Comparative Examples 1 and 2 were prepared by sticking to a body. Then, in the same manner as in Example 1, the laser processing apparatus 21 shown in FIG. 4 performed imaging with a CCD camera in order to determine the flow path position where the plugged portion should be formed.

However, in Comparative Examples 1 and 2, by using the films having an average transmittance of 29.0% and 10.9%, respectively, the position of the channel of the first ceramic honeycomb fired body can be recognized by the CCD camera. As a result, the irradiation position of the laser beam could not be determined. Therefore, the laser beam could not be irradiated and the through hole was not formed. After that, an attempt was made to further form through holes in two more ceramic honeycomb fired bodies, but the through holes could not be formed because the irradiation position of the laser beam could not be determined. Therefore, in Comparative Examples 1 and 2, no through hole was formed after the fourth hole.

Comparative example 3
After polishing both end faces of 50 ceramic honeycomb fired bodies produced in the same manner as in Example 1, with both ends, the average transmittance shown in Table 2 (wavelength 480 ~ 590 measured using an integrating sphere). A film F (average thickness of light of nm) (thickness 70 μm, substrate thickness 50 μm, substrate material: polypropylene, adhesive layer: thickness 20 μm, acrylic rubber) is attached to 50 ceramic honeycomb fired bodies Then, fifty ceramic honeycomb fired bodies of Comparative Example 3 were prepared. Then, in the same manner as in Example 1, the laser processing apparatus 21 shown in FIG. 4 performed imaging with a CCD camera in order to determine the flow path position where the plugged portion should be formed. In each of the ceramic honeycomb fired bodies of Comparative Example 3, it was possible to determine the flow path position where the plugged portion should be formed.Therefore, based on the determined flow path position data, the irradiation position of the laser light is The determined through hole was irradiated with a laser beam to form a through hole. The through hole was set at the center of the flow channel so as to be 60% of the flow channel area.

In Comparative Example 3, since the film having the average transmittance of 89.5% was used, the position of the flow path could be recognized by the CCD camera, and the position of the flow path where the plugged portion should be formed could be easily determined. Further, after forming the through holes on the film surface, visual inspection was performed for a defective opening in which a through hole was formed in a channel that should not be sealed, and the detection rate of the defective opening was 0%. However, as a result of forming the plugging portion by filling the plugging material slurry into the flow path end portion of the ceramic honeycomb fired body in which no defective opening was found, plugging the flow path that should not be plugged It was found that 4% of the defective plugging in which parts were formed occurred, and visual inspection of the through holes formed in the film did not allow easy determination of defective holes, thus preventing the occurrence of defective plugging. You can see that it was not possible.

FIG. 3 shows the spectral transmittances measured using the integrating spheres of Films A to F used in Examples and Comparative Examples. From these data, the average transmittance of light having a wavelength of 480 to 590 nm (range indicated by an arrow) (value obtained by measuring the transmittance of light having a wavelength of 480 to 590 nm every 10 nm and averaging) was determined. The results are shown in Table 1.

Note (1): Value obtained by measuring the transmittance of light with a wavelength of 480 to 590 nm measured using an integrating sphere every 10 nm and averaging it.

From the results in Table 1, the films A to C, which have an average transmittance of 50 to 88% for light with a wavelength of 480 to 590 nm measured using an integrating sphere, can recognize the flow path without any problem by the imaging device, The visual inspection of the opening failure could be performed without any problems, and the occurrence of the plugging failure could be prevented.

10... Honeycomb filter
1... Outer wall
2... Porous partition wall
3 Outflow side sealed flow path
4... Inflow side sealed flow path
5a...Upstream side sealing part
5b...Downstream sealing part
6...Exhaust gas inflow side end face
7...Exhaust gas outflow side end face
11...Ceramic honeycomb structure
20...Laser processing device 2
21...Constant temperature chamber
22...XY stage
23...CCD camera
24...Control device
25...Laser head
26...Heater
27...Galvanometer
31...Film

Claims (4)

A method for producing a ceramic honeycomb filter by forming a plugging portion at a predetermined channel end portion of a ceramic honeycomb structure including a plurality of channels partitioned by porous partition walls,
The formation of the plugged portion includes a step of attaching a film to the end face of the ceramic honeycomb structure, a step of determining a flow path position where the plugged portion is to be formed by an imaging device, and the plugged portion is formed. Forming a through hole at the position of the film corresponding to the desired flow path, filling the plugging material slurry into the flow path end portion from the through hole, and drying the filled plugging material slurry Have
The average transmittance of light having a wavelength of 480 to 590 nm measured using the integrating sphere of the film (value obtained by measuring the transmittance of light of 480 to 590 nm every 10 nm and averaging) is 50 to 88%. A method for manufacturing a ceramic honeycomb filter, comprising: In the method for manufacturing a ceramic honeycomb filter according to claim 1,
The method for producing a ceramic honeycomb filter, wherein the average transmittance of light having a wavelength of 480 to 590 nm measured using an integrating sphere of the film is 55 to 88%. In the method for manufacturing a ceramic honeycomb filter according to claim 1 or 2,
A method of manufacturing a ceramic honeycomb filter, which comprises, after the step of forming the through holes, visually inspecting for defective opening of the through holes formed on the film. In the method for manufacturing a ceramic honeycomb filter according to any one of claims 1 to 3,
The method for producing a ceramic honeycomb filter, wherein the film has a film base material having a thickness of 20 to 90 μm and an adhesive layer having a thickness of 10 to 40 μm.