JP5523871B2 - Manufacturing method of honeycomb filter - Google Patents

Description

  The present invention relates to a method for manufacturing a honeycomb filter. More specifically, it is possible to produce a honeycomb filter in which a catalyst is supported on the partition wall surface in the cell, the amount of the catalyst entering the partition wall is small, and the plugging portion is not easily detached from the honeycomb-shaped porous substrate. The present invention relates to a method for manufacturing a possible honeycomb filter.

  Particulate matter in exhaust gas discharged from internal combustion engines such as automobile engines, construction machinery engines, stationary engines for industrial machinery, and other combustion equipment must be removed from the exhaust gases in consideration of environmental impact. The nature is increasing. Therefore, a honeycomb filter made of ceramic is widely used as a filter (diesel particulate filter: DPF) for removing particulate matter. The DPF includes, for example, a porous partition wall that partitions and forms a plurality of cells that serve as fluid flow paths, one end surface is plugged and the other end surface is open (predetermined cell), A structure in which cells having one end face opened and the other end face plugged (the remaining cells) are alternately arranged is used. In use, the fluid (exhaust gas) is caused to flow from the one end face where the remaining cells of the DPF are opened, and the inflowed exhaust gas is allowed to permeate the partition walls and flow out into the predetermined cell as a permeate fluid. By letting the permeating fluid flow out from the other end where the predetermined cell opens, the particulate matter in the exhaust gas is collected and removed by the partition walls.

  In general, the DPF is continuously used while being regenerated by burning and removing the collected particulate matter. The combustion reaction of particulate matter is usually promoted by a catalyst supported on DPF.

  Conventionally, the catalyst is supported on the DPF after forming plugged portions on both end faces of the honeycomb formed body (see, for example, Patent Document 1).

  Also disclosed is a method of forming a plugged portion on the other end surface where the plugged portion is formed after forming the plugged portion only on one end surface of the honeycomb formed body and then supporting the catalyst. (For example, see Patent Documents 2 and 3).

JP-A-62-247111 JP 59-211708 JP 2006-46200 A

  The method described in Patent Document 1 has a problem that it is difficult to carry a catalyst because plugging is performed on both end faces of a ceramic honeycomb formed body. In addition, as a method of supporting the catalyst with both end faces plugged in this way, for example, the catalyst slurry is caused to flow in from the other end face side while sucking from one end face side of the honeycomb formed body. Thus, a method of supporting the catalyst on the honeycomb formed body can be mentioned. In this case, the catalyst slurry flows into the cell that opens to the other end face, and moves by the suction from one end face to the cell that passes through the porous partition wall and opens to the one end face. It flows in the cell opened to the end face and is discharged from one end face side. When the catalyst slurry flows in the cell and permeates through the porous partition walls, the catalyst component is deposited in the partition wall surfaces and pores formed in the partition walls, whereby the catalyst is supported on the honeycomb formed body. . However, in this method, since the catalyst slurry permeates through the partition walls by suction, a large amount of catalyst component is supported (deposited) in the pores of the partition walls. Most of the particulate matter burned and removed by the catalyst is deposited on the partition wall surface, so the catalyst present in the pores of the partition wall cannot contact the particulate matter and contributes almost to the combustion of the particulate matter. I can't. Therefore, when the catalyst is supported on the honeycomb formed body by this method, there is a problem that the contact efficiency between the catalyst and the particulate matter is lowered. In addition, when a large amount of catalyst component is loaded in the pores, the porosity of the honeycomb structure (ie, the porous substrate) decreases, and the pressure loss as a filter increases. It was.

  Further, in the methods described in Patent Documents 2 and 3, since the plugged portion is formed after the catalyst is supported, sufficient adhesion between the plugged portion and the partition wall cannot be obtained. There has been a problem that the stopper is easily detached from the honeycomb structure.

  The present invention has been made in view of such problems of the prior art, and the catalyst is supported on the surface of the partition wall in the cell, the amount of the catalyst entering the partition wall is small, and the plugged portion is It is an object of the present invention to provide a method for manufacturing a honeycomb filter that manufactures a honeycomb filter that does not easily come off the honeycomb structure.

  As a result of intensive studies to solve the above-described problems of the prior art, the present inventor carried a catalyst after forming a plugged portion on one end face of the honeycomb formed body, and then the other end face. In the manufacturing method for forming the plugged portion in the first step, the hydraulic diameter at the other end surface of the cell to be plugged later (that is, after supporting the catalyst) is set to the plugging portion first (that is, before the catalyst is loaded). The present invention has been completed by conceiving that the above problems can be solved by making the diameter smaller than the hydraulic diameter at one end face of the cell to be performed. Specifically, the present invention provides the following method for manufacturing a honeycomb filter.

[1] Forming a kneaded clay containing a ceramic raw material into a honeycomb shape having partition walls that form a plurality of cells that penetrate from one end face to the other end face and serve as fluid flow paths. And a honeycomb molded body in which the first plugging slurry is filled in an opening of a predetermined cell on one end face of the obtained honeycomb molded body, and the first plugged slurry is filled Is fired to sinter the first plugged slurry and the honeycomb formed body to form a one-side plugged honeycomb formed body having a first plugged portion on one end face. From the one end face side where the first plugged portion of the obtained one-side plugged honeycomb formed body is formed, the catalyst slurry is placed in the remaining cells whose both end faces are open. The partition walls in the remaining cells A catalyst supporting step of forming a honeycomb catalyst body by applying a catalyst to the surface, and the first plugged portions of the honeycomb catalyst body of the remaining cells of the obtained honeycomb catalyst body are formed. A second plugging slurry is filled in an opening that is open on the other end face side, and the honeycomb catalyst body filled with the second plugging slurry is less than the deterioration temperature of the supported catalyst. A second plugging step of solidifying the second plugging slurry by drying at a temperature to produce a second plugged portion to obtain a honeycomb filter, and in the molding step, The honeycomb formed body is formed into a shape in which the cross-sectional shape orthogonal to the central axis of the predetermined cell is substantially octagonal, and the cross-sectional shape orthogonal to the central axis of the remaining cells is substantially rectangular. and, the other of the remaining cells Hydraulic diameter in the plane is, the manufacturing method of the honeycomb filter to be formed becomes smaller shape than the hydraulic diameter of one end surface of the given cell.

[2] In the forming step, the hydraulic diameter of the remaining cells gradually decreases toward the other end face in the area where the honeycomb molded body is filled with at least the second plugging slurry. The method for manufacturing a honeycomb filter according to [1], wherein the honeycomb filter is formed into a shape.

[ 3 ] In the forming step, the honeycomb formed body is formed in a shape having irregularities on a partition wall surface that partitions and forms the remaining cells in a region filled with the second plugging slurry. ] The manufacturing method of the honey-comb filter of description.

[ 4 ] The method for manufacturing a honeycomb filter according to any one of [1] to [ 3 ], wherein the firing is performed at a temperature equal to or higher than a deterioration temperature of the supported catalyst in the first plugging step.

[ 5 ] The method for manufacturing a honeycomb filter according to any one of [1] to [ 4 ], wherein the drying is performed at a temperature lower than a deterioration temperature of the supported catalyst in the second plugging step.

[ 6 ] The method for manufacturing a honeycomb filter according to [ 5 ], wherein the second plugging slurry is a ceramic cement that is solidified by drying at a temperature lower than a deterioration temperature of the supported catalyst.

  In the method for manufacturing a honeycomb filter of the present invention, the hydraulic diameter on the end surface (that is, the other end surface) on the side where plugging of the cells (that is, the remaining cells) to be plugged later is performed first. By producing a honeycomb molded body so as to be smaller than the hydraulic diameter at the end face (that is, the one end face) on the plugging side of the plugging cell (that is, the predetermined cell), a catalyst is obtained. It is possible to make it difficult for the second plugged portion formed after the support is removed from the honeycomb structure (honeycomb porous substrate). Furthermore, in the step of supporting the catalyst, the catalyst slurry can be prevented from permeating through the porous partition walls, so that the supported catalyst can be effectively deposited on the surface of the partition walls in the cell and the catalyst support is supported. The previously formed first plugged portion can be sintered at a high temperature to be strong. Since the second plugging portion is formed by solidifying at a low temperature, it is possible to effectively prevent deterioration of the catalyst already supported (deposited) on the surface of the partition wall.

The honeycomb filter manufactured in accordance with one embodiment of the method for manufacturing a wafer Nikamufiruta is a perspective view schematically showing. 1B is a schematic view showing a cross section parallel to the central axis direction of the honeycomb filter shown in FIG. 1A. FIG. It is a schematic diagram showing a manufacturing process in an embodiment of the method for manufacturing a wafer Nikamufiruta. It is a schematic diagram which shows the cross section parallel to the central-axis direction of the honey-comb filter manufactured by other embodiment of the manufacturing method of the honey-comb filter of this invention. It is the top view to which the other end surface of the honey-comb filter shown to FIG. 3A was expanded. It is a schematic view showing a section parallel to the central axis direction of the honeycomb filter manufactured according to another embodiment of the method for manufacturing the wafer Nikamufiruta. FIG. 4B is an enlarged plan view of the other end face of the honeycomb filter shown in FIG. 4A. It is the top view to which the remaining cell in the other end surface of the honey-comb filter shown to FIG. 4A was expanded. It is a schematic diagram which shows a cross section parallel to the central axis direction of a honeycomb filter.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments, and is within the scope of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on the general knowledge of vendors.

(1) Manufacturing method of honeycomb filter:
One embodiment of Ha Nikamufiruta, such as shown in FIGS. 1A and 1B, penetrates to form partitioning a plurality of cells 2 functioning as a flow path of the fluid from one end face 11 to the other end face 12, the ceramic porous Honeycomb-shaped porous base material 1 having partition walls 3 containing as a main component, and a first plugged portion 21 (21a) disposed so as to close an opening of a predetermined cell 2a on one end face 11 And a second plugging portion 21 (21b) disposed so as to close the opening of the remaining cell 2b on the other end face 12, and a second plugging portion 21 (21b). This is a method of manufacturing a honeycomb filter provided with the catalyst layer 22 disposed on the surface of the partition wall 3 in the cell 2 (remaining cell 2b).

Here, FIG. 1A, the honeycomb filter manufactured according to one embodiment of the method for manufacturing a wafer Nikamufiruta is a perspective view schematically showing, FIG. 1B, parallel to the central axis direction of the honeycomb filter shown in FIG. 1A It is a schematic diagram which shows a cross section.

Method of manufacturing a wafer Nikamufiruta, as shown in FIG. 2, a clay containing a ceramic raw material, defining a plurality of cells 32 functioning as a flow path of the fluid passing from one end face 34 to the other end face 35 A forming step of forming a honeycomb formed body 31 by forming into a honeycomb shape having partition walls 33, and a first plugging slurry at an opening of a predetermined cell 32a on one end face 34 of the obtained honeycomb formed body 31. The honeycomb formed body 31 filled with the first plugging slurry is fired to sinter the first plugged slurry and the honeycomb formed body 31, and the first end surface 34 has the first The first plugging step for forming the one-side plugged honeycomb formed body 36 having the plugged portions 41 and the first plugged portion 41 of the obtained one-side plugged honeycomb formed body 36 are formed. From the other end face 34 side, A honeycomb catalyst body in which a catalyst slurry is caused to flow into the remaining cells 32b having an open end face, the catalyst is applied to the surfaces of the partition walls 33 in the remaining cells 32b, and the catalyst layer 43 is disposed on the surfaces of the partition walls 33. And the opening of the remaining cells 32b of the obtained honeycomb catalyst body 37 on the side of the other end face 35 where the first plugging portions 41 of the honeycomb catalyst body 37 are not formed. The portion is filled with the second plugging slurry, and the honeycomb catalyst body 37 filled with the second plugging slurry is dried at a temperature lower than the deterioration temperature of the supported catalyst. A second plugging step of solidifying the sealing slurry to form a second plugging portion 42 to obtain a honeycomb filter 38.

  In the honeycomb filter manufacturing method of the present embodiment, in the above-described forming step, the honeycomb formed body 31 has a hydraulic diameter at the other end face 35 of the remaining cell 32b, at the one end face 34 of the predetermined cell 32a. The shape is smaller than the hydraulic diameter. The predetermined cell means one or more cells (that is, specific cells plugged on one end face) plugged on one end face, and the remaining cells means the other end face. It means a cell other than the predetermined cell that is plugged at the end face.

  As described above, the honeycomb filter manufacturing method of the present embodiment has a hydraulic diameter on the end surface (that is, the other end surface) on the side where plugging of the cells (that is, the remaining cells) to be plugged later is performed. By forming a honeycomb molded body so as to be smaller than the hydraulic diameter at the end face (that is, the one end face) opposite to the cell to be plugged first (that is, the predetermined cell). It is possible to make it difficult for the second plugged portion formed after the support is removed from the honeycomb structure (porous substrate). Furthermore, in the catalyst supporting step, the catalyst slurry can be prevented from permeating through the porous partition walls, so that the supported catalyst can be effectively deposited on the surface of the partition walls in the cell, and before the catalyst is supported. The formed first plugging portion can be made strong by sintering at a high temperature. Since the second plugged portion is formed by solidifying at a low temperature, it is possible to effectively prevent the deterioration of the catalyst (that is, the catalyst layer) already supported (deposited) on the surface of the partition wall. .

  In the honeycomb filter manufacturing method of the present embodiment, the “cell hydraulic diameter” is calculated as “4 × (opening area) / (peripheral length)” based on the opening area and the peripheral length at a predetermined end surface of the cell. Value. Here, the opening area (of the cell) refers to the opening area at the end face of the cell, and the circumference of the (cell) is the length around the shape of the cell (the length of the closed line surrounding the shape, In other words, it refers to the peripheral length measured along the partition wall surface defining the cell. When measuring the perimeter along the partition wall that forms the cell, measure the perimeter of the actual cell shape, which corresponds to the perimeter of the cell shape at the time of design. For example, it is not necessary to measure an extremely fine unevenness on an unintended partition wall surface. On the other hand, when unevenness is intentionally formed on the partition wall surface, the circumference length is measured along the unevenness on the partition wall surface.

  Although not particularly limited, in the honeycomb filter manufacturing method of the present embodiment, the hydraulic diameter of the other end face of the remaining cells is 0.10 than the hydraulic diameter of one end face of the predetermined cell. It is preferable to be smaller by ˜0.80 mm, and further preferably smaller by 0.30 to 0.60 mm. By comprising in this way, a 2nd plugging part can be made hard to remove | deviate favorably. In addition, although the magnitude | size of the hydraulic diameter of a specific cell changes with the magnitude | size of a remaining cell and a predetermined cell (namely, area of a cross section perpendicular | vertical to the cell extending direction), for example, the other cell of a remaining cell The hydraulic diameter of the end surface is preferably 0.50 to 1.40 mm, and more preferably 0.80 to 1.25 mm. On the other hand, the hydraulic diameter of one end face of the predetermined cell is preferably 1.00 to 1.90 mm, and more preferably 1.15 to 1.60 mm.

  As described above, the manufacturing method of the honeycomb filter of the present embodiment is such that the hydraulic diameter on the end surface (the other end surface) on which the remaining cells are plugged later is plugged first. If the honeycomb formed body is prepared so as to be smaller than the hydraulic diameter at the end face (one end face) on the opposite side of the cell (that is, the above-mentioned predetermined cell), the honeycomb as shown in FIG. The molded body 31 may be formed in such a shape that the hydraulic diameter of the remaining cells 32b gradually decreases toward the other end face side 35 in the region filled with at least the second plugging slurry.

  In addition, the hydraulic diameter of the remaining cells is not only small in the end surface (the other end surface) on the side where plugging is performed, but also in the portion where the cells are plugged in the extending direction (plugged portion). ), It may be configured to gradually become smaller from other parts (parts not plugged) (for example, the form shown in FIG. 2), or in the cell extending direction (plugged) The hydraulic diameter may be configured to gradually decrease toward the other end face side (over the stop portion).

  For example, as in the honeycomb filter 500 shown in FIG. 5, the hydraulic diameter of the remaining cells 102b gradually decreases from one end surface 111 side to the other end surface 112 side, and the hydraulic diameter of a predetermined cell 102a is the other. Also, the plugging portion 121 (121b) of the remaining cell 102b can be made difficult to come off by forming in a shape that gradually increases from the end surface 112 side toward the one end surface 111 side. Here, FIG. 5 is a schematic view showing a cross section parallel to the central axis direction of the honeycomb filter. Reference numeral 121a denotes a first plugging portion that plugs one end face 111 of a predetermined cell 102a, and reference numeral 122 denotes a catalyst layer disposed on the surface of the partition wall 103 in the remaining cell 102b. Indicates.

Further, in the present embodiment, the remaining cells and the predetermined cells are formed so as to have different sizes (that is, areas of cross sections perpendicular to the cell extending direction), and the remaining cells are formed on the other end surfaces of the remaining cells. You may comprise so that a hydraulic diameter may become smaller than the hydraulic diameter in one end surface of a predetermined cell. In the present embodiment, as in the honeycomb filter 300 shown in FIGS. 3A and 3B, in the forming step, the honeycomb molded body has a substantially octagonal shape in cross section perpendicular to the central axis of the predetermined cell 2a. the shape of the cross section perpendicular to the central axis of the remaining cells 2b are you formed into a shape such as a substantially quadrangular. 3A and 3B, the hydraulic diameter at the other end face 12 of the remaining cell 2b is smaller than the hydraulic diameter at the one end face 11 of the predetermined cell 2a.

  In the above-described embodiment, the example in which the hydraulic diameter of the cell is reduced by actually reducing the opening area on the other end face of the remaining cell has been described. For example, FIG. 4A and FIG. 4B As in the honeycomb filter 400 shown in FIG. 5, the peripheral length of the other end face 12 of the remaining cell 2b may be increased to relatively reduce the hydraulic diameter of the cell. 4A and 4B show the honeycomb molded body (the porous substrate 1 after firing in FIGS. 4A and 4B), the end of the remaining cell 2b on the other end face 12 side, more specifically, at least An example is shown in which the surface of the partition wall 3 that partitions and forms the remaining cells 2b in the region filled with the second plugging slurry is formed in a shape having irregularities.

  By comprising in this way, the contact area of the 2nd plugging part produced by filling up the 2nd plugging slurry, and the partition which defines the remaining cell can be enlarged, The second plugging portion can be made difficult to come off. That is, since the load per unit area applied to the partition wall can be reduced with respect to the magnitude of the force generated when the second plugged portion is detached, the second plugged portion is hardly detached.

  In addition, as shown in FIG. 4B, in the case where unevenness is formed on the inner surface (that is, the surface of the partition wall 3) on the other end face 12 side of the remaining cell 2b to increase the peripheral length, for example, After the formation of a square cell with a smooth inner surface, a bar-like member (for example, a top bar) with irregularities formed on the surface is pushed into the opening of the remaining cell, and the other end surface of the remaining cell An example is a method in which the unevenness of the rod-shaped member is cut into the inner surface on the side (that is, the surface of the partition wall).

  In addition, as described above, there is no particular limitation on the shape of the unevenness in the case where unevenness is formed on the inner surface (that is, the surface of the partition wall) on the other end face side of the remaining cell 2b to increase the peripheral length. As shown to 4C, it is preferable that the height H of the convex part in the inner surface by the side of the other end surface of the remaining cell 2b is 0.03-0.20 mm, and it is 0.07-0.15 mm. Further preferred. Further, the angle θ of the convex portion (that is, the angle θ formed by the two sides forming the convex portion) is preferably 50 to 130 °, and more preferably 60 to 110 °. By configuring in this manner, the uneven shape can be formed satisfactorily, and the peripheral length of the remaining cell 2b can be increased to make it difficult to remove the second plugged portion. The uneven shape may be a wave shape.

Here, FIG. 3A is a schematic diagram showing a cross section parallel to the central axis direction of a honeycomb filter manufactured by another embodiment of the manufacturing method of the honeycomb filter of the present invention, and FIG. 3B is a honeycomb filter shown in FIG. 3A. It is the top view to which the other end surface of was expanded. Further, FIG. 4A is a schematic view showing still a section parallel to the central axis direction of the honeycomb filter manufactured by another embodiment of a method of manufacturing a wafer Nikamufiruta, FIG. 4B, the honeycomb filter shown in FIG. 4A 4C is an enlarged plan view of the other end face, and FIG. 4C is an enlarged plan view of the remaining cells on the other end face of the honeycomb filter shown in FIG. 4A. In FIG. 3, FIG. 4A, FIG. 4B, and FIG. 4C, the same components as those of the honeycomb filter shown in FIG.

  Hereinafter, the manufacturing method of the honeycomb filter of the present embodiment will be described in more detail for each step.

(1-1) Molding process:
As shown in FIG. 2, the forming step has a partition wall 33 that divides and forms a plurality of cells 32 that pass through a clay containing a ceramic raw material from one end surface 34 to the other end surface 35 and serve as fluid flow paths. This is a step of forming a honeycomb formed body 31 by forming into a honeycomb shape.

  More specifically, a binder, a surfactant, a pore former, water and the like are added to the ceramic raw material to obtain a forming raw material. Ceramic raw materials include silicon carbide, cordierite forming raw material, alumina titanate, sialon, mullite, silicon nitride, zirconium phosphate, zirconia, titania, alumina, silica, and LAS (lithium aluminum silicate) or a combination thereof. It can be mentioned as a suitable example. In particular, ceramics such as silicon carbide, cordierite, mullite, silicon nitride, alumina, and alumina titanate are suitable in terms of thermal shock resistance and alkali resistance. Among these, an oxide-based ceramic is preferable in terms of cost. In addition, it is preferable that a ceramic raw material shall be 30-95 mass% with respect to the whole shaping | molding raw material.

  By adjusting the particle size and blending amount of the ceramic raw material (aggregate particles) to be used and the particle size and blending amount of the pore former to be added, a honeycomb filter having a desired porosity and average pore size (porous substrate) ) Can be obtained.

  Examples of the binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The content of the binder is preferably 1 to 20% by mass with respect to the entire forming raw material.

  The water content is preferably 18 to 45 mass% with respect to the entire forming raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the surfactant is preferably 0 to 5% by mass with respect to the entire forming raw material.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include starch, foamed resin, water absorbent resin, silica gel and the like. The pore former content is preferably 0 to 20% by mass with respect to the entire forming raw material.

  Next, the obtained forming raw material is kneaded to form a clay. There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, a clay is formed to form a honeycomb formed body. The method for forming the kneaded clay to form the honeycomb formed body is not particularly limited, and a conventionally known forming method such as extrusion molding or injection molding can be used. Preferred examples include a method of forming a honeycomb formed body by extrusion using a die having a desired cell shape, partition wall thickness, and cell density. As the material of the die, a cemented carbide which does not easily wear is preferable.

  The thickness of the partition wall of the honeycomb formed body is preferably 0.20 to 0.50 mm after firing, and is 0.25 to 0.45 mm after firing in terms of ease of manufacture. It is preferable that If it is thinner than 0.20 mm, the strength of the resulting honeycomb filter may be reduced, and if it is thicker than 0.50 mm, the pressure loss when exhaust gas passes through the cell may increase when the honeycomb filter is used. . The thickness of the partition wall is an average value measured by a method of observing an axial cross section with a microscope.

The cell density of a cross section perpendicular to the central axis of the honeycomb formed body is preferably 0.9 to 93 cells / cm ^2, more preferably 7.8 to 62 cells / cm ^2. When it is less than 0.9 cell / cm ² , the strength of the obtained honeycomb filter may be reduced, and when it is more than 93 cell / cm ² , the pressure loss of the obtained honeycomb filter may be increased. The cell density of the honeycomb formed body described above is a value measured on any one end face.

The cell shape of the honeycomb formed body is substantially octagonal in cross section perpendicular to the center axis of the predetermined cell, and substantially square in cross section perpendicular to the center axis of the remaining cells. is there.

  The outer shape of the honeycomb formed body is not particularly limited, and examples thereof include a cylindrical shape such as a cylindrical shape, an elliptical cylindrical shape, and a rectangular cylindrical shape, and a cylindrical shape whose bottom surface is indefinite. Further, the size of the honeycomb formed body is not particularly limited, but the length in the central axis direction is preferably 40 to 500 mm. For example, when the honeycomb molded body has a cylindrical outer shape, it is preferable that the bottom surface has a radius of 50 to 500 mm.

  Moreover, the honeycomb formed body may have an outer peripheral wall located at the outermost periphery thereof. The outer peripheral wall is preferably a molded integral wall formed integrally with the honeycomb molded body at the time of molding, but after molding or firing, the outer periphery of the honeycomb molded body is ground to a predetermined shape, and is made of ceramic cement or the like. An outer peripheral wall can also be formed.

  In the forming step in the manufacturing method of the honeycomb filter of the present embodiment, the honeycomb formed body has a hydraulic diameter at the other end face of the remaining cells (that is, cells to be plugged later). A shape smaller than the diameter is formed.

  More specifically, for example, a jig formed of a single or a plurality of square-pyramidal crest bars having a smooth surface is pressed on the other end face of a predetermined cell of a honeycomb formed body formed by extrusion molding or the like. By applying, the hydraulic diameter of the other end face of the remaining cells can be reduced. As a similar method, for example, a groove having a depth of 0.03 to 0.20 mm and an angle of 50 to 130 ° is formed on the other end face of the remaining cells of the honeycomb formed body formed by extrusion molding or the like. Pressing a jig made of single or multiple square pyramid crests processed in parallel to the direction of pressing against the cell, increasing the outer peripheral length of the remaining cell, and the hydraulic diameter at the other end of the remaining cell Can be reduced. The uneven shape on the surface of the top bar may be a wave shape.

  The method for reducing the hydraulic diameter at the other end face of the remaining cell is not limited to the above-described method. For example, at the stage of forming the cell by extrusion, the hydraulic force at one end face of the predetermined cell is set. It can also be formed so that the hydraulic diameter of the remaining cells is smaller than the diameter. In this case, the cross-sectional shape of the predetermined cell is made substantially octagonal, and the cross-sectional shape of the remaining cells is made substantially square, so that the thickness of the porous partition wall forming the cell is made constant and the pressure loss is lowered. A method can also be mentioned.

  After forming the honeycomb formed body, the obtained honeycomb formed body may be dried. The drying method is not particularly limited, and examples thereof include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like. Among them, dielectric drying, microwave drying or It is preferable to perform hot air drying alone or in combination. The drying conditions are preferably a drying temperature of 30 to 150 ° C. and a drying time of 1 minute to 2 hours.

(1-2) First plugging step:
Next, as shown in FIG. 2, the first plugging slurry is filled in the openings of predetermined cells 32 a on one end face 34 of the obtained honeycomb formed body 31. The honeycomb molded body 31 filled with sinter is fired to sinter the first plugging slurry and the honeycomb molded body 31, and the one-side plugged having the first plugged portion 41 on one end face 34 A fixed honeycomb formed body 36 (that is, a fired body of the honeycomb formed body in which one end face side is plugged) is formed.

  When the first plugging slurry is filled in the opening of a predetermined cell on one end face of the honeycomb formed body, for example, first, the opening of the remaining cell is plugged on one end face of the honeycomb formed body. Apply a mask in a checkered pattern. The method of applying the mask does not have to be a checkered pattern. And the 1st plugging slurry containing a ceramic raw material, water or alcohol, and an organic binder is stored in the storage container.

  The ceramic raw material for the first plugging slurry is preferably the same as the ceramic raw material used for forming the honeycomb formed body. The ceramic raw material is preferably 70 to 90% by mass of the entire first plugging slurry. Moreover, it is preferable that water or alcohol is 10-30 mass% of the whole 1st plugging slurry, and an organic binder is 0.1-2.0 mass% of the whole 1st plugging slurry. Preferably there is. Examples of the organic binder include hydroxypropoxyl methylcellulose and methylcellulose.

  Next, one end face side on the side where the mask is applied is dipped in a storage container, and the first plugging slurry is filled into the opening of a predetermined cell where the mask is not applied. The viscosity of the first plugging slurry is preferably 600 to 1200 Pa · s. The viscosity of the plugging slurry is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a slurry temperature of 30 ° C.

  As described above, it is preferable to dry the honeycomb formed body after the first plugging slurry is filled in the opening of a predetermined cell. The drying method is not particularly limited, and for example, a known drying method such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, or the like can be used. Especially, the drying method which combined hot air drying and microwave drying or dielectric drying is preferable at the point which can dry the whole molded object rapidly and uniformly.

  Moreover, it is preferable that the honeycomb formed body in which the opening portion of a predetermined cell on one end face is filled with the first plugging slurry is calcined before the main firing. “Preliminary firing” means an operation of burning and removing organic matter (organic binder, pore former, etc.) in the honeycomb formed body. Generally, the combustion temperature of the organic binder is about 100 to 300 ° C., and the combustion temperature of the pore former is about 200 to 800 ° C. Therefore, the calcining temperature may be about 200 to 1000 ° C. Although there is no restriction | limiting in particular as a calcination time, Usually, it is about 10 to 100 hours.

  After performing drying and calcining as described above as necessary, firing (main firing) the honeycomb formed body in which the opening of a predetermined cell on one end face is filled with the first plugging slurry. Thus, a one-side plugged honeycomb formed body is obtained.

  In the present invention, “main firing” means an operation for sintering and densifying the honeycomb formed body and the plugging slurry to ensure a predetermined strength. Here, “sinter the honeycomb formed body and the plugging slurry” means that the forming raw material contained in the honeycomb formed body and the plugging slurry is sintered. The firing temperature is preferably a temperature equal to or higher than the deterioration temperature of the supported catalyst. For example, when the material of the honeycomb formed body and the material of the plugging portion are cordierite, 1380 to 1450 ° C is preferable, and 1400 to 1400 1440 ° C. is more preferable. For example, the firing temperature when the material of the honeycomb formed body and the material of the plugging portion is silicon carbide is preferably 1200 to 1600 ° C, and more preferably 1300 to 1500 ° C. Thereby, the 1st plugging part can be firmly fused to the partition of a honeycomb fabrication object. The firing time is preferably about 1 to 200 hours.

(1-3) Catalyst supporting step:
Next, as shown in FIG. 2, from one end surface 34 side where the first plugged portion 41 of the one-side plugged honeycomb formed body 36 is formed, into the remaining cells 32 b where both end surfaces open, The catalyst slurry is allowed to flow, and the catalyst is applied to the surface of the partition walls 33 in the remaining cells 32b to form the honeycomb catalyst body 37.

  In the method for manufacturing the honeycomb filter of the present embodiment, the first plugged portion is formed on the honeycomb formed body, the catalyst is supported, and then the second plugged portion is formed. When the catalyst is supported after forming the first plugged portion, the plugged portion is not yet formed on the other end portion side of the honeycomb formed body, so the catalyst slurry is formed in the first plugged portion. The catalyst can be supported on the partition wall surface in the cell only by passing through the inside of the cell.

  Thereby, since it can suppress that a catalyst slurry permeate | transmits a partition, the honey-comb filter with little catalyst amount which penetrate | invaded in the pore formed in the partition can be manufactured. The amount of catalyst supported in the pores of the partition walls is preferably 0 to 35% by mass, and preferably 0 to 25% by mass, based on the total amount of catalyst supported on the honeycomb filter. When it is more than 35% by mass, the contact efficiency between the particulate matter collected from the exhaust gas and the catalyst may be lowered. The smaller the amount of catalyst supported in the pores of the partition walls, the better. However, in practice, 5% by mass is the lower limit.

  The method for coating (supporting) the catalyst and disposing (forming) the catalyst layer is not particularly limited, and can be supported by a known method. For example, first, a catalyst slurry containing a predetermined catalyst is prepared. Next, this catalyst slurry is caused to flow from one end face side of the one-side plugged honeycomb formed body into a cell (remaining cell) having both end faces open. When the catalyst slurry is allowed to flow into the cell, it is preferable to adopt a dipping or suction method. The catalyst slurry is preferably applied to the entire surface of the partition walls in the cell. Thereafter, the catalyst layer can be disposed on the honeycomb filter by drying at room temperature or under heating conditions.

  After flowing the catalyst slurry into the cell, it is preferable to blow off the excess slurry with compressed air. Thereafter, it is preferable to obtain a honeycomb catalyst body in which the catalyst is coated (supported) on the partition wall surfaces in the remaining cells by drying and baking the catalyst. The drying conditions are preferably 80 to 150 ° C. and 1 to 6 hours. Moreover, it is preferable that baking conditions shall be 450-700 degreeC and 0.5 to 6 hours.

Specific examples of the catalyst applied to the partition wall surface include an oxidation catalyst for purifying diesel engine exhaust gas. The oxidation catalyst for purifying diesel engine exhaust gas contains a noble metal. As this noble metal, one or more selected from the group consisting of Pt, Rh and Pd can be cited as a preferred example. The total amount of noble metals is preferably 0.17 to 7.07 g per liter of honeycomb filter volume. The NO _X selective reduction SCR catalyst and the NO _X storage catalyst can be used in combination.

The SCR catalyst for NO _X selective reduction contains at least one selected from the group consisting of metal-substituted zeolite, vanadium, titania, tungsten oxide, silver, and alumina. The NO _X storage catalyst contains alkali metal and alkaline earth metal. Examples of the alkali metal include K, Na, and Li. Examples of the alkaline earth metal include Ca. The total amount of K, Na, Li, and Ca is preferably 5 g or more per liter of honeycomb filter volume.

  Moreover, alumina etc. are mentioned as components other than the catalyst contained in a catalyst slurry.

(1-4) Second sealing step:
Next, as shown in FIG. 2, the remaining cells 32b of the obtained honeycomb catalyst body 37 are opened to the other end face 35 side where the first plugging portions 41 of the honeycomb catalyst body 37 are not formed. The opening is filled with the second plugging slurry, and the honeycomb catalyst body 37 filled with the second plugging slurry is dried at a temperature lower than the deterioration temperature of the supported catalyst to obtain the second The honeycomb filter 38 is obtained by solidifying the plugging slurry to form the second plugging portion 42.

  The method of filling the other end face side with the second plugging slurry is preferably the same method as the method of filling the one end face with the first plugging slurry. In this case, a mask is applied to the other end surface of the predetermined cell in which the first plugging portion is formed on one end surface, and the second plugging slurry is filled into the opening of the remaining cell. As will be described later, by adjusting the ratio of the depth (mm) of the second plugging portion and the hydraulic diameter (mm) of the other end surface of the remaining cells, the second plugging portion It is possible to manufacture a honeycomb filter in which an excessive decrease in the filtration area of the filter is suppressed. Therefore, when filling the second plugging slurry, the ratio between the filling depth (mm) of the second plugging slurry and the hydraulic diameter (mm) of the other end face of the remaining cells, In consideration of the above, it is more preferable to appropriately determine the filling depth of the second plugging slurry.

  As the second plugging slurry, it is preferable to use a slurry that solidifies by drying at a temperature lower than the deterioration temperature of the supported catalyst. Specific examples include colloidal silica, water glass (sodium silicate aqueous solution), alumina-zirconia composite cement, and the like, and ceramic powders such as cordierite and silicon carbide can be added thereto. The viscosity of the second plugging slurry is preferably 400 to 1800 Pa · s. The viscosity of the second plugging slurry is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a slurry temperature of 30 ° C.

Note that “catalyst degradation” means that the function of the supported catalyst to purify carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO _X ) in the exhaust gas is drastically reduced. This means that the temperature at which the particulate matter collected by the honeycomb filter is removed by combustion is rapidly increased. When the catalyst has deteriorated, the concentration of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO _x ) before and after passing through the honeycomb filter is measured, or the particles collected by the honeycomb filter It can be confirmed by a method such as measuring the time required to burn off the particulate matter. “Catalyst degradation temperature” means that the function of purifying carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO _X ) in exhaust gas is drastically reduced, or particles collected by the honeycomb filter. The temperature at which the particulate matter is burned and removed suddenly rises and varies depending on the type of the supported catalyst, but generally means a temperature of 800 to 1000 ° C.

  By drying the honeycomb catalyst body filled with the second plugging slurry at a temperature lower than the deterioration temperature of the supported catalyst, it is possible to prevent deterioration of the previously supported catalyst. The drying temperature when the honeycomb catalyst body filled with the second plugging slurry is dried at a temperature lower than the deterioration temperature of the supported catalyst is preferably 150 to 950 ° C, and more preferably 300 to 800 ° C. If it is lower than 150 ° C., the drying is insufficient and the adhesive force between the plugged portion and the porous substrate is weak and the plugged portion may come off during use. If it is higher than 950 ° C., the catalyst deteriorates, The function of the honeycomb filter may not be exhibited. The drying time is preferably 0.5 to 12 hours.

  As described above, the main component is a porous ceramic, as shown in FIG. 1A and FIG. 1B, that defines a plurality of cells 2 that penetrate from one end face 11 to the other end face 12 and serve as fluid flow paths. A honeycomb-shaped porous substrate 1 having partition walls 3, a first plugged portion 21 (21 a) disposed so as to close an opening of a predetermined cell 2 a on one end surface 11, and the other The second plugged portion 21 (21b) disposed so as to close the opening of the remaining cell 2b on the end face 12 of the cell 2 and the cell 2 provided with the second plugged portion 21 (21b) A honeycomb filter including the catalyst layer 22 disposed on the surface of the partition walls 3 in the (remaining cells 2b) can be manufactured.

  When a plurality of honeycomb segments are joined to produce one honeycomb filter, a plurality of honeycomb filters are produced by the manufacturing method described above, and the obtained honeycomb filters are used as honeycomb segments. It is preferable to obtain a honeycomb filter by bonding the side surfaces. The honeycomb segments are preferably bonded with a bonding material. The bonding material is not particularly limited, and a known ceramic-containing bonding material can be used.

(2) Honeycomb filter:
Next, the honeycomb filter manufactured by the method for manufacturing a honeycomb filter of the present invention will be described in more detail.

As shown in FIG. 1A and FIG. 1B, the honeycomb filter manufactured by the method for manufacturing a honeycomb filter of the present invention has a cell 2 in which the second plugging portion 21b is disposed (residual cell 2b).
A catalyst layer 22 supported on the surface of the inner partition wall 3 is provided. By providing such a catalyst layer 22, it is possible to effectively burn and remove the particulate matter collected in the partition walls 3. Further, the first plugged portion 21a is disposed by supporting the catalyst layer on the surface of the partition wall 3 in the cell 2 (remaining cell 2b) in which the second plugged portion 21b is disposed. When exhaust gas is caused to flow from one end face 11 side, exhaust gas flows from the opening of the cell 2 (remaining cell 2b) in which the second plugging portion 21b is disposed, and the second plugging portion 21b. Since the particulate matter is deposited on the surface of the partition wall 3 of the cell 2 (remaining cell 2b) in which the catalyst is disposed, the catalyst layer 22 and the particulate matter can be efficiently contacted, and the particulate matter is efficiently Can be burned away.

  Further, since the second plugging portion 21b is formed in the opening of the remaining cell 2b at a temperature lower than the deterioration temperature of the catalyst, the catalyst is heated (deteriorated) at the stage of forming the second plugging portion. And the catalyst can be effectively prevented from being deteriorated. For this reason, even if the amount of the catalyst supported in the pores of the partition walls is reduced as compared with the conventional honeycomb filter, the processing ability of the catalyst can be expressed well.

  In the honeycomb filter 100, the hydraulic diameter at the other end face 12 of the remaining cell 2 b is smaller than the hydraulic diameter at the one end face 11, so the second plugging portion 21 b is formed in the porous substrate 1. It is hard to come off.

  The plugged portion 21 preferably has an average pore diameter of 0.1 to 20 μm, and more preferably 1 to 15 μm. If the average pore diameter is larger than 20 μm, the particulate matter may enter the pores and close the pores, and the pressure loss may increase. If the average pore diameter of the plugging portion 21 is smaller than 0.1 μm, the exhaust gas hardly passes and the pressure loss may increase. The average pore diameter of the plugged portion 21 is a value measured with a mercury porosimeter.

  The porosity of the plugged portion 21 is preferably 30 to 60%, and more preferably 35 to 55%. If it is less than 30%, the pressure loss increases and the amount of exhaust gas treated may be reduced. If it is more than 60%, the plugging portion 21 becomes brittle and is likely to be lost. There is a risk that cracks are likely to occur due to thermal stress. The porosity of the plugged portion 21 is a value measured with a mercury porosimeter. Since the plugged portion 21 has the above average pore diameter and gas efficiency, it can function as a filter, thereby increasing the effective filter area.

  The length (plugging depth) of the plugged portion 21 in the cell extending direction is preferably 1 to 15 mm, and more preferably 1 to 10 mm. If it is shorter than 1 mm (shallow), the strength may decrease. If it is longer (deep) than 15 mm, the filtration area of the filter (area of the partition wall that can collect particulate matter) may be small. The plugging depth can be adjusted by adjusting the filling depth of the plugging slurry (the first plugging slurry and the second plugging slurry).

  It should be noted that the second plugging portion 21b can be made more difficult to come off from the porous substrate 1 by adjusting the plugging depth of the second plugging portion 21b. However, as described above, since the filtration area of the filter is reduced by increasing the plugging depth, the detachment strength of the second plugging portion 21b and the ratio of the reduction of the filtration area are set as follows. In consideration, it is preferable to set a preferable plugging depth as appropriate.

  Although it is not particularly limited, specifically, it is more practically preferable that the disengagement strength (MPa) of the second plugging portion measured by the following method is 5 MPa or more.

  As a method for measuring the detachment strength of the second plugged portion, first, the honeycomb filter is longer than the length in which the second plugged portion on the other end face of the honeycomb filter is completely left, and the honeycomb filter is extended in the cell extending direction. The length of the honeycomb filter that is cut vertically and is smaller than the cell opening diameter from the remaining cells (cells having the second plugging portions) on the cut end face of the honeycomb filter on the other end face side Insert a straight, hard bar longer than (cut length). Next, the rod is stopped at a position where it comes into contact with the second plugging portion, and then the load is applied to the rod while measuring the load with a load cell, the plugging portion is detached and the load increases. Measure the load when it is gone. Note that the disconnection strength of the plugged portion (second plugged portion) is a pressure (MPa) obtained by dividing the load at the time when the above-described load stops increasing by the cross-sectional area of the second plugged portion. And Moreover, it is preferable to perform the measurement at a plurality (for example, 10 locations) of plugged portions and calculate the average value.

  In order to increase the disengagement strength of the second plugged portion and make it difficult to disengage the second plugged portion, the second eye against the hydraulic diameter (mm) of the other end face of the remaining cell The ratio value of the depth (mm) of the sealing portion (“depth of second plugging portion (mm)” / “hydraulic diameter (mm) of the other end face of the remaining cell)” is 5 or more It is preferable that Hereinafter, the value of this ratio may be referred to as “anti-plugging loss coefficient”.

  By setting the anti-plugging loss coefficient within the above numerical range, the second plugging portion is difficult to be removed (that is, the second plugging portion has a high detachment strength), and the filtration area is excessively reduced. Can be obtained. In addition, when the anti-plugging loss coefficient is less than 5, the second plugging portion may have a low peeling strength, and the second plugging portion may be relatively easily detached. The upper limit value of the anti-plugging factor is not particularly limited. However, if the anti-plugging factor is excessively large, the second plugging portion is difficult to come off. The depth of the plugged portion becomes excessive, and the filtration area may decrease or the pressure loss may increase. In addition, the hydraulic diameter of the other end face of the remaining cells becomes too small, and it may be extremely difficult to manufacture a honeycomb formed body. For this reason, the upper limit value of the anti-plugging coefficient is that the honeycomb filter (specifically, the porous substrate) having a predetermined shape can be manufactured relatively easily and the filtration area is excessively reduced. Therefore, the optimum value can be determined as appropriate in consideration of the condition that the pressure loss does not increase excessively.

  Note that the anti-plugging coefficient is the size (mm) of the hydraulic diameter of the other end face of the remaining cells in the honeycomb formed body obtained in the step of forming the honeycomb formed body (forming step), and the second In each of the manufacturing steps, the honeycomb formed body is determined by the depth (mm) of filling the second plugging slurry in the step of filling the plugging slurry (second plugging step). By adjusting the shape and the filling depth of the second plugging slurry, it is possible to set the anti-plugging loss coefficient to a desired value.

  In the honeycomb filter 100, the cells 2 in which the plugged portions 21 are formed at one end and the cells 2 in which the plugged portions 21 are formed at the other end are alternately arranged, and each end face is It is preferable that a checkered pattern is formed by the plugged cells and the cells not plugged (sealed).

  The porous substrate 1 has a honeycomb shape having partition walls 3 mainly composed of a porous ceramic that partition and form a plurality of cells 2 serving as fluid flow paths. The average pore diameter of the partition walls 3 is 5 to 5. It is preferable that it is 30 micrometers, and it is still more preferable that it is 10-25 micrometers. If it is smaller than 5 μm, the pressure loss may increase even when the amount of particulate matter deposited is small. If it is larger than 30 μm, the honeycomb filter 100 may become brittle and may be easily lost, or the soot collection performance may be reduced. There is a risk. The average pore diameter of the partition walls 3 is a value measured with a mercury porosimeter. In addition, the phrase “having ceramic as a main component” means containing 90% by mass or more of the entire ceramic. Although it does not specifically limit as components other than a ceramic, A metal etc. can be mentioned.

  The porosity of the partition walls 3 is preferably 30 to 70%, and more preferably 40 to 60% in terms of ease of manufacture. If it is less than 30%, the pressure loss may increase, and if it is more than 70%, the honeycomb filter 100 may become brittle and easily missing. The porosity of the partition walls 3 is a value measured with a mercury porosimeter.

In the honeycomb filter, it is preferable that a mark visible from the outside is printed on an end surface or a side surface at one end portion in the central axis direction. Thereby, the end surface on which the first plugging portion is disposed can be distinguished from the end surface on which the second plugging portion is disposed. Further, it is preferable that three “marks” are printed so as to be arranged at equal intervals in the circumferential direction. This makes it possible to visually recognize the “mark” from any direction when the outer periphery of the honeycomb filter is viewed from any direction. The shape of the “mark” is not particularly limited, and examples thereof include a filled circle, a white circle, and an arrow. The size of the “mark” is preferably about 10 to 200 mm ² . The printing method of “mark” is preferably an ink-jet or laser printing method using heat-resistant ink.

  In addition, the honeycomb filter 100 is attached to the exhaust pipe so that one end surface 11 on which the first plugging portions 21a are disposed is an end surface on the exhaust gas inflow side, and purifies the exhaust gas. It is preferable. Accordingly, it is possible to effectively prevent the second plugging portion 21b from coming off, and particulate matter is deposited in the cell 2 on the side where the second plugging portion 21b is disposed, The contact efficiency with the layer can be increased.

  Further, the honeycomb filter may be a bonded honeycomb filter in which a plurality of honeycomb filters are bonded to each side surface.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

( Reference Example 1)
The cordierite-forming raw material from which the cordierite is obtained by firing is mixed with water and binder, mixed, kneaded, and extruded to partition a plurality of cells that penetrate from one end face to the other end face and serve as fluid flow paths. A honeycomb formed body having porous partition walls mainly composed of ceramic to be formed was obtained. The honeycomb molded body has a cylindrical shape with a partition wall thickness of 300 μm, a cell density of 46.5 cells / cm ² after firing, a bottom diameter of 143.8 mm, and a length of 152.4 mm. The shape was such that In addition, the honeycomb formed body has a hydrodynamic diameter of cells after firing, the predetermined cells described in Table 1 on one end face, and the remaining cells described in Table 1 on the other end face. Are arranged alternately. At the time of extrusion molding, both the predetermined cell and the remaining cell are formed so that the hydraulic diameter of the cell is 1.16 mm after firing, and the surface of the predetermined cell is smooth on the other end face of the predetermined cell and the predetermined cell is opened. The hydraulic diameter of the other end face of the remaining cells was adjusted to 0.96 mm by pressing a square pyramid crest stick larger than the aperture. The difference in hydraulic diameter in Reference Example 1 is 0.2 mm.

  Next, the first plugging slurry is filled in an opening of a predetermined cell on one end face of the obtained honeycomb formed body, and the honeycomb formed body filled with the first plugging slurry is supported. The one-side plugged honeycomb molded body having the first plugged portion on one end surface is sintered by firing at a temperature equal to or higher than the deterioration temperature of the catalyst. Formed. On one end face, the cells in which the first plugged portions are formed and the cells in which the first plugged portions are not formed are arranged in a checkered pattern. When filling the first plugging slurry, a plastic film mask is applied to one end face, a hole is made in a predetermined cell using a laser, and the first plugging slurry is filled from the hole. did. And the filling method is such that the first plugging slurry is stored in the container, and the end face on the side where the plugging portion of the honeycomb formed body is formed is immersed in the container so that 5 mm is immersed from the end face of the honeycomb formed body. It was set as the method of immersing in.

  The composition of the first plugging slurry was 80% by mass of the cordierite forming raw material used for forming the honeycomb formed body, 19% by mass of water, and 1% by mass of the organic binder. The viscosity of the first plugging slurry was 900 Pa · s. The viscosity of the first plugging slurry is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a slurry temperature of 30 ° C.

  The honeycomb formed body filled with the first plugging slurry was dried before firing. Thereafter, calcination was performed at about 400 ° C., followed by firing (main firing) at about 1420 ° C. to obtain a one-side plugged honeycomb formed body having a first plugged portion on one end face.

  Next, the catalyst slurry is caused to flow from one end surface side where the first plugged honeycomb formed body of the one-side plugged honeycomb body is formed into cells (remaining cells) having both end surfaces open, A catalyst was applied to the entire partition wall surface in the cell where the surface was open to form a honeycomb catalyst body.

  When the catalyst slurry was allowed to flow into the cell, the excess slurry was blown off with compressed air after the catalyst slurry was allowed to flow into the cell. Then, by drying and baking the catalyst, a honeycomb catalyst body in which the catalyst was coated (supported) on the entire partition wall surface in the cell was obtained. The drying condition of the catalyst was 150 ° C. The baking condition of the catalyst was 550 ° C. The amount of catalyst supported was 2 g of precious metal (Pt) per liter of honeycomb filter. The coating amount of the catalyst slurry was 100 g per liter of honeycomb filter. The viscosity of the catalyst slurry was 900 Pa · s. The viscosity of the catalyst slurry is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a slurry temperature of 30 ° C. Moreover, the deterioration temperature of the catalyst was 900 degreeC. The deterioration temperature of the catalyst was measured at a temperature at which the temperature at which the particulate matter collected by the honeycomb filter was removed by combustion was 600 ° C. or higher.

Next, the second plugging slurry is filled in the opening portion of the remaining cell that opens to the other end surface side where the first plugging portion of the honeycomb catalyst body is not formed. The honeycomb catalyst body filled with the sealing slurry was dried at a temperature lower than the deterioration temperature of the supported catalyst to solidify the second plugging slurry to obtain a honeycomb filter. When filling the second plugging slurry into the opening portion opened to the other end surface side where the first plugging portion of the honeycomb catalyst body is not formed, a mask made of a plastic film is applied to the other end surface. Then, holes were made in the remaining cells using a laser, and the second plugging slurry was filled from the holes. As for the filling method, the second plugging slurry is stored in a container, and the depth from the end face of the honeycomb formed body to the second plugging portion described in Table 1 (5 mm in Reference Example 1) is In order to immerse, the end surface on the side where the plugging of the honeycomb formed body was formed was immersed in the container.

  The conditions for drying the honeycomb catalyst body filled with the second plugging slurry were set at 800 ° C. for 6 hours.

  The composition of the second plugging slurry was 80% by mass of silica sol and 20% by mass of cordierite. The viscosity of the second plugging slurry was 900 Pa · s. The viscosity of the second plugging slurry is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a slurry temperature of 30 ° C.

In the obtained honeycomb filter, the cell density of the porous substrate was 46.5 cells / cm ² , and the partition wall thickness was 300 μm. Table 1 shows the cell density, the partition wall thickness, and the depth of the second plugging portion. In addition, the depth of plugging was measured in 10 places and made the average value. The porous substrate (partition wall) had an average pore diameter of 18 μm and a porosity of 50%. The plugged portion had a porosity of 50% and an average pore diameter of 10 μm. The porosity and average pore diameter are values measured with a commercially available mercury porosimeter. With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured by the following methods. The results are shown in Table 1. In addition, the value of the ratio of the depth (mm) of the second plugged portion to the hydraulic diameter (mm) of the other end face of the remaining cell was calculated as “anti-plugging loss coefficient”. The results are shown in Table 1.

(Reproduction efficiency)
A ceramic non-thermally expandable mat is wound around the outer periphery of the obtained honeycomb filter as a gripping material and is pushed into a can body made of SUS409 to form a canning structure. Thereafter, combustion gas containing particulate matter generated by the combustion of diesel fuel (light oil) is introduced from one end face (end face where the first plugging is formed) of the filter, and the other end face (second face). 5 g of particulate matter is deposited in the honeycomb filter per 1 liter of the volume of the honeycomb filter. And after cooling to room temperature once, the combustion gas containing oxygen of a fixed ratio is flowed in from the said one end surface of a honeycomb filter at 500 degreeC, and the particulate matter deposited on the honeycomb filter is combusted. The measurement results of the regeneration efficiency shown in Table 1 indicate the percentage of the value obtained by dividing the amount of particulate matter burned by the above method by the amount of particulate matter deposited on the honeycomb filter before the test. It is practically preferable that the regeneration efficiency is 80% or more.

(Stripping strength of the second plugging portion)
Cutting the honeycomb filter perpendicularly to the cell extending direction with a length equal to or longer than the length at which the second plugging portion on the other end face of the obtained honeycomb filter is completely left, and cutting the honeycomb filter on the other end face side Insert a straight and hard rod that is smaller than the cell opening diameter and longer than the length of the honeycomb filter (cut length) from the remaining cells (cells with the second plugging portion) on the end face on the finished side To do. The rod is stopped at the position where it comes into contact with the second plugging portion, and then the load is applied to the rod while measuring the load with the load cell, the plugging portion comes off and the load does not increase. Measure the load at the moment. The off-strength of the plugged portion described in Table 1 is indicated by the pressure (MPa) obtained by dividing the load at the time when the load stops increasing by the cross-sectional area of the second plugged portion. The measurement was performed at 10 plugged portions, and the average value was obtained. It is practically preferable that the disengagement strength of the second plugging portion is 5 MPa or more.

( Reference Examples 2 and 3)
The shape of the honeycomb filter at the time of extrusion molding was set to the partition wall thickness and cell density shown in Table 1, and at the time of extrusion molding, in Reference Example 2, the predetermined cell and the remaining cells had a hydraulic diameter of 1.49 mm after firing. Thus, in Reference Example 3, a cell is formed so that a predetermined cell and the remaining cell have a hydraulic diameter of 1.69 mm, and the surface of the other cell is smooth on the other end surface. Further, by pressing a square pyramid crest stick larger than the opening diameter of the predetermined cell, the hydraulic diameter of the other end face of the remaining cell is set to the value shown in Table 1, and the second plugging is further performed. A honeycomb filter was manufactured in the same manner as in Reference Example 1 except that the depth of the stopper was changed to the value shown in Table 1. With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured in the same manner as in Reference Example 1. Further, the anti-plugging coefficient of the honeycomb filter was calculated. The results are shown in Table 1.

( Reference Examples 4-9)
At the time of extrusion molding of the honeycomb filter, the outer peripheral length of the remaining cell is increased by pressing a square pyramid crest having a groove formed on the surface of the other cell to the other end surface of the remaining cell. A honeycomb filter was manufactured by the same method as in Reference Example 1 except that the hydraulic diameter of the end face was set to the value shown in Table 1 and the depth of the second plugging portion was set to the value shown in Table 1. did. In addition, the groove | channel formed in the top stick was formed by processing the surface of the top stick so that a groove might be formed in parallel with the direction pressed against a cell.

In Reference Examples 4 to 6, the outer peripheral length of the remaining cells was increased by providing irregularities with a convex portion height of 0.1 mm and an angle of 90 degrees on the surface of the partition walls that partition the remaining cells. . Further, in Reference Examples 7 to 9, the outer peripheral length of the remaining cells was increased by providing the surface of the partition walls partitioning the remaining cells with a convex portion with a height of 0.2 mm and an angle of 60 degrees. . With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured in the same manner as in Reference Example 1. Further, the anti-plugging coefficient of the honeycomb filter was calculated. The results are shown in Table 1.

( Reference Examples 10-13)
From the time of extrusion molding of the honeycomb filter, the hydraulic diameters of the predetermined cells and the remaining cells are set to the values shown in Table 1, and the depth of the second plugging portion is set to the value shown in Table 1. Produced a honeycomb filter by the same method as in Reference Example 1. With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured in the same manner as in Reference Example 1. Further, the anti-plugging coefficient of the honeycomb filter was calculated. The results are shown in Table 1.

(Comparative Examples 1-8)
Reference Examples 1, 2, and 3 except that the honeycomb formed body was formed so that the hydraulic diameter of a predetermined cell and the hydraulic diameter of the remaining cells were the same size on one end face side and the other end face side. A honeycomb filter was manufactured by the same method. With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured by the same method as in Reference Example 1. Further, the anti-plugging coefficient of the honeycomb filter was calculated. The results are shown in Table 1.

(Comparative Example 9)
In the same manner as in Reference Example 1, a one-side plugged honeycomb formed body was prepared, and before supporting the catalyst, the other end face side where the first plugged portions of the remaining cells were not formed, The second plugged portion was formed by the same method as the first plugged portion.

Next, the same catalyst slurry as the catalyst slurry used in Reference Example 1 was pressed into a cell opened from one end surface side to one end surface. Thereafter, excess catalyst slurry was blown off with compressed air. Then, in Example 1, the catalyst was dried at baking and a procedure similar to, carrying the (press-fitting the) catalyst dried and baked to obtain a honeycomb filter. With respect to the obtained honeycomb filter, “regeneration efficiency” and “detachment strength of the second plugging portion” were measured in the same manner as in Reference Example 1. Further, the anti-plugging coefficient of the honeycomb filter was calculated. The results are shown in Table 1.

From Table 1, it can be seen that the honeycomb filters of Reference Examples 1 to 13 have good regeneration efficiency. Furthermore, in the honeycomb filters of Reference Examples 1 to 13, the second plugging portions were less likely to come off than the honeycomb filters of Comparative Examples 1 to 8. Further, the release strength of the second plugging portion is particularly good. Specifically, in Reference Examples 1 to 3, 5 to 8, 10 and 12 having 5 MPa or more, the anti-plugging coefficient is 5 or more. It can be seen that it is. That is, when the honeycomb filter of the present invention is manufactured, the hydraulic diameter (mm) of the other end face of the remaining cells and the second plugging portion are set so that the anti-plugging coefficient is 5 or more. By adjusting the ratio to the depth (mm), a honeycomb filter with particularly good disengagement strength of the second plugged portion can be manufactured.

  On the other hand, in the honeycomb filters of Comparative Examples 1 to 8, the second plugging portion is easily detached, and in the honeycomb filter of Comparative Example 9, the second plugging portion is difficult to remove, but the regeneration efficiency is not good. I understand that.

  The method for manufacturing a honeycomb filter of the present invention collects and removes particulate matter in exhaust gas discharged from internal combustion engines such as automobile engines, construction machine engines, and stationary engines for industrial machines, and other combustion equipment. Therefore, it can be used as a method for manufacturing a filter.

1: porous substrate, 2: cell, 2a, 102a: cell (predetermined cell), 2b, 102b: cell (remaining cell), 3,103: partition wall, 11, 111: one end surface, 12, 112 : Other end face, 21, 121: plugged portion, 21a, 121a: first plugged portion, 21b, 121b: second plugged portion, 22, 122: catalyst layer, 31: honeycomb formed body 32: cell, 32a: cell (predetermined cell), 32b: cell (remaining cell), 33: partition wall, 34: one end surface, 35: other end surface, 36: one-side plugged honeycomb formed body, 37 : Honeycomb catalyst body, 38: honeycomb filter, 41: first plugged portion, 42: second plugged portion, 43: catalyst layer, 100, 200, 300, 400, 500: honeycomb filter.

Claims (6)

A forming step of forming a honeycomb formed body by forming a clay containing ceramic raw material into a honeycomb shape having partition walls that form a plurality of cells that penetrate from one end face to the other end face and serve as fluid flow paths. When,
Filling an opening portion of a predetermined cell on one end face of the obtained honeycomb molded body with the first plugging slurry, and firing the honeycomb molded body filled with the first plugging slurry. A first plugging step of sintering the first plugged slurry and the honeycomb formed body to form a one-side plugged honeycomb formed body having a first plugged portion on one end face; ,
From the one end face side where the first plugged portion of the obtained one-side plugged honeycomb formed body was formed, the catalyst slurry was allowed to flow into the remaining cells having both end faces opened, A catalyst supporting step of forming a honeycomb catalyst body by applying a catalyst to the partition wall surfaces in the remaining cells;
A second plugging is made in the opening of the remaining cells of the honeycomb catalyst body obtained on the other end face side where the first plugging portion of the honeycomb catalyst body is not formed. Filling the slurry, drying the honeycomb catalyst body filled with the second plugging slurry at a temperature lower than the deterioration temperature of the supported catalyst to solidify the second plugging slurry, and A second plugging step of producing a plugged portion of 2 to obtain a honeycomb filter,
In the forming step, the honeycomb formed body has a substantially octagonal cross-sectional shape orthogonal to the central axis of the predetermined cell, and a substantially quadrangular cross-sectional shape orthogonal to the central axis of the remaining cells. A method for manufacturing a honeycomb filter, which is formed into a shape such that a hydraulic diameter at the other end face of the remaining cell is smaller than a hydraulic diameter at one end face of the predetermined cell.   In the forming step, the honeycomb formed body is formed in a shape such that the hydraulic diameter of the remaining cells gradually decreases toward the other end face in at least the region filled with the second plugging slurry. The method for manufacturing a honeycomb filter according to claim 1.   The said forming process WHEREIN: The said honeycomb molded object is formed in the area | region where the said 2nd plugging slurry is filled in the shape which has an unevenness | corrugation in the partition wall surface which divides and forms the said remaining cell. Manufacturing method of honeycomb filter. The method for manufacturing a honeycomb filter according to any one of claims 1 to 3 , wherein the firing is performed at a temperature equal to or higher than a deterioration temperature of a supported catalyst in the first plugging step. The method for manufacturing a honeycomb filter according to any one of claims 1 to 4 , wherein in the second plugging step, the drying is performed at a temperature lower than a deterioration temperature of the supported catalyst. The method for manufacturing a honeycomb filter according to claim 5 , wherein the second plugging slurry is a ceramic cement that is solidified by drying at a temperature lower than a deterioration temperature of the supported catalyst.