JP2018122244A - Method for manufacturing honeycomb structure and honeycomb structure - Google Patents

Abstract

A method for manufacturing a honeycomb structure that can prevent cracks from occurring in the outer peripheral wall during firing of the formed honeycomb structure. A honeycomb formed body is integrally formed using a clay containing a cordierite-forming raw material, dried, and then an outer peripheral wall 4 is formed on at least one of four predetermined portions 6a to 6d. a step of forming a notch 5 penetrating through to produce a notched honeycomb formed body 10; a step of filling the notch 5 of the notched honeycomb formed body 10 with a slurry containing a cordierite-forming raw material; firing the notched honeycomb formed body 10 in which the notches 5 are filled with the slurry to manufacture a honeycomb structure, wherein the honeycomb structure is formed after the slurry becomes the filling portion through firing. A method for manufacturing a honeycomb structure having a porosity 5% or more higher than that of a structure body. [Selection drawing] Fig. 4

Description

  The present invention relates to a honeycomb structure used for a catalyst carrier in an exhaust gas purification catalytic converter, a particulate collection filter such as a diesel particulate filter, a gasoline particulate filter, and the like, and a method for manufacturing the honeycomb structure.

  Honeycomb structures are widely used in catalyst carriers in exhaust gas purification catalytic converters of internal combustion engines such as automobile engines, and particulate collection filters such as diesel particulate filters (DPF) and gasoline particulate filters (GPF). .

  When manufacturing such a honeycomb structure, first, a partition including a plurality of cells extending from one end surface to the other end surface of a clay containing a predetermined ceramic raw material by an extrusion method or the like, and the partition wall Is formed into a honeycomb shape having an outer peripheral wall surrounding the. Next, the honeycomb formed body thus obtained is dried and then fired to obtain a porous honeycomb structure.

  By the way, in the manufacture of a honeycomb structure having a square cell shape, during firing of the honeycomb molded body, the outer peripheral wall passes through the center of gravity of the cross section of the honeycomb molded body, and in the diagonal direction of the square of the cell shape. There was a problem that cracks were likely to occur at a site intersecting with the extending straight line. In particular, in the production of a large honeycomb structure, since such cracks are prominent, countermeasures are required.

  Conventionally, as measures to prevent the occurrence of cracks as described above, methods have been adopted in which the heat curve during firing is adjusted (extended) or the number of honeycomb formed bodies packed in the kiln (firing furnace) is reduced. I came. Moreover, the method of restrict | limiting the quantity of the additive (organic binder etc.) added to a raw material in order to improve a moldability, or adding an inorganic binder was also implemented.

  Furthermore, before firing the honeycomb formed body, by grinding a predetermined portion of the outer peripheral wall or forming a slit, the stress applied to the predetermined portion of the outer peripheral wall during firing of the honeycomb formed body is relieved, A method for making it difficult for cracks to occur is proposed (see Patent Documents 1 and 2).

International Publication No. 2009/035049 JP 2004-74564 A

  However, even if the heat curve during firing is adjusted (extended), it is difficult to sufficiently suppress the generation of cracks. In addition, the method of adjusting (extending) the heat curve at the time of firing or reducing the number of honeycomb formed bodies packed in the kiln (firing furnace) has a problem that the productivity is lowered. Furthermore, the method of limiting the amount of the additive added to the raw material has a problem of adversely affecting the moldability. In addition, the method of adding an inorganic binder to the raw material has a problem that the production cost increases and the characteristics of the honeycomb structure deteriorate.

  Furthermore, the method proposed in Patent Document 1 is to grind and remove the outer peripheral wall once after firing the honeycomb formed body, and then newly form the outer peripheral wall using a coating material. Since it takes time and effort, productivity tends to decrease. In addition, the method proposed in Patent Document 2 also needs to bury the slits using a burying agent and fire again after firing the honeycomb formed body, and it takes time and effort to manufacture, thus reducing productivity. There is a tendency.

  The present invention has been made in view of such conventional circumstances. That is, the present invention provides a honeycomb structure that can prevent cracks on the outer peripheral wall during firing of the honeycomb molded body without causing adverse effects on formability, deterioration of characteristics, increase in production cost, and decrease in productivity. And a honeycomb structure obtained thereby.

  In order to achieve the above object, according to the present invention, there are provided the following honeycomb structure manufacturing method and honeycomb structure.

[1] Using a clay containing a cordierite forming raw material, the partition has a partition wall that defines a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall surrounding the partition wall, and the cell extends In the cross section orthogonal to the direction, the plurality of cells are arranged in two orthogonal directions, and at least a part of the plurality of cells has a quadrilateral shape in the cross section orthogonal to the cell extending direction. After the honeycomb formed body, which is a main quadrilateral cell, in which at least 20% of the square cells are arranged in the same direction in which the diagonal lines extend, is integrally formed and dried In a cross section orthogonal to the cell extending direction, two straight lines extending in the diagonal direction of the main quadrangular cell through the center of gravity of the cross section are being rotated. As a cutout for forming a notched honeycomb formed body by forming a notch penetrating the outer peripheral wall in at least one of the four portions existing in the rotation region when rotated in the range of ± x ° as A notched honeycomb molded body manufacturing step, and a slurry filling step of filling the notch of the notched honeycomb molded body manufactured in the notched honeycomb molded body manufacturing step with a slurry containing a cordierite forming raw material. In the slurry filling step, the notched honeycomb formed body in which the slurry is filled with the slurry is fired, the honeycomb structure main body derived from the notched honeycomb formed body, and the slurry derived from A firing step of manufacturing a honeycomb structure having a filling portion, wherein x is a value in the range of 2 to 27, and is used in the slurry filling step After the slurry has been fired in the firing step to become the filling portion, the honeycomb structure manufacturing method (first method) having a porosity higher by 5% or more than the porosity of the honeycomb structure body Manufacturing method).

[2] Using a clay containing a cordierite forming raw material, the partition has a partition wall that defines a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall surrounding the partition wall, and the cell extends In the cross section orthogonal to the direction, the plurality of cells are arranged in two orthogonal directions, and at least a part of the plurality of cells has a quadrilateral shape in the cross section orthogonal to the cell extending direction. A cell, and at least 20% of the quadrangular cells are main quadrangular cells arranged in the same direction in which the diagonal lines extend, and the cross section is perpendicular to the cell extending direction. Rotation region when two straight lines extending in the diagonal direction of the main rectangular cell through the center of gravity are rotated within a range of ± x ° with the center of gravity as the center of rotation. A notch for forming a notched honeycomb formed body by integrally forming and drying a honeycomb formed body in which a notch penetrating the outer peripheral wall is formed in at least one of the four existing portions A notched honeycomb formed body manufacturing step, and a notch of the notched honeycomb formed body manufactured in the notched honeycomb formed body manufacturing step, a slurry filling step of filling a slurry containing a cordierite forming raw material into the notch, In the slurry filling step, the notched honeycomb molded body in which the slurry is filled with the slurry is fired, and the honeycomb structure main body derived from the notched honeycomb molded body and the filling derived from the slurry And a firing step of manufacturing a honeycomb structure having a portion, wherein x is a value in the range of 2 to 27, and is used in the slurry filling step. A method for manufacturing a honeycomb structure having a porosity of 5% or more higher than the porosity of the main body of the honeycomb structure after the slurry becomes the filling portion through firing in the firing step (second method) Manufacturing method).

[3] In the cross section perpendicular to the cell extending direction, the length of the notch in the direction from the outer periphery of the honeycomb formed body toward the center of gravity is 0.1 to 4.0 mm [1] or [2 ] The manufacturing method of the honeycomb structure as described in any one of Claims 1-3.

[4] The method for manufacturing a honeycomb structured body according to any one of [1] to [3], wherein x is a value in a range of 8 to 27.

[5] The slurry used in the slurry filling step has a porosity 5 to 50% higher than the porosity of the honeycomb structure main body after becoming the filling portion through firing in the firing step. The method for manufacturing a honeycomb structure according to any one of [1] to [4].

[6] The honeycomb structure according to any one of [1] to [5], wherein the thickness of the outer peripheral wall of the honeycomb formed body is 0.1 to 4.0 mm after being fired in the firing step. Body manufacturing method.

[7] The method for manufacturing a honeycomb structure according to any one of [1] to [6], wherein all of the plurality of cells are quadrangular cells having a quadrangular shape in a cross section orthogonal to the cell extending direction.

[8] In the cross section orthogonal to the cell extending direction, each of the plurality of cells includes a quadrangular cell having a quadrangular shape and an octagonal cell having an octagonal shape, and the quadrangular cells and the octagonal cells are alternately arranged. A method for manufacturing a honeycomb structure according to any one of [1] to [6], wherein

[9] A partition having a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall surrounding the partition, and in the cross section orthogonal to the cell extending direction, the plurality of cells are: Arranged in two orthogonal directions, at least a part of the plurality of cells is a quadrangular cell having a quadrangular shape in a cross section orthogonal to the cell extending direction, and at least 20% of the quadrangular cells. Are the main rectangular cells arranged in the same direction in which the diagonal lines extend, and in the cross section orthogonal to the cell extending direction, through the center of gravity of the cross section, in the diagonal direction of the main rectangular cell. At least one of the four parts existing in the rotation region when the two extending straight lines are rotated within a range of ± x ° around the center of gravity as the rotation center, respectively. A honeycomb structure main body formed with a notch penetrating the outer peripheral wall, and a filling portion filled in the notch, wherein x is a value in the range of 2 to 27, and the filling portion The honeycomb structure has a porosity of 5% or more higher than the porosity of the honeycomb structure body, and the honeycomb structure body and the filling portion are cordierite.

[10] The section according to [9], wherein a length of the notch in a direction from the outer periphery of the honeycomb structure toward the center of gravity is 0.1 to 4.0 mm in a cross section orthogonal to the cell extending direction. Honeycomb structure.

[11] The honeycomb structure according to [9] or [10], wherein x is a value in the range of 8 to 27.

[12] The honeycomb structure according to any one of [9] to [11], wherein the porosity of the filling portion is 5 to 50% higher than the porosity of the honeycomb structure body.

[13] The honeycomb structure according to any one of [9] to [12], wherein the outer peripheral wall has a thickness of 0.1 to 4.0 mm.

[14] The honeycomb structure according to any one of [9] to [13], wherein all of the plurality of cells are quadrangular cells having a quadrangular shape in a cross section orthogonal to the cell extending direction.

[15] In the cross section orthogonal to the cell extending direction, the plurality of cells include quadrangular cells that form a quadrangle and octagonal cells that form an octagon, and the quadrangular cells and the octagonal cells are alternately arranged. [9] The honeycomb structure according to any one of [13] to [13].

  In the method for manufacturing a honeycomb structured body of the present invention, a notch penetrating the outer peripheral wall is formed at a specific portion of the honeycomb formed body. As a result, the stress applied to a specific part of the outer peripheral wall of the honeycomb molded body where cracks are likely to occur during firing is relaxed, and a honeycomb structure can be manufactured without generating cracks in the part. Further, since it is not necessary to limit the amount of an additive (organic binder or the like) added to the raw material in order to improve the moldability, the moldability is not adversely affected. In addition, since there is no need to add an inorganic binder to the raw material, the inorganic binder does not deteriorate the characteristics of the honeycomb structure or increase the production cost. Furthermore, cracks on the outer peripheral wall during firing of the honeycomb molded body can be prevented without adjusting (extending) the heat curve during firing or reducing the number of honeycomb molded bodies packed in the kiln (firing furnace). it can. Further, after firing the honeycomb formed body, there is no need to remove the outer peripheral wall and then form a new outer peripheral wall or perform firing of the honeycomb formed body a plurality of times. Can be manufactured. Therefore, according to the method for manufacturing a honeycomb structure of the present invention, high productivity can be obtained in manufacturing a honeycomb structure having no cracks on the outer peripheral wall.

  The honeycomb structure of the present invention can be manufactured by the method for manufacturing a honeycomb structure of the present invention. Therefore, the honeycomb structure of the present invention is less prone to cracks in the outer peripheral wall in the manufacturing process, and has high productivity and can be manufactured at a low production cost.

FIG. 2 is a perspective view schematically showing an example of a honeycomb formed body formed in the notched honeycomb formed body manufacturing step. Fig. 2 is a cross-sectional view schematically showing a cross section orthogonal to the cell extending direction of the honeycomb formed body shown in Fig. 1. Fig. 3 is a partial cross-sectional view schematically showing an aspect in which quadrangular cells and octagonal cells are alternately arranged in a cross section orthogonal to the cell extending direction of the honeycomb formed body. It is explanatory drawing which shows the site | part which forms a notch in a honeycomb molded object manufacturing process with a notch. FIG. 3 is a perspective view schematically showing an example of a notched honeycomb formed body manufactured in a notched honeycomb formed body manufacturing step. FIG. 3 is a perspective view schematically showing an example of a honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention. It is a perspective view showing typically an example of the honeycomb structure of the present invention. Fig. 8 is a cross-sectional view schematically showing a cross section orthogonal to the cell extending direction of the honeycomb structure shown in Fig. 7. It is explanatory drawing which shows the formation part of a notch. Fig. 3 is a partial cross-sectional view schematically showing an aspect in which quadrangular cells and octagonal cells are alternately arranged in a cross section orthogonal to the cell extending direction of the honeycomb structure. In Comparative Examples 1-4, it is explanatory drawing which shows the site | part which forms a notch.

  Hereinafter, the present invention will be described based on specific embodiments. However, the present invention is not construed as being limited to these embodiments, and is within the scope of the present invention. Based on the knowledge, design changes and improvements can be added as appropriate.

(1) Manufacturing method of honeycomb structure (first manufacturing method):
The first production method of the present invention includes a notched honeycomb molded body manufacturing step, a slurry filling step, and a firing step. Hereinafter, these steps will be described in order.

(1-1) Manufacturing process of notched honeycomb molded body:
In this step, the honeycomb formed body is integrally formed using the clay containing the cordierite forming raw material. Here, the "cordierite raw material" means a raw material that becomes cordierite by firing, and silica is in the range of 40 to 60% by mass, alumina is in the range of 15 to 45% by mass, and magnesia is in the range of 5 to 30% by mass. It is a ceramic raw material blended to have a chemical composition. Specific examples include those containing a plurality of inorganic raw materials selected from talc, kaolin, calcined kaolin, alumina, aluminum hydroxide, and silica in a proportion such that the chemical composition is obtained. By using the clay containing the cordierite forming raw material, a cordierite honeycomb structure excellent in heat resistance can be manufactured.

  The clay for molding is added to such a cordierite-forming raw material by adding a dispersion medium such as water and a pore former, and further, if necessary, adding an organic binder, a dispersant, etc., and mixing and kneading. It is preferable that it is produced.

  As the pore former, any material having a property of scattering and disappearing from firing may be used in the firing step described below, and an inorganic substance such as coke, a polymer compound such as foamed resin, and an organic substance such as starch are preferably used. be able to. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the organic binder, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like can be suitably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the dispersant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be suitably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  The method for preparing the kneaded material by mixing and kneading the cordierite forming raw material is not particularly limited, and for example, a method of mixing and kneading with a kneader, a vacuum kneader or the like can be used.

  The method for integrally forming the honeycomb formed body is not particularly limited, and a conventionally known forming method such as extrusion molding, injection molding, or press molding can be used. Among them, a preferable example is a method in which the clay prepared as described above is extruded using a die corresponding to a desired cell shape, partition wall thickness, and cell density.

  FIG. 1 is a perspective view schematically showing an example of a honeycomb formed body formed in this step, and FIG. 2 schematically shows a cross section orthogonal to the cell extending direction of the honeycomb formed body shown in FIG. It is sectional drawing. As shown in these drawings, the honeycomb formed body 1 formed in this step includes a partition wall 3 that partitions and forms a plurality of cells 2 extending from one end surface 8 to the other end surface 9, and an outer peripheral wall 4 that surrounds the partition wall 3. And have.

  The plurality of cells 2 are arranged in two orthogonal directions indicated by arrows A1 and A2 in FIG. 2 in a cross section orthogonal to the extending direction of the cells 2. At least a part of the plurality of cells 2 is a quadrangular cell 2 a that exhibits a quadrangular shape in a cross section perpendicular to the extending direction of the cells 2. At least 20% of the quadrangular cells 2a are main quadrangular cells that are arranged in such an orientation that the diagonal lines extend in the same direction. In addition, it is preferable that at least 40% of the quadrangular cells 2a are main quadrangular cells, and it is particularly preferable that all the quadrangular cells 2a are main quadrangular cells. The type of quadrangle that the quadrangular cell 2a exhibits in the cross section orthogonal to the cell extending direction is not particularly limited, and may be any of square, rectangular, rhombus, parallelogram, and the like. In the method for manufacturing a honeycomb structure of the present invention, as in the embodiment shown in FIGS. 1 and 2, all the cells 2 of the honeycomb molded body 1 (however, because they are in contact with the outer peripheral wall, a part of the shape thereof) However, it is preferable that the rectangular cell 2a. Further, a part of the plurality of cells 2 may have a shape other than a quadrangle in a cross section orthogonal to the extending direction of the cells 2. For example, as shown in FIG. 3, the plurality of cells 2 of the honeycomb formed body 1 includes a quadrangular cell 2 a having a quadrangular shape and an octagonal cell 2 b having an octagonal shape in a cross section orthogonal to the extending direction of the cells 2. It may be an embodiment in which they are arranged alternately.

  After such a honeycomb formed body 1 is formed and dried, a notch penetrating the outer peripheral wall 4 is formed at a predetermined portion to produce a notched honeycomb formed body. The method for drying the honeycomb formed body 1 is not particularly limited. For example, a conventionally known drying method such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like can be used. . Especially, the drying method which combined hot air drying, microwave drying, or dielectric drying is preferable at the point which can dry the honeycomb molded object 1 whole rapidly and uniformly.

  FIG. 4 is an explanatory view showing a part where a notch is formed. As shown in FIG. 4, the portion where the notch 5 is formed has two straight lines L1 extending in the diagonal direction of the main rectangular cell 2a through the center of gravity G of the cross section in a cross section orthogonal to the extending direction of the cell 2. , L2 as a reference. Specifically, among the four parts 6a, 6b, 6c, 6d existing in the rotation region when the two straight lines L1, L2 are rotated in the range of ± x ° with the center of gravity G as the rotation center, respectively. A notch is formed in at least one of the two. The “center of gravity G” referred to here is the center of gravity of the figure drawn by the outer peripheral edge of the honeycomb formed body 1 in a cross section orthogonal to the cell 2 extending direction of the honeycomb formed body 1.

  In the first method for manufacturing a honeycomb structure of the present invention, x is a value in the range of 2 to 27, preferably in the range of 8 to 27, and more preferably in the range of 15 to 27. Is the value of By forming a notch 5 in at least one of the four portions 6a, 6b, 6c, 6d so that x is in such a range, cracks in the outer peripheral wall 4 during firing can be reduced. Generation can be effectively prevented. When x is less than 2, even if the notch 5 is formed, the occurrence of cracks in the outer peripheral wall 4 during firing may not be prevented. Moreover, when x is a value exceeding 27, the strength of the finally obtained honeycomb structure may be insufficient.

  The method for forming the notch 5 in the honeycomb formed body 1 is not particularly limited, and for example, a method such as grinding can be used.

  In the cross section perpendicular to the extending direction of the cells 2, the length D of the notch 5 in the direction from the outer periphery of the honeycomb formed body 1 to the center of gravity G is preferably 0.1 to 4.0 mm. In the present specification, the length of the notch 5 in the direction from the outer periphery of the honeycomb formed body 1 toward the center of gravity G may be referred to as “the depth of the notch”. By setting the depth D of the notch 5 in such a range, the thermal stress applied to the outer peripheral wall 4 at the time of firing can be effectively relieved, and the slurry filling operation to the notch 5 in the slurry filling step described later is performed. Becomes easy. If the notch 5 penetrates (cuts out) the outer peripheral wall 4, the thermal stress applied to the outer peripheral wall 4 at the time of firing can be effectively alleviated, and the occurrence of cracks can be prevented. Note that the notch 5 may penetrate (notch) not only the outer peripheral wall 4 but also a part of the partition 3 inside the outer peripheral wall 4.

  The thickness of the outer peripheral wall 4 of the honeycomb formed body 1 is preferably such that the thickness becomes 0.1 to 4.0 mm after firing in the firing step described later. By setting the thickness of the outer peripheral wall 4 of the honeycomb formed body 1 to a thickness of 4.0 mm or less after firing in the firing step described later, cracks are generated in the outer peripheral wall 4 during firing. It becomes difficult to occur. However, when the thickness of the outer peripheral wall 4 of the honeycomb formed body 1 is such that the thickness is less than 0.1 mm after firing in the firing step described later, the honeycomb structure finally obtained In this case, the strength of the outer peripheral wall may be insufficient.

  FIG. 5 is a perspective view schematically showing an example of a notched honeycomb formed body manufactured in the notched honeycomb formed body manufacturing step. In the notched honeycomb molded body 10 in this example, the notches 5 are formed in all of the above-described four portions 6a, 6b, 6c, and 6d. However, in the present invention, if the notch 5 is formed in at least one of these four parts 6a, 6b, 6c, 6d, it is possible to effectively prevent the outer wall 4 from cracking during firing. it can. As shown in FIG. 5, the notch 5 is preferably formed continuously in the extending direction of the cells 2 over the entire length of the honeycomb formed body 10.

(1-2) Slurry filling process:
In this step, the slurry containing the cordierite forming raw material is filled into the notch 5 of the notched honeycomb formed body 10 produced in the notched honeycomb formed body producing step. In addition to the notch 5, the slurry may be filled into the cell 2 ′ communicated with the notch 5 by forming the notch 5.

  The slurry is preferably prepared by adding a dispersion medium such as water and a pore former to the cordierite forming raw material, and further adding an organic binder, a dispersing agent and the like as necessary.

  As the pore former, any material having a property of scattering and disappearing from firing may be used in the firing step described below, and an inorganic substance such as coke, a polymer compound such as foamed resin, and an organic substance such as starch are preferably used. be able to. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the organic binder, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like can be suitably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the dispersant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be suitably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  The slurry becomes a filling part after firing in a firing step described later. When the slurry becomes a filling portion through firing in the firing step, the filling portion becomes a part of the outer peripheral wall of the honeycomb structure finally obtained. When the notch 5 of the notched honeycomb formed body 10 is not filled with slurry, the strength of the finally obtained honeycomb structure becomes insufficient, and the honeycomb structure may be damaged by pressure during canning. is there.

  The slurry has a porosity of 5% or more higher than that of the honeycomb structure main body (the notched honeycomb formed body that has been fired in the firing step described later) after becoming the filling portion, and preferably has a honeycomb structure. It has a porosity of 5 to 50% higher than that of the body body. The “porosity” mentioned here is a value measured by a mercury porosimeter.

  If the slurry has a porosity equal to or lower than the porosity of the honeycomb structure body after it becomes the filling portion, cracks may occur in the outer peripheral wall of the honeycomb structure body. In addition, the slurry has a porosity higher than the porosity of the honeycomb structure main body after becoming the filling portion, but the same applies when the difference in porosity is less than 5%.

  The porosity after the slurry has been fired to become the filling portion can be controlled by adjusting the amount of the pore former contained in the slurry, for example. The amount of the pore former contained in the slurry is preferably 0.5 to 25% by mass, more preferably 1.0 to 20% by mass, based on the total mass of the slurry. The porosity after the slurry has been baked to become a filling part is preferably 30 to 90%, more preferably 35 to 85%.

  The method for filling the notch 5 of the notched honeycomb formed body 10 with the slurry is not particularly limited, and for example, a method such as brushing can be used.

(1-3) Firing step:
In this step, the notched honeycomb molded body 10 in which the slurry is filled in the notch 5 is fired in the slurry filling step. The firing temperature is preferably 1350 to 1440 ° C. Further, the firing time is preferably set so that the keeping time at the maximum temperature is 3 to 10 hours. By firing under such conditions, the cordierite forming raw materials respectively contained in the notched honeycomb formed body 10 and the slurry react efficiently, and cordierite is formed from the cordierite forming raw materials.

  By this firing, as shown in FIG. 6, a honeycomb structure 11 having a honeycomb structure body 12 derived from the notched honeycomb formed body and a filling portion 13 derived from the slurry is manufactured. Here, “derived from the notched honeycomb formed body” means that the notched honeycomb formed body (a portion of the notched honeycomb formed body in which the slurry is filled with the slurry is removed) by firing. It is formed from. In addition, “derived from the slurry” means that it is formed from a slurry (a part of the notched honeycomb formed body in which the notch is filled with the slurry excluding the notched honeycomb formed body) by firing. means.

  In addition, the convex part resulting from the filling part 13 may generate | occur | produce in the outer peripheral surface of the honeycomb structure 11 obtained through this baking process. When a catalytic converter using the honeycomb structure 11 is mounted in an automobile or the like, a gripping material such as a mat is wound around the outer periphery of the honeycomb structure 11 supporting the catalyst, and the honeycomb structure 11 is wound around the outer periphery of the honeycomb structure 11 via the gripping material. In a state where pressure is applied, it is held (canned) in a cylindrical can body. If there is a convex portion on the outer peripheral surface of the honeycomb structure 11, a high pressure is applied to the convex portion during canning, and the honeycomb structure 11 may be damaged. You may grind the convex part of 11 outer peripheral surfaces.

(2) Manufacturing method of honeycomb structure (second manufacturing method):
The second production method of the present invention includes a notched honeycomb molded body manufacturing step, a slurry filling step, and a firing step. Among these steps, the slurry filling step and the firing step are the same steps as the slurry filling step and the firing step in the first manufacturing method of the present invention described above, and therefore, here, a notched honeycomb molded body production step Only will be described.

(2-1) Notched honeycomb molded body manufacturing process:
In this step, a honeycomb formed body in which a notch penetrating the outer peripheral wall is formed at a predetermined portion is integrally formed using a clay containing a cordierite forming raw material. That is, the notched honeycomb molded body manufacturing step in the second manufacturing method is the first manufacturing in that the notch is formed by integrally (simultaneously) molding with the partition walls and the outer peripheral wall of the honeycomb molded body. This is different from the notched honeycomb formed body manufacturing step in the method.

  As a method for integrally forming the honeycomb formed body, it is preferable to use extrusion molding. When using extrusion molding, a notched honeycomb molded body can be easily formed by using an extrusion die having a portion corresponding to the notch.

  The structure of the notched honeycomb formed body produced in this step is the same as the structure of the notched honeycomb formed body produced in the notched honeycomb formed body producing step in the first manufacturing method. That is, the notched honeycomb formed body manufactured in the notched honeycomb formed body manufacturing step in the second manufacturing method is also the notched honeycomb formed body manufactured in the notched honeycomb formed body manufacturing step in the first manufacturing method. A notch is formed at the same position as the molded body. Except for the conditions relating to the notch formation method, the conditions that are preferable in the notched honeycomb molded body manufacturing step in the first manufacturing method are also preferable in the notched honeycomb molded body manufacturing step in the second manufacturing method. Can be applied as a condition.

  As described above, in the method for manufacturing a honeycomb structure according to the present invention (the first manufacturing method and the second manufacturing method), a notch penetrating the outer peripheral wall is formed in a specific portion of the honeycomb formed body. As a result, the stress applied to a specific part of the outer peripheral wall of the honeycomb molded body where cracks are likely to occur during firing is relaxed, and a honeycomb structure can be manufactured without generating cracks in the part.

  Further, since it is not necessary to limit the amount of an additive (organic binder or the like) added to the raw material in order to improve the moldability, the moldability is not adversely affected. In addition, since there is no need to add an inorganic binder to the raw material, the inorganic binder does not deteriorate the characteristics of the honeycomb structure or increase the production cost. Furthermore, cracks on the outer peripheral wall during firing of the honeycomb molded body can be prevented without adjusting (extending) the heat curve during firing or reducing the number of honeycomb molded bodies packed in the kiln (firing furnace). it can.

  Further, after firing the honeycomb formed body, there is no need to remove the outer peripheral wall and then form a new outer peripheral wall or perform firing of the honeycomb formed body a plurality of times. Can be manufactured. Therefore, according to the method for manufacturing a honeycomb structure of the present invention, high productivity can be obtained in manufacturing a honeycomb structure having no cracks on the outer peripheral wall.

(3) Honeycomb structure:
The honeycomb structure of the present invention is manufactured by the above-described manufacturing method (first manufacturing method and second manufacturing method) of the honeycomb structure of the present invention. Therefore, the honeycomb structure of the present invention has a feature indicating that it is manufactured by the manufacturing method.

  FIG. 7 is a perspective view schematically showing an example of the honeycomb structure of the present invention, and FIG. 8 is a cross-sectional view schematically showing a cross section perpendicular to the cell extending direction of the honeycomb structure shown in FIG. is there. As shown in these drawings, the honeycomb structure 11 of the present invention includes a honeycomb structure body 12 and a filling portion 13.

  The honeycomb structure main body 12 includes partition walls 3 that define a plurality of cells 2 extending from one end face 8 to the other end face 9, and an outer peripheral wall 4 that surrounds the partition walls 3. The plurality of cells 2 are arranged in two orthogonal directions indicated by arrows B1 and B2 in FIG. 8 in a cross section orthogonal to the extending direction of the cells 2. At least a part of the plurality of cells 2 is a quadrangular cell 2 a that exhibits a quadrangular shape in a cross section perpendicular to the extending direction of the cells 2. At least 20% of the quadrangular cells 2a are main quadrangular cells that are arranged in such an orientation that the diagonal lines extend in the same direction. Note that the type of quadrangle that the quadrangular cell 2a exhibits in a cross section orthogonal to the cell extending direction is not particularly limited, and may be any of a square, a rectangle, a rhombus, a parallelogram, and the like.

  Further, a notch 5 penetrating the outer peripheral wall 4 is formed at a predetermined portion of the honeycomb structure body 12. As shown in FIG. 9, the notch 5 has, as a reference, two straight lines L3 and L4 extending in the diagonal direction of the main quadrangular cell 2a through the center of gravity G of the cross section in a cross section orthogonal to the extending direction of the cell 2, It is formed in a defined part. Specifically, of the four parts 16a, 16b, 16c, and 16d existing in the rotation region when the two straight lines L3 and L4 are rotated in the range of ± x ° with the center of gravity G as the rotation center, respectively. A notch is formed in at least one of these. The “center of gravity G” referred to here is the center of gravity of the figure drawn by the outer peripheral edge of the honeycomb structure body 12 in the cross section orthogonal to the cell 2 extension direction of the honeycomb structure body 12. In the honeycomb structure 11 of the present invention, the x is a value in the range of 2 to 27. Note that the notch 5 may penetrate (notch) not only the outer peripheral wall 4 but also a part of the partition 3 inside the outer peripheral wall 4.

  The filling portion 13 is filled in the notch 5 formed in the honeycomb structure main body 12. The filling portion 13 may be filled not only in the notch 5 but also in the cell 2 ′ communicated with the notch 5 by forming the notch 5. In the honeycomb structure 11 of the present invention, the filling portion 13 has a porosity of 5% or more higher than the porosity of the honeycomb structure body 12. The “porosity” mentioned here is a value measured by a mercury porosimeter.

  As described above, the honeycomb structure main body 12 and the filling portion 13 have different porosities, but both are made of cordierite.

  The honeycomb structure 11 of the present invention is preferably manufactured by adopting the conditions preferable in the above-described method for manufacturing the honeycomb structure of the present invention, and is caused by adopting such conditions. It is preferable to have the above characteristics.

  That is, in the honeycomb structure 11 of the present invention, as in the embodiment shown in FIGS. 7 and 8, all the cells 2 (however, the cells lacking a part of the shape because they are in contact with the outer peripheral wall). Is preferably a square cell 2a. Moreover, a part of the plurality of cells 2 may have a shape other than a quadrangle in a cross section orthogonal to the extending direction of the cells. For example, as shown in FIG. 10, the plurality of cells 2 of the honeycomb structure 11 includes a quadrangular cell 2 a that exhibits a quadrangle and an octagonal cell 2 b that exhibits an octagon in a cross section orthogonal to the extending direction of the cells 2. It may be an embodiment in which they are arranged alternately. Moreover, it is preferable that at least 40% of the quadrangular cells 2a are main quadrangular cells, and it is particularly preferable that all the quadrangular cells 2a are main quadrangular cells.

  Moreover, in the honeycomb structure 11 of the present invention, the x is preferably a value in the range of 8 to 27, and more preferably a value in the range of 15 to 27. Furthermore, the thickness of the outer peripheral wall 4 of the honeycomb structure 11 is preferably 0.4 to 4.0 mm, and the porosity of the filling portion 13 is 5.0 to more than the porosity of the honeycomb structure body 12. 50% higher is preferred. Moreover, in the cross section orthogonal to the extending direction of the cells 2, the length D of the notch 5 in the direction from the outer periphery of the honeycomb structure 11 toward the center of gravity G is preferably 0.1 to 4.0 mm.

  Since the honeycomb structure of the present invention can be manufactured by the method for manufacturing the honeycomb structure of the present invention, cracks in the outer peripheral wall are hardly generated in the manufacturing process, and the productivity is high and the production cost is low. It is possible to manufacture with.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

Example 1
As the cordierite forming raw material, alumina, aluminum hydroxide, kaolin, talc and silica were used. To 100 parts by mass of this cordierite-forming raw material, 1 part by mass of a pore former, 32 parts by mass of a dispersion medium, 6 parts by mass of an organic binder, and 1 part by mass of a dispersant are added, mixed, kneaded, and kneaded. Was prepared. Water was used as the dispersion medium, and a foamed resin having an average particle diameter of 40 μm was used as the pore former. Hydroxypropyl methylcellulose was used as the organic binder, and ethylene glycol was used as the dispersant.

  Next, a honeycomb molded body having a partition wall formed by extruding a clay using a predetermined mold to partition a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall surrounding the partition wall. Molded. This honeycomb formed body has a cylindrical shape as a whole, and a plurality of cells are arranged in two directions orthogonal to each other in a cross section orthogonal to the cell extending direction. In addition, all cells (excluding cells that are in contact with the outer peripheral wall and lack a part of the shape) are square cells (square cells) that take a square shape in a cross section perpendicular to the cell extending direction. )Met. In addition, all the quadrangular cells are main quadrangular cells arranged in such an orientation that the diagonal lines extend in the same direction.

  Next, the obtained honeycomb molded body was dried with a microwave dryer and further completely dried with a hot air dryer, and then a notch penetrating the outer peripheral wall was formed by grinding to form a notched honeycomb. A molded body was produced. As shown in FIG. 4, in the cross section orthogonal to the extending direction of the cell 2, the portion where the notch is formed has two straight lines L1, L2 extending through the center of gravity G of the cross section in the diagonal direction of the main rectangular cell 2a. As a standard. Specifically, among the four parts 6a, 6b, 6c, 6d existing in the rotation region when the two straight lines L1, L2 are rotated in the range of ± x ° with the center of gravity G as the rotation center, respectively. A notch was formed in one of these. The value of x in this example was 27. The notch depth was 1.2 mm.

  Next, the slurry was filled into the notches of the obtained notched honeycomb formed body. The slurry is a cordierite forming raw material, 5.0% by mass of foamed resin (copolymer of acrylonitrile having an average particle diameter of 40 μm and a shell wall thickness of 0.2 μm), 35% by mass of water, and 2% by mass. The organic binder and 1% by mass of a dispersant. In addition, the same thing as what was used for the said clay was used for the cordierite-forming raw material, the organic binder and the dispersant.

  Subsequently, by firing the notched honeycomb molded body in which the notch is filled with the slurry, a honeycomb structure main body derived from the notched honeycomb formed body, and a honeycomb structure having a filling portion derived from the slurry. Produced. Firing was performed at a maximum temperature of 1440 ° C. and a keeping time at the maximum temperature of 5 hours.

The obtained honeycomb structure has a partition wall thickness of 4 mil (102 μm), a cell density of 400 cells / square inch (62 cells / cm ² ), an outer peripheral wall thickness of 0.4 mm, and pores of the honeycomb structure body. The rate was 32%, and the porosity of the filled portion was 82%. Moreover, the diameter of the honeycomb structure was 144 mm, and the length of the honeycomb structure was 152 mm.

About the obtained honeycomb structure, the presence or absence of the generation | occurrence | production of the crack in an outer peripheral wall and the state of the generated crack were observed, and the following references | standards evaluated. The evaluation results are shown in Table 1.
A: No crack.
B: Although there were minute cracks in the filled portion, there was no crack in the honeycomb structure body.
C: There are minute cracks in the filling portion, and there is also a crack in the honeycomb structure body.

(Examples 2 to 5)
A honeycomb structure was manufactured in the same manner as in Example 1 except that the value of x and the depth of the notch were changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Example 6)
The honeycomb structure was changed in the same manner as in Example 1 except that the value of x was changed as shown in Table 1, and notches were formed in all of the four portions 6a, 6b, 6c and 6d shown in FIG. Was made. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Examples 7 and 8)
A honeycomb structure was manufactured in the same manner as in Example 1 except that the value of x was changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

Example 9
A honeycomb structure was manufactured in the same manner as in Example 6 except that the value of x was changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Examples 10 to 13)
A honeycomb structure was manufactured in the same manner as in Example 8 except that the amount of the foamed resin in the slurry was changed so that the porosity of the filling portion became the value shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Example 14)
A honeycomb structure was manufactured in the same manner as in Example 13 except that notches were formed in all of the four portions 6a, 6b, 6c, and 6d shown in FIG. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 1)
A honeycomb structure was manufactured in the same manner as in Example 1 except that the part for forming the notch was changed. As shown in FIG. 11, the portion where the cutout is formed is based on two straight lines L5 and L6 extending in the arrangement direction of the cell 2 through the center of gravity G of the cross section in a cross section orthogonal to the extending direction of the cell 2. As determined. Specifically, the two straight lines L5 and L6 are respectively applied to all four portions 26a, 26b, 26c, and 26d existing in the rotation region when rotated within a range of ± x ° with the center of gravity G as the rotation center. A notch 5 penetrating the outer peripheral wall 4 was formed to produce a notched honeycomb formed body 30. The value of x in this comparative example was 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 2)
A honeycomb structure was manufactured in the same manner as in Comparative Example 1 except that the value of x was changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 3)
In addition to changing the value of x as shown in Table 1 and forming a notch in one of the four parts 26a, 26b, 26c, and 26d shown in FIG. A honeycomb structure was produced. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 4)
A honeycomb structure was manufactured in the same manner as in Comparative Example 3 except that notches were formed in all of the four portions 26a, 26b, 26c, and 26d shown in FIG. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 5)
A honeycomb structure was manufactured in the same manner as in Example 1 except that the value of x was changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 6)
A honeycomb structure was manufactured in the same manner as in Example 6 except that the value of x was changed as shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Examples 7 and 8)
A honeycomb structure was manufactured in the same manner as in Example 6 except that the amount of the foamed resin in the slurry was changed so that the porosity of the filled portion became the value shown in Table 1. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Comparative Example 9)
A honeycomb structure having no cuts and no filling portions was produced in the same manner as in Example 1 except that the cuts were not formed and the slurry was not filled. The obtained honeycomb structure was evaluated according to the same criteria as in Example 1, and the evaluation results are shown in Table 1.

(Discussion)
As shown in Table 1, Examples 1 to 14, which are examples of the present invention, were evaluated as “A” or “B”, and none of the honeycomb structure bodies had cracks. On the other hand, Comparative Examples 1 to 4 in which cuts were formed in a part different from the part specified in the present invention were evaluated as “C”, and cracks occurred in the honeycomb structure body. In Comparative Examples 5 and 6 in which the value of x is less than 2, the evaluation was “C”, and cracks occurred in the honeycomb structure body. Comparative Examples 7 and 8 in which the porosity of the filling portion is the same as the porosity of the honeycomb structure body or lower than the porosity of the honeycomb structure body are also evaluated as “C”. Cracks have occurred. The comparative example 9 in which the formation of the cuts and the filling of the slurry was not performed was also evaluated as “C”, and the honeycomb structure body was cracked.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a honeycomb structure used for a catalyst carrier in an exhaust gas purification catalytic converter, a particulate collection filter such as a diesel particulate filter, a gasoline particulate filter, and the like, and a method for manufacturing the honeycomb structure. .

1: honeycomb formed body, 2: cell, 2a: square cell, 2b: octagonal cell, 2 ': cell communicating with notch, 3: partition, 4: outer peripheral wall, 5: notch, 6a, 6b, 6c , 6d: notch forming portion, 8: one end face, 9: other end face, 10: notched honeycomb formed body, 11: honeycomb structure, 12: honeycomb structure body, 13: filling portion, 16a , 16b, 16c, 16d: notch formation site, 26a, 26b, 26c, 26d: notch formation site, 30: notched honeycomb molded body, A1, A2: arrows indicating cell arrangement direction, B1 , B2: arrows indicating the cell arrangement direction, D: depth of notches, G: center of gravity, L1, L2: straight lines extending in the diagonal direction of the quadrangular cells, L3, L4: straight lines extending in the diagonal direction of the quadrangular cells.

Claims (15)

Using a clay containing a cordierite forming raw material, it has a partition wall that defines a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall that surrounds the partition wall, and is orthogonal to the cell extending direction. In the cross section, the plurality of cells are arranged in two orthogonal directions, and at least a part of the plurality of cells is a quadrangular cell presenting a quadrangle in the cross section orthogonal to the cell extending direction. The honeycomb molded body, which is a main square cell in which at least 20% of the square cells are arranged in the same direction in which the diagonal lines extend, is integrally formed and dried, and then the cell is dried. In the cross section orthogonal to the extending direction, the two straight lines extending in the diagonal direction of the main quadrangular cell through the center of gravity of the section are respectively centered on the center of rotation. A notched structure for forming a notched honeycomb formed body by forming a notch penetrating the outer peripheral wall in at least one of four portions existing in the rotation region when rotated in the range of x °. Honeycomb molded body manufacturing process;
A slurry filling step of filling the notch of the notched honeycomb formed body produced in the notched honeycomb formed body producing step with a slurry containing a cordierite forming raw material;
In the slurry filling step, the notched honeycomb molded body in which the slurry is filled with the slurry is fired, and the honeycomb structure main body derived from the notched honeycomb molded body and the filling derived from the slurry And a firing step of manufacturing a honeycomb structure having a portion,
X is a value in the range of 2 to 27;
The honeycomb used in the slurry filling step has a porosity higher by 5% or more than the porosity of the honeycomb structure main body after becoming the filling portion through firing in the firing step. Manufacturing method of structure. Using a clay containing a cordierite forming raw material, it has a partition wall that defines a plurality of cells extending from one end surface to the other end surface, and an outer peripheral wall that surrounds the partition wall, and is orthogonal to the cell extending direction. In the cross section, the plurality of cells are arranged in two orthogonal directions, and at least a part of the plurality of cells is a quadrangular cell presenting a quadrangle in the cross section orthogonal to the cell extending direction. , At least 20% of the quadrangular cells are main quadrangular cells arranged in the same direction in which the diagonal lines extend, and in the cross section orthogonal to the cell extending direction, Two straight lines extending in the diagonal direction of the main quadrilateral cell are present in a rotation region when rotated in a range of ± x ° around the center of gravity as a rotation center. A notched article for producing a notched honeycomb formed body by integrally forming a honeycomb formed body having a notch penetrating the outer peripheral wall and drying it in at least one of the four parts. Honeycomb molded body manufacturing process;
A slurry filling step of filling the notch of the notched honeycomb formed body produced in the notched honeycomb formed body producing step with a slurry containing a cordierite forming raw material;
In the slurry filling step, the notched honeycomb molded body in which the slurry is filled with the slurry is fired, and the honeycomb structure main body derived from the notched honeycomb molded body and the filling derived from the slurry And a firing step of manufacturing a honeycomb structure having a portion,
X is a value in the range of 2 to 27;
The honeycomb used in the slurry filling step has a porosity higher by 5% or more than the porosity of the honeycomb structure main body after becoming the filling portion through firing in the firing step. Manufacturing method of structure.   3. The honeycomb according to claim 1, wherein a length of the notch in a direction from the outer periphery of the honeycomb formed body toward the center of gravity is 0.1 to 4.0 mm in a cross section perpendicular to the cell extending direction. Manufacturing method of structure.   The method for manufacturing a honeycomb structured body according to any one of claims 1 to 3, wherein x is a value in a range of 8 to 27.   The slurry used in the slurry filling step has a porosity that is 5 to 50% higher than the porosity of the honeycomb structure main body after becoming the filling portion through firing in the firing step. The manufacturing method of the honeycomb structure as described in any one of Claims 1-4.   The honeycomb structure according to any one of claims 1 to 5, wherein a thickness of the outer peripheral wall of the honeycomb formed body is 0.1 to 4.0 mm after firing in the firing step. Method.   The method for manufacturing a honeycomb structured body according to any one of claims 1 to 6, wherein all of the plurality of cells are quadrangular cells having a quadrangular shape in a cross section orthogonal to a direction in which the cells extend.   The plurality of cells, in a cross section orthogonal to the extending direction of the cells, are composed of quadrangular cells having a quadrangular shape and octagonal cells having an octagonal shape, and the quadrangular cells and the octagonal cells are alternately arranged. A method for manufacturing a honeycomb structured body according to any one of claims 1 to 6. A partition having a plurality of cells extending from one end surface to the other end surface and an outer peripheral wall surrounding the partition, and the plurality of cells are orthogonal to each other in a cross section orthogonal to the cell extending direction. Arranged in a direction, and at least a part of the plurality of cells is a quadrangular cell having a quadrangular shape in a cross section orthogonal to a direction in which the cells extend, and at least 20% of the quadrangular cells are Two main rectangular cells arranged in the same direction in which the diagonal lines extend, and two cross-sections extending in the diagonal direction of the main rectangular cell through the center of gravity of the cross section in a cross section orthogonal to the cell extending direction At least one of the four parts existing in the rotation region when the straight line is rotated in the range of ± x ° around the center of gravity as the rotation center. A honeycomb structure body formed with a notch penetrating the peripheral wall;
A filling portion filled in the notch,
X is a value in the range of 2 to 27;
A honeycomb structure in which the porosity of the filling portion is 5% or more higher than the porosity of the honeycomb structure body, and the honeycomb structure body and the filling portion are cordierite.   10. The honeycomb structure according to claim 9, wherein a length of the notch in a direction from an outer periphery of the honeycomb structure toward the center of gravity is 0.1 to 4.0 mm in a cross section perpendicular to the cell extending direction. .   The honeycomb structure according to claim 9 or 10, wherein x is a value in a range of 8 to 27.   The honeycomb structure according to any one of claims 9 to 11, wherein a porosity of the filling portion is 5 to 50% higher than a porosity of the honeycomb structure main body.   The honeycomb structure according to any one of claims 9 to 12, wherein the outer peripheral wall has a thickness of 0.1 to 4.0 mm.   The honeycomb structure according to any one of claims 9 to 13, wherein all of the plurality of cells are quadrangular cells having a quadrangular shape in a cross section perpendicular to a direction in which the cells extend.   The plurality of cells, in a cross section orthogonal to the extending direction of the cells, are composed of quadrangular cells having a quadrangular shape and octagonal cells having an octagonal shape, and the quadrangular cells and the octagonal cells are alternately arranged. The honeycomb structure according to any one of claims 9 to 13.

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