JP7065670B2 - Manufacturing method of honeycomb structure for exhaust gas purification and exhaust gas purification filter using the honeycomb structure - Google Patents

Description

The present invention relates to a honeycomb structure, a method for manufacturing the honeycomb structure, and a honeycomb structure for exhaust gas purification suitable for an exhaust gas purification filter, particularly a GPF (Gasoline Particulate Filter), a method for manufacturing the honeycomb structure, and the honeycomb. Regarding an exhaust gas purification filter using a structure.

GPF, which is one of the exhaust gas purification devices, uses PN (Particulate Number) of PM (Particulate Matter) in the exhaust gas of vehicles traveling on gasoline in order to comply with recent exhaust gas regulations. It is a filter that reduces to the regulated value, and at the same time, it is also desired to remove specific components subject to regulation from the exhaust gas. In such a GPF, a honeycomb structure portion in which a plurality of cells extend in the flow direction of the exhaust gas is formed inside the tubular body, and either one end or the other end of each cell is closed (eyes). A honeycomb structure is used in which the partition wall separating the cells is composed of a porous partition wall through which exhaust gas can pass. Then, the honeycomb structure is coated with a catalyst to form an exhaust gas purification filter for GPF, and therefore the pores of the porous partition wall separating the cells are also coated.

In this GPF exhaust gas purification device, exhaust gas flows in from a cell whose inlet side is open, however, because the outlet side of the cell is blocked, the exhaust gas passes through the pores of the partition wall and the outlet side is open. It flows into and out of the cell. PM is removed from the exhaust gas when passing through the partition wall, and when the exhaust gas comes into contact with the catalyst coated on the pores of the partition wall, a specific component subject to regulation is removed. As such an exhaust gas purification device, for example, there is one described in Patent Document 1 below. In this exhaust gas purification device, for example, when the exhaust gas passing through the partition wall is more likely to concentrate at the exhaust gas outlet side end of the honeycomb structure than at the inlet side end, the vicinity of the inlet side end face of the honeycomb structure is located. It is disclosed that the porosity is made higher than the porosity in the vicinity of the end face on the inlet side to increase the exhaust gas flow rate passing through the partition wall in the vicinity of the end face on the inlet side, and the exhaust gas flow rate in the entire honeycomb structure is made uniform. ing.

Japanese Unexamined Patent Publication No. 2007-289926

However, in the exhaust gas purification device described in Patent Document 1, when the exhaust gas passing through the partition wall is more likely to concentrate on the exhaust gas outlet side end of the honeycomb structure than on the inlet side end, the inlet side of the honeycomb structure portion. Although it is disclosed that the pore ratio in the vicinity of the end face is made higher than the pore ratio in the vicinity of the end face on the outlet side to make the exhaust gas flow rate of the entire honeycomb structure uniform, the distribution state of the pore ratio in the honeycomb structure is disclosed. It is not described how to obtain what kind of effect or how to obtain a honeycomb structure having such a honeycomb structure portion. In particular, in the GPF exhaust gas purification device, since the exhaust gas outlet side of about half of the cells is blocked, ash gradually accumulates from the blocked outlet side of the cell as the exhaust gas is purified. It is desired to extend the life of the purification performance and to reduce the cost by efficiently using the expensive precious metal used for the catalyst.

The present invention has been made in view of the above problems, and an object thereof is a honeycomb structure for exhaust gas purification capable of extending the life of exhaust gas purification performance and reducing the cost, and a method for manufacturing the honeycomb structure. And to provide an exhaust gas purification filter using the honeycomb structure.

The honeycomb structure for exhaust gas purification to achieve the above purpose is
A plurality of cells have a honeycomb structure portion extending in the flow direction of the exhaust gas inside the tubular body, and each cell is closed at either one end or the other end in the extension direction and each cell. The partition wall separating the exhaust gas is a honeycomb structure for purifying exhaust gas configured as a porous partition wall through which the exhaust gas can pass, and the porous partition wall is on the inlet side of the porosity of the exhaust gas outlet side region in the tubular body. It is formed so that the porosity of the region gradually increases.

According to this configuration, ash in the exhaust gas may be gradually accumulated from the exhaust gas outlet side in the cell in which the exhaust gas outlet side is closed as the exhaust gas is purified. Then, the pores of the porous partition wall are closed in the outlet side region where the ash is deposited. However, since the porosity of the partition wall of the cell according to the present invention increases from the exhaust gas outlet side region to the exhaust gas inlet side region, a state in which a large number of pores are still open is maintained even after long-term exhaust gas purification. Porosity or pores with an opening cross-sectional area larger than the outlet side region are kept open. Further, the coating amount of the catalyst is also larger in the region where the porosity is large. Therefore, good exhaust gas purification is continued through the pores of the porous partition wall in the open exhaust gas inlet side region, and as a result, the life of the exhaust gas purification performance can be extended. Further, since the porosity is gradually changed, it is possible to suppress the occurrence of a sudden decrease in the purification function in a stepped manner during the exhaust gas purification. As a result, it is possible to ensure stable exhaust gas purification performance while efficiently reducing the coating amount of expensive precious metals and reducing the cost.

The method for manufacturing the honeycomb structure includes a step of mixing while changing the mixing ratio of a plurality of types of porous materials having different porosities at regular intervals to generate a porous material and sequentially moving the mixture to the next step. A step of extruding the porous material through a mouthpiece for forming the honeycomb structure, and a position where the porosity changes from an increase to a decrease or a position where the porosity changes from a decrease to an increase. It is characterized by having a process of cutting with.

According to this configuration, the porous material extruded from the mouthpiece gradually changes from a large porosity state to a small porosity state and from a small porosity state to a large porosity state at regular intervals due to the periodic change of the mixing ratio. Therefore, simply by cutting the extruded porous material at the position where the porosity changes from increase to decrease and at the position where the porosity changes from decrease to increase, the porosity is directed toward the flow direction of the exhaust gas (from the inlet side to the outlet side). It becomes possible to continuously mass-produce a honeycomb structure having a honeycomb structure portion having a porous partition wall in which the amount is gradually reduced.

Further , while changing the supply amount of the pore-increasing agent supplied to the inlet side of the mouthpiece for forming the honeycomb structure portion at regular intervals, the porous material is mixed with the porous material to generate the porous material, and the process is sequentially carried out to the next step. The step of moving, the step of extruding the porous material through the mouthpiece, and the step of cutting the extruded porous material at a position where the porosity changes from an increase to a decrease or a position where the porosity changes from a decrease to an increase. It is characterized by having a process of performing.

The exhaust gas purification filter using the honeycomb structure is characterized in that the honeycomb structure manufactured by the manufacturing method is coated with a catalyst.

The exhaust gas purification filter using the honeycomb structure according to claim 4 is characterized in that the honeycomb structure manufactured by the method for manufacturing the honeycomb structure according to claim 2 or 3 is coated with a catalyst. ..

According to this configuration, ash in the exhaust gas may be gradually accumulated from the exhaust gas outlet side in the cell in which the exhaust gas outlet side is closed as the exhaust gas is purified. Then, the pores of the porous partition wall are closed in the outlet side region where the ash is deposited. However, since the porosity of the partition wall of the cell according to the present invention increases from the exhaust gas outlet side region to the exhaust gas inlet side region, a state in which a large number of pores are still open is maintained even after long-term exhaust gas purification. Porosity or pores with an opening cross-sectional area larger than the outlet side region are kept open. Further, the coating amount of the catalyst is also larger in the region where the porosity is large. Therefore, good exhaust gas purification is continued through the pores of the porous partition wall in the open exhaust gas inlet side region, and as a result, the life of the exhaust gas purification performance can be extended. Further, since the porosity is gradually changed, it is possible to suppress the occurrence of a sudden decrease in the purification function in a stepped manner during the exhaust gas purification. As a result, it is possible to ensure stable exhaust gas purification performance while efficiently reducing the coating amount of expensive precious metals and reducing the cost.

As described above, according to the present invention, the porous partition wall of the honeycomb structure is formed so that the porosity of the inlet side region is gradually larger than the porosity of the exhaust gas outlet side region, thereby forming a stepped shape. The long-term exhaust gas purification performance is enhanced by suppressing the rapid deterioration of the exhaust gas purification function and continuing good exhaust gas purification through the pores and catalyst in the exhaust gas inlet side region that is open with a large porosity even after long-term exhaust gas purification. The life can be extended, which makes it possible to efficiently reduce the coating amount of expensive noble metal and reduce the cost.

It is a perspective view which shows one Embodiment of the honeycomb structure for the exhaust gas purification filter of this invention. It is explanatory drawing of the operation of the exhaust gas purification filter composed of the honeycomb structure of FIG. It is a schematic explanatory drawing which shows an example of the manufacturing method of the honeycomb structure of FIG. It is a schematic explanatory drawing which shows the other example of the manufacturing method of the honeycomb structure of FIG. 1 is an explanatory view of a portion of the honeycomb structure having a large porosity, FIG. 5A is a cross-sectional view of the partition wall / pores before catalyst coating, and FIG. 5B is a partition wall / pores after catalyst coating. It is a cross-sectional view of. It is explanatory drawing of the part where the porosity of the partition wall of the honeycomb structure of FIG. 1 is small, FIG. 6A is a cross-sectional view of a partition wall / pore before catalyst coating, and FIG. 6B is a partition wall / pore after catalyst coating. It is a cross-sectional view of.

Hereinafter, a cam structure for purifying exhaust gas of the present invention, a method for manufacturing the honeycomb structure, and an embodiment of an exhaust gas purification filter using the honeycomb structure will be described in detail with reference to the drawings. FIG. 1 is a perspective view of an exhaust gas purification filter 10 using the honeycomb structure 12 of this embodiment. The honeycomb structure 12 of this embodiment is mainly intended to be used as the exhaust gas purification filter 10 for the above-mentioned GPF. The honeycomb structure 12 is configured to include a honeycomb structure portion 14 for purifying exhaust gas by flowing exhaust gas from the right side to the left side in the figure inside the cylindrical body 20 having a cylindrical shape. The honeycomb structure portion 14 is composed of a plurality of cells (chambers) 18 formed by partitioning the inside of the cylindrical body 20 by a partition wall 16, and each cell 18 is in the axial direction of the cylinder 20. It extends from the inlet side end surface 14b on the right side of the drawing to the exit side end surface 14a on the left side of the drawing. In this embodiment, the cell 18 having a square cross-sectional shape is formed, but the cross-sectional shape of the cell 18 may be other than this.

In this embodiment, as will be described later, the tubular body 20 and the partition wall 16 are simultaneously molded using, for example, a porous ceramic material. Therefore, the partition wall 16 is a porous partition wall having a large number of pores (continuous pores). In this embodiment, the tubular body 20 and the partition wall 16 are simultaneously formed by extrusion molding using a porous material by a manufacturing method described later, but both may be formed individually. Further, a ceramic material or the like may be applied to the outer periphery of the tubular body 20. Further, the dots in the figure schematically represent the pores formed in the honeycomb structure portion 14, but the dot display is omitted on the outlet side end surface 14a in order to avoid complication. Further, the shape of the tubular body 20 is not limited to the cylindrical shape.

FIG. 2 is an explanatory diagram of the operation of the GPF exhaust gas purification filter 10 made of the honeycomb structure 12 of FIG. When the honeycomb structure portion 14 is a GPF which is one of the exhaust gas purification filters 10, the preset cells 18 among the plurality of cells 18 are closed (sealed) on one end face side, for example, the inlet side end face 14b side. ), And the honeycomb structure 12 in which the rest is closed on the other end face side, for example, the outlet side end face 14a side is used. In this example, the cells 18 staggered in a row or row on the exit side end surface 14a side on the left side of the drawing are closed in a staggered manner, and on the entrance side end surface 14b side on the right side of the drawing, the cells are opened on the exit side end surface 14a side. The cell 18 is closed. That is, on the inlet side end surface 14b side, the staggered cells 18 opened on the exit side end surface 14a side are also blocked in a staggered manner. The GPF exhaust gas purification filter 10 is produced, for example, by coating a fired honeycomb structure 12 with a catalyst, and at that time, as will be described later, the catalyst 24 is also formed in the pores 22 of the partition wall 16 together with the partition wall 16 (see FIGS. 5 and 6). ) Is applied. As a catalyst coating method, for example, a well-known wash coat method or the like is used.

For the exhaust gas purification filter 10 made of the honeycomb structure 12 in which one of the adjacent cells 18 is closed on the outlet side end surface 14a side and the other is closed on the inlet side end surface 14b side, for example, the exhaust gas is exhaust gas from the inlet side end surface 14b. The exhaust gas flowing into the open cell 18 loses its place at the closed outlet side end surface 14b, flows into the adjacent cell 18 through the pore 22 of the partition wall 16, and flows into the adjacent cell 18 on the outlet side of the cell 18. It flows out from the opening of the end 14b. Therefore, PM in the exhaust gas is removed when passing through the pores. Further, by contacting with the catalyst 24 coated on the pores 22, a specific component subject to regulation in the exhaust gas is removed. The technique of passing exhaust gas through the pores of the partition wall 16 is also called wall flow.

In this embodiment, the porous partition wall constituting the partition wall 16 of the honeycomb structure portion 14 has a porosity of the inlet side end surface 14b region on the right side of the drawing gradually larger than the porosity of the outlet side end surface 14a region on the left side of the drawing. Is formed in. In this embodiment, since the cylindrical body 20 and the partition wall 16 are extruded at the same time, as shown in FIG. 1, both the cylindrical body 20 and the partition wall 16 are from the exit side end surface 14a side on the left side of the drawing to the entrance on the right side of the drawing. It is formed of a porous material whose porosity gradually increases toward the side end surface 14b side. With the inlet side end surface 14b as a reference, the porosity gradually decreases from the inlet side end surface 14b on the right side of the figure toward the exit side end surface 14a on the left side of the figure.

A porous material having such a structure can be obtained, for example, by the method for producing the honeycomb structure 12 shown in FIG. In this method for manufacturing the honeycomb structure 12, two types of porous materials having different porosities, such as ceramics, specifically, a high porosity (large) high porosity material and a low (small) low porosity material. Each of the materials is stored in individual storage portions 30a and 30b, and the high porosity material and the low porosity material are charged into the mixing unit 32 from the two storage units 30a and 30b and mixed, whereby the honeycomb structure portion 14 is formed. Obtain the constituent porous material. At that time, the porosity is mixed in the mixing unit 32 by gradually increasing or decreasing the mixing ratio of the two types of porous materials having different porosities and changing the increase and decrease at regular intervals. In the material, a portion having a high porosity (large) and a portion having a low porosity (small) are alternately present at regular intervals. When this porous material is sequentially moved to the exit side in the mixing portion 32 and passed through the base 26 for forming the honeycomb structure portion 14 and extruded, the extruded porous material has a high porosity. A blank of the honeycomb structure portion 14 is formed in which the (large) portion and the (small) portion having a low porosity gradually change at regular intervals. Therefore, the position where the porosity is the highest (large), that is, the position where the porosity changes from increase to decrease and the part where the porosity is the lowest (small), that is, the position where the porosity changes from decrease to increase is set as the cutting position. Then, by cutting the porous material extruded at those cutting positions, a honeycomb structure 12 having a honeycomb structure portion 14 in which the porosity gradually increases from the outlet side end surface 14a to the inlet side end surface 14b can be obtained. ..

Further, as described above, the porous material whose porosity gradually increases from the outlet side end surface 14a side to the inlet side end surface 14b side can also be obtained by, for example, the method for producing the honeycomb structure 12 shown in FIG. In this method for manufacturing the honeycomb structure 12, a porous material having a constant porosity or a porosity of 0, such as ceramics, is supplied from the upstream side and directly upstream of the base 26 for forming the honeycomb structure portion 14. A pore-increasing agent such as polymer particles is supplied to obtain a porous material constituting the honeycomb structure portion 14. At that time, the porosity is high in the porous material supplied to the base 26 by gradually increasing or decreasing the supply amount of the pore-increasing agent and supplying the increase and decrease while changing the increase and decrease at regular intervals (the porosity is high). Large) parts and low (small) parts with low porosity can alternate. When this porous material is moved to the base 26 side and passed through the base 26 for forming the honeycomb structure portion 14 and extruded, the extruded porous material has a high porosity (large) portion. A blank of the honeycomb structure portion 14 is formed in which the portion having a low porosity (small) gradually changes at regular intervals. Therefore, the position where the porosity is the highest (large), that is, the position where the porosity changes from increase to decrease and the part where the porosity is the lowest (small), that is, the position where the porosity changes from decrease to increase is set as the cutting position. Then, by cutting the porous material extruded at those cutting positions, a honeycomb structure 12 having a honeycomb structure portion 14 in which the porosity gradually increases from the outlet side end surface 14a to the inlet side end surface 14b can be obtained. ..

5 is an explanatory view of a portion of the partition wall 16 of the honeycomb structure 12 of FIG. 1 having a large porosity, and FIG. 5A is a cross-sectional view of the partition wall 16 and pores 22 before catalyst coating, FIG. 5B. Is a cross-sectional view of the partition wall 16 and the pores 22 after the catalyst coating, FIG. 6 is an explanatory view of a portion of the partition wall 16 of the honeycomb structure 12 of FIG. 1 where the porosity is small, and FIG. 6A is an explanatory view before the catalyst coating. FIG. 6B is a cross-sectional view of the partition wall 16 and the pores 22, and FIG. 6B is a cross-sectional view of the partition wall 16 and the pores 22 after the catalyst coating. Porosity is, in a broad sense, the ratio of the open cross-sectional area of pores (spaces) formed in, for example, a partition wall. FIG. 5A is a partition wall 16 having a large porosity, and the cross-sectional area of the pores 22 formed as a space is large. Therefore, as shown in FIG. 5B, the catalyst coated on the inner wall of the pores 22 is coated. The surface area of the 24 is also large, and therefore the amount of exhaust gas in contact with the catalyst 24 is also large. On the other hand, FIG. 6A is a partition wall 16 having a small porosity, and the cross-sectional area of the pores 22 formed as a space is small. Therefore, as shown in FIG. 6B, the inner wall of the pores 22 is coated. The surface area of the catalyst 24 is small, and therefore the amount of exhaust gas in contact with the catalyst 24 is also small.

As is well known, in the cell 18 in which the exhaust gas outlet side is closed, ash in the exhaust gas may be gradually accumulated from the exhaust gas outlet side as the exhaust gas is purified. Since the pores 22 are blocked in the outlet side region of the cell 18 where the ash has completely accumulated and the exhaust gas does not pass through the pores 22 of the partition wall 16, PM removal by the pores 22 and removal of specific components by the catalyst 24 are performed. not. On the other hand, in the exhaust gas purification filter 10 of the embodiment in which the pore ratio of the partition wall 16 of the honeycomb structure 12 gradually increases in the exhaust gas inlet side region rather than the exhaust gas outlet side region, ash content is accumulated on the exhaust gas outlet side of the cell 18. However, since a large amount of exhaust gas comes into contact with the catalyst 24 having a large surface surface coated on the pore 22 having a large opening cross-sectional area in the exhaust gas inlet side region, it is possible to effectively purify the exhaust gas even after long-term use. Therefore, it is possible to extend the life of the exhaust gas purification performance. At that time, the exhaust gas purification function does not suddenly decrease stepwise. Further, a partition wall 16 having a small porosity is arranged in the exhaust gas outlet side region of the cell 18 where ash is likely to be deposited, and since the pores 22 have a small opening cross-sectional area, the amount of the catalyst 24 coated is also small. Generally, since an expensive precious metal is used for the catalyst 24, if the amount of the catalyst 24 used for coating can be reduced, the cost can be reduced.

As described above, in the honeycomb structure 12 and the exhaust gas purification filter 10 of this embodiment, the honeycomb structure portion 12 in which the plurality of cells 18 extend in the flow direction of the exhaust gas is provided inside the tubular body 20, and each cell 18 is provided. Is one end in the extension direction or one of the other ends is closed, and the partition wall 16 separating the cells 18 is configured as a porous partition wall through which exhaust gas can pass, and the porous partition wall is an outlet for exhaust gas. It is formed so that the porosity of the inlet side region is gradually larger than the porosity of the side region. As a result, ash in the exhaust gas is gradually accumulated from the exhaust gas outlet side in the cell 18 in which the exhaust gas outlet side is closed, and the pores 22 of the porous partition wall 16 are closed in the portion where the ash is accumulated. In the porous partition wall 16 in the exhaust gas inlet side region where the porosity is gradually larger than that in the exhaust gas outlet side region, even after long-term exhaust gas purification, a large number of pores 22 are still open or the pores 22 having a larger opening cross-sectional area are 22. Is still open, the exhaust gas purification is continued through the pores 22 of the open exhaust gas inlet side porous partition wall 16, and the exhaust gas purification function does not suddenly decrease in a stepwise manner. As a result, the life of the exhaust gas purification performance can be extended. Further, when the catalyst 24 is coated on the honeycomb structure portion 14 as the exhaust gas purification filter 10, the pore ratio of the porous partition wall 16 on the exhaust gas outlet side, which is blocked by the ash in the exhaust gas first during the exhaust gas purification, is on the exhaust gas inlet side. Since the porosity is gradually set to be smaller than that of the pore ratio, the amount of the catalyst 24 on the peripheral wall of the pores 22 that does not contribute to exhaust gas purification can be efficiently reduced, that is, the coating amount of expensive noble metal can be efficiently reduced. Since the expensive noble metal used in 24 is efficiently used, the cost can be reduced.

Further, the mixing ratio of the two types of porous materials having different porosities is gradually increased or decreased, and the increase and decrease thereof are changed at regular intervals to produce a porous material, and the porous material is used. The honeycomb structure 12 is manufactured by passing through the base 26 forming the honeycomb structure portion 14 and extruding the extruded porous material at a predetermined cutting position. At this time, the porous material extruded from the mouthpiece 26 gradually changes from a large porosity state to a small porosity state or from a small porosity state to a large porosity state at regular intervals. If the porous material extruded at those cutting positions is cut with both positions as the cutting positions, the porosity of the honeycomb structure portion 14 gradually increases from the outlet side end surface 14a to the inlet side end surface 14b. The structure 12 can be easily obtained.

Further, the amount of the pore-increasing agent supplied to the inlet side of the base 26 forming the honeycomb structure portion 14 is gradually and continuously increased or decreased, and the increase and decrease are changed at regular intervals to form a porous material. The porous material is mixed to produce a porous material, the porous material is passed through the base 26 and extruded, and the extruded porous material is cut at a predetermined cutting position to produce a honeycomb structure 12. At this time, the porous material extruded from the mouthpiece 26 gradually changes from a large porosity state to a small porosity state or from a small porosity state to a large porosity state at regular intervals. If the porous material extruded at those cutting positions is cut at both positions, the porosity gradually increases from the outlet side end surface 14a to the inlet side end surface 14b. Honeycomb structure 12 can be easily obtained.

When a porous material having a different porosity is mixed to produce a porous material suitable for the porous partition wall of the honeycomb structure of the present invention, three or more kinds of porous materials having different porosities are mixed and obtained. You may.

It goes without saying that the present invention includes various embodiments not described above. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention described in the claims that are valid from the above description.

10 Exhaust gas purification filter 12 Honeycomb structure 14 Honeycomb structure 16 Partition wall 18 Cell 20 Cylindrical body 22 Pore 24 Catalyst 26 Base

Claims (3)

A plurality of cells have a honeycomb structure portion extending in the flow direction of the exhaust gas inside the tubular body, and each cell is closed at either one end or the other end in the extension direction and each cell. The partition wall separating the exhaust gas is configured as a porous partition wall through which the exhaust gas can pass, and the porous partition wall has a porosity in the inlet side region gradually larger than the porosity in the outlet side region of the exhaust gas in the tubular body. It is a method of manufacturing a honeycomb structure for purifying exhaust gas formed in
A step of mixing while changing the mixing ratio of a plurality of types of porous materials having different porosities at regular intervals to generate a porous material and sequentially moving it to the next step.
A step of extruding the porous material through a base for forming the honeycomb structure portion, and a step of extruding the porous material.
A method for producing a honeycomb structure, comprising a step of cutting the extruded porous material at a position where the porosity changes from an increase to a decrease and a position where the porosity changes from a decrease to an increase. A plurality of cells have a honeycomb structure portion extending in the flow direction of the exhaust gas inside the tubular body, and each cell is closed at either one end or the other end in the extension direction and each cell. The partition wall separating the exhaust gas is configured as a porous partition wall through which the exhaust gas can pass, and the porous partition wall has a porosity in the inlet side region gradually larger than the porosity in the outlet side region of the exhaust gas in the tubular body. It is a method of manufacturing a honeycomb structure for purifying exhaust gas formed in
The amount of the pore-increasing agent supplied to the inlet side of the base for forming the honeycomb structure is changed at regular intervals and mixed with the porous material to generate the porous material, which is then sequentially moved to the next step. Process and
The step of extruding the porous material through the mouthpiece and
A method for producing a honeycomb structure, comprising a step of cutting the extruded porous material at a position where the porosity changes from an increase to a decrease and a position where the porosity changes from a decrease to an increase. An exhaust gas purification filter using a honeycomb structure, wherein the honeycomb structure manufactured by the method for manufacturing a honeycomb structure according to claim 1 or 2 is coated with a catalyst.

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