JP6091282B2 - Catalyst coated filter and carrier for catalyst coated filter - Google Patents

Description

  The present invention relates to a catalyst-coated filter and a catalyst-coated filter carrier. More specifically, the present invention relates to a catalyst-coated filter and a catalyst-coated filter carrier in which pressure loss is reduced without deteriorating exhaust gas purification performance by maintaining a supported amount of catalyst.

  In recent years, development of automobile engines with reduced carbon dioxide emissions has been eagerly desired. Diesel engines among automotive engines have better thermal efficiency than gasoline engines, and meet the requirement to reduce carbon dioxide emissions as a measure against global warming. On the other hand, diesel engines generate fine particles by diffusion combustion, and these fine particles are recognized to be carcinogenic. Therefore, it is necessary to prevent the fine particles from being released into the atmosphere. Recently, in addition to the conventional particulate emission control, the number of discharged particulates is regulated (the number of discharged particulates is regulated), and strict regulations are imposed on the particulates released into the atmosphere.

  For gasoline engines, direct fuel injection (GDI) is expected to become the mainstream in the future from the viewpoint of improving fuel efficiency. However, the direct fuel injection type gasoline engine has a problem of generating a large amount of soot (fine particles) as compared with the case of the conventional port fuel injection. For this reason, it is planned to impose restrictions on the number of discharged particulates that were applied to diesel engines.

  In this way, diesel engines and gasoline engines (GDI) are subject to particulate emission regulations and emission particulate count regulations. Both engines can reduce the particulate emissions by improving combustion. There was a limit. Therefore, in order to satisfy the above regulations, the only effective means at present is to install a filter in the exhaust passage of the engine.

  As the filter, a wall flow type filter designed to allow exhaust gas to pass through a porous partition wall is effective, and this filter is currently the most effective as a method for collecting the fine particles.

On the other hand, as a problem in the exhaust of an automobile engine, there is removal of gas emissions such as CO, HC, NO _{X and the} like that have been conventionally regulated in addition to removal of fine particles such as soot. That is, while a filter for removing fine particles such as soot is required, a converter for removing gas emission is also required, and these must be arranged in series and installed in the exhaust system. However, the exhaust system has a problem that the space for installing these is small, making it difficult to install the converter, and increasing the cost.

  As a countermeasure against these problems, a catalyst-coated filter has been reported in which a catalyst for gas emission removal is carried on a filter and gas emission removal and soot and other particulates can be removed at the same time (for example, Patent Documents). 1-4).

JP 2011-098337 A International Publication No. 2011/042991 International Publication No. 2007/094379 JP 2008-296218 A

  The catalyst-coated filters described in Patent Documents 1 to 4 can simultaneously remove gas emissions and fine particles such as soot, but a large amount of catalyst is required for purification of exhaust gas. Specifically, a large amount of a three-way catalyst is required for purification of exhaust gas from a gasoline engine, and a large amount of SCR catalyst is required for purification of exhaust gas from a diesel engine. For this reason, there is a problem that the pressure loss becomes excessive due to loading a large amount of catalyst on the filter, which deteriorates the fuel consumption and output of the engine.

  As a countermeasure for such a problem, an attempt has been made to increase the porosity of the partition wall of the filter so as to ensure as much as possible the passage route of the exhaust gas that permeates the partition wall. However, there are limits to such attempts.

  Thus, there has been a strong demand for the development of a catalyst-coated filter with reduced pressure loss without deteriorating exhaust gas purification performance by maintaining the amount of catalyst supported.

The present invention has been made in view of such problems of the prior art. It is an object of the present invention, without decreasing the purification performance of the exhaust gas by maintaining the amount of catalyst supported can be used as a carrier for the catalyst coating filter and the catalyst-coated filter pressure loss is reduced, the catalyst An object of the present invention is to provide a catalyst-coated filter carrier capable of easily and efficiently producing a coated filter.

  According to the present invention, the following catalyst-coated filter and catalyst-coated filter carrier are provided.

[1] A honeycomb structure part having a partition wall in which a plurality of pores are formed which extend from an inflow end surface which is one end surface to an outflow end surface which is the other end surface and which form a plurality of cells serving as exhaust gas flow paths; Plugged portions disposed in the opening on the outflow end face side of the inlet cell that is the predetermined cell of the honeycomb structure part and the opening on the inflow end face side of the outlet cell that is the remaining cell; An exhaust gas purifying catalyst supported on the surface of the partition walls and the inner surfaces of the pores formed in the partition walls, and having an average value of the supported amount in the entire honeycomb structure portion of 100 g / L or more, and the honeycomb structure An inflow end surface side portion which is a portion on the inflow end surface side of the portion and an outflow end surface side portion which is a portion on the outflow end surface side, and the outflow end surface side portion includes the inflow end surface side portion and the outflow end surface side portion. 2 of the total volume of A catalyst coat that occupies 0 to 80% , and the amount of catalyst supported on the inflow end surface side portion is larger than the amount of catalyst supported on the outflow end surface side portion, and the outflow end surface side portion satisfies the following condition (A) filter.
Condition (A): In the cross section orthogonal to the cell extending direction of the honeycomb structure portion in the outflow end face side portion, the partition supporting the catalyst is 5 etc. in the direction orthogonal to the thickness direction of the partition Divide into 5 areas. The calculated value (α) calculated by the following formula (1) and the following formula (2) is 50% or more.
Formula (1); (Average pore diameter (μm) of the partition wall after the catalyst is supported) 2 × (Porosity (%) of the partition wall after the catalyst is supported) = first permeation characteristic value Formula (2); ((maximum first transmission characteristic value−minimum first transmission characteristic value) / average first transmission characteristic value) × 100 = calculated value (α)
In the formula (2), the minimum first transmission characteristic value is the minimum first transmission characteristic value among the first transmission characteristic values of the five regions. The maximum first transmission characteristic value is the maximum first transmission characteristic value among the first transmission characteristic values of the five regions. The average first transmission characteristic value is an average value of the first transmission characteristic values of the five regions.

[2] The catalyst-coated filter according to [1], wherein the calculated value (α) is 70% or more.

[3] In the honeycomb structure part, the partition wall has a porosity of 55 to 70%, the partition wall has an average pore diameter of 15 to 30 μm, and the partition wall satisfies the following condition (B) [1] Or the catalyst coat filter as described in [2].
Condition (B): In the cross section perpendicular to the cell extending direction of the honeycomb structure portion, the partition wall is divided into five regions in the direction orthogonal to the thickness direction of the partition wall to form five regions. The calculated value (β) calculated by the following formula (3) and the following formula (4) is 10 to 90%.
(Average pore diameter (μm) of the partition wall) ² × (porosity (%) of the partition wall) = second transmission characteristic value expression (4); ((maximum second transmission characteristic value−minimum number) 2 transmission characteristic value) / average second transmission characteristic value) × 100 = calculated value (β)
In the formula (4), the minimum second transmission characteristic value is the minimum second transmission characteristic value among the second transmission characteristic values of the five regions. The maximum second transmission characteristic value is the maximum second transmission characteristic value among the second transmission characteristic values of the five regions. The average second transmission characteristic value is an average value of the second transmission characteristic values of the five regions.

[4] The catalyst-coated filter according to [3], wherein the calculated value (β) is 20 to 90%.

[5] A honeycomb structure part having a partition wall in which a plurality of pores are formed that extend from an inflow end face that is one end face to an outflow end face that is the other end face to form a plurality of cells that serve as exhaust gas flow paths; Plugged portions disposed in the opening on the outflow end face side of the inlet cell that is the predetermined cell of the honeycomb structure part and the opening on the inflow end face side of the outlet cell that is the remaining cell; And the honeycomb structure part has a partition wall porosity of 55 to 70%, the partition wall average pore diameter is 15 to 30 μm, and the partition wall satisfies the following condition (C): Carrier.
Condition (C): In the cross section perpendicular to the cell extending direction of the honeycomb structure portion, the partition walls are divided into five equal parts in the direction orthogonal to the thickness direction of the partition walls to form five regions. The calculated value (γ) calculated by the following formula (5) and the following formula (6) is 10 to 90%.
(Average pore diameter (μm) of the partition walls) ² × (porosity (%) of the partition walls) = third transmission characteristic value expression (6); ((maximum third transmission characteristic value−minimum number) 3 transmission characteristic value) / average third transmission characteristic value) × 100 = calculated value (γ)
In the equation (6), the minimum third transmission characteristic value is the minimum third transmission characteristic value among the third transmission characteristic values of the five regions. The maximum third transmission characteristic value is the maximum third transmission characteristic value among the third transmission characteristic values of the five regions. The average third transmission characteristic value is an average value of the third transmission characteristic values of the five regions.

[6] The catalyst-coated filter carrier according to [5], wherein the calculated value (γ) is 20 to 90%.

In the catalyst-coated filter of the present invention, since the average value of the catalyst loading amount in the entire honeycomb structure is 100 g / L or more, the catalyst loading amount used in the conventional catalyst-coated filter is maintained. Therefore, the catalyst-coated filter of the present invention does not deteriorate the exhaust gas purification performance. The catalyst coat filter of the present invention comprises an inflow end surface side portion and an outflow end surface side portion, and the outflow end surface side portion occupies 20 to 80% of the total volume of the inflow end surface side portion and the outflow end surface side portion. Thus, the amount of catalyst supported on the inflow end face side portion is larger than the amount of catalyst supported on the outflow end face side portion, and the condition (A) is satisfied. Therefore, in addition to being able to purify the exhaust gas, the catalyst-coated filter of the present invention secures a flow path for the exhaust gas at the outflow end face side portion, thereby reducing pressure loss.

  The catalyst-coated filter carrier of the present invention is the above-described catalyst-coated filter carrier of the present invention. By using the catalyst-coated filter carrier of the present invention, the catalyst-coated filter of the present invention is easily and efficiently produced. be able to.

It is sectional drawing which shows typically the cross section cut | disconnected in parallel with the cell extending direction of one Embodiment of the catalyst coat filter of this invention. It is sectional drawing which shows typically the cross section cut | disconnected in the direction orthogonal to the cell extending direction in the outflow end surface side part of the catalyst coat filter shown in FIG. It is a schematic diagram which expands and shows the part P which is a part of partition in the outflow end surface side part of the catalyst coat filter shown in FIG. It is a schematic diagram which expands and shows each 5 area | region obtained by dividing the partition shown in FIG. 3 into 5 equal parts.

  Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments, and appropriate modifications and improvements are added to the following embodiments on the basis of ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that what has been described also falls within the scope of the invention.

[1] Catalyst coated filter:
As an embodiment of the catalyst-coated filter of the present invention, there is a catalyst-coated filter 100 shown in FIG. The catalyst coat filter 100 includes a honeycomb structure portion 10 having porous partition walls 15, plugging portions 12 disposed in the cells 2 of the honeycomb structure portion 10, and purification of exhaust gas carried on the honeycomb structure portion 10. And a catalyst layer 16 containing a catalyst for use. The honeycomb structure portion 10 has partition walls 15 that extend from an inflow end surface 11a, which is one end surface, to an outflow end surface 11b, which is the other end surface, and define a plurality of cells 2 serving as exhaust gas flow paths. The plugging portions 12 are arranged in the opening portion on the outflow end surface 11b side of the inlet cell 2a which is the predetermined cell 2 of the honeycomb structure portion 10 and the opening portion of the inflow end surface 11a of the outlet cell 2b which is the remaining cell 2. Has been. The catalyst is for purifying exhaust gas carried on the surface of the partition wall 15 and the inner surface of the pores formed in the partition wall 15. The average value of the amount of catalyst supported in the entire honeycomb structure 10 is 100 g / L or more. Further, the catalyst coat filter 100 includes an inflow end surface side portion 21 that is a portion on the inflow end surface 11a side of the honeycomb structure portion 10 and an outflow end surface side portion 22 that is a portion on the outflow end surface 11b side. In the catalyst coat filter 100, the outflow end surface side portion 22 occupies 20 to 80% of the total volume of the inflow end surface side portion 21 and the outflow end surface side portion 22. Further, the amount of catalyst supported on the inflow end surface side portion is larger than the amount of catalyst supported on the outflow end surface side portion. In the catalyst coat filter 100, the outflow end face side portion 22 satisfies the following condition (A).
Condition (A): In the cross section (see FIG. 2) orthogonal to the cell 2 extending direction of the honeycomb structure 10 in the outflow end face side portion 22, the partition wall 15 carrying the catalyst is orthogonal to the thickness direction of the partition wall 15. Dividing into five equal directions, five regions R1, R2, R3, R4, and R5 are obtained (see FIG. 3). At this time, the calculated value (α) calculated by the following formula (1) and the following formula (2) is 50% or more. That is, after obtaining the five regions R1, R2, R3, R4, and R5, the first transmission characteristic that is a value calculated by the following formula (1) in each of the five regions R1, R2, R3, R4, and R5. Calculate the value. Thereafter, when the calculated value (α) is obtained from the following formula (2), the calculated value (α) is 50% or more.
Formula (1): (Average pore diameter (μm) of partition wall 15 after catalyst is supported) 2 × (Porosity (%) of partition wall 15 after catalyst is supported) = First transmission characteristic value formula ( 2): ((maximum first transmission characteristic value−minimum first transmission characteristic value) / average first transmission characteristic value) × 100 = calculated value (α)
In Equation (2), the minimum first transmission characteristic value is the minimum first transmission characteristic value among the first transmission characteristic values of the five regions R1, R2, R3, R4, and R5. The maximum first transmission characteristic value is the maximum first transmission characteristic value among the first transmission characteristic values of the five regions R1, R2, R3, R4, and R5. The average first transmission characteristic value is an average value of the first transmission characteristic values of the five regions R1, R2, R3, R4, and R5.

In such a catalyst-coated filter 100, since the average value of the catalyst loading amount in the entire honeycomb structure 10 is 100 g / L or more, the catalyst loading amount used in the conventional catalyst-coated filter is maintained. Therefore, the exhaust gas purification performance of the catalyst coat filter 100 does not deteriorate. The catalyst coat filter 100 includes an inflow end surface side portion 21 and an outflow end surface side portion 22, and the outflow end surface side portion 22 is 20 to 80% of the total volume of the inflow end surface side portion 21 and the outflow end surface side portion 22. The amount of catalyst supported on the inflow end surface side portion is larger than the amount of catalyst supported on the outflow end surface side portion and satisfies the condition (A). Therefore, in addition to being able to purify the exhaust gas, the catalyst coat filter 100 secures a flow path for the exhaust gas at the outflow end face side portion 22 and reduces pressure loss.

  FIG. 1 is a cross-sectional view schematically showing a cross section cut parallel to the cell extending direction of one embodiment of the catalyst-coated filter of the present invention. FIG. 2 is a cross-sectional view schematically showing a cross section cut in a direction orthogonal to the cell extending direction in the outflow end face side portion of the catalyst coat filter shown in FIG. FIG. 3 is an enlarged schematic view showing a portion P which is a part of the partition wall in the outflow end face side portion of the catalyst coat filter shown in FIG. 2 and 3, the catalyst layer 16 is omitted.

  In this specification, “average pore diameter” and “porosity” are values calculated from images obtained by image analysis using a scanning electron microscope (SEM). Specifically, it is a value calculated as follows. First, the catalyst coat filter is cut in a direction orthogonal to the cell extending direction to obtain a cross section. Next, a plurality of arbitrary partition walls in the cross section are selected, and these partition walls are photographed using a scanning electron microscope to obtain a cross section image of the partition walls. Then, in the cross-sectional image of each partition, it divides into 5 parts in the direction orthogonal to the thickness direction of a partition, and five areas are obtained (refer FIG. 3). Thereafter, in each region (five regions) of each partition wall, image analysis such as binarization by dividing into pores (pores) and partition walls is performed to measure “average pore diameter” and “porosity”.

  The catalyst-coated filter of the present invention satisfies the condition (A) as described above. That is, the catalyst-coated filter of the present invention is provided with a distinction between “a region for allowing the exhaust gas to permeate” and “a region for contacting the exhaust gas and the catalyst” in one partition wall. Specifically, in FIG. 4, for example, the region R <b> 2 corresponds to a “region for allowing the exhaust gas to permeate” and the region R <b> 1 corresponds to a “region for bringing the exhaust gas into contact with the catalyst”. These “region for allowing the exhaust gas to permeate” and “region for bringing the exhaust gas into contact with the catalyst” need to exist at a distance close to each other. If the distance between the “region for allowing the exhaust gas to permeate” and the “region for bringing the exhaust gas into contact with the catalyst” is too far, many exhaust gases pass through the “region for allowing the exhaust gas to permeate”. This is because it becomes difficult for the catalyst and the catalyst to come into contact with each other, and the purification rate of exhaust gas becomes worse. Therefore, as described above, the catalyst-coated filter of the present invention is provided with “a region for allowing the exhaust gas to permeate” and “a region for contacting the exhaust gas and the catalyst” in one partition wall.

  Thus, the catalyst-coated filter of the present invention satisfies the condition (A), so that “a region for allowing the exhaust gas to permeate” and “a region for bringing the exhaust gas and the catalyst into contact with each other” in one partition wall. Will exist. Therefore, the catalyst-coated filter of the present invention can reduce pressure loss without deteriorating exhaust gas purification performance. In the present specification, the “partition wall” is a wall that partitions one cell. FIG. 4 is an enlarged schematic view showing five regions R1, R2, R3, R4, and R5 obtained by equally dividing the partition wall shown in FIG. As shown in FIG. 4, a plurality of pores 3 are formed in the partition wall 15, and a catalyst layer 16 containing a catalyst is formed on the inner surface 3 a of the pores 3. “The average pore diameter of the partition walls after the catalyst is supported” is the state in which the catalyst is supported on the inner surface 3a of the pore 3 formed in the partition wall 15 as shown in FIG. 4 (the state in which the catalyst layer 16 is formed). ) Means the average diameter of the pores 3. That is, it is the average value of the diameters of the hollow portions that serve as exhaust gas flow paths. In addition, the “porosity of the partition walls after the catalyst is supported” is the same as the above “average pore diameter of the partition walls after the catalyst is supported”, and the catalyst is supported on the inner surfaces of the pores formed in the partition walls. It means the ratio of pores (pores) in the closed state (the ratio of the hollow portion).

  The catalyst coat filter of this invention should just satisfy | fill conditions (A) as mentioned above. In order to satisfy this condition (A), the catalyst-coated filter carrier of the present invention to be described later can be suitably used. For example, a conventionally known honeycomb structure (catalyst-coated filter carrier) may be used. . In the case where a conventionally known honeycomb structure is used, in order to have “a region for allowing exhaust gas to permeate” and “a region for contacting exhaust gas and the catalyst” in one partition wall, one partition wall is used. There is a method of providing a difference in the amount of catalyst supported. That is, the catalyst is not uniformly supported on all of the partition walls in one partition, but the catalyst support amount is distributed, and the catalyst support amount is reduced in a predetermined region within one partition. By doing in this way, pressure loss can be reduced, without reducing the purification performance of exhaust gas.

  In the condition (A), the calculated value (α) is 50% or more, preferably 70% or more, and more preferably 75 to 150%, as described above. By setting the calculated value (α) in the above range, the flow path of the exhaust gas that passes through the partition wall is secured, and the contact opportunity between the exhaust gas and the catalyst is maintained, so that the pressure loss can be reduced, The exhaust gas purification rate can be maintained high. If the calculated value (α) is less than 50%, the exhaust gas flow path in the partition wall does not secure a sufficient space as a flow path through which the exhaust gas passes, and thus pressure loss may increase.

  As described above, in the catalyst-coated filter of the present invention, the outflow end surface side portion 22 occupies 20% or more of the total volume of the inflow end surface side portion 21 and the outflow end surface side portion 22 and occupies 30 to 80%. It is preferable that it occupies 60 to 80%. Since the outflow end face side portion 22 occupies 20% or more of the volume of the outflow end face side portion 22 in the total volume of the inflow end face side portion 21 and the outflow end face side portion 22, the number of exhaust gas passage channels in the partition wall Therefore, the total area of the exhaust gas flow path is secured. Therefore, an increase in pressure loss of the catalyst coat filter can be suppressed. On the other hand, if it is less than 20%, the ratio of the outflow end face side portion 22 where the partition wall having the “region for allowing the exhaust gas to permeate” is reduced decreases, so the total area of the exhaust gas flow path decreases and the pressure loss increases. Resulting in.

[1-1] Honeycomb structure part:
The honeycomb structure portion 10 includes partition walls 15 that extend from an inflow end surface 11a, which is one end surface, to an outflow end surface 11b, which is the other end surface, and define a plurality of cells 2 serving as exhaust gas flow paths. There are no particular restrictions. The catalyst-coated filter of the present invention preferably includes the following catalyst-coated filter carrier (preferred embodiment of the honeycomb structure in the catalyst-coated filter) as the honeycomb structure. That is, the honeycomb structure portion of the catalyst-coated filter of the present invention has a partition wall porosity of 55 to 70%, an average partition wall pore size of 15 to 30 μm, and the partition wall satisfying the following condition (B). A filter carrier is preferred. In the honeycomb structure portion, at least a part of the partition walls may satisfy the condition (B). Specifically, in the honeycomb structure portion, partition walls in a portion corresponding to the outflow end face side portion of the catalyst coat filter may satisfy the condition (B). Further, in the honeycomb structure portion, the partition walls in the entire area from the inflow end surface to the outflow end surface may satisfy the condition (B).
Condition (B): In the cross section perpendicular to the cell extending direction of the honeycomb structure portion, the partition walls are divided into five regions in the direction orthogonal to the thickness direction of the partition walls to form five regions. The calculated value (β) calculated by the following formula (3) and the following formula (4) is 10 to 90%. That is, after obtaining five regions, the second transmission characteristic value, which is a value calculated by the following equation (3), is calculated in each of the five regions. Thereafter, when the calculated value (β) is obtained from the following formula (4), the calculated value (β) is 10 to 90%.
(Average pore diameter (μm) of the partition wall) ² × (porosity (%) of the partition wall) = second transmission characteristic value expression (4); ((maximum second transmission characteristic value−minimum number) 2 transmission characteristic value) / average second transmission characteristic value) × 100 = calculated value (β)
In Expression (4), the minimum second transmission characteristic value is the minimum second transmission characteristic value among the second transmission characteristic values of the five regions. The maximum second transmission characteristic value is the maximum second transmission characteristic value among the second transmission characteristic values of the five regions. The average second transmission characteristic value is an average value of the second transmission characteristic values of the five regions.

  By using this catalyst-coated filter carrier as the honeycomb structure part, the catalyst-coated filter of the present invention can be produced simply and efficiently.

  In the condition (B), the calculated value (β) is preferably 10 to 90%, more preferably 20 to 90%, and particularly preferably 60 to 90% as described above. By setting the calculated value (β) within the above range, the pressure of the exhaust gas passage through the partition wall is secured after the catalyst is loaded, and the contact opportunity between the exhaust gas and the catalyst is maintained. Loss can be reduced and the exhaust gas purification rate can be kept high. If the calculated value (β) is less than 10%, the flow path of the exhaust gas in the partition wall is blocked, which may increase the pressure loss. On the other hand, if the calculated value (β) is more than 90%, after the catalyst is supported, the contact opportunity between the catalyst and the exhaust gas becomes insufficient, and the exhaust gas purification rate may be reduced.

  The porosity of the partition walls of the honeycomb structure portion is preferably 55 to 70%, more preferably 58 to 68%, and particularly preferably 60 to 66%. If the porosity is less than 55%, pressure loss may increase. On the other hand, if it exceeds 70%, the strength of the partition may be lowered.

  The average pore diameter of the partition walls of the honeycomb structure portion is preferably 15 to 30 μm, more preferably 15 to 25 μm, and particularly preferably 15 to 23 μm. There exists a possibility that a pressure loss may increase that the said average pore diameter is less than 15 micrometers. On the other hand, if it exceeds 30 μm, the collection efficiency for collecting the particulate matter in the exhaust gas may decrease.

  The thickness of the partition walls of the honeycomb structure portion is preferably 75 to 400 μm, more preferably 145 to 350 μm, and particularly preferably 250 to 350 μm. When the partition wall thickness is less than 75 μm, the partition wall strength is insufficient, and the trapping efficiency of the particulate matter in the exhaust gas may be reduced. On the other hand, if it exceeds 400 μm, the pressure loss may increase.

The cell density of the honeycomb structure portion is preferably 15 to 65 cells / cm ² , more preferably 20 to 50 cells / cm ² , and particularly preferably 30 to 50 cells / cm ² . If the cell density is less than 15 cells / cm ² , the filtration area as a filter may be too small, and the collection efficiency for collecting particulate matter in the exhaust gas may deteriorate, or the pressure loss may increase. is there. On the other hand, if it exceeds 65 cells / cm ² , the pressure loss may increase.

  The shape of the honeycomb structure 10 may be a cylindrical shape, an elliptical column shape, a quadrangular column shape, a hexagonal column shape, or the like. Among these, a cylindrical shape and a quadrangular prism shape are preferable.

  The length of the honeycomb structure 10 (catalyst coat filter 100) in the cell extending direction can be set to 50 to 400 mm. Moreover, when the end surface of the catalyst coat filter 100 is circular, the diameter of an end surface can be 70-400 mm.

[1-2] Plugging portion:
As described above, the plugging portion 12 includes the opening on the outflow end surface 11b side of the inlet cell 2a that is the predetermined cell 2 of the honeycomb structure portion 10 and the opening of the inflow end surface 11a of the outlet cell 2b that is the remaining cell 2. Are disposed on the part. The arrangement state of the plugged portion is not particularly limited as long as the plugged portion is formed so as to plug the cell at either the inflow end surface side or the outflow end surface side. For example, as shown in FIG. 1, the plugged portions 12 are preferably arranged so that the inlet cells 2a and the outlet cells 2b are alternately arranged.

  The material of the plugging portion can be the same as the material of the partition walls constituting the honeycomb structure portion. Therefore, a plurality of pores (pores) are formed in the plugged portion in the same manner as the partition walls of the honeycomb structure portion, and the porosity and average pore diameter of the plugged portions are the above-described porosity and average pore diameter of the partition walls. Can be in the same range.

[1-3] Catalyst:
The catalyst is a catalyst for exhaust gas purification, and examples thereof include a three-way catalyst, an SCR catalyst, a NO _X storage reduction catalyst, an oxidation catalyst, and a NO _X selective reduction catalyst mainly composed of a metal-substituted zeolite.

  The catalyst is supported on the surfaces of the partition walls and the inner surfaces of the pores formed in the partition walls. The “inner surface of the pore formed in the partition wall” refers to the surface of the wall constituting the pore (pore) formed in the partition wall.

  The average value of the amount of catalyst supported in the entire honeycomb structure is 100 g / L or more, preferably 100 to 250 g / L, more preferably 100 to 200 g / L, and more preferably 100 to 180 g / L. It is particularly preferred. When the amount of the catalyst supported is less than 100 g / L, the amount of the catalyst supported becomes too small, and the exhaust gas purification performance of the catalyst-coated filter decreases. Here, the “average value of the amount of catalyst supported in the entire honeycomb structure” is calculated by calculating the total amount of catalyst supported from the difference in dry weight before and after catalyst loading, and then calculating the total amount of catalyst supported by the carrier (honeycomb structure portion). It is the value divided by the volume of the whole. That is, it does not mean the average value of the amount of catalyst supported only on the inflow end face side portion of the catalyst coat filter or the average value of the catalyst support amount only on the outflow end face side portion of the catalyst coat filter. In other words, even if the amount of catalyst supported on the outflow end face side portion of the catalyst coat filter is less than 100 g / L, the amount of catalyst supported on the inflow end face side portion exceeds 100 g / L, It is sufficient that the supported amount of the catalyst is 100 g / L or more.

[2] Method for producing catalyst-coated filter of the present invention:
The catalyst-coated filter of the present invention can be manufactured as follows. That is, the method for producing a catalyst-coated filter of the present invention includes a honeycomb structure part manufacturing step in which a clay containing a ceramic material and a pore forming agent is formed into a honeycomb shape and fired to prepare a honeycomb structure part. The honeycomb structure portion has a porous partition wall that extends from an inflow end surface, which is one end surface, to an outflow end surface, which is the other end surface, and defines a plurality of cells serving as exhaust gas flow paths. In the method for producing a catalyst-coated filter of the present invention, the plugged honeycomb structure part in which the plugged slurry is disposed in the honeycomb structure part is prepared by filling the prepared honeycomb structure part with a slurry for plugging and drying. It has a plugged honeycomb structure manufacturing step to be manufactured. The plugging slurry is filled into the openings on the outflow end face side of the inlet cells, which are predetermined cells of the honeycomb structure part, and the openings on the inflow end face of the outlet cells, which are remaining cells. In the method for producing a catalyst-coated filter of the present invention, a catalyst-coated filter is produced by applying a catalyst slurry to the surfaces of the partition walls of the plugged honeycomb structure and the inner surfaces of the pores formed in the partition walls and drying the slurry. It has a catalyst coat filter production process. The catalyst slurry contains an exhaust gas purifying catalyst. The catalyst coat filter carries a catalyst on the surfaces of the partition walls of the honeycomb structure and the inner surfaces of the pores formed in the partition walls.

  According to this method for producing a catalyst-coated filter, the catalyst-coated filter of the present invention can be easily produced.

[2-1] Honeycomb structure manufacturing process:
Examples of the ceramic material include cordierite, silicon carbide, aluminum titanate, silicon nitride, and mullite.

  As the pore-forming agent, carbon (carbon powder), foamed resin, starch and the like can be used. Among these, carbon is preferable because it is easy to obtain raw materials having various particle distributions (“porous material raw materials made of carbon” having various particle distributions) and to easily adjust the particle diameter.

  As the pore former, those having an average particle diameter of 20 to 40 μm and a particle distribution of 15 to 100 μm can be used, and those having an average particle diameter of 25 to 30 μm and a particle distribution of 20 to 40 μm. It is preferable to use it.

  When a pore former made of carbon having an average particle diameter of 20 to 40 μm and a particle distribution of 15 to 100 μm is used, the above-described “preferred embodiment of the honeycomb structure portion in the catalyst-coated filter” can be easily produced. it can. That is, when a pore-forming agent satisfying the above predetermined conditions is used, the honeycomb structure portion of the catalyst-coated filter carrier of the present invention can be easily produced. The calculated value (α) is the particle diameter of the catalyst contained in the catalyst slurry, specifically the alumina particle diameter in the case of a three-way catalyst, the zeolite particle diameter in the case of an SCR catalyst, and the catalyst slurry. The viscosity can be adjusted to a desired value by adjusting the viscosity. The slurry viscosity can be adjusted by changing the pH.

  The clay can be molded to have a honeycomb structure by an extrusion molding method, an injection molding method, a press molding method, or the like.

[2-2] Plugged honeycomb structure manufacturing process:
Filling the honeycomb structure with the plugging slurry can be performed as follows. First, a mask is applied to a part of one end face (inflow end face) of a predetermined cell of the honeycomb structure part, and the end part on the end face side is immersed in a storage container in which a plugging slurry is stored, A plugging slurry is filled in a cell that is not masked. Similarly, a mask is applied to a part of the other end surface (outflow end surface) of the remaining cells of the honeycomb structure portion, and the end portion on the end surface side is immersed in the storage container in which the plugging slurry is stored. Then, the plugging slurry is filled in the cells that are not masked.

  As the plugging slurry, the same material as the clay forming the partition walls (honeycomb structure portion) may be used, or a different material may be used. Specifically, the ceramic material, the surfactant, and water are mixed, and if necessary, a sintering aid, a pore forming agent, and the like are added to form a slurry.

  The plugging slurry can be dried by hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, or the like.

[2-3] Catalyst coated filter production process:
In this step, the catalyst slurry contains an exhaust gas purifying catalyst. Examples of the catalyst include a three-way catalyst, an SCR catalyst, a NO _X storage reduction catalyst, an oxidation catalyst, and a NO _X selective reduction catalyst mainly composed of a metal-substituted zeolite.

  In addition to the catalyst, the catalyst slurry may contain a noble metal, a catalyst auxiliary, a noble metal holding material, and the like. Examples of the noble metal include platinum, rhodium, and palladium. Examples of the catalyst auxiliary include alumina, zirconia, and ceria.

  As a method of applying the catalyst slurry, a conventionally known method such as a method of sucking the catalyst slurry or a dipping method can be employed. The method of sucking the catalyst slurry is to immerse one end of the catalyst-coated filter carrier in a container filled with the catalyst slurry, and then suck the catalyst slurry from the other end to draw the surface of the partition wall, etc. In this method, the slurry for catalyst is applied. In the method for producing a catalyst-coated filter of the present invention, for example, after one end of the catalyst-coated filter carrier is immersed in the catalyst slurry and applied to the inflow end portion, the other end is It is immersed in the catalyst slurry, and the catalyst slurry is applied to the outflow end side portion. In the dipping method, the catalyst-coated filter carrier is immersed in a catalyst-filled filter carrier in a container filled with the catalyst slurry, so that the catalyst slurry is applied to the surface of partition walls that partition the cells of the honeycomb structure of the catalyst-coated filter carrier. It is a method of coating.

  In the method for producing a catalyst-coated filter according to the present invention, the viscosity of the catalyst slurry applied to the portion serving as the inflow end portion of the catalyst coat filter and the catalyst slurry applied to the portion serving as the outflow end portion are described. It is preferable to make the viscosity different. The viscosity of the “catalyst slurry applied to the portion serving as the inflow end portion” is preferably greater than the viscosity of the “catalyst slurry applied to the portion serving as the outflow end portion”. Specifically, the viscosity of the slurry for catalyst applied to the “part which becomes the outflow end portion side portion” of the catalyst coat filter is preferably 1 to 10 Pa · s, and preferably 2 to 8 Pa · s. Further preferred. Further, the viscosity of the catalyst slurry applied to the “portion on the inflow end portion side” of the catalyst coat filter is preferably 5 to 20 Pa · s, and more preferably 8 to 15 Pa · s. In the method for producing a catalyst-coated filter of the present invention, when the catalyst-coated filter carrier of the present invention is used, the viscosity of the catalyst slurry is in the above range, and further, the above “method for sucking the catalyst slurry” is adopted, The catalyst-coated filter of the present invention can be produced efficiently.

  The drying conditions of the catalyst slurry can be 300 to 600 ° C. and 0.5 to 3 hours. The drying conditions for the catalyst slurry are the drying conditions for the catalyst-coated filter carrier coated with the catalyst slurry.

[3] Catalyst coated filter carrier:
The catalyst-coated filter carrier of the present invention includes a honeycomb structure portion having partition walls in which a plurality of pores are formed, an opening portion on the outflow end face side of an inlet cell that is a predetermined cell of the honeycomb structure portion, and a remaining cell. And a plugging portion disposed at an opening on the inflow end face side of a certain outlet cell. The honeycomb structure portion has partition walls that define a plurality of cells that extend from an inflow end surface that is one end surface to an outflow end surface that is the other end surface and serve as exhaust gas flow paths.

The honeycomb structure part of the catalyst-coated filter carrier of the present invention has partition wall porosity of 55 to 70%, and partition wall average pore diameter of 15 to 30 μm. Furthermore, the partition walls of the honeycomb structure portion satisfy the following condition (C).
Condition (C): In the cross section perpendicular to the cell extending direction of the honeycomb structure part, the partition walls are divided into five equal parts in the direction orthogonal to the thickness direction of the partition walls to form five regions. The calculated value (γ) calculated by the following formula (5) and the following formula (6) is 10 to 90%. That is, after obtaining five areas, a third transmission characteristic value that is a value calculated by the following equation (5) is calculated in each of the five areas. Thereafter, when the calculated value (γ) is obtained from the following formula (6), the calculated value (γ) is 10 to 90%.
(Average pore diameter (μm) of the partition walls) ² × (porosity (%) of the partition walls) = third transmission characteristic value expression (6); ((maximum third transmission characteristic value−minimum number) 3 transmission characteristic value) / average third transmission characteristic value) × 100 = calculated value (γ)
In Equation (6), the minimum third transmission characteristic value is the smallest third transmission characteristic value among the third transmission characteristic values of the five regions. The maximum third transmission characteristic value is the maximum third transmission characteristic value among the third transmission characteristic values of the five regions. The average third transmission characteristic value is an average value of the third transmission characteristic values of the five regions.

  Such a catalyst-coated filter carrier can be suitably used as the above-described catalyst-coated filter carrier of the present invention. By using this catalyst-coated filter carrier, the catalyst-coated filter of the present invention can be easily and efficiently used. It can be manufactured well.

  In the catalyst-coated filter carrier of the present invention, the calculated value (γ) is 10 to 90% as described above, preferably 20 to 90%, and more preferably 60 to 90%. . By setting the calculated value (γ) within the above range, it is possible to easily achieve a suitable non-uniform distribution of the catalyst (see FIG. 4) when the catalyst is loaded, so that the exhaust gas passes through the partition walls. Resistance can be reduced. That is, even after the catalyst is supported, pores having a reasonably large diameter, which are flow paths for allowing the exhaust gas to permeate well, can be left in the partition walls. Therefore, an increase in pressure loss can be suppressed. Furthermore, since a sufficient amount can be supported without reducing the amount of catalyst supported, the exhaust gas purification rate is maintained. When the calculated value (γ) is less than 10%, the ratio of large pores (pores having a large diameter) that is a channel for allowing the exhaust gas to permeate satisfactorily decreases, and thus pressure loss increases. On the other hand, if the calculated value (γ) is more than 90%, a sufficient opportunity for contact between the exhaust gas and the catalyst cannot be obtained, and the exhaust gas purification rate decreases.

  One embodiment of the catalyst-coated filter carrier of the present invention includes the above-described “honeycomb structure portion in the catalyst-coated filter” and the honeycomb structure portion and the plugging portion.

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

[Average pore diameter (μm)]
The catalyst coat filter is cut in a direction perpendicular to the cell extending direction to obtain a cross section. The partition wall in this cross section is subjected to image analysis using SEM. Specifically, arbitrary three partition walls are selected in the cross section, and five regions are obtained by dividing each partition wall into five equal parts in a direction orthogonal to the thickness direction of each partition wall (see FIG. 3). Thereafter, the pores and the partition walls are binarized in each region (5 regions) of each partition wall, image analysis is performed, and the average pore diameter (μm) is measured.

[Porosity (%)]
In each region (five regions) of the partition walls obtained by the measurement of the [average pore diameter (μm)], the pores and the partition walls are binarized, image analysis is performed, and the porosity (%) is measured.

Example 1
First, a honeycomb structure used for a catalyst-coated filter (that is, a catalyst-coated filter carrier) was produced. Specifically, water, hydroxypropylmethylcellulose, ethylene glycol, and carbon as a pore-forming agent were added to the cordierite forming raw material to prepare a clay for molding. The amount of the dispersion medium added was 35 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The amount of the organic binder added was 6 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The addition amount of the dispersant was 0.5 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The amount of pore-forming agent added was 10 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. Moreover, the average particle diameter of the pore former was 30 μm, and the particle distribution was 25 to 70 μm.

  The cordierite-forming raw material is composed of 38.9 parts by mass of talc having an average particle diameter of 4 μm, 40.7 parts by mass of kaolin having an average particle diameter of 2 μm, 5.9 parts by mass of alumina having an average particle diameter of 0.3 μm, and an average It consisted of 11.5 parts by weight of boehmite with a particle size of 0.5 μm. In addition, the said average particle diameter is a median diameter (d50) in the particle size distribution of each particle | grain.

  Next, the obtained kneaded material was extruded to produce a cylindrical honeycomb formed body having a honeycomb structure. Thereafter, both end faces of the manufactured honeycomb formed body were cut and adjusted to predetermined dimensions. Then, it dried with the microwave dryer and obtained the honeycomb dried body.

  Next, the plugging slurry was filled in the opening on the outflow end face side of the inlet cell which is a predetermined cell of the obtained dried honeycomb body and the opening part on the inflow end face of the outlet cell which is the remaining cell. Thereafter, the honeycomb dried body filled with the plugging slurry was dried with a microwave dryer and fired at 1445 ° C. for 5 hours. In this manner, a honeycomb structure (catalyst-coated filter carrier) in which plugging portions were disposed at predetermined positions of the honeycomb structure portion was produced. This honeycomb structure has a partition wall in which a plurality of pores are formed that extend from an inflow end surface that is one end surface to an outflow end surface that is the other end surface to partition a plurality of cells that serve as exhaust gas flow paths. Had a department. Further, in this honeycomb structure, plugging portions are disposed at the opening portion on the outflow end face side of the inlet cell which is a predetermined cell of the honeycomb structure portion and the opening portion on the inflow end face of the outlet cell which is a remaining cell. It was.

The honeycomb structure had a diameter of 144 mm at both end faces and a length in the cell extending direction of 152 mm. The partition wall thickness of the honeycomb structure was 300 μm. The porosity of the honeycomb structure was 65%. The average pore diameter of the honeycomb structure was 20 μm. The cell density of the honeycomb structure was 47 cells / cm ² . The maximum second transmission characteristic value (denoted as “maximum second” in Table 1) is 12500 μm ² ×%, and the minimum second transmission characteristic value (denoted as “minimum second” in Table 1) is 9300 μm. ^The average second transmission characteristic value (denoted as “average second” in Table 1) was 10400 μm ² ×%. Furthermore, the calculated value (β) was 30.5%. The measurement results are shown in Table 1.

  Next, the resulting honeycomb structure was loaded with a Cu-substituted zeolite catalyst as an SCR catalyst to produce a catalyst-coated filter. As a method of supporting the SCR catalyst on the honeycomb structure, “method of sucking catalyst slurry” was adopted.

  Specifically, first, a catalyst slurry containing an SCR catalyst was prepared. The catalyst slurry is supported on the inflow end side portion (that is, “catalyst slurry applied to the inflow end side portion”) has a viscosity of 8 Pa · s and is supported on the outflow end side portion ( That is, water was added and adjusted so that the viscosity of “the slurry for the catalyst applied to the portion to be the outflow end portion”) was 5 Pa · s. Next, the inflow end portion of the obtained honeycomb structure was immersed in a container filled with “catalyst slurry to be supported on the inflow end portion side portion”, and the catalyst slurry was sucked from the outflow end portion side. At this time, the catalyst slurry was sucked to a position corresponding to the inflow end face side portion of the catalyst coat filter. Next, the outflow end portion of the honeycomb structure was immersed in a container filled with “catalyst slurry to be carried on the outflow end portion side portion”, and the catalyst slurry was sucked from the inflow end portion side. At this time, the catalyst slurry was sucked to a position corresponding to the outflow end face side portion of the catalyst coat filter (the outflow end face side portion occupies 20% of the total volume of the inflow end face side portion and the outflow end face side portion). . Thereafter, hot air drying was performed at 500 ° C. for 2 hours to produce a catalyst-coated filter.

In the produced catalyst-coated filter, the outflow end face side portion occupied 20% of the “total volume of the inflow end face side portion and the outflow end face side portion” (in Table 2, described as “outflow end face side portion”). . In addition, the average value of the amount of SCR catalyst supported on the entire honeycomb structure was 120 g / L (referred to as “average value of catalyst amount” in Table 2). Furthermore, the amount of SCR catalyst supported on the inflow end face side portion of the catalyst coat filter was 128 g / L. The amount of SCR catalyst supported on the outflow end face side portion of the catalyst coat filter was 86 g / L. Moreover, the porosity of the outflow end face side portion was 60%. The average pore diameter of the outflow end face side portion was 17 μm. The maximum first transmission characteristic value (denoted as “maximum first” in Table 2) is 19440 μm ² ×%, and the minimum first transmission characteristic value (denoted as “minimum first” in Table 2) is 6480 μm. ^The average first transmission characteristic value (denoted as “average first” in Table 2) was 13600 μm ² ×%. Furthermore, the calculated value (α) was 95.3%. The measurement results are shown in Table 2.

Each of the following evaluations of [pressure loss] and [NO _X purification rate] were performed on the produced catalyst-coated filter of this example. The evaluation results are shown in Table 3.

[Pressure loss]
Air was passed through the catalyst-coated filter at a flow rate of 10 m ³ / min under room temperature conditions. In this state, the pressure at the air inflow end and the air outflow end of the catalyst coat filter were measured, and the difference between them was calculated. This pressure difference was defined as pressure loss. The evaluation standard for pressure loss is “OK” (passed) when the pressure loss is less than 9 kPa. When the pressure loss is 9 kPa or more, it is determined as “NG” (failed).

[NO _X purification rate]
The regulation operation mode (LA-4) of US regulation (FTP) was performed for both cases where the produced catalyst coat filter was installed in an exhaust system of a vehicle equipped with a 2-liter gasoline engine and when it was not installed. Then, from the ratio of the bag emission measurement value when the catalyst coat filter is not installed and the bag emission value when the catalyst coat filter is installed, which is measured by performing the regulation operation mode (LA-4) of this US regulation. It was calculated NO _X purification rate.

Evaluation criteria of the NO _X purification rate, when NO _X purification rate is 95% or more is "OK" (pass). If NO _X purification rate is less than 95% is "NG" (fail).

(Example 2)
In Example 2, the conditions shown in Tables 1 and 2 were satisfied except that the upper limit value of the particle distribution of the pore forming agent was changed to 80 μm (that is, the particle distribution of the pore forming agent was changed to 25 to 80 μm). Thus, a catalyst-coated filter was produced in the same manner as in Example 1. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Example 3)
In Example 3, the conditions shown in Tables 1 and 2 were satisfied except that the lower limit of the pore distribution particle distribution was changed to 15 μm (that is, the pore distribution particle distribution was set to 15 to 70 μm). Thus, a catalyst-coated filter was produced in the same manner as in Example 1. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

Example 4
In Example 4, except that the average particle diameter of the pore-forming agent was changed to 25 μm, and the viscosity of the “slurry for catalyst applied to the portion to be the inflow end portion side” was changed to 9 Pa · s, A catalyst-coated filter was produced in the same manner as in Example 1 so as to satisfy the conditions shown in Tables 1 and 2. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Example 1)
In Comparative Example 1, the conditions shown in Tables 1 and 2 were satisfied except that the lower limit of the pore distribution particle distribution was changed to 10 μm (that is, the pore distribution particle distribution was changed to 10 to 70 μm). Thus, a catalyst-coated filter was produced in the same manner as in Example 1. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Example 2)
In Comparative Example 2, the conditions shown in Tables 1 and 2 were satisfied except that the ratio of the outflow end face side portion to the “total volume of the inflow end face side portion and the outflow end face side portion” was changed to 2%. A catalyst-coated filter was produced in the same manner as in Example 1. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Example 3)
In Comparative Example 3, the conditions shown in Tables 1 and 2 were satisfied except that the ratio of the outflow end face side portion to the “total volume of the inflow end face side portion and the outflow end face side portion” was changed to 5%. A catalyst-coated filter was produced in the same manner as in Example 1. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Example 4)
In Comparative Example 4, the ratio of the outflow end face side portion to the “total volume of the inflow end face side portion and the outflow end face side portion” (hereinafter referred to as “the ratio of the outflow end face side portion”) was changed to 8%. Produced a catalyst-coated filter in the same manner as in Example 1 so as to satisfy the conditions shown in Tables 1 and 2. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Example 5)
Comparative Example 5 was carried out so as to satisfy the conditions shown in Tables 1 and 2 except that the average particle diameter of the pore former was 35 μm, the particle distribution was 30 to 80 μm, and the proportion of the outflow end face side portion was 25%. A catalyst coated filter was produced in the same manner as in Example 2. The viscosity of the catalyst slurry was out of the preferred range described above. Each evaluation of [pressure loss] and [NO _X purification rate] was performed on the produced catalyst-coated filter in the same manner as in Example 1. The evaluation results are shown in Table 3.

  It was confirmed that the exhaust gas purification performance of the catalyst-coated filters of Examples 1 to 4 did not deteriorate by maintaining the amount of catalyst supported. Moreover, it has confirmed that the pressure loss of the catalyst coat filter of Examples 1-4 was reduced compared with the catalyst coat filter of Comparative Examples 1-5.

  The catalyst coat filter of the present invention can be used as a filter for purifying exhaust gas discharged from an automobile or the like. The catalyst-coated filter carrier of the present invention can be used as a catalyst carrier for the catalyst-coated filter.

2: cell, 2a: inlet cell, 2b: outlet cell, 3: pore, 3a: inner surface of pore, 10: honeycomb structure, 11a: inflow end surface, 11b: outflow end surface, 12: plugging portion, 15 : Partition wall, 16: catalyst layer, 21: inflow end face side portion, 22: outflow end face side portion, 100: catalyst coat filter, P: portion, R1, R2, R3, R4, R5: region.

Claims (6)

A honeycomb structure part having a partition wall in which a plurality of pores are formed to partition a plurality of cells serving as exhaust gas flow paths extending from an inflow end surface as one end surface to an outflow end surface as the other end surface;
Plugged portions disposed in the opening on the outflow end face side of the inlet cell that is the predetermined cell of the honeycomb structure part and the opening on the inflow end face side of the outlet cell that is the remaining cell;
An exhaust gas purifying catalyst that is supported on the surface of the partition walls and the inner surfaces of the pores formed in the partition walls, and the average value of the supported amount in the entire honeycomb structure portion is 100 g / L or more,
The honeycomb structure portion includes an inflow end surface side portion that is a portion on the inflow end surface side of the honeycomb structure portion, and an outflow end surface side portion that is a portion on the outflow end surface side, and the outflow end surface side portion includes the inflow end surface side portion and the outflow end surface side. Occupies 20-80% of the total volume with the side part,
The amount of catalyst supported on the inflow end face side portion is larger than the amount of catalyst supported on the outflow end face side portion,
The catalyst coat filter in which the outflow end face side portion satisfies the following condition (A).
Condition (A): In the cross section orthogonal to the cell extending direction of the honeycomb structure portion in the outflow end face side portion, the partition supporting the catalyst is 5 etc. in the direction orthogonal to the thickness direction of the partition Divide into 5 areas. The calculated value (α) calculated by the following formula (1) and the following formula (2) is 50% or more.
Formula (1); (Average pore diameter (μm) of the partition wall after the catalyst is supported) 2 × (Porosity (%) of the partition wall after the catalyst is supported) = first permeation characteristic value Formula (2); ((maximum first transmission characteristic value−minimum first transmission characteristic value) / average first transmission characteristic value) × 100 = calculated value (α)
In the formula (2), the minimum first transmission characteristic value is the minimum first transmission characteristic value among the first transmission characteristic values of the five regions. The maximum first transmission characteristic value is the maximum first transmission characteristic value among the first transmission characteristic values of the five regions. The average first transmission characteristic value is an average value of the first transmission characteristic values of the five regions.   The catalyst-coated filter according to claim 1, wherein the calculated value (α) is 70% or more. 3. The honeycomb structure part according to claim 1, wherein the partition wall has a porosity of 55 to 70%, an average pore diameter of the partition wall of 15 to 30 μm, and the partition wall satisfies the following condition (B). Catalyst coated filter.
Condition (B): In the cross section perpendicular to the cell extending direction of the honeycomb structure portion, the partition wall is divided into five regions in the direction orthogonal to the thickness direction of the partition wall to form five regions. The calculated value (β) calculated by the following formula (3) and the following formula (4) is 10 to 90%.
(Average pore diameter (μm) of the partition wall) 2 × (porosity (%) of the partition wall) = second transmission characteristic value expression (4); ((maximum second transmission characteristic value−minimum number) 2 transmission characteristic value) / average second transmission characteristic value) × 100 = calculated value (β)
In the formula (4), the minimum second transmission characteristic value is the minimum second transmission characteristic value among the second transmission characteristic values of the five regions. The maximum second transmission characteristic value is the maximum second transmission characteristic value among the second transmission characteristic values of the five regions. The average second transmission characteristic value is an average value of the second transmission characteristic values of the five regions. The catalyst-coated filter according to claim 3 , wherein the calculated value (β) is 20 to 90%. A honeycomb structure part having a partition wall in which a plurality of pores are formed to partition a plurality of cells serving as exhaust gas flow paths extending from an inflow end surface as one end surface to an outflow end surface as the other end surface;
Plugged portions disposed in the opening on the outflow end face side of the inlet cell that is the predetermined cell of the honeycomb structure part and the opening on the inflow end face side of the outlet cell that is the remaining cell; With
The honeycomb structure part is a catalyst-coated filter carrier in which the partition wall has a porosity of 55 to 70%, the partition wall has an average pore diameter of 15 to 30 µm, and the partition wall satisfies the following condition (C).
Condition (C): In the cross section perpendicular to the cell extending direction of the honeycomb structure portion, the partition walls are divided into five equal parts in the direction orthogonal to the thickness direction of the partition walls to form five regions. The calculated value (γ) calculated by the following formula (5) and the following formula (6) is 10 to 90%.
(Average pore diameter (μm) of the partition wall) 2 × (porosity (%) of the partition wall) = third transmission characteristic value expression (6); ((maximum third transmission characteristic value−minimum number) 3 transmission characteristic value) / average third transmission characteristic value) × 100 = calculated value (γ)
In the equation (6), the minimum third transmission characteristic value is the minimum third transmission characteristic value among the third transmission characteristic values of the five regions. The maximum third transmission characteristic value is the maximum third transmission characteristic value among the third transmission characteristic values of the five regions. The average third transmission characteristic value is an average value of the third transmission characteristic values of the five regions.   The carrier for a catalyst-coated filter according to claim 5, wherein the calculated value (γ) is 20 to 90%.

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