JP2018153723A - Method for producing exhaust gas purification catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an exhaust gas purification catalyst capable of achieving separation from a holding jig even if a catalyst slurry is leached to a honeycomb skin portion during catalyst washcoating for a honeycomb.SOLUTION: There is provided a method for separating an elastic holding jig 3 from a honeycomb skin portion fixed by the leaching of a catalyst slurry in which using an elastic holding jig 3 having a balloon-shaped supporter 2 forming a protrusion towards a honeycomb outer peripheral part 1, the balloon-shaped supporter 2 is expanded to hold the honeycomb outer peripheral part 1, subsequently supplying a catalyst slurry from a honeycomb end face, applying an air current from the honeycomb end face in a state of holding a honeycomb 3 to coat a catalyst component in a cell. There is provided a method for producing an exhaust gas purification catalyst which accelerates separation of a honeycomb skin and a supporter by shrinking the balloon-shaped supporter 2 in the separation step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing an exhaust gas purification catalyst, and more particularly, exhaust gas purification that enables separation from a gripping jig even when catalyst slurry is leached to the outer skin portion during wash coating in which the catalyst is supported on a honeycomb carrier. The present invention relates to a method for producing a catalyst.

  Exhaust gas from automobiles contains various harmful components such as nitrogen oxides (NOx), unburned hydrocarbons derived from fuel (HC), and carbon monoxide (CO). Has been proposed and implemented.

  In addition to automobiles using gasoline as fuel, there are diesel cars equipped with diesel engines that use light oil as fuel. Regarding exhaust gas discharged from diesel vehicles, in addition to the above NOx, HC, and CO, PM (Particulate Matter) as a particulate component is also known, and DPF (Diesel) is used as a device for purifying such PM. Particulate Filter) has been widely used.

DPF is a general term for an exhaust gas purification filter device, also called a wall flow honeycomb filter, but its structure is composed of a plurality of cells partitioned by partition walls from the inlet end portion toward the outlet end portion. And a honeycomb structure alternately plugged at the outlet end. The partition which comprises a cell has air permeability, PM is removed by filtering PM out of waste gas using this air permeability.
If the PM filtered out from the exhaust gas by the DPF is left as it is, it will continue to accumulate in the DPF and cause clogging. Therefore, the PM is generated by the heat of the exhaust gas or the injection of fuel into the combustion chamber or exhaust gas of the engine. To regenerate the DPF on which PM is deposited. For the purpose of promoting such regeneration, a catalyst component may be coated on the partition walls of the DPF cell, and the DPF coated with the catalyst component may be referred to as a CSF (Catalyzed Soot Filter). The present applicant has also proposed a system incorporating these catalysts (see, for example, Patent Document 1).

  Conventionally, most of diesel engines have been required to purify PM in exhaust gas, but it is due to the use of light oil that is difficult to burn compared to gasoline, which is easy to burn like gasoline, Until now, automobiles that use fuel that generates a small amount of PM have not received much attention as an environmental problem.

However, with increasing interest in environmental problems, regulations on harmful components in exhaust gas have become more stringent, and there is a movement to regulate the amount of PM emitted from gasoline automobiles. In recent years, in particular, the market is also concerned about fuel consumption, and direct-injection engines that supply gasoline directly into the combustion chamber under precise control are becoming mainstream in gasoline engines.
However, in such a direct-injection gasoline engine (GDI: Gasoline Direct Injection), the combustion chamber is in a combustion state while a part of the sprayed gasoline is kept in a particulate state, so that the particulate fuel The resulting incomplete combustion can generate more PM than a gasoline vehicle that supplies a mixed gas of fuel and air from a conventional intake manifold, and the need for emission regulations has become more realistic. It was.

  It is conceivable to use a wall flow honeycomb filter to remove PM emitted from such a gasoline vehicle as in the case of a DPF for a diesel vehicle, but the DPF for a diesel vehicle is diverted as it is because of the characteristics of the gasoline vehicle. This was difficult for the following reasons.

  One of the major differences between gasoline vehicles and diesel vehicles is the exhaust gas flow velocity. A diesel engine injects fuel into air compressed at high pressure, and takes out kinetic energy by igniting and exploding the fuel by the action of the pressure. Although it is an efficient engine due to its high compression, it needs to create a high compression state, so the engine speed is lower than that of a gasoline car, and therefore the exhaust gas temperature is also low, so the conventional filter type In order to improve the strength of the honeycomb carrier, that is, in the DPF, the outer skin portion is made of a dense high-strength ceramic material.

However, the situation of exhaust gas from gasoline engines is different from that of diesel engines. Since the gasoline engine ignites the air-fuel mixture by the spark plug, the compression ratio is smaller than that of a general diesel engine. For this reason, the engine can be operated at a high speed and a high output can be obtained, but the exhaust gas temperature during traveling becomes high.
Furthermore, due to demands from the market concerning fuel efficiency improvement in recent years, there is a tendency to reduce the size of high-power engines for the purpose of reducing the weight of vehicles. In order to obtain high output with a small engine, it is necessary to operate the engine at a high speed or supply a large amount of air into the cylinder by a supercharger. The temperature of the exhaust gas discharged becomes higher. For such high-temperature exhaust gas, if a honeycomb carrier such as a conventional DPF, that is, a wall made of a different material in its outer shell (hereinafter also referred to as outer shell), the temperature during running is higher than that of a diesel engine. In such a gasoline engine catalyst, there is a concern that a crack may occur due to a difference in thermal expansion coefficient. For this reason, an integral molding may be preferable.

Therefore, as a filter for removing PM from the exhaust gas of a gasoline engine, a honeycomb filter that does not have a dense outer skin portion for obtaining strength, such as DPF, has been studied. Such a PM filter for a gasoline engine is sometimes referred to as a GPF (Gasoline Particulate Filter) (see, for example, Patent Document 3).
If it is GPF, while it is possible to remove PM in the exhaust gas of the gasoline engine which becomes high temperature, a new problem has arisen in the catalyst manufacturing process.

  In general, for purification of exhaust gas from gasoline engines, a three-way catalyst (TWC: Three Way Catalyst) containing noble metals such as platinum, palladium, rhodium, etc., is a catalyst that is catalyzed with a component that simultaneously purifies NOx, HC, and CO. A carrier is used. Conventional TWC is not a honeycomb carrier plugged with each other at both end faces of the cell like DPF, but a catalyst component is coated on the cell partition walls of the honeycomb where both end faces of the cells are called flow-through honeycombs. Have been used. With such a flow-through honeycomb, there is little increase in back pressure and it is suitable for exhaust gas treatment at a high flow rate like a gasoline engine.

Not only the flow-through honeycomb and DPF but also a honeycomb carrier is catalyzed with a catalyst composition such as TWC, a manufacturing method generally called a wash coat method is applied (see, for example, Patent Document 2).
Various methods have been proposed and implemented for wash coating. For example, after gripping the intermediate position of the honeycomb carrier with a clamp, the lower part is immersed in a liquid bath and impregnated with the catalyst component-containing liquid. There is a method in which the honeycomb carrier is pulled up from the slurry and inverted, and then the excess slurry is separated by air blowing to the carrier, and the entire carrier is impregnated with a catalyst component-containing liquid (for example, Patent Document 5).
The basic principle includes “a step of supplying the slurry catalyst component into the honeycomb cell” and “a step of discharging the supplied catalyst slurry by air pressure”. In the “step of discharging the supplied catalyst slurry by air pressure”, if the flow-through honeycomb is used, it is possible to remove excess slurry without any particular trouble. In addition, since the conventional DPF also has a dense outer skin portion, the excess slurry can be removed without any trouble in this case.
Here, the honeycomb carrier clamp in the wash coat apparatus is clamped by a soft and elastic gripping apparatus such as a balloon, and is processed in each step of the wash coat. The reason for using such a soft and elastic gripping device is to prevent the honeycomb carrier from being damaged. Particularly in the case of a carrier such as GPF, there is a concern that the strength is insufficient due to the high porosity as described later and the structural features. Therefore, it is necessary to proceed carefully using an elastic gripping device.

  Since GPF treats high-temperature exhaust gas, the outer skin of the GPF is composed of a porous material having air permeability like the cell partition walls, and a honeycomb carrier having a porosity of 30% or more, and further a porosity of 50% or more is used. It is necessary to use it.

  In such a honeycomb carrier for GPF, the partition wall and the outer skin may be integrally formed. The integrally formed honeycomb substrate is formed by simultaneously forming the partition walls and the outer skin by extrusion molding, and firing the obtained molded body, and the outer skin and the partition walls have the same porosity. Have

  Since GPF is used in a higher temperature environment than DPF, if a dense skin part such as DPF is provided, a difference in thermal expansion coefficient occurs between the cell partition wall and the skin part, and cracks are generated. There was also a problem that it was likely to occur. The honeycomb having cracks loses its function as a filter. For this reason, in the honeycomb used for GPF, it is necessary to set the cell partition walls and the outer skin portion to the same quality, that is, to set the same thermal expansion coefficient. In this way, as a means for making the cell partition wall and the skin portion the same quality, it is conceivable that the cell partition wall and the skin portion are integrally formed of the same material. By integrally forming the partition walls and the outer skin of the honeycomb, the thermal expansion coefficients of the outer skin and the partition walls are equalized, so that cracks (damage) due to a thermal history during manufacture or use as a catalyst can be suppressed.

In addition, in the honeycomb carrier formed with a porous material having a high porosity up to the outer skin with the end of the cell plugged, the plug is sealed in the “step of discharging the supplied catalyst slurry by air pressure” at the time of wash coating. The stop portion becomes an obstacle, and there is a problem that the catalyst slurry discharged by air pressure is very easily leached from the outer skin portion.
Such leaching out of the catalyst slurry does not always occur only in the step of discharging the slurry by air pressure. As described above, the honeycomb carrier for GPF has a high porosity, but the porosity is extremely high, the viscosity of the catalyst slurry is low, or the particle size of the inorganic fine particles in the catalyst slurry is extremely small Depending on the combination of these conditions, the catalyst slurry may ooze out from the outer skin portion only by supplying the slurry to the honeycomb carrier. In such a case, the leaching is further promoted when a treatment such as discharge of the catalyst slurry by air pressure, spreading, and impregnation into the cell wall is performed with a wash coat.

As described above, the catalyst slurry contains a noble metal as an active component. As the particle size of the noble metal is smaller, the geometric surface area per unit volume is larger and the activity as a catalyst is higher. For this reason, the noble metal in the catalyst slurry is used by being supported on heat-resistant inorganic fine particles having a high specific surface area value. Such heat-resistant inorganic fine particles become a high-viscosity slurry when mixed with a solution.
When such a high-viscosity catalyst slurry is leached from the outer skin portion of the honeycomb carrier, the catalyst slurry works like an adhesive, and is fixed to the clamp portion in the wash coat apparatus, that is, the balloon of the elastic gripper, The honeycomb carrier may not be able to be removed from the washcoat apparatus.

  In order to eliminate such a sticking state, it is necessary to forcibly retract the balloon as a clamping part until the clamping state is canceled. However, if the balloon is merely retracted, the clamping state is vigorous. The honeycomb carrier may tilt and shift from a predetermined position in the wash coat device, and when the momentum is strong, the honeycomb carrier comes in contact with the device or jig and the honeycomb carrier is chipped or cracked. There was something to do.

  In particular, in GPF, since the elastic gripping jig is desired to be gripped by a soft member such as a balloon because of its fragility, the outer shell of the honeycomb carrier and the elastic gripper are easily fixed by the flexibility, and once fixed. It was difficult to separate. Therefore, in order to mass-produce a honeycomb carrier carrying an exhaust gas purification catalyst, a method for facilitating separation of the honeycomb carrier and the balloon has been demanded.

  In Patent Document 6, the entire circumference of a cylindrical honeycomb carrier is covered with a balloon and pressurized with air, and then the catalyst is attached to the outside of the honeycomb carrier when the catalyst slurry is poured from above the inside of the honeycomb carrier to carry the catalyst. Means for suppressing this are described. However, the position where the catalyst adheres is particularly intense in the vicinity of both ends of the carrier, and specific means for solving the state of leaching into the outer skin from the inside of the honeycomb carrier and sticking to the balloon is described. Not.

  Thus, there is a demand for a means suitable for GPF that facilitates separation from the holding jig even if the catalyst slurry from the honeycomb outer skin portion leaches out, and can be stably and inexpensively applied to mass production. It is also desirable that this is a possible means.

Republished 2013-172128 Special table 2003-506221 gazette JP-T-2015-528868 Japanese Patent Laid-Open No. 7-10650 Special table 2003-506221 gazette Japanese Utility Model Publication No. 2-45139

  In view of such circumstances, an object of the present invention is to provide an exhaust gas purification catalyst manufacturing method that can be separated from a gripping jig even when catalyst slurry is leached to the outer skin portion during wash coating in which a catalyst is supported on a honeycomb carrier. Is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have supplied air to the balloon-shaped support of the elastic gripping jig, gripped the honeycomb carrier with the balloon, and washed the catalyst slurry with the wash coat into the honeycomb. After coating the carrier cells, the pressure applied by the air supplied to the balloon-shaped support of the elastic gripping jig is eliminated, so that the honeycomb outer shell and the support fixed by leaching of the catalyst slurry can be easily removed. As a result, the present invention was completed.

That is, according to the first invention of the present invention, the porous partition wall forming a plurality of cells, and the end face in which at least a part of the cells constituted by the partition walls are opened, and the porosity is 30% or more. A catalyst component is supported by a wash coat method including a step of supplying a slurry catalyst component into a cell of a honeycomb carrier made of a porous outer skin portion and a step of pneumatically discharging the catalyst slurry in the supplied cell. An exhaust gas purification catalyst manufacturing method comprising:
In the wash coating method, an elastic gripping jig having a balloon-shaped support having convex portions formed toward the outer periphery of the honeycomb carrier is used, and the balloon-shaped support is pressurized and expanded to grip the outer periphery of the honeycomb carrier. After fixing,
A slurry liquid containing a catalyst component is supplied from the end face of the honeycomb carrier, and the honeycomb carrier to which the catalyst slurry is supplied is held by a balloon-like support, and an air stream is applied to the cell from the end face of the honeycomb carrier to which the catalyst slurry is supplied. The catalyst component is coated inside,
The honeycomb carrier separated through the separation step of separating the elastic gripping jig from the outer skin portion of the honeycomb carrier fixed by the leaching of the catalyst slurry is dried and then fired to carry the catalyst component. In the separation step, Provided is a method for producing an exhaust gas purifying catalyst characterized in that the balloon-like support that has been pressurized and expanded contracts while expanding the gap starting from the convex portion, thereby promoting separation of the honeycomb outer shell and the support. The

  According to a second invention of the present invention, in the first invention, the balloon-like support of the elastic gripping jig in the separation step is contracted by a depressurization operation. A method is provided.

  According to a third aspect of the present invention, in the first or second aspect, the honeycomb carrier has a porosity of an outer skin portion of 50 to 80%. A method is provided.

  According to the fourth invention of the present invention, in any one of the first to third inventions, the outer skin portion of the honeycomb carrier has an average pore diameter measured by a mercury porosimeter of 10 to 30 μm. A method for producing an exhaust gas purifying catalyst according to claim 1 is provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the cells of the honeycomb carrier are plugged at the opening end on the inlet end face side and the opening end on the outlet end face side. There is provided a method for producing an exhaust gas purifying catalyst, characterized in that the plugging portions are alternately arranged.

  Furthermore, according to a sixth aspect of the present invention, in any one of the first to fifth aspects, the catalyst composition contains one or more noble metal elements selected from Pt, Pd, and Rh. A method for producing an exhaust gas purification catalyst is provided.

  According to the method for producing an exhaust gas purification catalyst of the present invention, when the catalyst slurry is coated on the cell partition walls of the honeycomb carrier, the catalyst slurry is leached from the outer skin portion and is supported by the support of the elastic gripping jig of the washcoat device. Even if a certain balloon is fixed to the honeycomb, the balloon and the honeycomb can be easily separated. Thereby, the production efficiency of the exhaust gas purification catalyst can be improved.

It is explanatory drawing which showed typically the essential process of the wash coat method to which this invention is applied. It is the perspective view which showed typically the external appearance of the honeycomb support | carrier (carrier | carrier). FIG. 2 schematically shows balloon supports (a) and (b) having protrusions and a cross-sectional view (c) of one form thereof in a state where the honeycomb carrier is arranged at a predetermined position of the coating apparatus according to the present invention. FIG. FIG. 2 is an explanatory view schematically showing a state (a) in which a honeycomb carrier having a convex portion is gripped in the present invention and a honeycomb carrier is gripped, and a cross section (b) thereof. FIG. 2 is an explanatory view schematically showing a state (a) in which catalyst slurry has oozed out from the outer skin portion of the honeycomb carrier by air blow, and a cross section (b) thereof. In the present invention, an explanatory view schematically showing an initial state (a) in which the pressurized state inside the balloon support is canceled and the close contact between the honeycomb carrier and the balloon support begins to be resolved, and a cross section (b) thereof. It is. Furthermore, it is explanatory drawing which showed typically the state (a) and the cross section (b) which the cancellation | release of adhesion | attachment of a honeycomb support | carrier and a balloon support is progressing. Then, it is explanatory drawing which showed typically the state (a) and the cross section (b) which the adhesion | attachment of a honeycomb support | carrier and a balloon support body was eliminated completely. FIG. 4 is an explanatory view schematically showing a state (a) in which sticking of the honeycomb carrier is not eliminated in a balloon support having no projection in the separation process of the honeycomb carrier and the balloon support, and a cross section (b) thereof.

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

1. Honeycomb carrier A honeycomb carrier (also referred to simply as a honeycomb) used in the present invention comprises a porous partition wall forming a plurality of cells and a porous outer skin portion having a porosity of 30% or more, as shown in FIG. It is the honeycomb-shaped base material 1 which has an opening edge part up and down.

In the honeycomb-shaped base material, a large number of through holes (cells) extending from one end face to the other end face are formed by partition walls, and these gather together to form a honeycomb.
Honeycomb carriers are roughly classified into a flow-through type (flow-through honeycomb) and a wall-flow type (wall-flow honeycomb) because of their structural features. The flow-through type is widely used for oxidation catalysts, reduction catalysts, and three-way catalysts because a large number of through-hole ends that open from one open end surface to the other open end surface are not sealed.
On the other hand, in the wall flow type, one end of the through-hole is alternately sealed, and solid components such as soot and SOF (Soluble Organic Fraction) in exhaust gas can be filtered out. Therefore, it is used as a DPF.
The present invention can be used for either of them, but a honeycomb-like base material having a porous outer skin such as GPF and having the sealing portion which becomes an obstacle when discharged with air pressure is used in the production of a catalyst slurry. Can be prevented from leaching into the outer skin portion, and can be suitably used particularly for a wall flow honeycomb used for GPF.

Moreover, since it is necessary to let exhaust gas escape from the partition which comprises a honeycomb, the partition is formed with a porous body. Consisting of inorganic oxides usually used as porous materials, silicon carbide, silicon-silicon carbide based composite materials, cordierite, mullite, alumina, silica-alumina, spinel, silicon carbide-cordierite based composite materials, lithium Ceramic materials such as aluminum silicate and aluminum titanate are preferred. Among these, cordierite is particularly preferable. This is because when the honeycomb base material is cordierite, a honeycomb carrier having a small thermal expansion coefficient and excellent thermal shock resistance can be obtained.
The partition wall and the outer skin portion may be made of the same material or different materials. In GPF, it is preferably formed of the same material. The homogeneous material refers to a material having a range of difference in thermal expansion coefficient or porosity that can prevent cracking due to thermal shock. Further, it is preferably manufactured by integral molding using the same material. This is because efficient production is possible and problems due to differences in materials can be avoided. Moreover, in a gasoline engine catalyst that becomes high temperature, there is a concern that problems such as cracks occur due to the difference in thermal expansion coefficient. For this reason, it is preferable that the partition wall and the outer skin portion have the same thermal expansion coefficient or are integrally molded.
The material of the plugging portion is preferably the same material as that of the honeycomb substrate. The material of the plugging portion and the material of the honeycomb substrate may be the same material or different materials.

It is preferable that a large number of pores exist in the partition walls and the outer skin portion. Such characteristics of pores are also expressed as pore volume and pore diameter, and can be measured by various methods such as gas adsorption method, Archimedes method, mercury intrusion method, etc. It means a value obtained by measuring at a pressure of 400 MPa by the method.
The honeycomb structure of the present invention is effective when the pore volume of the partition walls and the outer skin of the cell is 0.3 to 1.6 ml / g, and is 0.8 to 1.6 ml / g. Is preferable, and it is more preferable in it being 1.0-1.6 ml / g. Further, the average pore diameter of the honeycomb substrate (partition and outer skin) is effective when it is 10 to 25 μm, preferably 15 to 25 μm, and more preferably 20 to 25 μm.
Such characteristics of the pores can also be expressed as porosity (pore volume ratio). The porosity of the honeycomb structure in the present invention means the ratio of the pore volume to the geometric volume of the porous body determined from the thickness and length of the partition walls and the outer skin portion of the cell and the cell density. In the present invention, it is 50 to 80%, preferably 60 to 80%, more preferably 60 to 70%.
If the pore volume, pore system, and porosity are too large, the pressure loss of the honeycomb carrier becomes too high, and when used as a GPF, the engine output may be reduced. In addition, if the pore volume, pore system, and porosity are too small, sufficient strength may not be obtained.

Moreover, 1-18 mil (0.025-0.47 mm) is preferable and, as for the thickness of the partition which is a cell wall, 6-12 mil (0.16-0.32 mm) is more preferable. If the partition wall is too thin, it becomes structurally brittle, and if it is too thick, the geometric surface area of the cell becomes small, which may reduce the effective usage rate of the catalyst. In addition, if the partition wall is too thick, the pressure loss becomes high, and when used as a GPF, there is a risk of causing a decrease in engine output.
The thickness of the outer skin of the honeycomb base material is preferably 300 to 1000 μm, particularly preferably 500 to 800 μm. If the thickness of the outer skin is less than 300 μm, sufficient strength may not be obtained. On the other hand, if the thickness of the outer skin exceeds 1000 μm, the pressure loss of the honeycomb carrier becomes too high, and when used as a GPF, the engine output may be reduced.

The cell formed by the partition walls is usually about 0.8 to 2.5 mm in diameter or one side, and its density is expressed by the number of holes per unit cross-sectional area, which is also called cell density. The cell density of the honeycomb carrier is not particularly limited, but is preferably 100 to 1200 cells / inch2 (15.5 to 186 cells / cm2), more preferably 150 to 600 cells / inch2 (23 to 93 cells / cm2), 200 It is especially preferable that it is -400 cell / inch2 (31-62 cell / cm2). When the cell density exceeds 1200 cells / inch2 (186 cells / cm2), clogging is likely to occur due to catalyst components and solids in the exhaust gas, pressure loss becomes too high, and when used as a GPF, The engine output may be reduced.
If it is less than 100 cells / inch 2 (15.5 cells / cm 2), the geometric surface area becomes small, so that the effective usage rate of the catalyst is lowered and the usefulness as an exhaust gas purification catalyst may be lost. Further, when used as a GPF, the effective area as a filter is insufficient, the pressure loss after PM deposition becomes high, and the output of the engine may be reduced.

  The honeycomb carrier used in the present invention may be a flow-through carrier without plugging used for TWC for gasoline vehicles, in addition to the GPF and DPF as described above. In this case as well, in order for the effect of the present invention to be exhibited, it is necessary that at least the outer skin portion is formed of a porous body having the same quality as the partition walls. The porosity is 30% or more, preferably 50 to 80%, and more preferably 60 to 70%. Moreover, 10-30 micrometers is preferable and, as for a pore diameter, it is more preferable that it is 15-25 micrometers. In this case, the porosity and pore diameter can be measured by a mercury porosimeter in the same manner as the GPF honeycomb carrier.

The shape of the honeycomb carrier is not particularly limited, and includes a generally known columnar shape, an elliptical columnar shape similar to a columnar shape, and a polygonal column. A cylindrical shape or an elliptical column shape is preferable.
Further, the shape of the cell in the cross section perpendicular to the longitudinal direction of the honeycomb substrate (hereinafter referred to as “cell shape”) is not particularly limited, but is a polygon such as a quadrangle, hexagon, octagon, or a combination thereof. For example, a rectangle, a hexagon, a combination of a rectangle and an octagon, and the like are preferable.
The size of the honeycomb base material is relatively small such as a diameter of about 60 mm and a length of 70 mm, and a large size such as a diameter of about 300 mm and a length of 200 mm. Not limited by size.

When the honeycomb carrier is used for a PM collection filter such as GPF, a plugging portion for plugging an opening end portion on the inlet end face side of a predetermined cell and an opening end portion on the outlet end face side of the remaining cells is formed. Yes. Thus, by forming the plugged portion at one open end of each cell of the honeycomb base material, the honeycomb carrier becomes a wall flow type filter having high PM collection efficiency. In this wall flow type filter, the exhaust gas flowing into the cell from the inlet end face passes through the partition wall and then flows out of the cell from the outlet end face. And when exhaust gas permeate | transmits a partition, a partition functions as a filtration layer and PM contained in exhaust gas is collected.
The plugged portions are arranged such that the inlet end surface and the outlet end surface are arranged in a checkered pattern by the cells in which the respective open ends are plugged and the cells that are not plugged. It is preferable to be formed. However, the embodiment of the present invention is not limited to such a wall flow filter.

  The problem of leaching of the catalyst slurry to the outer surface of the outer skin and insufficient strength are particularly noticeable in a honeycomb substrate having a high porosity such that the porosity is 50% or more. Therefore, the present invention is highly useful when a honeycomb substrate having a porosity of 50 to 80% is used, and is particularly useful when a honeycomb substrate having a porosity of 60 to 70% is used.

2. Manufacturing method of exhaust gas purification catalyst The manufacturing method of the exhaust gas purification catalyst of the present invention applies an elastic gripping jig having a balloon-shaped support body having convex portions formed toward the outer peripheral portion of the honeycomb carrier in the wash coating method. After contacting and fixing the balloon by pressure expansion, the slurry liquid containing the catalyst component is supplied from the end face of the honeycomb carrier, and the catalyst slurry is held in a state where the honeycomb carrier supplied with the catalyst slurry is held by the support. A honeycomb separated through a separation step in which an air flow is applied from the end face of the supplied honeycomb carrier to cover the catalyst component in the cell, and the elastic gripping jig is separated from the outer skin portion of the honeycomb carrier fixed by the leaching of the catalyst slurry. The carrier is dried and then baked to carry the catalyst component. In the separation step, the pressure-expanded balloon-shaped support is a void starting from the convex portion. By expanding while deflated to facilitate separation of the honeycomb skin and the support.

In the present invention, the balloon is, for example, a hollow donut-shaped member that allows air to enter and exit like a balloon, a float, or a tire tube, or a soft resin member that has a slightly stretched surface. In the present invention, the former is preferably used. These can control the adhesion to the honeycomb with sufficient confidentiality by adjusting the contact and pressure of air.
Therefore, the elastic gripping jig used in the present invention may have one air circulation port from the balloon-shaped support, but in order to easily separate from the honeycomb carrier fixed by the leached catalyst slurry, A plurality of air circulation ports from the support may be provided. This is because even if the balloon blocks the circulation port due to air suction, the air in the balloon can be extracted from another circulation port. Therefore, it is more preferable that the air circulation ports are arranged at substantially equal intervals on the same circumference as the honeycomb carrier.
In another embodiment, as shown in FIG. 3 (b), a groove extending on the outer periphery of the honeycomb carrier is provided inside the balloon of the elastic gripping jig, and the groove is connected to the air circulation port of the balloon-shaped support. You may use what is connected. When a groove is provided along the outer periphery of the honeycomb carrier and the groove communicates with the air circulation port of the balloon-shaped support, the balloon is sucked into the air circulation port when air is extracted from the air circulation port. However, since the holes are not blocked, the outer shell of the honeycomb carrier and the balloon can be reliably separated.

  When the catalyst slurry is coated in the honeycomb carrier cells by the wash coat method, the honeycomb carrier is generally fixed in the apparatus by elastic gripping of the outer periphery of the honeycomb carrier as shown in FIG. In many cases, the honeycomb carrier is held by a balloon-like support of the tool. By gripping with such a balloon, it is possible to prevent the honeycomb carrier from being damaged by the gripping force even if it is a brittle carrier such as a GPF honeycomb carrier. Here, a plurality of balloons may be provided on the same circumference of the honeycomb. However, it is preferable that the balloons are held by one balloon that makes one air chamber on the same circumference. By using one balloon for gripping the circumference, it becomes easy to grip the honeycomb with uniform pressure, and it is possible to suppress breakage due to gripping force when handling a fragile honeycomb such as for GPF. .

  In the honeycomb carrier to which the wash coat is applied, after the honeycomb carrier is gripped by the balloon of the elastic gripping jig, the catalyst slurry is supplied to the honeycomb carrier, and then air is blown (air blow) from the opening end face of the honeycomb carrier to form the catalyst on the cell wall. Coat or impregnate ingredients. When a pressure for blowing air is applied here, the catalyst slurry is leached violently in the outer skin portion of a carrier having a large porosity in the outer skin portion, such as the GPF carrier. Such a tendency is particularly remarkable when the pressure when blowing air is large.

The slurry liquid supply direction and supply means in this slurry liquid supply step are not particularly limited. The slurry liquid may be supplied from the lower end opening of the honeycomb carrier to the upper end side or from the upper end opening of the honeycomb carrier to the lower end side.
Also, the slurry liquid supply means may be suction from the lower end or supply by gravity descending from the upper end, and if necessary, a pressure intended for filling the slurry liquid into the cell may be applied. good.
In addition, when the porosity of the honeycomb carrier shell is remarkably high, the viscosity of the catalyst slurry is low, or the particle size of the inorganic fine particles in the catalyst slurry is remarkably low, and depending on the combination of these conditions, At the stage of supply, the catalyst slurry may ooze out from the outer skin portion.

  The honeycomb carrier coated or impregnated with the catalyst slurry by the wash coat has its outer peripheral portion fixed to the holding surface of the balloon due to the catalyst slurry composition. In order to eliminate this sticking state, in the present invention, when a convex portion is provided on the grasping surface of the balloon and the internal pressure of the balloon is reduced, the elastic grasping treatment is performed while expanding the gap from the convex portion as a starting point. The separation of the tool and the honeycomb carrier is facilitated.

  The catalyst produced according to the present invention uses a honeycomb carrier as a filter in order to remove fine particulate matter contained in exhaust gas from an automobile. Therefore, there are macropores on the outer wall, and there are places where they communicate. Exists. That is, the catalyst slurry liquid is likely to ooze out from the voids in the outer skin.

  When the honeycomb catalyst manufactured according to the present invention is GPF, the honeycomb filter carrier that captures the fine particulate matter (PM) in the exhaust gas discharged from the gasoline vehicle is gripped by an elastic gripping jig at the outer periphery thereof. In addition, the catalyst component of a three-way catalyst (TWC) that purifies NOx, CO, and hydrocarbons is supported in the cell or inside the partition wall that constitutes the cell. It can also be applied to the manufacture of honeycomb catalysts.

The catalyst slurry is not particularly limited as long as it has fluidity capable of catalyzing the honeycomb carrier by wash coating, but the separation operation of the honeycomb carrier and the balloon peeling action are exhibited by the separation operation according to the present invention, This is particularly effective in a catalyst slurry having a viscosity that is expected to increase the efficiency of catalyst production. The noble metal component supported on particles such as alumina is dispersed in an aqueous medium and prepared as a catalyst slurry containing additives such as a thickener as necessary. The slurry containing such a component is in the form of a slurry. It is sticky because it is, and it also causes sticking to the balloon.
Examples of the catalyst slurry that is feared to adhere to the balloon as described above include those having a viscosity of 10 to 200 mPas by a B-type viscometer. The catalyst slurry viscosity is also affected by the content of inorganic fine particles such as alumina, and examples of the concentration of such inorganic fine particles include catalyst slurries such as 5 to 60% by mass. Moreover, about the viscosity originating in an inorganic fine particle, the influence of the particle size of an inorganic fine particle cannot be disregarded, For example, the catalyst slurry containing 0.1-10 micrometers inorganic fine particle is mentioned.

  In the present invention, the composition of the catalyst slurry is not particularly limited. However, in the case of a three-way catalyst (TWC), a precious metal such as platinum (Pt), palladium (Pd), rhodium (Rh) is mainly used. A catalyst component is used. Since a catalyst such as a noble metal is supported in a highly dispersed state on the surface of the cell partition walls or in the interior thereof, the catalyst is temporarily supported on a heat resistant inorganic oxide having a large specific surface area such as alumina, and then coated on the cell partition walls of the honeycomb carrier. It is preferable to impregnate. As the heat-resistant inorganic oxide for supporting the catalyst, silica, zeolite, zirconia, ceria, titania, or a composite oxide thereof can be used in addition to alumina. The amount of the precious metal supported may be about 0.3 to 3.5 g / L per unit volume of the honeycomb carrier.

  The catalyst slurry is not limited by the type and particle size of the inorganic particles, but it is preferable that at least a part of the catalyst slurry can penetrate into the pores of the partition walls. It is preferable that the particle diameter D90 when the cumulative distribution from the diameter side becomes 90% is 5 μm or less, such that it is finely divided by a ball mill or the like, and more preferably D90 is 3 μm or less. When D90 is 5 μm or less, an appropriate amount of the catalyst component can enter the pores of the partition walls. In particular, when a wall flow honeycomb is used for GPF applications, the ability to purify particulate components such as soot as well as harmful components in exhaust gas is sufficiently exerted, and pressure loss is not unnecessarily caused.

  Next, the manufacturing method of the exhaust gas purification catalyst of the present invention will be described in detail for each basic process with reference to the drawings.

(1) Holding of the honeycomb carrier First, as shown in FIG. 1A, an elastic holding jig 3 having a balloon-like support 2 is brought into contact with the outer peripheral portion of the honeycomb carrier 1, and the balloon-like support Air is supplied to the inside and the honeycomb carrier is held with a balloon.

  As shown in FIG. 3A, the elastic gripping jig used in the present invention has a convex portion 2 ′ at the tip of the balloon-shaped support 2. The convex portions 2 ′ may be arranged in the longitudinal direction on the same circumference as the honeycomb carrier, or may be arranged in the circumferential direction on the outer circumference of the honeycomb carrier.

Further, the shape and size are not limited, and the length may be short as long as separation is improved without reducing the gripping force, and the length is not limited to a linear shape, but may be a dot or a circle although not shown. In the case of dot-like, it is preferable to arrange them in a line along the circumference at approximately equal intervals.
The air circulation port 4 in the present invention may be one that feeds air into the balloon 2 individually, one that releases air inside the balloon 2 or one that sucks air, and one function of both. It may have. The operation of the air circulation port is the same below. If a groove is formed in the air circulation port 4 of the balloon support as shown in FIG. 3B, the balloon is contracted when sucked and the hole is not easily blocked.

  Further, the number of the convex portions 2 ′ of the balloon-like support 2 of the elastic gripping jig 3 may be one, or a plurality of convex portions 2 ′ may be provided. If an appropriate convex part is installed, the honeycomb outer shell and the balloon can be easily separated, and the honeycomb carrier outer shell and the balloon are not clamped at a stretch. There is no risk of damage.

Here, the honeycomb holding position by the elastic holding jig is not particularly limited. The middle part may be the upper end part or the lower end part. In addition, as described above, the balloon used in these examples is preferably one that is held by one balloon having the same air chamber on the same circumference of the honeycomb.
In the state gripped by the balloon, the surface of the balloon follows the honeycomb outer skin, and as shown in FIG. 4 (b), there is no space around the convex portion 2 ′, or there is a very slight state.

(2) Supply of catalyst slurry liquid under reduced pressure While holding the honeycomb carrier with a balloon of an elastic holding jig, as shown in the center of FIG. 1, slurry containing a catalyst component is supplied to the honeycomb carrier. The way of supplying such catalyst slurry is not particularly limited, and as shown in two directions by arrows (1) in FIG. 1 as well, from the liquid tank 6 at either the upper end or the lower end of the honeycomb, the honeycomb is supplied. To supply. Note that a slight pressure may be applied in the supply of the catalyst slurry before air blowing. When supplying the catalyst slurry from the upper end of the honeycomb carrier, pressurization from the upper end or suction from the lower end is performed. When supplying the catalyst slurry from the lower end of the honeycomb carrier, suction from the upper end or pressurization from the lower end is performed. be able to.

(3) Application of airflow: air blow Next, as shown in the right side of FIG. 1, that is, as indicated by the arrow (2), the honeycomb carrier 1 to which the catalyst slurry has been supplied Air blow is applied from one end face to remove excess catalyst slurry, spread the catalyst slurry on the cell wall surface, and fill the catalyst slurry into the cell wall.

  The problem of catalyst slurry leaching, which has been pointed out in the conventional method, becomes more serious when the air blow pressure (air flow rate) is strong. When the catalyst slurry liquid is sucked, the amount of the liquid stays in the cell and enters the pores on the outer wall is small. However, when air is blown into the honeycomb carrier, the liquid adhering to the inner surface of the cell at that pressure (air flow rate) tends to be pushed out from the pores and ooze out from the outer wall to the outside.

(4) Separation of elastic gripping jig The honeycomb carrier to which the air blow is applied and the catalyst slurry is applied is then separated from the elastic gripping tool. As shown in FIG. In the case of a porous body having a high porosity, the catalyst slurry is oozed out due to the influence of air blow.

  Here, the catalyst slurry has adhesiveness because it contains a large amount of inorganic fine particles, and the catalyst slurry leached out from the outer skin fixes the balloon 2 of the elastic gripping jig 3 and the outer skin of the honeycomb carrier 1. End up. Such a sticking state cannot be easily eliminated by using only a self-shrinking force when, for example, a conventional balloon having no convex portion and a smooth surface is used. In addition, if the surface of the balloon is forcibly removed by simply sucking the air inside the balloon against the smooth surface of the balloon, the balloon peels off at once, causing the honeycomb carrier to tilt or break in the washcoat device. There is a risk of inviting.

Such leaching of the catalyst slurry is a fact well known to those skilled in the art. For example, as in Patent Document 6, when the entire circumference of a cylindrical honeycomb carrier is covered with a balloon and pressurized with air and then the catalyst slurry is poured from the upper part inside the honeycomb carrier to carry the catalyst, the catalyst is supported on the carrier. Means for suppressing adhesion to the outside are known.
Although this document does not describe a specific means for solving the state of leaching into the outer skin from the inside of the honeycomb carrier and fixing it to the balloon, there is only one pipe for introducing compressed air. Yes, compressed air is introduced from here, and when the valve is opened, the air is released to atmospheric pressure.

  However, in such an apparatus, the honeycomb and the balloon are fixed as shown in FIG. 9A, and the state shown in FIG. That is, when the catalyst slurry is leached by gripping the honeycomb 1 and sucking the catalyst slurry and then air blowing, the pressurized air inside the balloon 2 is released to take out the honeycomb carrier from the elastic gripping jig 3. However, as shown in FIG. 9, the sticking of the contact surface between the balloon 2 and the outer skin of the honeycomb carrier 1 is not eliminated due to the viscosity of the catalyst slurry, and the honeycomb carrier 1 cannot be taken out from the wash coat apparatus. In particular, in the manufacture of a honeycomb catalyst using a brittle carrier such as GPF, it is desirable to use a flexible rubber that is easily plastically deformed for the balloon used to prevent the honeycomb carrier from being damaged. Prone to state.

  The balloon-like support used in the present invention has one or more protrusions at a site that comes into contact with the honeycomb carrier skin. Such a convex portion may be provided at one place, but a plurality of such convex portions are preferable. Moreover, the same material as a balloon may be used for formation of such a convex part, and the material from which hardness and shrinkage | contraction rate differ may be used. When different materials are used, it may be preferable that they are harder than the whole.

  In the case of the balloon-shaped support in the present invention, the number of convex portions is one in FIG. 3, but it may be plural as described above. The larger the number, the more effective. However, 2 to 10 locations are preferable, and 3 to 8 locations are more preferable in consideration of work efficiency and maintenance. The intervals are preferably equal intervals.

  Moreover, the size of a convex part, ie, a width | variety, height, etc. is not specifically limited, For example, it can be set as 1-10 mm, respectively. The longitudinal cross-sectional shape may be any of a semicircle, a triangle, a rectangle, and the like, and the length and shape of the groove are not limited, and may be concentric, elliptical, wave-like, or branched in the middle. As described above, a plurality may be provided at different positions.

With such a configuration of the present invention, even when the honeycomb is immersed in the catalyst slurry from the outer skin portion and the balloon of the elastic gripping jig is partially fixed to the honeycomb carrier, the balloon-shaped support body having the convex portion is provided with air. By opening the gap, the outer shell of the honeycomb carrier can be smoothly separated by the convex portion on the balloon as a trigger. Here, it is preferable that the material of the balloon-like support is an elastic body such as rubber that self-shrinks by releasing air. Further, when releasing the pressurized air from the balloon-shaped support, it may be released to atmospheric pressure, or may be forcibly depressurized in order to promote the contraction of the balloon-shaped support. By performing such pressure reduction treatment, the peeling time between the honeycomb carrier and the balloon support is shortened.

  Further, the elastic gripping jig of the present invention has at least one air circulation port capable of introducing and sucking air inside the balloon-shaped support, and such an air circulation port is provided at one place. There may be a plurality of them. Further, as shown in FIG. 3B, the air circulation path may be connected to the air circulation port 4, and may hold a groove 5 that opens to the inside of the balloon 2 through the air circulation port 4. As a result, the balloon is sucked during suction from the air circulation port, and the air inside the balloon can be reliably sucked without blocking the air circulation port. Even when the air circulation port is provided in various manners as described above, the pressurized air in the balloon support body may be released to the atmosphere, but may be depressurized as described above.

  In the case of the balloon-shaped support in the present invention, there may be a plurality of air circulation ports. For example, the air circulation ports may be provided at approximately four intervals in the circumferential direction. In this way, when air is discharged from each hole, the air is gradually contracted at a constant pace by equalizing the air discharge amount. The more air circulation ports, the more effective. However, 2 to 10 locations are preferable, and 3 to 8 locations are more preferable in consideration of work efficiency and maintenance. The intervals are preferably equal intervals.

  In addition, the groove provided so as to be connected to the air circulation port may be one place or a plurality of grooves. For example, a groove that opens to the inside of the balloon through the air circulation port may be provided. By the action of the groove, when the air inside the balloon is sucked and discharged, the air circulation port is not blocked by the balloon and can be reliably contracted. In addition, the size of this groove | channel, ie, a width | variety, a depth, etc. is not specifically limited, For example, it can be set as 1-10 mm respectively. The cross-sectional shape may be any of a semicircle, a triangle, a rectangle, and the length and shape of the groove are not limited, and may be concentric, elliptical, wave-like, or branched in the middle.

(5) Drying and firing In the present invention, the honeycomb carrier on which the catalyst slurry is finally applied is dried and then fired to carry the catalyst component. As a result, the catalyst component is supported on the honeycomb carrier.
Here, the conditions for drying and firing are not particularly limited. Drying can be performed, for example, at 100 to 200 ° C. for 0.1 to 3 hours, and firing can be performed, for example, at 400 to 600 ° C. for 0.5 to 5 hours in an oxidizing atmosphere.

  The above-described series of steps are automated, and arm expansion / contraction, rotation, traveling, honeycomb movement by a belt conveyor, hood attachment / detachment, decompression device, air blow device, and the like are automatically controlled. During this time, the honeycomb is depressurized and a predetermined amount of the catalyst slurry enters the cell, and the honeycomb catalyst spread in the cell is obtained by air blowing.

  Hereinafter, the embodiments of the present invention will be described in more detail, but the present invention is not limited thereto.

<Embodiment 1>
A cordierite wall flow honeycomb carrier (diameter 120 mm, length 90 mm) is used as a GPF honeycomb carrier, and the upper end portion of the honeycomb carrier 1 is elastically gripping jig 3 as shown in FIG. This is a case where the honeycomb carrier is held in contact with the balloon 2. In FIG. 1, the balloon 2 is shown in a bowl shape, but it is like a tire hose and is appropriately tightly gripped on the outer peripheral surface of the honeycomb carrier.
As shown in FIG. 1 (b1) or (b2), catalyst slurry is supplied to the honeycomb carrier held by the balloon 2 from the liquid tank 6 or the like. In (b1), the catalyst slurry is supplied from the upper end of the honeycomb carrier, and in (b2), it is supplied from the lower end of the honeycomb carrier. Although not shown in FIG. 1, a decompression device may be connected to the balloon-like support 2.

In this embodiment, a case will be described in which an elastic gripping tool 3 having one convex portion 2 ′ on the inner circumference of the balloon 2 as shown in FIG.
FIG. 3C shows a state in which the honeycomb carrier 1 is arranged at a predetermined position of the apparatus when the honeycomb carrier 1 is mounted on the washcoat apparatus by the balloon 2 of the elastic gripping tool 3.

Subsequently, air is introduced into the balloon 2 from the air circulation port 4 inside the balloon 2 of the elastic gripping tool 3 so as to be gripped by the balloon 2 of the elastic gripping jig as shown in FIG. Catalyst slurry is supplied to the honeycomb carrier 1 as shown in (b1) and (b2) of FIG. As shown in FIG. 5 (a), air blow is applied to the honeycomb carrier 1 to which the catalyst slurry has been supplied to eliminate excess catalyst slurry, to spread the catalyst slurry inside the honeycomb carrier, and to the inside of the honeycomb carrier cell wall. The catalyst slurry is impregnated.
In the highly porous honeycomb carrier 1 to which air blow is applied, as shown in FIG. 5, the catalyst slurry oozes from the outer skin portion. Here, the balloon and the honeycomb carrier are fixed through the catalyst slurry.

In FIG. 6 (a), the air inside the balloon 2 is released from the air flow port 4 provided inside the balloon 2 in a state where the outer skin portion of the honeycomb carrier 1 is fixed via the catalyst slurry. The adhering state has begun to be eliminated by using the portion 2 'as a trigger.
Such an action is because the convex portion 2 ′ creates a gap with the honeycomb in the gripped state. The width of the gap is more difficult to limit to the size of the honeycomb and the like, but is preferably about 1 to 5 mm on each side. For this purpose, the protrusion height and width are, for example, 1 to 3 mm, or the material of the protrusions should be hard.

  In FIG. 7 (a), by continuing the release state following FIG. 6, the area where the fixed state has been eliminated gradually increases, and the detachment between the outer skin portion of the honeycomb carrier 1 and the balloon 2 proceeds smoothly. ing.

  In FIG. 8 (a), the released state is continued from FIG. 7, so that the outer skin portion of the honeycomb carrier 1 and the balloon 2 are completely fixed.

  In this embodiment, one convex portion 2 ′ is provided on the circumference inside the balloon, and even if the inside of the balloon is adsorbed to the outer skin of the honeycomb carrier as shown in FIG. As a result of 2 ′, the gap changes as shown in FIGS. 6 to 8 can be smoothly separated from the outer skin.

  Thereafter, the catalyst carrier coated honeycomb carrier separated from the balloon is dried at 25 to 100 ° C. by standing or heating, and then calcined at 400 to 600 ° C. for 0.5 to 3 hours. Is carried.

<Reference aspect 1>
Except for the use of a balloon having no projections, the holding of the honeycomb carrier, the supply of the catalyst slurry, the air blowing, the drying and the firing in the first embodiment are the same. Hereinafter, it will be described in detail with reference to FIG.

FIG. 9A shows a state in which the catalyst slurry has oozed out from the outer skin portion of the honeycomb 1 inside the balloon 2.
When the air in the pressurized state inside the balloon 2 is released from the air circulation port 4 provided inside the balloon 2 with respect to the balloon 2 in the state of holding the honeycomb 1 in which the catalyst slurry has leached from the outer skin portion, the balloon 2 9 and the outer skin of the honeycomb carrier 1 tend to be as shown in FIG.
When a balloon without a convex portion is used, sticking to the outer skin of the honeycomb carrier is difficult to be eliminated as shown in FIG. 9 (b) AA sectional view. This state is also a case where the honeycomb carrier is catalyzed using an apparatus used in the conventional washcoat method, and corresponds to a comparative example for the present invention.

  The present invention relates to a filter for collecting particulate matter contained in exhaust gas from a diesel engine or a gasoline engine, and more particularly to production of a catalytic filter (GPF) for capturing particulate matter in exhaust gas from a gasoline engine. Can be suitably used.

1: Honeycomb carrier 2: Balloon (support)
2 ': Convex part 3: Elastic gripping jig 4: Air circulation port 5: Groove 6: Catalyst slurry liquid tank

Claims (6)

In a cell of a honeycomb carrier comprising a porous partition wall forming a plurality of cells, and a porous skin portion having an end face where at least a part of the cells constituted by the partition wall is open and having a porosity of 30% or more And a method for producing an exhaust gas purification catalyst carrying a catalyst component by a washcoat method, comprising a step of supplying a slurry catalyst component and a step of pneumatically discharging the catalyst slurry in the supplied cell,
In the wash coating method, an elastic gripping jig having a balloon-shaped support having convex portions formed toward the outer periphery of the honeycomb carrier is used, and the balloon-shaped support is pressurized and expanded to grip the outer periphery of the honeycomb carrier. After fixing,
A slurry liquid containing a catalyst component is supplied from the end face of the honeycomb carrier, and the honeycomb carrier to which the catalyst slurry is supplied is held by a balloon-like support, and an air stream is applied to the cell from the end face of the honeycomb carrier to which the catalyst slurry is supplied. The catalyst component is coated inside,
The honeycomb carrier separated through the separation step of separating the elastic gripping jig from the outer skin portion of the honeycomb carrier fixed by the leaching of the catalyst slurry is dried and then fired to carry the catalyst component. In the separation step, A method for producing an exhaust gas purifying catalyst, characterized in that separation of a honeycomb outer shell and a support is promoted by causing the balloon-like support that has been inflated under pressure to contract while enlarging a gap from a convex portion.   The method for producing an exhaust gas purification catalyst according to claim 1, wherein the balloon-like support of the elastic gripping jig in the separation step is contracted by a decompression operation.   The method for manufacturing an exhaust gas purification catalyst according to claim 1 or 2, wherein the honeycomb carrier has a porosity of an outer skin portion of 50 to 80%.   The method for manufacturing an exhaust gas purification catalyst according to any one of claims 1 to 3, wherein the outer skin portion of the honeycomb carrier has an average pore diameter measured by a mercury porosimeter of 10 to 30 µm.   The cell of the honeycomb carrier has plugging portions at an opening end portion on an inlet end surface side and an opening end portion on an outlet end surface side, and the plugging portions are alternately arranged. The manufacturing method of the exhaust-gas purification catalyst in any one of 1-4. The method for producing an exhaust gas purification catalyst according to any one of claims 1 to 5, wherein the catalyst composition contains one or more noble metal elements selected from Pt, Pd, and Rh.