JP2018153720A - 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 preventing the leaching of a catalyst slurry to a skin portion during washcoating to carry a catalyst on a honeycomb carrier and shortening the process time in mass production.SOLUTION: There is provided a method for producing an exhaust gas purification catalyst capable of suppressing the immersion of a catalyst slurry from the inside of a honeycomb to a skin portion, in a step where when air is supplied to a balloon-shaped supporter of an elastic holding jig to hold a honeycomb carrier 1 with a balloon 2 and a catalyst slurry is coated on a cell of the honeycomb carrier by washcoating, the immersion of a catalyst composition slurry to the skin can be suppressed even when a sealer is not fully dried by applying a sealer such as an aqueous solution of a resin composition 81 to the skin portion of the honeycomb carrier and pressurizing the inside of a space formed by the skin and a supporter with a balloon-shaped supporter during washcoating even if the aqueous solution of a resin composition is not fully dried and the catalyst slurry is put out by air pressure during washcoating.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for producing an exhaust gas purifying catalyst, and more particularly, it is possible to prevent the catalyst slurry from entering the outer skin portion of the honeycomb carrier at the time of wash coating for carrying the catalyst on the honeycomb carrier, and a process in mass production The present invention relates to a method for producing an exhaust gas purification catalyst capable of reducing time.

  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 remains in a fine particle 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 compressed air at high pressure, and kinetic energy is extracted by igniting and exploding the fuel by the action of the pressure. Although it is an efficient engine due to its high compression, it is necessary to create a highly compressed state, so the engine speed is lower than that of a gasoline car and the exhaust gas temperature is also low, so the conventional filter type In the honeycomb carrier, that is, the DPF, in order to improve the strength of the honeycomb carrier, the outer skin portion can be 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 and supply a large amount of air into the cylinder by a supercharger. The temperature of the exhaust gas is further increased. 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 integrally molded product having the same quality as the partition walls of the cells of the honeycomb carrier 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, a three-way catalyst (TWC: Three Way Catalyst) containing noble metals such as platinum, palladium, rhodium, etc., is used for purification of exhaust gas from gasoline engines. Is used. The conventional TWC is not a honeycomb carrier (wall flow honeycomb) plugged at both end faces of the cells as in the DPF, but the cell walls of the honeycomb cells in which both end faces of the cells, called flow-through honeycombs, are released. The catalyst component has been coated. 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 to be inverted, and then air blown to the carrier to separate excess slurry, 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 “process of discharging the supplied catalyst slurry in the cell by air pressure”, if the flow-through honeycomb is used, excess slurry can be removed from the open end face 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. In particular, 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 and high-speed exhaust gas, the outer skin of the GPF is made of a porous material that is air-permeable like the cell partition walls, and has a porosity of 30% or more, and further a porosity of 50% or more. It is necessary to use a carrier.
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, resulting in cracks. There was also a problem that it was easy to do. 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 molding the honeycomb partition walls and the outer skin in this way, the thermal expansion coefficient of the outer skin and the partition walls becomes equal, so that cracks (damage) due to thermal history during manufacture and use as a catalyst can be suppressed. it can.

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 Moreover, 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.

  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, in Patent Document 6, although the catalyst slurry can be prevented from leaching from the outer skin portion of the honeycomb carrier to the outside, the catalyst permeates into the outer skin portion (also referred to as an outer peripheral wall). For this reason, it has been impossible to prevent the occurrence of cracks due to the thermal history as described above derived from the catalyst component that has entered the outer skin portion and the increase in the back pressure.

  In this way, as a honeycomb catalyst having a porous outer skin portion such as a GPF carrier, the catalyst slurry from the honeycomb outer skin portion is prevented from leaching during manufacturing, so that cracks due to thermal history do not occur. Even when used, it is difficult to increase the back pressure, and a method for producing an exhaust gas purification catalyst is desired. Moreover, in manufacturing such an exhaust gas purification catalyst, the process time must be long during mass production.

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, the object of the present invention is to prevent the catalyst slurry from leaching to the outer skin part during the wash coating in which the catalyst is supported on the honeycomb carrier, and to reduce the process time in mass production. It is providing the manufacturing method of a purification catalyst.

  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. When coating the cells of the carrier, a sealer such as a resin composition aqueous solution is applied to the outer skin portion of the honeycomb carrier, and the resin composition aqueous solution is undried, that is, cured by the balloon-like support of the elastic gripping jig. Even when there is no seal, pressurizing the space formed by the outer skin and the support during wash coating can suppress the infiltration of the catalyst composition slurry into the outer skin even when the sealer is not dried. In the process of discharging with air pressure, the catalyst slurry can be prevented from entering from the inside of the honeycomb to the outer skin, and the process time can be reduced. I have found that you can shrink, which resulted in the completion of the present invention.

That is, according to the first invention of the present invention, a honeycomb carrier comprising a porous partition wall forming a plurality of cells and a porous outer skin portion having a porosity of 30% or more, and having open ends at the top and bottom. A method for producing an exhaust gas purifying catalyst carrying a catalyst component in the cell,
Using the step of impregnating the resin composition solution as a sealer in the pores in the entire outer skin of the honeycomb carrier, and two elastic gripping jigs having a balloon-like support, the support is provided on the upper and lower ends of the honeycomb carrier, respectively. A step of bringing the body into close contact with each other, a step of supplying the catalyst component-containing slurry liquid from one end of the honeycomb carrier, a step of coating the catalyst component in the cell by air blow, and an elasticity from the honeycomb carrier Including a step of separating the holding jig and a step of drying and firing the separated honeycomb carrier to carry a catalyst component,
In the air blowing step, a space formed by the support body located at the upper part, the outer peripheral part of the honeycomb carrier, the side face of the elastic gripping tool, and the support body located at the lower part is pressurized with an air flow from the opening, The present invention provides a method for producing an exhaust gas purifying catalyst, characterized in that the catalyst slurry is prevented from oozing out.

Further, according to the second invention of the present invention, in the first invention, when the sealer in the cell is in an undried state in the wash coating method, the upper and lower skin portions of the honeycomb carrier are attached to the elastic gripping jig. Liquid-tight gripping and fixing with a balloon-shaped support,
Thereafter, the catalyst slurry liquid containing the catalyst component is supplied from the end face of the honeycomb carrier, and the catalyst component is coated in the cells by applying an air flow from the end face of the honeycomb carrier to which the catalyst slurry is supplied, and then from the outer skin portion of the honeycomb carrier. There is provided a method for producing an exhaust gas purifying catalyst characterized in that after the step of separating the elastic gripping jig, the separated honeycomb carrier is dried and then fired to carry the catalyst component.

  According to a third aspect of the present invention, in the air blowing step according to the first aspect, the [pressure for pressurizing the space] satisfies a condition of [blowing pressure] ≦ [pressure for pressurizing the space]. A method for producing an exhaust gas purifying catalyst characterized by being satisfied is provided.

  According to the fourth aspect of the present invention, in any one of the first to third aspects, the honeycomb carrier impregnated with the resin composition solution by the elastic gripping jig in the step of gripping the honeycomb carrier. Is provided before the resin composition solution is completely dried, and a method for producing an exhaust gas purifying catalyst is provided.

  According to the fifth invention of the present invention, in the step of impregnating the resin composition solution according to any one of the first to fourth inventions, the impregnation depth of the resin composition solution into the honeycomb carrier is There is provided a method for producing an exhaust gas purifying catalyst, characterized in that it corresponds to the thickness of the outer skin.

  According to a sixth aspect of the present invention, in the air blowing step according to any one of the first to fifth aspects, the air flow from the opening to the space continues during the air blowing. A method for producing an exhaust gas purifying catalyst is provided.

  According to a seventh aspect of the present invention, the exhaust gas according to any one of the first to sixth aspects is characterized in that the openings are arranged at substantially equal intervals at a plurality of locations on the outer periphery of the honeycomb. A method for producing a purification catalyst is provided.

  Further, according to an eighth invention of the present invention, in any one of the first to seventh inventions, the honeycomb carrier has an outer shell portion with a porosity of 50 to 80%. A manufacturing method is provided.

  According to the ninth invention of the present invention, in any one of the first to eighth 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 a featured exhaust gas purification catalyst is provided.

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

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

According to the method for producing an exhaust gas purification catalyst of the present invention, since the catalyst slurry can be prevented from entering the porous outer skin portion, the occurrence of cracks in the honeycomb carrier can be suppressed, and when mounted on an automobile. Can also suppress an increase in back pressure.
In addition, when the catalyst slurry is coated on the cell partition walls of the honeycomb carrier, since the outer coating with the resin composition aqueous solution is performed in advance, the catalyst slurry can be prevented from leaching into the outer skin portion, so that the periphery of the apparatus is not contaminated. .
In addition, if the honeycomb carrier is gripped in a liquid-tight state, wash coating can be performed without waiting for the resin composition solution to be completely dried, so that the drying time of the resin composition can be saved. Can also 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 the external appearance of the honeycomb carrier typically. When producing an exhaust gas purification catalyst according to the present invention, (a) a state before the honeycomb carrier coated with the resin composition aqueous solution is held by the support, and (b) a step of holding the honeycomb carrier by the support are schematically shown. It is explanatory drawing shown in figure. FIG. 5 is an explanatory view schematically showing a process of discharging catalyst slurry by applying an air flow to a honeycomb carrier when manufacturing an exhaust gas purification catalyst according to the present invention. FIG. 3 is an explanatory view schematically showing an example of a state in which an aqueous resin composition is applied to the outer skin portion of a honeycomb carrier when manufacturing an exhaust gas purification catalyst according to the present invention. When manufacturing an exhaust gas purification catalyst, the honeycomb carrier is grasped by the conventional technique, and when the resin composition aqueous solution is undried, the resin composition aqueous solution leaches out from the outer skin portion. FIG.

  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 in the honeycomb-like base material having a porous outer skin such as GPF and having the sealing portion that becomes an obstacle when the air is discharged by air pressure, as described later. Since it is possible to prevent the catalyst slurry from leaching into the outer skin part during production, it can be suitably used particularly for a wall flow honeycomb used for GPF.

In addition, since the exhaust gas needs to escape to the outside from the partition walls constituting the honeycomb, the partition walls are formed of a porous body. The material used for the production of the porous body is not particularly limited, and may be made of an inorganic oxide usually used as a raw material for the honeycomb carrier. Examples of such inorganic oxides include silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, silica-alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, aluminum titanate, etc. There are ceramic materials. 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. It is preferable that the honeycomb carrier for GPF is formed of a homogeneous material. The homogeneous material refers to a material having a range of difference in thermal expansion coefficient and 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. In addition, there is a concern about problems such as cracks caused by a difference in thermal expansion coefficient in a gasoline engine catalyst that becomes high temperature. For this reason, it is preferable that the partition wall and the outer skin part have the same thermal expansion coefficient or are integrally molded of the same material.
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.

The thickness of the partition walls constituting the cells of the honeycomb carrier is preferably 1 to 18 mil (0.025 to 0.47 mm), more preferably 6 to 12 mil (0.16 to 0.32 mm). 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). If 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, and the pressure loss becomes too high. 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. Moreover, when used as a honeycomb carrier for GPF, the effective area as a filter is insufficient, the pressure loss after PM deposition becomes high, and the engine output may be reduced.

  The honeycomb carrier used in the present invention may be a flow-through carrier without plugging used in a TWC for a gasoline vehicle, 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 purifying catalyst The manufacturing method of the exhaust gas purifying catalyst of the present invention has a porous partition wall forming a plurality of cells, and an end face in which at least a part of the cells constituted by the partition walls is open, and the porosity is For a honeycomb carrier comprising a porous outer skin portion of 30% or more,
Using the step of impregnating the resin composition solution as a sealer in the pores in the entire outer skin of the honeycomb carrier, and two elastic gripping jigs having a balloon-like support, the support is provided on the upper and lower ends of the honeycomb carrier, respectively. A step of bringing the body into close contact with each other, a step of supplying the catalyst component-containing slurry liquid from one end of the honeycomb carrier, a step of coating the catalyst component in the cell by air blow, and an elasticity from the honeycomb carrier Including a step of separating the holding jig and a step of drying and firing the separated honeycomb carrier to carry a catalyst component,
In the air blowing step, a space formed by the support body located at the upper part, the outer peripheral part of the honeycomb carrier, the side face of the elastic gripping tool, and the support body located at the lower part is pressurized with an air flow from the opening, The catalyst slurry is prevented from oozing out.

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

(1) Sealing of outer skin portion with resin composition or hydrophobic oil / fat In the present invention, a sealer (also referred to as a sealing component) selected from the resin composition or hydrophobic oil / fat so that the catalyst slurry does not penetrate into the outer skin portion. Impregnation into the outer skin of the honeycomb carrier. The type of the sealer is not particularly limited, but a water-soluble resin or resin composition is preferable from the viewpoint of cost and ease of handling (also referred to as a water-soluble resin composition).
In the step of impregnating the resin composition solution, the impregnation depth of the resin composition solution into the honeycomb carrier corresponds to the outer shell thickness of the honeycomb carrier.

  Examples of such a water-soluble resin composition include polyvinyl alcohol (PVA), polyester resin, phenol resin, and acrylic resin. PVA is preferable, and when PVA is used as a water-soluble resin composition, the outer skin portion of the honeycomb carrier can be impregnated by using an aqueous solution. The physical properties of PVA are not particularly limited, but those having an average degree of polymerization of 1,000 to 3,000 are preferable, and those of 1,500 to 2,500 are more preferable. In addition, when water is used as a solvent and PVA is dissolved, the concentration is not particularly limited, but is preferably 1 to 10% by mass, and more preferably 3 to 7% by mass. If PVA having such a concentration is selected and applied to the honeycomb substrate, impregnation into the outer skin portion 9 is easy, and more than necessary depth, that is, impregnation of PVA into the partition walls 4 in the honeycomb central axis direction. Will not be too deep. In addition, polyester resin, phenol resin, acrylic resin, and the like require a specific hydrophilic group in the molecule, and a treatment such as blending a dispersant may be performed.

  The impregnation depth of the honeycomb carrier such as PVA needs to be able to impregnate the thickness of the outer skin portion, but in order to completely impregnate the inner portion of the outer skin portion, the depth of the cell is deeper than the outer skin portion. It is desirable to control to reach a depth of about one. However, if the water-soluble resin composition is impregnated deeper than that, the impregnated water-soluble resin composition becomes an obstacle, making it difficult for the catalyst slurry to impregnate inside the partition walls of the cell, and the honeycomb carrier that exhibits the catalytic function. Geometric area is reduced.

In addition to the water-soluble resin composition as described above, a hydrophobic component such as an oil and fat component can also be used as the seal component for the outer skin portion. Since the catalyst slurry used in the washcoat uses water as a medium, the hydrophobic slurry that has no affinity with the catalyst slurry becomes a barrier when used as a seal component, and the catalyst slurry diffuses into the outer skin. Can be suppressed.
Usually, it is difficult to dry such hydrophobic fats and oils, so when the conventional wash coat method is applied as it is, the hydrophobic fats and oils impregnated in the outer skin part are pushed outward by the pressure at the time of air flow application. However, in the method of the present invention, the outer skin part is pressurized with the airflow from the side surface, so even if fluid hydrophobic oil or fat is used as a sealing component of the outer skin part, Hydrophobic oil and fat components are extruded, and the catalyst slurry does not enter the outer skin portion.
The kind of the hydrophobic oil / fat component is not particularly limited, and can be appropriately selected from normally available oil / fat components, but preferably does not contain an inorganic component in the oil / fat, Moreover, since it removes by volatilization or combustion in the baking process which is a latter stage operation, it is preferable to use plant-derived fats and oils, such as rapeseed oil, and animal fats, such as beef tallow.

(2) Coating device for resin composition aqueous solution The means for coating a sealer such as a resin composition aqueous solution on the outer skin portion of the honeycomb carrier is not particularly limited. For example, the coating may be performed with a coating device as shown in FIG. it can.
5 schematically shows an example in which two drive / application rollers 7 are arranged, a honeycomb substrate is placed thereon, and the application liquid is attached to the circumferential side surface by rotating with the rollers. ing.

More specifically, the honeycomb carrier 1 is placed on the drive / application roller 7 supplied with the resin composition by immersing the lower end in a liquid bath in which the aqueous resin composition solution 8 is stored, and the drive / application roller. 7 The surface is brought into contact with the circumferential side surface of the honeycomb carrier 1. The drive / application roller 7 preferably has a sponge-like outermost surface. A water-soluble resin composition 8 is supplied to the drive / application roller 7 on which the honeycomb carrier 1 is placed. When the sponge-like material portion on the outermost surface of the drive / application roller 7 is immersed in a container filled with the application liquid, the water-soluble resin composition 8 is easily supplied to the honeycomb carrier 1. When two or more drive / application rollers are used, the water-soluble resin composition 8 may be supplied to only one of them, or the application liquid may be supplied to both.
The amount of the resin composition aqueous solution 8 supplied to the honeycomb carrier 1 can be controlled by the rotational speed of the drive / application roller 7, the placement time on the drive / application roller 7 and the like. Thus, the resin composition aqueous solution 81 that has entered the outer skin portion 9 of the honeycomb carrier 1 to which the predetermined amount of the resin composition aqueous solution 8 has been supplied functions as a layer that prevents the catalyst slurry from entering the outer skin portion.

Thus, the catalyst carrier coating, that is, the wash coat, is applied to the honeycomb carrier coated with the aqueous resin composition solution in the latter stage of the manufacturing process.
Conventionally, if the outer skin of the honeycomb carrier is not coated with the resin composition, the balloon to be gripped covers only a part of the honeycomb carrier. The catalyst slurry entered the inside of the part.

  However, in the present invention, when the catalyst slurry is coated in the honeycomb carrier cells by the wash coat method, the seepage of the slurry from the outer peripheral portion of the honeycomb carrier is suppressed, and the carrier is a fragile carrier such as a GPF honeycomb carrier. However, if a sealer such as a curable resin composition is applied, the mechanical strength of the honeycomb carrier is expected to be improved by curing the resin.

(3) Influence of the degree of drying of the aqueous resin composition solution The honeycomb carrier coated with the aqueous solution of the composition is next applied with a catalyst slurry coating, that is, a wash coat, but the aqueous resin composition solution is not sufficiently dried. When it is, a big effect is not acquired with respect to the leaching suppression of a slurry.

  The aqueous resin composition is applied in order to prevent the catalyst slurry from leaching out of the outer skin portion in the wash coat, that is, for sealing (sealing) the pores of the outer skin portion. And in order to obtain sufficient sealing performance, it is necessary that the applied resin composition aqueous solution is completely dried, and if it is incompletely dried, the air current is reduced during wash coating as shown in FIG. The catalyst slurry oozes out from the undried portion under pressure.

At first glance, the resin composition aqueous solution also has a considerable viscosity, and even if the drying after coating is insufficient, there is also an increase in viscosity due to the volatilization of the solvent. It is. However, if the drying is insufficient, the catalyst slurry easily leaches out due to the application of airflow in the washcoat.
There are several possible causes of the catalyst slurry leaching out easily due to insufficient drying of the aqueous resin composition solution, one of which may be due to the thinness of the outer skin of the honeycomb substrate. As described above, the outer skin of the honeycomb substrate is usually extremely thin, 300 to 1000 μm. Therefore, if the resin composition aqueous solution is not completely dried, it is difficult to stay in the pores against the pressure of the air flow if the viscosity is somewhat increased. It is considered that the catalyst slurry oozes due to the diffusion of the aqueous catalyst slurry into the aqueous solution sealer and the capillary action of the pores constituting the external part.

  In order to dry and cure the resin composition aqueous solution to such an extent that the catalyst slurry does not ooze out during air blowing in the wash coat, a long drying time of about 5 hours or more is required at room temperature. Such a drying time is not limited to the case where the combination of the water-soluble resin composition and the solvent is PVA and water, but also varies depending on the concentration of the resin composition aqueous solution and the coating amount. However, in any combination, a suitable drying time is still required, and such a drying time of several hours is a great disadvantage in terms of production efficiency in an industrial manufacturing process.

Further, when the sealer composition used in the present invention contains a volatile solvent such as water, even when applied for the purpose of sealing the outer skin, the volume of the sealer is reduced by drying, In some cases, there is a concern that pores through which the catalyst composition slurry can pass are formed in the outer skin. In this case, in the conventional method, the slurry of the catalyst composition oozes out from the outer skin during wash coating.
However, in the present invention, as will be described in detail later, air pressure is applied to the honeycomb outer skin portion from the side at the same timing as the air blow to pressurize the pores, so that the sealer composition is in an undried state, that is, the outer skin. Wash coating is possible even when the pores are completely filled with the sealer composition.

(4) Holding of honeycomb carrier In the washcoat method of the present invention, first, as shown in FIG. 1 (a), an elastic holding jig 3 having a balloon-like support 2 is brought close to the outer periphery of the honeycomb carrier 1, Air is supplied to the inside of the balloon-shaped support, and the honeycomb carrier is held and fixed by the balloon.
As shown in FIG. 4, in the elastic gripping jig 3, an air circulation port that circulates air through the balloon-shaped support 2 opens toward the inside of the balloon 2. The air circulation port in the present invention serves as a passage when air is individually fed into the balloon 2 for pressurization and air is sucked from the balloon 2.

FIG. 1 shows one type of bowl-shaped balloon having a short vertical size. If the honeycomb carrier is simply held as in the prior art, this is sufficient, but in the present invention, in order to liquid-tightly hold the outer skin portion of the honeycomb carrier after applying the resin composition to the honeycomb carrier, Two balloons are used so that can be gripped.
In other words, in the present invention, since two balloons are used to hold the outer skin portion at the upper and lower portions of the honeycomb carrier, the honeycomb does not sway in the left-right direction due to movement between processes, and a fragile honeycomb such as for GPF use. When handling, damage due to gripping force is suppressed, and it becomes easy to maintain liquid tightness.

  In addition, the timing of gripping may be any period from when the sealer is applied to the honeycomb carrier until it is completely dried, but it is preferable to proceed to the gripping process without taking a drying time. That is, in the step of gripping the honeycomb carrier, the elastic carrier jig is used to grip the honeycomb carrier impregnated with the resin composition solution before the resin composition solution is completely dried, thereby shortening the process time. Is possible.

  Here, the gripping position of the honeycomb carrier by the balloon of the elastic gripping jig is such that the upper balloon support grips the uppermost end of the outer skin part and the lower balloon support grips the lowermost edge of the outer skin part as shown in FIG. It is preferable to do so. As a result, the resin composition impregnated in the outer skin can be gripped in a liquid-tight manner in a state where a space is formed in the side surface / intermediate portion of the honeycomb carrier.

  In the present invention, liquid-tight means that the movement of the undried resin composition aqueous solution is suppressed by the application of an air flow at the time of air blowing, and the catalyst slurry does not enter the outer skin portion of the honeycomb carrier.

(5) Supply of catalyst slurry liquid 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 method of supplying such a catalyst slurry is not particularly limited, and may be supplied from either the upper end or the lower end of the honeycomb as shown in two directions by arrows (1) in FIG.

  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 used. When supplying the catalyst slurry from the lower end of the honeycomb carrier, suction from the upper end or addition from the lower end is performed. Can depend on pressure.

The catalyst slurry used in the present invention is not particularly limited as long as it has fluidity capable of catalyzing a honeycomb carrier by wash coating, and Pt, Pd, Rh are added to inorganic oxide particles such as alumina. A catalyst component prepared by dispersing a catalyst component carrying a noble metal component such as the above in an aqueous medium and containing an additive such as a thickener as necessary can be used.
Thus, as a catalyst slurry used for this invention, the viscosity by a B-type viscometer is 10-200 mPas. 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 enter the pores of the partition walls of the cell. Such a catalyst slurry has a particle size distribution. It is preferable that the fine particles are formed by a ball mill or the like so that the particle diameter D90 when the cumulative distribution from the small particle diameter side becomes 90% is 5 μm or less, and more preferably D90 is 3 μm or less. If 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.

(6) Application of airflow: air blow Next, as shown in the right side of FIG. 1, that is, as shown by the arrow (2), the honeycomb carrier 1 supplied with the catalyst slurry is covered with the hood on the balloon 2 as necessary, and then the honeycomb carrier Air blow is applied from one end face of 1 to remove excess catalyst slurry, spread the catalyst slurry on the cell wall surface, and fill the catalyst slurry inside the cell wall.

  When the catalyst slurry is coated on the honeycomb carrier in which the resin composition aqueous solution 81 is undried by a conventional method in which the outer skin portion is not liquid-tightly held and fixed by the balloon 2, FIG. 6 (c-2 ), There is no problem in the portion gripped by pressurizing the balloon 2 with air from the air circulation port 41 of the elastic gripper 3, but the resin composition is not in the portion gripped by the balloon 2 in a liquid-tight manner. The aqueous solution 81 oozes from the outer skin. Therefore, the catalyst slurry enters the outer skin portion, cracks due to the thermal history occur in the honeycomb catalyst, and the back pressure increases.

  In order to prevent this, in the present invention, in this air blowing step, a space formed by the support body located at the upper part, the outer peripheral part of the honeycomb carrier, the side surface of the elastic gripping tool, and the support body located at the lower part is opened from the opening part. Pressurize with the air flow.

  At that time, in FIG. 3B, a jig having a shutter function, that is, an airflow jetting jig 10 is arranged outside the space to pressurize it. Although not shown, auxiliary equipment such as nozzles, pipes, and compressors are provided as necessary. When the opening is wide, the air density of the space can be increased by such means. It is preferable that the air flow ports 4 in the opening are arranged at approximately equal intervals at a plurality of locations on the outer periphery of the honeycomb. In FIG. 3, openings are shown at two places on the left and right, but a more preferable effect can be obtained if two openings are provided on the front and the back. In addition, when the honeycomb carrier is large and vertically long, the air flow ports 4 can be arranged in multiple stages. Thereby, even if an air flow concentrates on a specific location, it can suppress that the pressure which the resin composition 81 receives by the strong part and weak part of an air current can be made. Alternatively, the honeycomb may be held and moved to a separately provided side sealed container so that the space can be pressurized similarly.

  In addition to these, the present invention can attach an opening for generating an air flow to the balloon support itself, and accessory equipment such as nozzles, pipes, and compressors are branched from existing air blow equipment and partially shared. Can do.

  In this air blowing process, the space is pressurized with an air flow from the pressure opening of the elastic gripping jig toward the honeycomb carrier. The washcoat equipment of the present invention is placed under atmospheric pressure, but in the air blowing step, the [pressure for pressurizing the space] satisfies the condition [blow pressure] ≦ [pressure for pressurizing the space]. Preferably it is driven. If the [pressure for pressurizing the space] is small and [blow pressure]> [pressure for pressurizing the space], the leaching of slurry from the outer skin may not be suppressed.

The degree of pressurization is appropriately set depending on the size of the honeycomb carrier, the amount and viscosity of the catalyst slurry, the type of resin composition, the degree of drying, and the like so as to meet the above conditions. When the honeycomb carrier is large and the amount of the catalyst slurry is large and the viscosity is high, or when the resin composition has a low fluidity and a high degree of drying, the pressure can be increased. On the other hand, when the honeycomb carrier is small and the amount of the catalyst slurry is small and the viscosity is low, or when the resin composition has a high fluidity and a low degree of drying, it is necessary to suppress the degree of pressurization.
The degree of pressurization is difficult to define in the numerical range, but the pressure is set to 0.01 to 10 MPa, and the time is set to 0.1 to 5 seconds as a guide.

  The ejection of the airflow from the opening to the space continues during the air blow and stops with the end. A timer for this purpose can be incorporated in the control device, and can be linked to the air blow function. If the air flow of the washcoat continues even after the air blow is completed, if the resin composition is undried and the pressure is high, the airflow from the openings acts inside the honeycomb and impregnates the slurry inside the cell walls. In this case, the slurry may be pushed out onto the cell wall and discharged to the outside.

  In the present invention, immediately after the aqueous resin composition solution as a sealer is applied to the outer skin portion of the honeycomb carrier and even after the coating is insufficiently dried, the outer skin portion is liquid-tightly held by the balloon-shaped support. In addition, by applying pressure from the side of the honeycomb carrier at the time of wash coating with an air flow, leaching of the catalyst slurry from the outer skin portion can be suppressed, and the catalyst manufacturing process can be significantly shortened.

(7) Separation of elastic gripping jig The honeycomb carrier to which the air blow is applied and the catalyst slurry is applied is subsequently separated from the elastic gripping tool. Separation of the honeycomb carrier 1 from the elastic gripping tool 3 is performed by releasing the air inside the balloon 2 from the air circulation port 41 or performing a pressure reduction process.

This similar means is disclosed in Patent Document 6 as described above. In this document, 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. It is separated from the device by releasing.
Patent Document 6 further discloses an aspect in which the entire outer shell portion of the honeycomb carrier is gripped in order to prevent the catalyst slurry from seeping out into the outer shell from the inside of the honeycomb carrier. However, since Patent Document 6 has no description or suggestion about suppression of catalyst slurry intrusion by a sealer such as an aqueous resin composition solution according to the present invention, a manufacturing method such as Patent Document 6 is similar to GPF. Such a honeycomb catalyst cannot be applied to the production of cracks, resulting in generation of cracks due to thermal history and an increase in back pressure.

  In the present invention, two balloon-like supports are used and are gripped liquid-tightly at the upper and lower portions of the honeycomb carrier skin portion impregnated with the resin composition. During wash coating, the inside of the space formed by them is held. Since the airflow is applied from the side opening and the pressure is applied, the slurry does not ooze into the outer skin portion of the honeycomb in the air blowing process. Since the outer skin portion of the honeycomb is not fixed to the balloon by the slurry, it can be easily separated.

(8) 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, movement of honeycomb 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 catalyst slurry enters the cell, and a honeycomb catalyst spread in the cell is obtained by air blowing.

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

<Embodiment 1>
First, the resin composition aqueous solution 8 is applied to the outer skin portion 9 of the GPF honeycomb carrier of FIG. 2 using the coating apparatus shown in FIG. Here, PVA is used as the resin composition, and the aqueous resin composition 8 is applied to the outer skin portion 9 while rotating the honeycomb carrier 1 on the driving / application roller 7 of the coating apparatus. The coating amount of the resin composition aqueous solution 81 on the outer skin portion 9 is appropriately adjusted depending on the concentration of the resin composition aqueous solution 8, the rotational speed of the driving / application roller 7, and the coating time.
Thus, the resin composition aqueous solution 81 applied to the outer skin portion 9 of the honeycomb carrier 1 is transferred to the next washcoat without drying.
When the drying is insufficient, as shown in FIG. 3 (a), the balloon support 2 as shown in FIG. Thus, both ends of the honeycomb carrier 1 were gripped. As a result, openings are formed in the longitudinal direction and in the middle of the honeycomb.

  In FIG. 3B, a jig having a shutter function, that is, an airflow ejection jig 10 is disposed outside the space. When the opening is wide, the airtightness of the space can be increased by contacting such a jig with the support. Although not shown, auxiliary equipment such as a control device including a nozzle, piping, a compressor, and a timer is provided. The airflow ports 4 of the opening are arranged at a plurality of locations at substantially equal intervals on the outer peripheral portion of the honeycomb, and FIG. 3 shows the airflow ports 4 at two left and right sides. A more favorable effect can be obtained if airflow ports are provided at two locations.

  In addition to this embodiment, there is an embodiment in which an opening for ejecting gas is attached to the balloon support. As a result, auxiliary equipment such as nozzles, pipes, and compressors can be branched off from the existing air blow equipment, and can be partially shared, so that compactness and improved functionality can be achieved. This has the advantage that the start and end timings can be easily matched with respect to the air blow from above and the jet of airflow from the side.

Next, the balloon 2 of the elastic gripping jig 3 is brought close to the upper end portion and the lower end portion of the honeycomb carrier 1, and the honeycomb carrier is gripped and fixed by flowing air from the air circulation port 41. In this way, the undried honeycomb carrier with the resin composition aqueous solution 81 applied to the outer skin portion 9 is liquid-tightly gripped using the elastic gripper 3 having two balloons 2 and a space is formed on the outer side surface. The
Subsequently, the slurry of the catalyst-containing solution is supplied into the cells of the honeycomb carrier, and then proceeds to the air blowing process.

In this embodiment, the resin impregnated in the outer skin portion of the honeycomb is not dried. Then, as shown in FIG. 4, the catalyst slurry is supplied from the liquid tank 6 or the like in a state where a space is formed by the upper and lower end surfaces of the outer skin portion and the balloon. Although the catalyst slurry is supplied from the lower end of the honeycomb carrier, the catalyst slurry may be supplied from the upper end of the honeycomb carrier.
In this air blowing step, the space is pressurized with an airflow from the opening toward the honeycomb carrier. Although the washcoat facility is placed under atmospheric pressure, the airflow can be reduced so that the concentration of the airflow at a specific location can be alleviated and unevenness in the pressure received by the resin composition 81 is difficult at the strong and weak portions of the airflow. It is desirable to erupt. Usually, the degree of pressurization is about 0.01 to 10 MPa for pressure and about 0.1 to 5 seconds for time, but in this embodiment, when the honeycomb carrier is small, the amount of catalyst slurry is small, and the viscosity is low. Accordingly, the air blow is performed in a state where the degree of drying of the resin composition is low and the fluidity is high, and the pressure and time are suppressed to the mild side within the above range.
In this way, simultaneously with air blowing, the space formed by the elastic gripper and the outer skin is pressurized with airflow, but the control device including the timer is driven to stop the airflow when the air blowing is finished.

FIG. 4 of this embodiment shows that air is introduced into the balloon 2 of the elastic gripping tool 3 so that the honeycomb carrier 1 is gripped and attached to the washcoat device, and then air is applied to the honeycomb carrier 1 supplied with the catalyst slurry. Blow is applied.
According to this embodiment, the time required for the drying of the resin composition solution 81 is not added, and even if the catalyst slurry is wash coated immediately after coating, the honeycomb side surface is adjusted in accordance with the air blow timing. Since the pressure of the airflow is applied, the resin composition aqueous solution 81 can remain inside the outer skin portion 9 without being pushed out to the surface of the outer skin portion 9. For this reason, the catalyst slurry does not enter the outer skin portion 9, and the generation of cracks due to the thermal history during use in the firing step and the catalyst described later is suppressed, and the pores in the outer skin portion are blocked during use as the catalyst. There will be no increase in back pressure.
Since the honeycomb carrier to which the wash coat has been applied does not seep out and adhere to the catalyst slurry, it can be easily removed from the elastic gripper 3 by releasing or sucking the pressurized air inside the balloon from the air circulation port. After being separated, the state becomes as shown in FIG.

  The catalyst carrier coated honeycomb carrier separated from the balloon in this way is dried at 25 to 100 ° C. with a heating device and then calcined at 400 to 600 ° C. for 0.5 to 3 hours to carry the catalyst component. . The resin composition 81 filled in the pores of the outer skin portion 9 is burned and removed by this firing, and a honeycomb catalyst containing no catalyst component in the outer skin portion 9 is obtained. According to the present invention, the drying time of the sealer is obtained. This is suitable for industrial mass production.

  In addition, if the resin composition aqueous solution applied to the honeycomb carrier is completely dried, the movement of the resin composition aqueous solution is further suppressed by the application of the air flow during the wash coating. As described above, this is necessary.

The present invention relates to a filter for collecting particulate matter contained in exhaust gas of a diesel engine or a gasoline engine, in particular, a catalytic filter (GPF) for purifying particulate matter in exhaust gas of a gasoline engine. It can be suitably used for production.
The present invention can also be applied to manufacture of a honeycomb catalyst (CSF) for exhaust gas purification from a diesel vehicle.

1: Honeycomb carrier 2: Balloon (support)
3: Elastic gripping jig 4: Airflow port 41: Air circulation port (for gripping)
6: catalyst slurry liquid tank 7: coating liquid coating sponge 8: coating liquid 81: resin composition aqueous solution coated on honeycomb 9: skin portion 10: airflow jetting jig

Claims (11)

Exhaust gas purification in which a catalyst component is supported in a cell of a honeycomb carrier having a porous partition wall forming a plurality of cells and a porous outer skin part having a porosity of 30% or more and having open ends at the top and bottom A method for producing a catalyst for an automobile, comprising:
Impregnating the resin composition solution as a sealer in the pores of the entire outer surface of the honeycomb carrier; and
Using two elastic gripping jigs having a balloon-shaped support, the support is brought into close contact with the upper and lower end surfaces of the honeycomb support, respectively, and the honeycomb support is gripped; A step of supplying from the end of the substrate, a step of coating the catalyst component in the cell by air blow, a step of separating the elastic gripping jig from the honeycomb carrier, and drying the fired honeycomb carrier, followed by firing and catalytic component Including a step of supporting
In the air blowing step, a space formed by the support body located at the upper part, the outer peripheral part of the honeycomb carrier, the side face of the elastic gripping tool, and the support body located at the lower part is pressurized with an air flow from the opening, A method for producing an exhaust gas purifying catalyst, wherein the catalyst slurry is prevented from seeping out from the exhaust gas.   In the washcoat method, the upper and lower outer skin portions of the honeycomb carrier are liquid-tightly gripped and fixed with a balloon-shaped support of an elastic gripping jig in a state where the sealer in the cell is not dried, and then the catalyst is applied from the end surface of the honeycomb carrier. Supplying the catalyst slurry liquid containing the components, applying an air flow from the end face of the honeycomb carrier to which the catalyst slurry is supplied to coat the catalyst components in the cells, and then separating the elastic gripping jig from the outer skin portion of the honeycomb carrier 2. The method for producing an exhaust gas purification catalyst according to claim 1, wherein the separated honeycomb carrier is dried and then fired to carry the catalyst component.   2. The method for producing an exhaust gas purifying catalyst according to claim 1, wherein, in the air blowing step, the [pressure for pressurizing the space] satisfies a condition of [blowing pressure] ≦ [pressure for pressurizing the space]. .   2. The step of gripping the honeycomb carrier, wherein the elastic carrier jig grips the honeycomb carrier impregnated with the resin composition solution before the resin composition solution is completely dried. The manufacturing method of the exhaust gas purification catalyst in any one of -3.   The exhaust gas according to any one of claims 1 to 4, wherein in the step of impregnating the resin composition solution, an impregnation depth of the resin composition solution into the honeycomb carrier corresponds to a skin thickness of the honeycomb carrier. A method for producing a purification catalyst.   The method for producing an exhaust gas purifying catalyst according to any one of claims 1 to 5, wherein, in the air blowing step, the ejection of the airflow from the opening to the space is continued during the air blowing.   The method for producing an exhaust gas purifying catalyst according to any one of claims 1 to 6, wherein the openings are arranged at approximately equal intervals at a plurality of locations on the outer peripheral portion of the honeycomb.   The method for manufacturing an exhaust gas purification catalyst according to any one of claims 1 to 7, wherein the honeycomb carrier has a porosity of an outer skin portion of 50 to 80%. The method for producing an exhaust gas purification catalyst according to any one of claims 1 to 8, 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 1-9. The said catalyst composition contains 1 or more types of noble metal elements chosen from Pt, Pd, and Rh, The manufacturing method of the exhaust gas purification catalyst in any one of Claims 1-10 characterized by the above-mentioned.