JP2019013857A - Honeycomb filter intermediate product, honeycomb filter and manufacturing method of these - Google Patents

Abstract

To provide a ceramic honeycomb filter for an exhaust gas treatment, capable of suppressing a crack from occurring as well as allowing a catalyst function to fully exhibit, and also to provide a manufacturing method thereof.SOLUTION: A manufacturing method includes: a step of impregnating a liquid 200 containing organic polymer particles 200P and a dispersant to a columnar and porous ceramic honeycomb structural body 100; and a step of removing the dispersant from the impregnated liquid 200. In the step of impregnating, the liquid is impregnated only at one end side portion 100A including one end face in an axial direction of the ceramic honeycomb structural body 100. In a honeycomb filter intermediate product, a length in the axial direction at the one end side portion 100A is 10-70% to a total length in an axial direction of the ceramic honeycomb structural body 100.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a honeycomb filter intermediate body, a honeycomb filter, and a manufacturing method thereof.

  Conventionally, a ceramic honeycomb filter that collects soot in exhaust gas discharged from an internal combustion engine is known. When a certain amount of soot accumulates in the honeycomb filter, a so-called regeneration process is usually performed in which the collected soot is removed by combustion.

  It is also known to support a catalyst on a honeycomb filter to promote soot combustion promotion, exhaust gas chemical treatment, and the like.

JP 2013-17992 A Japanese Patent Laid-Open No. 2001-46886

  When the catalyst is supported, cracks are likely to occur in the honeycomb filter during the regeneration process. However, if the supported amount of the catalyst is reduced, it is difficult to sufficiently exert the catalyst function.

  The present invention has been made in view of the above problems, and provides a honeycomb filter and the like and a method for manufacturing the same that can suppress the occurrence of cracks during the regeneration process and can sufficiently exhibit the function of the catalyst. With the goal.

  As a result of studies by the present inventors, when the catalyst enters the micro cracks of the honeycomb filter, the linear expansion coefficient of the honeycomb filter increases, and soot accumulates relatively more at the outlet end side of the honeycomb filter. It was found that cracks are likely to occur due to high thermal stresses that are generated particularly at the outlet end of the filter during the regeneration process.

  The method for manufacturing a honeycomb filter intermediate according to the present invention includes a step of impregnating a columnar porous ceramic honeycomb structure with a liquid containing organic polymer particles and a dispersion medium (pre-coating step), and the dispersion from the impregnated liquid. Removing the medium. In the impregnation step (pre-coating step), the liquid is impregnated only in one end side portion including one end surface in the axial direction of the ceramic honeycomb structure, and the axial length of the one end side portion is determined by the ceramic honeycomb structure. It is 10 to 70% with respect to the total length in the axial direction of the structure.

  A honeycomb filter intermediate according to the present invention includes a columnar and porous ceramic honeycomb structure, and an organic polymer supported on the surface of the ceramic honeycomb structure. The organic polymer is supported only on one end side portion including the one end surface in the axial direction of the ceramic honeycomb structure, and the axial length of the one end side portion is equal to the total axial length of the ceramic honeycomb structure. In contrast, it is 10 to 70%.

  A method for manufacturing a honeycomb filter according to the present invention includes a step of supporting a catalyst on the honeycomb filter intermediate (catalyst supporting step), a step of removing the organic polymer from the honeycomb filter intermediate supporting the catalyst, Is provided.

  According to this, the microcracks are prevented from being blocked by the catalyst at the one end side portion where the organic polymer is supported before the catalyst is supported, and the thermal expansion coefficient of the one end side portion can be kept low. On the other hand, since the catalyst is also supported on the microcracks in the remaining portion where the organic polymer is not supported, the supported amount of the catalyst can be kept high.

A honeycomb filter according to the present invention is a honeycomb filter including a columnar ceramic honeycomb structure and a catalyst supported on the ceramic honeycomb structure.
And the void volume of the micro crack in the one end side portion including the one end surface in the axial direction of the honeycomb filter is larger than the void volume of the micro crack in the remaining portion of the honeycomb filter,
The supported amount of catalyst per apparent volume in the one end side portion is smaller than the supported amount of catalyst per apparent volume in the remaining portion,
The axial length of the one end portion is 10 to 70% with respect to the total axial length of the ceramic honeycomb structure.

  According to such a honeycomb filter, since the linear expansion coefficient is relatively low at the one end side portion, the use of the one end side portion as a gas outlet prevents the filter from being cracked due to thermal stress during soot combustion. Can be suppressed. Further, the catalyst function can be sufficiently expressed by utilizing the high catalyst loading in the remaining portion.

  Here, it is preferable that the linear expansion coefficient in the one end side portion is smaller than the linear expansion coefficient in the remaining portion.

  ADVANTAGE OF THE INVENTION According to this invention, the honeycomb filter etc. which can suppress generation | occurrence | production of the crack at the time of soot combustion, and can fully exhibit the function of a catalyst, and its manufacturing method are provided.

FIG. 1 is a schematic cross-sectional view of a ceramic honeycomb structure. FIGS. 2A and 2B are schematic cross-sectional views showing a pre-coating agent application step on the surface of the ceramic honeycomb structure at one end side portion and the remaining portion, respectively. 3 (a) and 3 (b) are schematic cross-sectional views subsequent to FIG. 2 showing a pre-coating agent application process on the surface of the ceramic honeycomb structure at one end side portion and the remaining portion, respectively. 4 (a) and 4 (b) are schematic cross-sectional views showing the steps of supporting the catalyst on the surface of the honeycomb filter intermediate body at the one end side portion and the remaining portion, respectively. FIGS. 5A and 5B are schematic cross-sectional views showing a process of removing the organic polymer of the honeycomb filter intermediate in the one end side portion and the remaining portion, respectively.

Embodiments of the present invention will be described with reference to the drawings.
(Honeycomb filter intermediate manufacturing method and honeycomb filter intermediate)
First, a porous ceramic honeycomb structure 100 shown in FIG. 1 is prepared. The ceramic honeycomb structure 100 has a column shape and has an inlet side end face 100a and an outlet side end face 100b.

  The ceramic honeycomb structure 100 includes a partition wall 120 and a sealing portion 130, and the partition wall 120 includes a plurality of inlet side channels (first channels) 110a and a plurality of outlet side channels (second channels) 110b. The cross-sectional shapes of the inlet-side channel 110a and the outlet-side channel 110b can be, for example, a circle, an ellipse, a rectangle, a hexagon, and an octagon.

  The inlet-side channel 110a opens at the inlet-side end face (other end face) 100a and is sealed at the outlet-side end face (one end face) 100b. Further, the outlet-side flow path 110b opens at the outlet-side end face (one end face) 100b and is sealed at the inlet-side end face (other end face) 100a. In FIG. 1, the inlet-side channel 110 a and the outlet-side channel 110 b are sealed by the plug-like sealing part 130, but can also be sealed by deforming the walls of the honeycomb structure 10.

  Examples of the ceramic are an aluminum titanate ceramic, a silicon carbide ceramic, and a cordierite ceramic.

  Especially, it is preferable that a ceramic is an aluminum titanate ceramic. The aluminum titanate-based ceramic can contain magnesium, silicon, and the like.

In particular, aluminum titanate-based ceramics _is a _{Al 2 (1-x) Mg} x Ti (1 + y) O 5-2x + 2y (x is 0 <x <1, y satisfies 0.5x <y <3x.) It is preferable. Here, the aluminum titanate-based ceramic preferably satisfies 0.03 ≦ x ≦ 0.5, and more preferably satisfies 0.05 ≦ x ≦ 0.2. The aluminum titanate-based ceramic preferably satisfies 0.5x <y <2x, and more preferably satisfies 0.7x <y <2x.

  The ceramic may contain trace components derived from raw materials or trace components inevitably contained in the production process.

  The porosity of the ceramic honeycomb structure 100 before pre-coating can be 50 to 75%. The porosity is preferably 55 to 70%, more preferably 55 to 65% in order to maintain the pressure loss performance and improve the catalyst activity. If the porosity exceeds 75%, the strength of the honeycomb filter may decrease.

The cell density can be, for example, 35 to 80 cells / cm ² .

  The length of the ceramic honeycomb structure in the axial direction can be set to, for example, 50 to 300 mm.

  In the present embodiment, the outlet side portion including the outlet side end face 100b of the ceramic honeycomb structure 100 is referred to as one end side portion 100A, and the remaining portion other than the one end side portion 100A of the ceramic honeycomb structure 100 is referred to as a remaining portion 100B. The axial length of the one end portion 100A is 10 to 70% with respect to the total axial length of the ceramic honeycomb structure 100. When the boundary between the one end side portion 100A and the remaining portion 100B is not a plane perpendicular to the axis, both the shortest distance and the longest distance from the outlet side end surface (one end surface) 100b to the boundary are the ceramic honeycomb structure 100. It may be 10 to 70% with respect to the total length in the axial direction.

  There is no substantial difference in material and structure (porosity, etc.) in particular between the one end side portion 100A and the remaining portion 100B before catalyst loading and precoating. Microcracks are present on the surfaces of the one end side portion 100A and the remaining portion 100B of the ceramic honeycomb structure 100, for example, the flow paths or the surfaces of the pores. The width of the microcrack is 0.1 to 2 μm, and is considered to be 0.5 μm on average. If the microcracks are voids, that is, if no solid is present in the microcracks, the linear expansion coefficient (thermal expansion coefficient) of the ceramic honeycomb structure is lowered.

  Such a ceramic honeycomb structure includes, for example, a ceramic raw material, an organic binder, a pore-forming agent, a solvent, and additives that are added as necessary, formed, fired, sintered, It can be obtained by sealing.

  Subsequently, the pre-coating agent 200 is impregnated only in the one end side portion 100 </ b> A of the ceramic honeycomb structure 100. 2A and 2B are enlarged schematic cross-sectional views of the surface of the ceramic honeycomb structure 100. The surfaces are the surfaces of the inlet-side channel 110a and the outlet-side channel 110b, or the empty space of the partition wall 120. It can mean the surface of a hole. As shown in FIG. 2B, the precoat agent 200 covers the surface of the ceramic honeycomb structure 100 having the microcracks 100MC in the one end side portion 100A. On the other hand, as shown in FIG. 2A, the surface of the ceramic honeycomb structure 100 having the microcracks 100MC in the remaining portion 100B is not covered with the precoat agent 200.

  The precoat agent 200 includes a liquid as a dispersion medium and organic polymer particles 200P as a dispersoid dispersed in the liquid. The average diameter of the organic polymer particles can be, for example, 0.1 to 0.8 μm. The precoat agent can be a so-called emulsion adhesive or latex adhesive. The average diameter of the organic polymer particles is preferably 0.1 to 0.4 μm, more preferably 0.1 to 0.2 μm.

  Examples of the liquid are water, hexane, acetone, and chloroform.

  An example of an organic polymer is rubber. Examples of rubber are styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber (IIR), ethylene propylene rubber (EPDM), natural rubber (NR) and the like.

  The organic polymer may be an organic polymer other than rubber, for example, an acrylic resin (acrylic ester or methacrylic ester polymer) or an ethylene vinyl acetate copolymer resin.

  The terminal part of the organic polymer can be substituted with a specific functional group to make a modified body that can react with a specific substance (monomer or the like), thereby adjusting the physical properties of the precoat agent.

  Examples of modified products include epoxy-modified products, carboxyl-modified products, isocyanate-modified products, and hydrogen-modified products. Further, the modification may be a graft modified product. A carboxyl-modified product is preferably used because the zeta potential of the organic polymer dispersoid in the emulsion can be negatively stabilized and the production is easy.

  The average diameter of the organic polymer particles can be D50 in the volume-based particle size distribution measured with a laser diffraction particle size distribution analyzer.

  The pH of the precoat agent can be 5-9.

  The zeta potential of the organic polymer particles of the precoat agent is preferably negative. In many cases, the zeta potential of the catalyst material in the liquid is also negative, and if the zeta potential of the organic polymer particles in the precoat agent is negative, the catalyst is avoided on the organic polymer in the catalyst supporting step described later. Can be directly supported on the ceramic. Therefore, even after the organic polymer is removed by combustion, the catalyst is hardly peeled off.

  A precoat agent can also contain additives, such as an emulsifier (surfactant). Examples of emulsifiers are anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and dispersion stabilizers. From the viewpoint of making the zeta potential of the emulsion negative, the emulsifier is preferably an anionic surfactant having a negative charge.

  Examples of anionic surfactants include rosinates such as potassium rosinate and sodium rosinate; fatty acid salts such as potassium oleate, potassium laurate, sodium laurate, sodium stearate, potassium stearate; sodium lauryl sulfate, etc. A sulfate ester salt of an aliphatic alcohol; an alkyl allyl sulfonate salt such as sodium dodecylbenzene sulfonate; and a phosphate ester such as lauryl phosphate, sodium lauryl phosphate, potassium lauryl phosphate. A plurality of emulsifiers can also be combined.

Examples of a method for impregnating the ceramic honeycomb structure 100 with the precoat agent include a dipping method, a brush coating method, an air spray method, and a roller coating method. The impregnation amount of the precoat agent can be adjusted so that the supported amount of the organic polymer is 1 to 50 g per 1 L apparent unit volume of the ceramic honeycomb structure 100 in the one end portion 100A. The amount of the organic polymer supported can be easily adjusted by adjusting the concentration of the organic polymer in the precoat agent and the viscosity of the precoat agent. The “apparent volume” in the present specification is a volume including not only a solid part made of a ceramic material but also a hollow part constituting a pore, each flow path, etc. The cubic volume is 1 m ³ regardless of the internal structure.

  In order to prevent the precoat agent from being applied to the remaining portion 100B, for example, a sponge impregnated with the precoat agent may be brought into contact with the outlet side end surface (one end surface) 100b of the ceramic honeycomb structure. By controlling the contact time, the impregnation distance from the outlet side end face (one end face) 100b to the inside can be controlled. In order to visualize the impregnated region, that is, the one end region, a dye or a pigment may be added to the precoat agent.

  Subsequently, the liquid as a dispersion medium is removed from the impregnated precoat liquid. Various known drying methods can be applied to the removal of the dispersion medium. As a result, as shown in FIG. 3B, in one end portion 100A, the organic polymer particles are aggregated / fused in the microcracks 100MC of the ceramic honeycomb structure 100 to form a film-like organic polymer portion 200F. It is formed. Note that not all of the applied organic polymer becomes the organic polymer part 200F in the microcrack, and a part of the organic polymer part 200FR is often formed on the ceramic surface other than the microcrack. On the other hand, as shown in FIG. 3A, in the remaining portion 100B, the inside of the microcrack 100MC is maintained as a void.

  Thereby, the honeycomb filter intermediate body 101 is completed. That is, the organic polymer is supported only on the one end side portion 100A and is not supported on the remaining portion 100B. The microcrack void volume in the one end side portion 100A is smaller than the microcrack void volume in the remaining portion 100B.

(Honeycomb filter manufacturing method and honeycomb filter)
Subsequently, a catalyst is supported on the honeycomb filter intermediate body 101. As an example of the supporting method, first, a catalyst support 302 called a “wash coat” is formed on the surface of the honeycomb filter intermediate body 101 and may function as a co-catalyst, and then the catalyst 304 is supported on the catalyst support 302. It is a method to make it. Further, the catalyst 304 may be directly supported on the honeycomb filter intermediate 101 without forming the catalyst support 302.

Examples of the catalyst support 302 are oxides such as alumina, silica, magnesia, titania, zirconia, ceria, La ₂ O ₃ , BaO, and zeolite, or composite oxides containing one or more of these. The catalyst support 302 can be formed by applying the slurry containing the oxide particles and the liquid to the honeycomb filter intermediate body 101, drying the liquid, and performing a heat treatment as necessary.

  The oxide particles may carry a catalyst in advance. Examples of the catalyst are particles of at least one metal element selected from the group consisting of Pt, Pd, Rh, silver, vanadium, chromium, manganese, iron, cobalt, nickel, copper, or zeolite catalyst. When the oxide particles do not carry these catalysts, the catalyst can be supported on the catalyst support after the wash coat. As an example of the catalyst loading method, a slurry containing a catalyst and a liquid is applied, the liquid is dried, and heat treatment is performed as necessary.

  Thus, the catalyst support 302 and the catalyst 304 are supported on the surface of the honeycomb filter intermediate body 101 as shown in FIGS. Here, as shown in FIG. 4B, in the one end side portion 100A, since the organic polymer part 200F is filled in the microcrack 100MC, the catalyst support 302 and the catalyst 304 enter the microcrack 100MC. It is suppressed. On the other hand, as shown in FIG. 4A, in the remaining portion 100B, since the organic polymer part 200F is not filled in the microcrack 100MC, the catalyst support 302 and the catalyst 304 enter the microcrack 100MC. Thus, the amount of catalyst supported can be increased in the remaining portion 100B.

(Heat treatment process)
Subsequently, heat treatment of the honeycomb filter intermediate body 101 is performed at 400 ° C. or higher in an oxidizing atmosphere such as the air, thereby filling the micro crack 100MC in the one end portion 100A as shown in FIG. 5B. The organic polymer portion 200F and the like thus formed are burned off, and the inside of the microcrack 100MC is returned to a void state. As shown in FIG. 5A, the state in which the catalyst or the like is filled in the microcrack 100MC in the remaining portion 100B does not change.

  In this way, the volume of the void portion of the microcrack 100MC is maintained in the one end portion 100A, and the honeycomb filter 102 in which the catalyst support 302 and the catalyst 304 are supported also in the microcrack 100MC in the remaining portion 100B. Complete. Note that the heat treatment in the step of supporting the catalyst can also serve as the heat treatment for burning off the organic polymer.

  In the completed honeycomb filter, the microcrack void volume in the one end side portion 100A is larger than the microcrack void volume in the remaining portion 100B.

Thereby, the linear expansion coefficient in the one end side part 100A becomes smaller than the linear expansion coefficient in the remaining part 100B. Specifically, the ratio of the linear expansion coefficient between the one end side portion 100A and the remaining portion 100B (linear expansion coefficient of the one end side portion 100A / linear expansion coefficient of the remaining portion 100B) is 0.2 to 0.8. Preferably, it is 0.4-0.8, More preferably, it is 0.6-0.8. It is preferable that this ratio is sufficiently small, since a sufficient effect of suppressing the generation of cracks during the honeycomb filter regeneration process by reducing the linear expansion coefficient of the one end portion 100A can be obtained. However, if this ratio is too small, the difference in the linear expansion coefficient at the boundary between the one end side portion 100A and the remaining portion 100B increases, and the distortion due to the difference in these linear expansion coefficients may increase. It is not preferable. For example, the linear expansion coefficient may be one end portion 0~3.5 × ¹⁰ -6 / K, a remaining portion is 2.5~6.0 × ^{10 -6} / K. The “linear expansion coefficient” may be a value in the axial direction of the filter or may be a value in the radial direction of the filter, and these are usually not the same as each other but are not greatly different.

  Furthermore, the catalyst loading per apparent volume in the one end side portion 100A of the completed honeycomb filter is smaller than the catalyst loading per apparent volume in the remaining portion 100B. As a result, the amount of catalyst supported per apparent volume of the honeycomb filter as a whole obtained in the present embodiment is smaller than when the catalyst is supported without pre-coating. When the reduction amount is large, the catalyst applied to the obtained honeycomb filter does not function sufficiently. In the present invention, the supported amount (g / L) of the catalyst per apparent volume as a whole of the honeycomb filter is 95% or more of the supported amount in the honeycomb filter manufactured without performing the pre-coating as described above. Is preferred. Even if the honeycomb filter is manufactured by performing exactly the same operation, if it is a manual operation as in the embodiment of the present specification, the amount of the catalyst supported per apparent volume varies by about 5 g / L. In some cases, this shift can be reduced by mechanization.

According to the present embodiment, the catalyst particles and the catalyst support material particles are filled in the microcracks in the one end side portion 100A by applying the precoat agent in advance only to the one end side portion 100A of the ceramic honeycomb structure. It is suppressed. Therefore, it is easy to maintain the microcrack void volume in the one end portion 100A even after the catalyst is supported. Therefore, even in the honeycomb filter supporting the catalyst, the linear expansion coefficient ( thermal expansion coefficient) in the one end portion 100A can be low, for example, 3.0 × 10 ⁻⁶ / K or less. In particular, the end portion on the gas outlet side often generates the greatest thermal stress during combustion of the soot, and the thermal shock resistance and the like can be improved by making this one end side portion the outlet side. The lower limit of the linear expansion coefficient of the one end side portion can be, for example, 0 / K. Further, in order to obtain such an effect, the axial length of the one end portion 100A is 10% or more, preferably 20% or more with respect to the total length of the axial length of the ceramic honeycomb structure 100. More preferably, it is 30% or more.

  In the remaining portion 100B, since the catalyst particles and the catalyst support material particles are supplied into the microcracks 100MC in the catalyst supporting step, the amount of the catalyst supported in the remaining portion 100B can be increased, The ability to burn firewood can be increased. If the length in the axial direction of the one end side portion 100A is long and the length of the remaining portion 100B is short, the amount of the catalyst supported on the honeycomb filter decreases. Therefore, in the present invention, the axial length of the one end side portion 100A is reduced. Is 70% or less, preferably 50% or less, and more preferably 40% or less with respect to the total axial length of the ceramic honeycomb structure 100.

Example 1
First, a ceramic honeycomb structure was prepared. This honeycomb structure was a cylindrical body having a diameter of 16.3 cm and a length of 14.0 cm, and the cell density was 59 cells / cm ² . The shape of each flow path was a hexagon. Ceramic _materials, Al _{2 (1-x)} a _{Mg x Ti (1 + y)} O 5-2x + 2y, x = 0.12, was y = 0.12. The porosity was 59%.
As a pre-coating agent, SMARTEX PA-6006HZ (styrene butadiene rubber latex (emulsion)) of Nippon A & L Co., Ltd., which is an aqueous emulsion, was prepared.

(Measurement of average diameter of organic polymer dispersoid in precoat agent)
Using a laser diffraction particle size distribution analyzer (Microtrack HRA (MODEL: 9320-X100) (Nikkiso Co., Ltd.)), a volume-based cumulative particle size distribution was obtained, and D50 was obtained.

  The measurement was performed as follows. About 0.2 g of a sample was dropped into the apparatus measurement unit and diluted with a solvent solution. The solvent solution was 0.2% sodium hexametaphosphate solution, and was dispersed by applying ultrasonic waves at 40 W for 300 seconds. A refractive index of 1.54 was used. The average diameter of the rubber dispersoid was 0.10 μm.

(Precoat)
The sponge impregnated with the precoat agent was brought into contact with one end surface of the ceramic honeycomb structure, and the length of the one end side portion 100A was controlled to 7.5 mm according to the contact time. Thereafter, the precoat agent was dried in hot air at 100 ° C. to obtain a honeycomb filter intermediate.

(Catalyst loading process)
The catalyst was supported on the honeycomb filter intermediate as follows. First, the entire honeycomb filter intermediate was immersed in an aqueous slurry containing 35% by weight of a zeolite catalyst (ZSM-5) for 2 minutes. Thereafter, excess slurry was removed by air blow and dried at 120 ° C. for 1 hour.

(Process of burning organic polymer by heat treatment)
The honeycomb filter intermediate after drying the slurry was heated in the air at 500 ° C. for 1 hour in an electric furnace to obtain a honeycomb filter.

(Measurement of linear expansion coefficient (CTE) after catalyst loading and heat treatment)
The linear expansion coefficient of the one end side portion and the remaining portion of the honeycomb filter was measured. The linear expansion coefficient was measured as follows. First, a cylindrical piece having a length of 20 mm and a radius of 7 mm was cut out from each of the one end side portion and the remaining portion from the honeycomb filter. Then, using a thermomechanical analyzer (TMA6300 manufactured by SII Technology Co., Ltd.), the temperature was raised from room temperature (25 ° C.) to 1000 ° C. at 600 ° C./h, and the expansion coefficient of the small piece in the temperature range of 40 to 800 ° C. It was measured.

(Catalyst loading)
Based on the difference in weight of the filter before and after catalyst loading, the catalyst loading per apparent unit volume of the entire filter was calculated.

(Acquisition method of maximum stress at one end during soot burning)
As software for performing the finite element method simulation, Mechanical (APDL) manufactured by ANSYS was used. A three-dimensional mesh was used for the calculation. The details of the structure of the honeycomb structure were as follows. The honeycomb structure had a diameter of 163.4 mm, a length of 140.5 mm, an external skin thickness of 0.5 mm, and a cell partition wall thickness of 0.33 mm. As a mechanical parameter, the elastic modulus was 1.5 GPa. The temperature gradient generated in the substrate was based on data obtained in a DTI (Drop To Idle) test in a state where 14 g / L of soot was accumulated.

(Example 2)
The same procedure as in Example 1 was performed except that the length of the one end side portion 100A was 15 mm.

(Example 3)
The same procedure as in Example 1 was performed except that the length of the one end side portion 100A was set to 30 mm.

(Example 4)
Example 1 was performed except that the length of the one end side part 100A was set to 60 mm.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that the entire honeycomb structure was precoated.

(Comparative Example 2)
Example 1 was performed except that the honeycomb structure was not precoated.
The results are shown in Table 1.

  DESCRIPTION OF SYMBOLS 100 ... Ceramic honeycomb structure, 100MC ... Micro crack, 101 ... Honeycomb filter intermediate body, 102 ... Honeycomb filter, 200 ... Precoat agent, 200P ... Organic polymer particle, 200F ... Organic polymer part, 302 ... Catalyst support agent, 304 ... Catalyst .

Claims (5)

Impregnating a columnar and porous ceramic honeycomb structure with a liquid containing organic polymer particles and a dispersion medium;
Removing the dispersion medium from the impregnated liquid, and
In the impregnation step, the liquid is impregnated only in one end side portion including one end face in the axial direction of the ceramic honeycomb structure,
The method for manufacturing a honeycomb filter intermediate body, wherein an axial length of the one end side portion is 10 to 70% with respect to a total axial length of the ceramic honeycomb structure. A columnar and porous ceramic honeycomb structure;
An organic polymer supported on the surface of the ceramic honeycomb structure,
The organic polymer is supported only on one end side portion including one end face in the axial direction of the ceramic honeycomb structure,
The honeycomb filter intermediate body, wherein an axial length of the one end side portion is 10 to 70% with respect to a total axial length of the ceramic honeycomb structure. Supporting the catalyst on the honeycomb filter intermediate according to claim 2;
Removing the organic polymer from the honeycomb filter intermediate carrying the catalyst. A columnar ceramic honeycomb structure;
A honeycomb filter comprising a catalyst supported on the ceramic honeycomb structure,
The void volume of the microcracks in the one end side portion including the one end surface in the axial direction of the honeycomb filter is larger than the void volume of the microcracks in the remaining portion of the honeycomb filter,
The supported amount of catalyst per apparent volume in the one end side portion is smaller than the supported amount of catalyst per apparent volume in the remaining portion,
The honeycomb filter according to claim 1, wherein an axial length of the one end side portion is 10 to 70% with respect to a total axial length of the ceramic honeycomb structure.   The honeycomb filter according to claim 4, wherein a linear expansion coefficient of the microcracks in the one end side portion is smaller than a linear expansion coefficient of the microcracks in the remaining portion.

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