JP2012075989A - Method for manufacturing honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a honeycomb structure with a capturing layer of high porosity arranged on the surface of a partition wall.SOLUTION: This method for manufacturing a honeycomb structure comprises the following steps: a step of making deposition of mixed particles to the surface of an internal partition wall of each cell of a sealed honeycomb base material by making an inflow of the mixed particles containing a ceramic particle and a pore-forming material into the residual cells from the end of the inflow side of the sealed honeycomb base material, and a step of obtaining the honeycomb structure by burning down the pore-forming material through heating the sealed honeycomb base material with the mixed particle deposited on the surface of the internal partition wall of the residual cells, thereby forming a capturing layer on the surface of the partition wall. In this case, the sealed honeycomb base material includes not only the honeycomb base material with the porous partition wall which compartmentalizes a plurality of cells serving as the flow path of a fluid, but also a sealed part arranged in the opening of the specified cells at the end of the fluid inflow side and in the opening of the residual cells at the end of the fluid outflow side.

Description

  The present invention relates to a method for manufacturing a honeycomb structure, and more particularly, to a method for manufacturing a honeycomb structure that manufactures a honeycomb structure in which a trapping layer having a high porosity is disposed on a partition wall surface.

  Gases discharged from internal combustion engines such as diesel engines and various combustion apparatuses contain a large amount of particulate matter (particulate matter (PM)) mainly composed of soot. If this PM is released into the atmosphere as it is, environmental pollution is caused. Therefore, a diesel particulate filter (DPF) for collecting PM is mounted on the exhaust gas exhaust system.

  As such a DPF, for example, “a porous partition wall that defines a plurality of cells that serve as fluid (exhaust gas, purified gas) flow paths and an outer peripheral wall located at the outermost periphery, A honeycomb structure having a plugged portion at an opening of a predetermined cell on the end face on the inflow side and an opening of a remaining cell on the end face on the outflow side of the fluid (purified gas) is used.

  When trying to collect PM in the exhaust gas using such a honeycomb structure, PM enters the inside of the porous partition wall, blocks the pores of the partition wall, and the pressure loss (pressure loss) increases rapidly. There was a problem that sometimes.

  In order to suppress such an increase in pressure loss, a trapping layer for trapping PM is provided on the surface of the partition wall, and the trapping layer prevents PM from entering the partition wall and suppresses an increase in pressure loss. (For example, refer to Patent Documents 1 and 2).

JP-A-10-249124 JP 2006-685 A

  In the manufacturing methods disclosed in Patent Documents 1 and 2, it is not always easy to form a trapping layer having a high porosity.

  The present invention has been made in view of the above-described problems, and provides a method for manufacturing a honeycomb structure capable of manufacturing a honeycomb structure in which a “trapping layer having a high porosity” is disposed on a partition wall surface. The purpose is to do.

[1] A honeycomb substrate having a porous partition wall that partitions and forms a plurality of cells serving as a fluid flow path, and an opening portion of a predetermined cell and an end surface on the fluid outflow side on an end surface on the fluid inflow side The mixed particles containing ceramic particles and pore former are allowed to flow into the remaining cells from the end surface on the inflow side of the plugged honeycomb base material provided with plugging portions in the openings of the remaining cells. The mixed particles are adhered to the partition wall surfaces in the cells of the plugged honeycomb substrate, and the plugged honeycomb substrate in which the mixed particles are adhered to the partition wall surfaces in the remaining cells is heated. And a step of burning the pore former to form a collection layer on the partition wall surface to obtain a honeycomb structure.

[2] When the plugged honeycomb substrate in which mixed particles adhere to the partition wall surfaces in the remaining cells is heated, the pore former is burned out and the ceramic particles are bonded to each other to be captured on the partition wall surfaces. The method for manufacturing a honeycomb structure according to [1], wherein the honeycomb structure is obtained by forming a collecting layer.

[3] The gas containing the mixed particles is caused to flow into the remaining cells from the end surface on the inflow side, thereby causing the mixed particles to flow into the remaining cells from the end surface on the inflow side. Or the manufacturing method of the honeycomb structure as described in [2].

[4] The method for manufacturing a honeycomb structured body according to any one of [1] to [3], wherein a median average particle diameter of the pore former is 0.002 to 10 μm.

[5] The method for manufacturing a honeycomb structure according to any one of [1] to [4], wherein the median average particle diameter of the ceramic particles is 0.5 to 15 μm.

[6] The honeycomb structure according to any one of [1] to [5], wherein a value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is 0.001 to 3. Manufacturing method.

[7] The method for manufacturing a honeycomb structure according to any one of [1] to [6], wherein the trapping layer of the obtained honeycomb structure has a porosity of 80 to 95%.

  According to the method for manufacturing a honeycomb structured body of the present invention, “mixed particles containing ceramic particles and pore former” are introduced into the remaining cells (inflow cells) from the end surface on the inflow side of the plugged honeycomb substrate. Injecting and adhering the mixed particles to the partition wall surfaces in the cells of the plugged honeycomb substrate, and heating the “plugged honeycomb substrate in which the mixed particles adhere to the partition wall surfaces in the inflow cell” And the step of burning the pore former to form a collection layer on the partition wall surface, a honeycomb structure having a collection layer with a high porosity of 80 to 95% can be produced. .

FIG. 3 is a perspective view schematically showing a honeycomb formed body manufactured in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. FIG. 3 is a schematic view showing a cross section of a honeycomb formed body manufactured in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. 1 is a perspective view schematically showing a plugged honeycomb substrate produced in the course of manufacturing a honeycomb structure in an embodiment of a method for manufacturing a honeycomb structure of the present invention. FIG. FIG. 3 is a schematic diagram showing a cross-section of a plugged honeycomb substrate produced in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. FIG. 3 is a schematic diagram for explaining a method of flowing mixed particles into a plugged honeycomb substrate in an embodiment of a method for manufacturing a honeycomb structure of the present invention. FIG. 3 is a schematic view showing a cross section of a “plugged honeycomb substrate to which mixed particles adhere” produced in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. 1 is a schematic view showing a cross section of a honeycomb structure manufactured by an embodiment of a method for manufacturing a honeycomb structure of the present invention. FIG. 6 is a schematic view showing a part of a cross section of a honeycomb structure manufactured by an embodiment of a conventional method for manufacturing a honeycomb structure. In Example 1, it is a schematic diagram for demonstrating the method to make mixed particle | grains flow in into a plugged honeycomb base material.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments, and a person skilled in the art can depart from the scope of the present invention. Based on this general knowledge, it should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

1. Manufacturing method of honeycomb structure:
One embodiment of a method for manufacturing a honeycomb structure of the present invention includes a honeycomb base material having porous partition walls that define and form “a plurality of cells that serve as fluid flow paths”, and an end face on the fluid inflow side ( Inflow of a plugged honeycomb substrate provided with a plugging portion at an opening of a predetermined cell (outflow cell) at one end face and an opening of the remaining cell at the end face on the fluid outflow side (the other end face) Step of allowing mixed particles containing ceramic particles and pore former to flow into the remaining cells (inflow cells) from the end face on the side and attaching the mixed particles to the partition wall surfaces in the cells of the plugged honeycomb substrate (Mixed particle adhering step) and heating the plugged honeycomb substrate with the mixed particles adhering to the partition wall surfaces in the remaining cells to burn away the pore former and form a trapping layer on the partition wall surfaces. A process of obtaining the structure (collecting layer forming process) Is shall. Here, the “end face” of the honeycomb substrate means a face on which cells are opened.

  According to the method for manufacturing a honeycomb structure of the present embodiment, from the end surface on the inflow side of the plugged honeycomb substrate, in the remaining cells (inflow cells), “mixed particles containing ceramic particles and pore former” And a process of adhering the mixed particles to the partition wall surfaces in the cells of the plugged honeycomb substrate and heating the “plugged honeycomb substrate in which the mixed particles adhere to the partition wall surfaces in the inflow cell” And forming a trapping layer on the partition wall surface by burning out the pore former, so that a honeycomb structure having a trapping layer having a high porosity of 80 to 95% can be produced. it can.

  Hereinafter, the manufacturing method of the honeycomb structure of the present embodiment will be described for each process.

(1) Honeycomb substrate manufacturing process;
First, a ceramic forming raw material containing a ceramic raw material is formed, and as shown in FIGS. 1 and 2, partition walls 1 for partitioning and forming a plurality of cells 2 serving as fluid flow paths and an outer peripheral wall 3 positioned at the outermost periphery. A tubular honeycomb formed body 100 is formed. In addition, the outer peripheral wall 3 does not need to be formed. FIG. 1 is a perspective view schematically showing a honeycomb formed body manufactured in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. FIG. 2 is a schematic diagram showing a cross section of a honeycomb formed body 100 manufactured in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention.

  The ceramic raw material contained in the ceramic forming raw material is preferably one containing at least one selected from the group consisting of cordierite forming raw material, cordierite, mullite, alumina, titania, silicon carbide, and aluminum titanate, More preferably, it is at least one selected from the group consisting of cordierite forming raw material, cordierite, mullite, alumina, titania, silicon carbide, and aluminum titanate, cordierite forming raw material, cordierite, mullite, alumina, Particularly preferred is one selected from the group consisting of titania, silicon carbide, and aluminum titanate. The cordierite forming raw material is a ceramic raw material blended so as to have a chemical composition that falls within a range of 42 to 56 mass% silica, 30 to 45 mass% alumina, and 12 to 16 mass% magnesia. It is fired to become cordierite.

  The ceramic forming raw material is preferably prepared by mixing the ceramic raw material with a dispersion medium, an organic binder, an inorganic binder, a pore former, a surfactant and the like. The composition ratio of each raw material is not particularly limited, and is preferably a composition ratio in accordance with the structure and material of the honeycomb structure to be manufactured.

  When forming the ceramic forming raw material, it is preferable to first knead the forming raw material to form a kneaded material, and the obtained kneaded material is formed into a honeycomb shape. There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned. A method for forming a kneaded clay to form a honeycomb formed body is not particularly limited, and a conventionally known forming method such as extrusion molding or injection molding can be used. For example, a method of forming a honeycomb formed body by extrusion molding using a die having a desired cell shape, partition wall thickness, and cell density can be cited as a suitable example. As the material of the die, a cemented carbide which does not easily wear is preferable.

  The shape of the honeycomb formed body is not particularly limited, and a cylindrical shape (columnar shape) as shown in FIG. 1, a cross section orthogonal to the central axis is an ellipse, a racetrack shape, a triangle, a quadrangle, a pentagon, a hexagon, an octagon Polygonal cylindrical shape (columnar shape) etc. can be mentioned. When the honeycomb structure to be manufactured is formed by joining a plurality of honeycomb segments, the shape of the honeycomb molded body is a triangle, a quadrangle, a pentagon, a hexagonal cross section perpendicular to the central axis, A polygonal cylindrical shape (columnar shape) such as an octagon is preferable.

  Further, after the above forming, the obtained honeycomb formed body may be dried. The drying method is not particularly limited, and examples thereof include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like. Among them, dielectric drying, microwave drying or It is preferable to perform hot air drying alone or in combination.

  Next, it is preferable to fire the obtained honeycomb formed body to obtain a honeycomb substrate. The honeycomb formed body may be fired after disposing the plugging portions on the honeycomb formed body.

  Further, before firing (main firing) the honeycomb formed body, it is preferable to calcine the honeycomb formed body. The calcination is performed for degreasing, and the method is not particularly limited as long as the organic matter (organic binder, dispersant, pore former, etc.) therein can be removed. In general, the combustion temperature of the organic binder is about 100 to 300 ° C., and the combustion temperature of the pore former is about 200 to 800 ° C. Therefore, the calcining conditions are about 200 to 1000 ° C. in an oxidizing atmosphere, 3 to It is preferable to heat for about 100 hours.

  Firing of the honeycomb formed body (main firing) is performed in order to sinter and densify the forming raw material constituting the calcined formed body to ensure a predetermined strength. Since the firing conditions (temperature, time, atmosphere) vary depending on the type of molding raw material, appropriate conditions may be selected according to the type. For example, when a cordierite forming raw material is used, the firing temperature is preferably 1410 to 1440 ° C. In addition, the firing time is preferably 4 to 6 hours as a keep time at the maximum temperature.

(2) plugging step;
Next, an opening of a predetermined cell (outflow cell) on one end face (end face on the fluid inflow side) of the honeycomb base material and a remaining cell (inflow cell) on the other end face (end face on the outflow side of fluid) ) Is filled with a plugging material, and the opening of a predetermined cell (outflow cell) on the end surface on the fluid inflow side and the opening of the remaining cell (inflow cell) on the end surface on the fluid outflow side A plugging portion is formed in

  When filling the honeycomb base material with the plugging material, first, the plugging material is filled on one end side, and then the plugging material is filled on the other end side. As a method of filling the plugging material on one end side, a sheet is attached to one end face of the honeycomb substrate, and holes are formed at positions where the “cells where plugging portions are to be formed” overlap in the sheet. A masking step for opening the sheet, and press-fitting the plugging material into the cells of the honeycomb base material by press-fitting the end of the honeycomb base material on the side where the sheet is attached into the container in which the plugging material is stored. And a press-fitting step of press-fitting into the step. When the plugging material is press-fitted into the cells of the honeycomb substrate, the plugging material passes through the holes formed in the sheet and is filled only in the cells communicating with the holes formed in the sheet.

  Further, the method of filling the plugging material on the other end side of the honeycomb substrate may be the same method as the method of filling the plugging material on the one end side of the honeycomb substrate. preferable. Moreover, the plugging material may be simultaneously filled in both ends of the honeycomb substrate.

  Next, the plugging material filled in the honeycomb substrate is dried to form plugged portions (see FIGS. 3 and 4), and the plugged honeycomb substrate 200 (see FIGS. 3 and 4). It is preferable to obtain The plugging material may be dried after filling both ends of the honeycomb base material, or after the plugging material filled in one end of the honeycomb base material is dried. The other end portion may be filled with a plugging material, and then the other end portion may be dried. Furthermore, the plugging material may be fired for the purpose of more reliably fixing. Further, the plugging material may be filled in the honeycomb formed body before drying or the dried honeycomb formed body, and the plugging material may be fired together with the honeycomb formed body before drying or the honeycomb formed body after drying. FIG. 3 is a perspective view schematically showing a plugged honeycomb substrate manufactured in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. FIG. 4 is a schematic diagram showing a cross-section of a plugged honeycomb substrate manufactured in the process of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention.

  As shown in FIGS. 3 and 4, the plugged honeycomb substrate 200 has inflow cells 2 a and outflow cells 2 b alternately arranged, and plugged portions 5 and cell openings at both end surfaces 11 and 12. A checkered pattern is preferably formed.

(3) mixed particle adhesion step;
In the mixed particle adhering step, mixed particles containing a ceramic particle and a pore former (mixed with a plurality of types of particles) are allowed to flow into the remaining cells from the end surface on the inflow side of the plugged honeycomb substrate. In this step, the mixed particles are adhered to the partition wall surfaces in the cells of the plugged honeycomb substrate. Thus, a high porosity collection layer can be formed by including a pore former in the mixed particles. Here, as shown in FIG. 4, the cell 2 that opens to the end surface 11 on the inflow side of the plugged honeycomb substrate 200 (the plugged portion 5 is not formed) is referred to as an “inflow cell 2 a”, The cell 2 that opens to the end surface 12 on the outflow side (no plugging portion 5 is formed) is referred to as an “outflow cell 2b”. The ceramic particles are preferably a ceramic powder in which a plurality of ceramic particles are aggregated.

  The median average particle size (median particle size) of the ceramic particles contained in the mixed particles is preferably 0.5 to 15 μm, more preferably 1 to 10 μm, and more preferably 2 to 5 μm. Particularly preferred. When the median average particle diameter of the ceramic particles is in such a range, there is an advantage that a trapping layer having good gas permeability and high PM trapping efficiency can be formed. If it is smaller than 0.5 μm, the ceramic particles are easily filled and the porosity may be lowered. If the pore size is larger than 15 μm, the pore forming material (mixed particles) flows into the cell and deposits on the cell surface, so that the resistance of the fluid acting on the ceramic particles is large, so that the pore forming material is crushed. In some cases, it is difficult to increase the porosity. Here, the median average particle diameter is the median particle diameter, and the particles are accumulated when the accumulated value is “50% of the total mass” by sequentially integrating the mass from the particles having the smallest particle diameter. The particle size of The median average particle diameter is a value measured with a laser diffraction particle size measuring machine. When forming the ceramic particles, the coarse particles are pulverized by a jet mill (dry type), a pot mill (wet type), etc. to obtain fine pulverized particles having a sharp particle size distribution, and the obtained pulverized particles are classified. Thus, it is preferable to obtain particles having a desired median average particle size (ceramic particles (powder)).

  The material of the ceramic particles contained in the mixed particles is preferably at least one selected from the group consisting of a cordierite forming raw material, cordierite, mullite, alumina, silicon carbide, and aluminum titanate. Furthermore, it is more preferable to select the material of the ceramic particles so that the material of the trapping layer to be formed is the same as the material of the honeycomb substrate.

  The median average particle diameter (median particle diameter) of the pore former contained in the mixed particles is preferably 0.002 to 10 μm, more preferably 0.002 to 7 μm, and 0.002 to A thickness of 5 μm is particularly preferable. When the median average particle diameter of the pore former is in such a range, it is possible to form a trapping layer having a high porosity, and when the mixed particles are allowed to flow into the cell, The ceramic particles can flow in a relatively uniformly dispersed state. If it is smaller than 0.002 μm, the pore former preferentially passes through the pores of the plugged honeycomb base material, and the effect of the pore former just introduced may not be exhibited. If it is larger than 10 μm, the dispersibility of the pore former with respect to the ceramic particles (dispersibility when mixed with the ceramic particles) is poor, and the pore former does not uniformly disperse within the mixed particles, so that a partially dense trap is obtained. A layered structure may be easily formed.

  As a material of the pore former contained in the mixed particles, any material can be used as long as it is burned off by heat treatment. For example, at least one selected from the group consisting of carbon black, coke, white powder, starch, natural resin, and synthetic resin. Preferably it is a seed. Among these, carbon black is preferable.

  The value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is preferably 0.001 to 3, more preferably 0.001 to 2, and 0.001 to 1. It is particularly preferred that A value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is within such a range, whereby a trapping layer having a high porosity can be formed. By making the dispersibility of the ceramic particles good, it is possible to allow the pore former to flow in a relatively uniformly dispersed state with respect to the ceramic particles when the mixed particles flow into the cell. . When the value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is smaller than 0.001, the pore former is too small with respect to the ceramic particle diameter. The pore former may not fulfill the role of forming pores, and even if the pore formers aggregate to form secondary particles, the secondary particle diameter is smaller than the ceramic particle diameter. (The effect of forming pores) may be reduced, and a dense collection layer may be formed. If the value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is larger than 3, the dispersibility of the pore former with respect to the ceramic particles (dispersibility when mixed with the ceramic particles) is poor. When the mixed particles are allowed to flow into the cell, it cannot be allowed to flow in a state where the pore former is sufficiently dispersed with respect to the ceramic particles, and a partially dense collection layer is likely to be formed. Sometimes.

  The ratio of the ceramic particle content to the pore former content in the mixed particles is preferably 20 to 400 parts by mass of the pore former with respect to 100 parts by mass of the ceramic particles, and the pore former with respect to 100 parts by mass of the ceramic particles. 30 to 350 parts by mass of the material is more preferable, and 50 to 200 parts by mass of the pore former is particularly preferable with respect to 100 parts by mass of the ceramic particles. When the pore former is less than 20 parts by mass with respect to 100 parts by mass of the ceramic particles, the porosity of the collection layer may be difficult to increase. Moreover, when there are more pore-forming materials with respect to 100 mass parts of ceramic particles than 400 mass parts, a collection layer may become weak.

  A method of flowing mixed particles into the cells of the plugged honeycomb substrate is not particularly limited, but a method of forming the aerosol by dispersing the mixed particles in a gas and flowing the aerosol into the cells Alternatively, there can be mentioned a method in which mixed particles are dispersed in a liquid to form a slurry and the slurry is allowed to flow into a cell. Among these, a method (aerosol method) is preferred in which aerosol (gas containing mixed particles) flows into the inflow cell from the end surface on the inflow side to cause the mixed particles to flow into the inflow cell from the end surface on the inflow side. . As an aerosol method, an aerosol containing mixed particles is formed in a container and the aerosol is supplied to a plugged honeycomb substrate, or an aerosol is formed using an ejector, and the aerosol is plugged into the plugged honeycomb. Examples thereof include a method of supplying the substrate (see FIG. 9 and the description thereof).

  Hereinafter, a method of forming an aerosol containing mixed particles in a container and supplying the aerosol to a plugged honeycomb substrate will be described.

  FIG. 5 is a schematic diagram for explaining a method of flowing mixed particles into a plugged honeycomb substrate in an embodiment of the method for manufacturing a honeycomb structure of the present invention. In FIG. 5, the plugged honeycomb substrate 200 is attached to the mixed particle supply device 21, and the aerosol 22 is caused to flow into the cell 2 (inflow cell 2 a). The mixed particle supply device 21 includes a container 23 in which an aerosol discharge port 24 and a gas supply port 25 are formed, a cylindrical body 26 disposed in the container 23 so as to communicate with the aerosol discharge port 24, and a gas in the container 23. A gas introduction pipe 27 inserted into the supply port 25 is provided. The plugged honeycomb substrate 200 is attached to a cylindrical body 26 composed of an inlet side cylindrical body 26a and an outlet side cylindrical body 26b. An inlet side tubular body 26 a is disposed on the end face 11 side, and an outlet side tubular body 26 b is disposed on the end face 12 side on the outflow side of the plugged honeycomb substrate 200. The plugged honeycomb base material 200 is “the aerosol discharged from the container 23 flows in from the“ inflow side end surface 11 ”through the inlet side cylindrical body 26 a, passes through the partition wall 1, and is“ outflow side end surface ”. 12 ”is arranged on the cylindrical body 26 so that the air flowing out from the outlet 12 passes through the outlet side cylindrical body 26b and is discharged to the outside. When the aerosol is supplied to the plugged honeycomb substrate, the air flowing out from the “outflow side end face 12” may contain mixed particles that have passed through the partition walls. The arrows in FIG. 5 indicate the flow of air or aerosol. FIG. 5 shows a state in which aerosol is formed in the container 23. Moreover, in FIG. 5, the cross section of each element is shown.

  When the aerosol is allowed to flow into the cell, the mixed particles are put into the container 23 and air is allowed to flow into the container 23 through the gas introduction pipe 27 to form an aerosol in the container 23, while the aerosol is formed through the cylindrical body 26. It is preferable to suck from the end face 12 side on the outflow side of the sealing honeycomb substrate 200. As a result, the “air containing the mixed particles (aerosol)” formed in the container 23 is efficiently moved in the cylindrical body 26, and the cells of the plugged honeycomb substrate 200 are moved from the end surface 11 on the inflow side. 2 (inflow cell 2a), the mixed particles can adhere to the surface of the partition wall 1 in the inflow cell 2a. At this time, the air in the aerosol passes through the partition walls 1 of the plugged honeycomb substrate 200, passes through the outflow cell 2b, and is discharged from the end surface 12 on the outflow side. The aerosol in the container 23 is formed by the air introduced into the container 23 through the gas introduction pipe 27 flowing in the container 23 while rolling up the mixed particles in the container 23.

  By causing the aerosol to flow into the cell (inflow cell) as described above, a “plugged honeycomb substrate (mixed particle-attached substrate) 300 having mixed particles attached” 300 as shown in FIG. 6 is obtained. Can do. The mixed particle adhering substrate 300 is one in which the mixed particles 13 adhere to the surface of the partition wall 1 in the inflow cell 2a of the plugged honeycomb substrate 200 (mixed particle layer formed by depositing mixed particles). FIG. 6 is a schematic diagram showing a cross section of a “plugged honeycomb substrate to which mixed particles adhere” produced in the course of manufacturing a honeycomb structure in an embodiment of the method for manufacturing a honeycomb structure of the present invention. is there.

  Conventionally, when an aerosol containing ceramic particles is caused to flow into the cells 32 (inflow cells 32a) of the plugged honeycomb substrate 201, and the ceramic particles are deposited (attached) on the surfaces of the partition walls 31 in the inflow cells 32a, As shown in FIG. 8, in the inflow cell 32a, the closer to the end surface 35 on the outflow side of the plugged honeycomb substrate 201, the thicker the ceramic particles (ceramic particle layer formed of ceramic particles) 33 tend to be deposited. there were. Therefore, in order to deposit a sufficient amount of mixed particles in a portion near the inflow side end surface 34 in the inflow cell 32a, the thickness of the mixed particle (mixed particle layer) 33 in a portion near the outflow side end surface 35 is deposited. Needed to be overly thick. Hereinafter, the layer of mixed particles deposited on the partition wall surface may be referred to as “mixed particle layer”. FIG. 8 is a schematic view showing a part of a cross section of a honeycomb structure manufactured by an embodiment of a conventional method for manufacturing a honeycomb structure.

  On the other hand, the manufacturing method of the honeycomb structure of the present embodiment adheres not only ceramic particles but also the pore former together with the pores (adhering mixed particles to the partition walls), so that only ceramic particles are deposited. The film thickness can be reduced as a whole as compared with the above. This is because a part of the amount of ceramic required for depositing a sufficient amount of mixed particles (ceramic particles) in a portion close to the end surface 34 on the inflow side can be covered by the pore former. This is because the amount of deposition can be reduced.

  The thickness of the mixed particle layer in the inflow cell is preferably adjusted so that the thickness of the collection layer of the honeycomb structure to be manufactured becomes a desired value.

  Further, in the method for manufacturing a honeycomb structure of the present embodiment, since the pore-forming material is contained in the mixed particles, the mixed particles are caused to flow into the plugged honeycomb substrate at a large flow rate in order to shorten the manufacturing time. However, since the portion where the pore former is present finally becomes pores, the collection layer is not densified, and the initial pressure loss can be reduced when the obtained honeycomb structure is used as a filter. it can.

In the method for manufacturing a honeycomb structured body of the present embodiment, the density (mixed particle mass / air volume) of “air containing mixed particles (aerosol)” formed in the container 23 is 1 g / m ³ or more and 1600 g / preferably m ³ or less, 20 g / ^{m 3} or more, further preferably 1600 g / ^{m 3} or less, 20 g / ^{m 3} or more, particularly preferably 1400 g / ^{m 3} or less. If it is less than 1 g / m ³ , it may take a long time for the mixed particles to adhere to the plugged honeycomb substrate. If it is greater than 1600 g / m ³ , the ceramic particles may aggregate to form a trapping layer in which irregularities are irregularly formed.

  The flow rate of the aerosol in the cell is preferably 0.2 (m / sec) or more and 100 (m / sec) or less, more preferably 0.2 (m / sec) or more and 95 (m / sec) or less. More preferably, it is particularly preferably 0.2 (m / sec) or more and 90 (m / sec) or less. If it is less than 0.2 (m / sec), the raw material yield may be lowered because the raw material cannot be efficiently flowed into the cell. If it is larger than 100 (m / sec), the ceramic particles may be easily deposited on the outlet side (the end face side of the plugged honeycomb substrate on the outflow side) in the cell, and further, the ceramic particles or pores may be formed. The material tends to deposit densely, and the mixed particle layer may become dense.

  Further, “(ceramic particle average particle diameter) / (base material average pore diameter)” is preferably in a range larger than 0.02 and smaller than 1.5, in a range larger than 0.02 and smaller than 1. More preferably, it is more preferably in the range of more than 0.02 and less than 0.5. When the ceramic particle average particle diameter / base material average pore diameter is 0.02 or less, the ceramic particles pass through the pores to reduce the yield, or the ceramic particles do not form a layer on the surface of the partition walls. There is a possibility that the pore diameter may be reduced by adhering inside. On the other hand, when the ceramic particle average particle diameter / base material average pore diameter is 1.5 or more, when used as a filter, PM passes through the collection layer and blocks the pores of the partition walls, thereby increasing the pressure loss of the filter. There is a possibility that it becomes easy to do. Here, “ceramic particle average particle size / base material average pore size” is the value of the ratio of the average particle size of the ceramic particles to the average pore size of the plugged honeycomb base material. More precisely, the average pore diameter of the base material is the average pore diameter of the partition walls forming the inflow cells of the honeycomb structure.

In particular, the aerosol density, 1 g / ^{m 3} or more, and 1600 g / ^{m 3} or less, the flow velocity in the aerosol cell, 0.2 m / sec. 100 m / sec. By setting the average particle diameter of the ceramic particles / the average pore diameter of the base material to a range larger than 0.02 and smaller than 1.5, the charged raw materials (ceramic particles) can be satisfactorily applied to the partition wall surface in the cell. It adheres and is used for the formation of a collection layer efficiently, and the raw material yield increases. This is presumably because the ceramic particles contained in the sucked gas adhere to the pore inlets of the partition walls and form a layer covering the pore inlets.

  After adhering and depositing the mixed particles on the partition wall surfaces in the cells of the plugged honeycomb substrate, the end surface on the inflow side of the plugged honeycomb substrate (on the side where the aerosol was fed) It is preferable to remove the mixed particles remaining on the end face.

(4) Collection layer forming step;
The trapping layer forming step heats the plugged honeycomb substrate with the mixed particles adhering to the partition wall surface in the remaining cells (inflow cells), burns the pore former, and forms the trap layer on the partition wall surface This is a step of obtaining a honeycomb structure. When heating the plugged honeycomb substrate to which the mixed particles adhere, heating is performed at a temperature at which the pore former burns away. Furthermore, after that, it is preferable that the temperature is raised and heating is performed at a temperature at which the ceramic particles are sintered (ceramic particles are bonded to each other). The ceramic particles do not have to be bonded, but are preferably bonded by sintering or the like. In addition, you may heat-process at once at the temperature which a ceramic particle sinters. Moreover, the temperature at which the ceramic particles are sintered is preferably lower than the firing temperature when the plugged honeycomb substrate is produced.

  As a condition for burning out the pore former, for example, it is preferable to heat at 400 to 800 ° C. for 0.5 to 20 hours in an air atmosphere. Conditions for sintering the ceramic particles (bonding the ceramic particles to each other) vary depending on the material of the plugged honeycomb substrate and the material of the ceramic particles. For example, in an air atmosphere, the conditions are 1 to 20 at 1200 to 1300 ° C. It is preferable to heat for a time. The method of burning the pore former and sintering the ceramic particles is not particularly limited, and examples thereof include a method of heating using an electric furnace, a gas furnace or the like.

  Further, after the plugged honeycomb substrate to which the mixed particles are adhered is heat-treated to form a collection layer, the outer peripheral portion is ground and adjusted to a desired shape, and then a coating material is applied to the outer periphery, A honeycomb structure may be manufactured by drying and disposing the outer peripheral portion. When the outer peripheral portion is provided, unevenness on the outer periphery of the honeycomb structure is reduced. As the coating material, a mixture of inorganic fiber, colloidal silica, clay, SiC particles, organic binder, foamed resin, dispersant, water, or the like can be used. The method of applying the coating material is not particularly limited, and a method of coating the plugged honeycomb substrate with the collection layer formed and the outer peripheral portion ground with a rubber spatula or the like while rotating on the wheel. Can be mentioned.

  Even if one honeycomb structure manufactured as described above is used as one honeycomb segment, a plurality of honeycomb segments are produced, and the plurality of honeycomb segments are joined together with a joining material to produce a joined honeycomb structure. Good.

2. Honeycomb structure:
As shown in FIG. 7, a honeycomb structure 400 manufactured by the method for manufacturing a honeycomb structure of the present invention has a honeycomb base material having porous partition walls 1 for partitioning a plurality of cells 2 serving as fluid flow paths. 4 and the opening of a predetermined cell 2 (outflow cell 2b) on the end surface 11 on the fluid inflow side and the opening of the remaining cell 2 (inflow cell 2a) on the end surface 12 on the outflow side of fluid. The sealing part 5 and the collection layer 14 arrange | positioned in the whole surface of the partition 1 in the cell 2 (inflow cell 2a) are provided.

  In the honeycomb structure 400, the trapping layer has a porosity of preferably 80 to 95%, more preferably 80 to 90%, and particularly preferably 85 to 90%. If it is less than 80%, the initial pressure loss may increase. If it is larger than 95%, the trapping layer tends to be brittle. The porosity of the collection layer is calculated by image analysis of the SEM image of the collection layer. Specifically, the honeycomb structure is cut by a plane orthogonal to the cell extending direction, and the area ratio is calculated from an image of a polished surface (two-dimensional) obtained by polishing the cut surface.

  In the honeycomb structure 400, the thickness of the collection layer in the thickest part of the collection layer in the inflow cell is preferably 10 to 100 μm, more preferably 15 to 80 μm, and more preferably 20 to 20 μm. It is especially preferable that it is 50 micrometers. Further, the thickness of the collecting layer in the thinnest part of the collecting layer in the inflow cell is preferably 5 to 50 μm, more preferably 10 to 40 μm, and more preferably 10 to 30 μm. Is particularly preferred. The average thickness of the collection layer is preferably 10 to 100 μm, more preferably 10 to 80 μm, and particularly preferably 10 to 50 μm. Thus, since the thickness in the thickest part of the collection layer can be reduced, the average thickness of the collection layer can be reduced, and the initial pressure loss (initial pressure loss) during exhaust gas treatment can be reduced. Can be lowered. Moreover, since the thickness of the thickest part of a collection layer can be made thin, the adhesion amount of the mixed particle which is a raw material of a collection layer can be reduced. Moreover, since the average thickness of a collection layer is thin, the space volume of an inflow cell becomes large and it can suppress the obstruction | occlusion by accumulation of ash. The thickest part of the collection layer in the inflow cell is usually the part closest to the end surface on the outflow side of the honeycomb structure in the inflow cell. Further, the thinnest portion of the collection layer in the inflow cell is usually the portion closest to the end surface on the inflow side of the honeycomb structure in the inflow cell. The term “thickness of the collection layer” means the thickness of the portion sandwiched between the space in the inflow cell and the partition wall (including the collection layer disposed on the surface of the plugging portion). Absent). The thickness of the collection layer can be obtained by image processing of an image of a cross section (cross section parallel to the thickness direction) of the collection layer. For example, the thickness of the collection layer can be measured using an image measurement system NEXIV (Nikon Corporation). Specifically, the thickness of the partition wall provided with the collection layer (the total thickness of the collection layer and the partition wall) is measured, and the thickness of only the partition wall is measured separately. It can be calculated by subtracting the thickness of only the partition wall from the thickness of the disposed partition wall. The partition wall provided with the collection layer is cut using a diamond cutter, and the observed cross-sectional image is an actual image of the cut surface.

  In the honeycomb structure 400, conditions other than the structure, shape, and other conditions derived from the method for manufacturing the honeycomb structure of the present invention are not particularly limited, and a honeycomb filter such as DPF (or a substrate of the honeycomb catalyst body) ) As a condition in a known honeycomb structure used.

  When exhaust gas containing PM is processed using a conventional honeycomb structure without a trapping layer as a filter, PM enters the pores of the partition walls and closes the pores, resulting in rapid initial pressure loss. There was a problem of rising. In contrast, in the honeycomb structure manufactured by the method for manufacturing a honeycomb structure according to the present invention, since the collection layer is formed on the surface of the partition wall in the inflow cell, PM is collected by the collection layer. Intrusion into the pores of the partition walls can be prevented, and a rapid increase in initial pressure loss can be suppressed.

  The honeycomb structure of the present invention may have a honeycomb base material obtained by firing “one molded body”, or a honeycomb obtained by firing such a “one molded body” A bonded honeycomb structure in which the honeycomb structure having a substrate is a honeycomb segment and the side surfaces of the plurality of honeycomb segments are bonded to each other by a bonding material may be used.

  Hereinafter, the manufacturing method of the honeycomb structure of the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
Silicon carbide and metal silicon were used as ceramic raw materials. The mass ratio of silicon carbide to metal silicon was 8: 2 (silicon carbide: metal silicon). To 100 parts by mass of the ceramic raw material, 13 parts by mass of a pore former, 35 parts by mass of a dispersion medium, 6 parts by mass of an organic binder, and 0.5 parts by mass of a dispersant were mixed and kneaded to prepare a clay. Coke having an average particle size of 10 μm was used as the pore former, water was used as the dispersion medium, hydroxypropyl methylcellulose was used as the organic binder, and ethylene glycol was used as the dispersant. The average particle diameter of coke is a value measured by a laser diffraction method.

  Next, the kneaded material was extruded using a mold having a predetermined slit width to obtain a honeycomb formed body having a square cell shape and a quadrangular prism shape as a whole. The obtained honeycomb formed body was dried with a microwave dryer and further completely dried with a hot air dryer. Thereafter, a mask was applied so that cells with a mask and cells without a mask were alternately arranged in a part of the plurality of cell openings on one end face of the honeycomb formed body. And the edge part by which the mask was given was immersed in the plugging slurry containing a silicon carbide, and the opening part of the cell which has not been masked was filled with the plugging slurry. Similarly, the plugging slurry was filled in the cell opening on the other end face of the honeycomb formed body. Thereby, the both end surfaces of the obtained honeycomb structure were in a state in which a checkered pattern was formed by the opening portions and the plugging portions of the cells. Thereafter, the honeycomb formed body filled with the plugging slurry was dried and fired at 1430 ° C. for 10 hours in an argon atmosphere. Thus, a quadrangular columnar plugged honeycomb substrate was produced. The average pore diameter (of the partition walls) of the obtained plugged honeycomb substrate was 13 μm. The average pore diameter is a value measured by the following method.

  Next, the mixed particles were attached to the partition wall surfaces in the cells of the plugged honeycomb substrate using the “method of forming an aerosol using an ejector and supplying the aerosol to the plugged honeycomb substrate”. . This will be described with reference to FIG. FIG. 9 is a schematic diagram for explaining a method of flowing mixed particles into a plugged honeycomb substrate in Example 1. FIG.

In FIG. 9, the plugged honeycomb substrate 200 is mounted on the ejector-type mixed particle supply device 51, and the aerosol 52 is caused to flow into the cells (inflow cells). The ejector-type mixed particle supply device 51 includes a container 53 in which mixed particles 57 are placed, an ejector 54 that sucks the mixed particles 57 contained in the container 53, mixes them with air 58 a, and discharges them as an aerosol 52, and an ejector 54. The plugged honeycomb substrate 200 is disposed so that the aerosol 52 discharged from the inlet flows and “the aerosol 52 flows in from the end surface 11 on the inflow side and the air 58b that has passed through the partition wall flows out from the end surface 12 on the outflow side”. And a cylindrical body 56 to be provided. The air 58 b flowing out from the end surface 12 on the outflow side of the plugged honeycomb substrate 200 was discharged to the outside through the tubular body 56. The plugged honeycomb substrate 200 was fixed to the tubular body 56 by the fixing portion 55. Further, in order to introduce the aerosol 52 discharged from the ejector 54 into the plugged honeycomb substrate 200, the aerosol 52 was sucked through the tubular body 56 from the end surface 12 side on the outflow side of the plugged honeycomb substrate 200. Suction was performed at a flow rate of 0.4 m ³ / min. The aerosol density was 100 g / m ³ .

  In this way, the aerosol was allowed to flow into the cell (inflow cell) to obtain a “plugged honeycomb substrate (mixed particle-adhered substrate) to which mixed particles adhered”. The mixed particle-adhered substrate is one in which mixed particles adhere to the surface of the partition walls in the inflow cell of the plugged honeycomb substrate (mixed particle layer formed by depositing mixed particles). The time required for the mixed particles to flow into the plugged honeycomb substrate was 0.4 minutes.

  As the mixed particles, silicon carbide particles (powder) having a median average particle diameter of 2.6 μm and carbon black (powder) having a median average particle diameter of 0.014 μm were mixed. The median average particle diameter is a value measured by the following method. The volume ratio of silicon carbide particles to carbon black was 1.0: 1.8 (silicon carbide particles: carbon black). The specific gravity of silicon carbide particles is 3.2, and the specific gravity of carbon black is 1.8. Moreover, the amount of the mixed particles adhering to the mixed particle-adhering substrate was 4 g / liter (the mass of the mixed particles per liter of the mixed particle-adhering substrate).

The obtained mixed particle-adhered substrate was heated at 700 ° C. for 3 hours, and further heated at 1300 ° C. for 1 hour to obtain a honeycomb structure provided with a collection layer. The obtained honeycomb structure had a quadrangular prism shape, a square with a length in the central axis direction of 152.4 mm and a cross section perpendicular to the central axis of 36.2 × 36.2 mm. The cell density was 46.5 cells / cm ² and the partition wall thickness was 300 μm. Further, the mass of the entire collection layer disposed in the honeycomb structure was 0.4 g. Moreover, the porosity of the collection layer was 90%. The porosity of the collection layer is a value measured by the following method.

  With respect to the obtained honeycomb structure, “the initial pressure loss increase rate” and “the wrinkled pressure loss reduction rate” were measured by the following methods. The obtained results are shown in Table 1. In Table 1, “aggregate” indicates ceramic particles (silicon carbide particles or cordierite particles) contained in the mixed particles. The “pore ratio / aggregate median average particle diameter ratio” is a value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the aggregate. The “volume ratio” in the column of “pore forming material / aggregate” is a value of the ratio of the volume of the pore forming material contained in the mixed particles to the volume of the aggregate contained in the mixed particles (pore forming material). / Aggregate). The “mass ratio” in the column of “pore forming material / aggregate” is a value of the ratio of the mass of the pore forming material contained in the mixed particles to the mass of the aggregate contained in the mixed particles (pore forming material). / Aggregate). The “mixed particle adhesion amount” is the amount of mixed particles adhering to the mixed particle adhesion substrate, and is indicated by the mass of the mixed particles per liter of the mixed particle adhesion substrate.

(Aerosol density)
The aerosol density was determined by the equation “mass of the entire collection layer [g] ÷ (aspiration flow rate [m ³ / min] × film formation time [min])”.

(Median average particle size)
Based on JIS R 1629, the measurement was performed with a laser diffraction / scattering particle size distribution measuring apparatus (manufactured by Horiba, Ltd .: LA-920 (trade name)).

(Average pore diameter)
A 5 mm × 5 mm × 15 mm sample was cut out from the plugged honeycomb substrate, and the average particle size was measured with a mercury porosimeter (manufactured by Shimadzu Corporation, mercury porosimeter MIC-9405 (trade name)).

(Porosity of collection layer)
Using a scanning electron microscope “S-3200N (manufactured by Hitachi, Ltd.)”, a polished surface obtained by cutting the honeycomb structure at a plane orthogonal to the cell extending direction and polishing the cut surface is 300 times. The observed image was stored as electronic data, and the data was analyzed with image analysis software (“Win ROOF” manufactured by Mitani Corporation). The area of the trapping layer and the pores present therein was calculated, and the porosity was calculated from the area ratio.

(Pressure loss reduction rate with hook)
A honeycomb structure with a trapping layer and a honeycomb structure without a trapping layer are mounted directly below the turbocharger of a common rail 2.0L diesel engine, and the engine is operated at an engine speed of 2000 rpm and a constant torque of 50 Nm. The pressure loss (pressure loss) in a state where 4 g / L of soot was deposited was measured. “L” means “liter”. Then, the difference between the pressure loss of the honeycomb structure without the collection layer and the pressure loss of the honeycomb structure with the collection layer is divided by the pressure loss of the honeycomb structure without the collection layer. The doubled value (value expressed as a percentage) was defined as the pressure loss reduction rate [%]. The soot accumulation amount is the soot accumulation amount [g] per 1 L of the honeycomb structure. Here, “reduction pressure loss reduction rate with wrinkles” refers to “the collection layer with wrinkles” with respect to the pressure loss of the “honeycomb structure without the collection layer” with wrinkles as described above. The degree of the small pressure loss of the “honeycomb structure” is shown. As for the pressure loss reduction rate with a flange, 30% or more is acceptable.

(Initial pressure loss increase rate)
About the honeycomb structure provided with the collection layer and the honeycomb structure not provided with the collection layer, the pressure loss at an air volume of 1 m ³ / min was measured using a large wind tunnel device. Then, the difference between the pressure loss of the honeycomb structure without the collection layer and the pressure loss of the honeycomb structure with the collection layer is divided by the pressure loss of the honeycomb structure without the collection layer. The doubled value (value expressed as a percentage) was defined as the initial pressure loss increase rate [%]. Here, the rate of increase in the initial pressure loss is the magnitude of the pressure loss of the “honeycomb structure with the collection layer” relative to the pressure loss of the “honeycomb structure without the collection layer” in the state without wrinkles. This indicates the degree (larger degree) of. The initial pressure loss increase rate is 5% or less.

(Examples 2 to 18)
A honeycomb structure was manufactured in the same manner as in Example 1 except that the conditions regarding “mixed particles” flowing into the plugged honeycomb substrate and the mixed particle adhesion amount were changed as shown in Table 1. By the above method, “the porosity of the trapping layer”, “the pressure loss reduction rate with the flange”, and “the initial pressure loss increase rate” were measured. The results are shown in Table 1.

(Comparative Examples 1-3)
When forming the collection layer, silicon carbide (particles) or cordierite (particles) was used instead of the mixed particles (excluding the pore former from the mixed particles, silicon carbide particles (powder) or cordierite particles ( A honeycomb structure was manufactured in the same manner as in Example 1 except that (powder) was used alone. By the above method, “the porosity of the trapping layer”, “the pressure loss reduction rate with the flange”, and “the initial pressure loss increase rate” were measured. The results are shown in Table 1.

  From Examples 1 to 18 and Comparative Examples 1 to 3, mixed particles containing silicon carbide and a pore former are attached to the partition walls to form a collection layer, and only silicon carbide or cordierite is attached to the partition walls. Thus, it can be seen that the porosity of the collection layer increases and the rate of increase in the initial pressure loss decreases as compared to the formation of the collection layer.

  The method for manufacturing a honeycomb structure of the present invention can be suitably used for manufacturing a honeycomb structure (filter) for purifying gas discharged from an internal combustion engine such as a diesel engine or various combustion apparatuses. .

1: partition wall, 2: cell, 2a: inflow cell, 2b: outflow cell, 3: outer peripheral wall, 4: honeycomb substrate, 5: plugging portion, 11: end surface on the inflow side, 12: end surface on the outflow side, 13: mixed particles, 14: collection layer, 21: mixed particle supply device, 22: aerosol, 23: container, 24: aerosol discharge port, 25: gas supply port, 26: cylindrical body, 26a: inlet side cylindrical shape Body, 26b: outlet side cylindrical body, 27: gas introduction pipe, 31: partition wall, 32: cell, 32a: inflow cell, 33: ceramic particles, 34: end surface on the inflow side, 35: end surface on the outflow side, 51: Ejector type mixed particle supply device, 52: aerosol, 53: container, 54: ejector, 55: fixed part, 56: cylindrical body, 57: mixed particle, 58a, 58b: air, 100: honeycomb formed body, 200, 201 : Plugged honeycomb substrate, 300: mixed grain Deposition substrate, 400: honeycomb structure.

Claims (7)

A honeycomb substrate having a porous partition wall that defines a plurality of cells serving as fluid flow paths, and a predetermined opening of the cell on the end surface on the fluid inflow side and a remaining portion on the end surface on the fluid outflow side A plugged honeycomb substrate provided with a plugging portion in the opening of the cell, the mixed particles containing ceramic particles and pore former are allowed to flow into the remaining cells from the end surface on the inflow side, Adhering the mixed particles to the partition wall surfaces in the cells of the plugged honeycomb substrate;
A step of heating a plugged honeycomb base material in which mixed particles adhere to the partition wall surfaces in the remaining cells to burn off the pore former to form a collection layer on the partition wall surfaces to obtain a honeycomb structure. The manufacturing method of the honeycomb structure which has these.   When the plugged honeycomb substrate in which mixed particles adhere to the partition wall surfaces in the remaining cells is heated, the pore former is burned out and the ceramic particles are bonded together to form a collection layer on the partition wall surfaces. The method for manufacturing a honeycomb structure according to claim 1, wherein the honeycomb structure is formed to obtain a honeycomb structure.   The gas containing the mixed particles is caused to flow into the remaining cells from the end surface on the inflow side, thereby causing the mixed particles to flow into the remaining cells from the end surface on the inflow side. The manufacturing method of the honeycomb structure as described.   The method for manufacturing a honeycomb structure according to any one of claims 1 to 3, wherein a median average particle diameter of the pore former is 0.002 to 10 µm.   The method for manufacturing a honeycomb structured body according to any one of claims 1 to 4, wherein the median average particle diameter of the ceramic particles is 0.5 to 15 µm.   The method for manufacturing a honeycomb structure according to any one of claims 1 to 5, wherein a value obtained by dividing the median average particle diameter of the pore former by the median average particle diameter of the ceramic particles is 0.001 to 3.   The method for manufacturing a honeycomb structure according to any one of claims 1 to 6, wherein a porosity of the collection layer of the obtained honeycomb structure is 80 to 95%.

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