JP2011235283A - Honeycomb structure, method for production of the honeycomb structure, honeycomb filter, and method for production of the honeycomb filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure which has high porosity, can catch a mass of PM (particulate matters) and has less pressure loss.SOLUTION: There is provided a columnar honeycomb structure having multiple cells disposed in parallel with a wall portion interposed therebetween along the longitudinal direction thereof. The honeycomb structure is characterized by mainly comprising the integrally formed inorganic fibers.

Description

The present invention relates to a honeycomb structure used for the purpose of purifying exhaust gas discharged from an internal combustion engine such as a diesel engine, a honeycomb structure manufacturing method, a honeycomb filter, and a honeycomb filter manufacturing method.

The exhaust gas discharged from an internal combustion engine such as a diesel engine contains particulate matter (hereinafter also referred to as PM) such as soot. In recent years, it has been a problem that this PM is harmful to the environment and the human body. ing.
Therefore, various filters using ceramic honeycomb filters made of cordierite or silicon carbide have been proposed as filters for collecting PM in the exhaust gas and purifying the exhaust gas. In addition, various laminated honeycomb filters produced by laminating laminated members having through holes have been proposed (see, for example, Patent Document 1).

Fig. 10 (a) is a perspective view schematically showing a specific example of a laminated honeycomb filter produced by laminating laminated members made of sheet-like inorganic fiber aggregates having through holes. ) Is a cross-sectional view taken along line AA. (C) is an enlarged sectional view of a portion indicated by B in (b).

The honeycomb filter 100 has a cylindrical shape in which a large number of cells 111 whose one ends are sealed are arranged in parallel in the longitudinal direction with a wall 113 therebetween.
That is, as shown in FIG. 10B, the cell 111 is sealed at either end corresponding to the inlet side or the outlet side of the exhaust gas, and the exhaust gas flowing into one cell 111 is always After passing through the wall portion 113 that separates the cells 111, it flows out of the other cells 111, and the wall portion 113 functions as a filter.

As shown in FIGS. 10A and 10B, the honeycomb filter is a laminated body formed by laminating sheet-like laminated members 110a having a thickness of 0.1 to 20 mm, and has through holes in the longitudinal direction. The stacked members 110a are stacked so that the two overlap each other.
Here, the laminated members are laminated so that the through holes overlap each other means that the laminated members are laminated so that the through holes formed in the adjacent laminated members communicate with each other.
Further, the end laminated member 10b formed so that the through-holes have a checkered pattern is laminated at the end, and one end of the cell 111 is sealed with the end laminated member 10b. .

In order to make each laminated member into a laminated body, the laminated member 110a and the end laminated member 10b are laminated in a casing (metal cylindrical body) to be mounted on the exhaust pipe, and pressure is applied. Thereby, the honeycomb filter 100 is formed.

When an exhaust gas purification filter composed of a honeycomb filter having such a configuration is installed in the exhaust passage of an internal combustion engine, PM in the exhaust gas discharged from the internal combustion engine is captured by the wall 113 when passing through the honeycomb filter. The exhaust gas is purified.

In particular, a honeycomb filter made of an inorganic fiber aggregate has a high porosity and can incorporate a large amount of PM into the wall. Therefore, compared with a honeycomb filter having a low porosity, the contact probability between the catalyst supported in the wall and the PM is increased, so that the energy for burning the PM can be kept low.

International Publication No. 2005/000445 Pamphlet

Here, the laminated member 110a made of an inorganic fiber aggregate constituting the honeycomb filter 100 is manufactured by making a paper using a mesh obtained by adding a sufficient amount of water to an inorganic fiber, an organic binder, an inorganic binder, or the like. However, when the laminated member 110a is manufactured by making the slurry, inorganic fibers tend to be more densely distributed on the surface portion of the laminated member 110a than inside.

When the laminated member 110a is laminated and a honeycomb filter is formed by applying pressure, the surface portions where the inorganic fibers are densely distributed among the laminated members 110a are compressed adjacent to each other. In the laminated interface 114 (see FIG. 10C) that is the boundary portion of the inorganic fibers, the inorganic fibers are more densely distributed than the other portions.

Here, since it is more difficult for the exhaust gas to pass through the part where the inorganic fibers are densely distributed than the exhaust gas passes through the other part, there is a laminated interface where such inorganic fibers are densely distributed. If present, the pressure loss of the entire honeycomb filter will increase.

Honeycomb filters made of inorganic fiber aggregates have a lower pressure loss than honeycomb filters using ceramics, but if there are parts where inorganic fibers are densely distributed, they are preferential to parts where inorganic fibers are sparsely distributed. In some cases, exhaust gas flowed, the entire wall could not be used effectively, and the energy of PM combustion could not be kept low. Therefore, in the case of manufacturing a honeycomb filter using inorganic fibers, there has been a demand for a method for making the honeycomb filter more homogeneous and having a low pressure loss.

As a result of intensive studies to solve the above problems, the present inventors have produced a honeycomb structure mainly composed of inorganic fibers and integrally formed with the inorganic fibers. Since there is no interface, there is no portion where inorganic fibers are relatively densely distributed inside the honeycomb structure, and there is no increase in pressure loss caused by the presence of the above portion, so the honeycomb structure has a low pressure loss. The honeycomb structure of the present invention was completed.
In addition, a honeycomb filter in which one end of a cell of the honeycomb structure having such a low pressure loss is plugged is also completed.
Further, the present inventors have also found a method for manufacturing such a honeycomb structure and a honeycomb filter with low pressure loss.

That is, the honeycomb structure of the first aspect of the present invention is a columnar honeycomb structure in which a plurality of cells are arranged in parallel in the longitudinal direction with a wall portion therebetween, and the honeycomb structure is mainly composed of inorganic fibers. The inorganic fibers are integrally formed.

The honeycomb structure according to the first aspect of the present invention is formed of the inorganic fiber and the inorganic material, and the inorganic fibers are preferably fixed to each other via the inorganic material.

In the honeycomb structure of the first aspect of the present invention, the inorganic substance is present at or near the intersection of the inorganic fibers, and
It is desirable that the inorganic material is localized at the intersection between the inorganic fibers or in the vicinity thereof.

Moreover, it is desirable that the inorganic substance is fixed by melting and solidifying the inorganic fibers.

In the honeycomb structure of the first aspect of the present invention, the inorganic material preferably contains silica, and the inorganic fiber is selected from the group consisting of silicon carbide, alumina, basalt, silica, silica-alumina, titania and zirconia. It is desirable to be composed of at least one selected.

In the honeycomb structure of the first aspect of the present invention, it is desirable that a catalyst is supported on at least a part of the inorganic fibers.

In the honeycomb structure of the first aspect of the present invention, the catalyst is preferably an oxide catalyst containing at least CeO _2. Moreover, the oxide _{catalyst, CeO 2, ZrO 2, FeO} 2, Fe 2 O 3, CuO, CuO 2, Mn 2 O 3, MnO, and the composition formula _{A n B 1-n CO 3} ( in the formula, A is La, Nd, Sm, Eu, Gd, or Y, B is an alkali metal or alkaline earth metal, and C is a composite oxide represented by Mn, Co, Fe, or Ni) It is desirable that

In the honeycomb structure of the first aspect of the present invention, it is desirable that the supported amount of the catalyst with respect to the apparent volume of the honeycomb structure is 10 to 200 g / l (liter).

The manufacturing method of the honeycomb structure according to the second aspect of the present invention includes a mixing step of mixing inorganic fibers A and inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated,
Extruding the mixture obtained in the mixing step through a die in which predetermined holes are formed, thereby forming a columnar shaped body in which a large number of cells are formed in the longitudinal direction,
The honeycomb structure according to the first aspect of the present invention is subjected to a heat treatment step of heat-treating the molded body at a temperature not higher than the heat resistance temperature of the inorganic fibers A and not lower than the softening temperature of the inorganic fibers B and / or the inorganic particles C. It is characterized by manufacturing.

The manufacturing method of the honeycomb structure of the third aspect of the present invention is a mixing step of mixing inorganic fibers A, inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated, and a resin. When,
The longitudinal direction of the cylindrical container for filling the mixture obtained in the mixing step and the long axis direction of the columnar core for forming the cells of the honeycomb structure are parallel to each other, and in a plan view lattice shape A core erecting step of erecting a plurality of the cores in the cylindrical container so as to be,
In the cylindrical container in which the core is erected in the core erecting step, the mixture filling step of filling the mixture,
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
By removing the core in the resin cured body obtained in the resin curing step, a core removing step for forming a columnar molded body in which a number of cells are formed in the longitudinal direction;
A degreasing step for removing the organic matter contained in the molded body obtained in the core removing step by heat degreasing;
A heat treatment step is performed in which the molded body degreased in the degreasing step is heat-treated at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particle C. The honeycomb structure of the present invention is manufactured.

The manufacturing method of the honeycomb structure according to the fourth aspect of the present invention includes a mixing step of mixing inorganic fibers A, inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated, and a resin. When,
A mold body for filling the mixture obtained in the above-mentioned mixing step, and pillars for forming cells of the honeycomb structure are erected in a lattice shape perpendicular to the main surface and in a plan view A mixture filling step of filling the mixture obtained in the mixing step into a mold body composed of the bottom plate body and an outer frame body provided so as to surround the bottom plate body and the column body;
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
A mold body that forms a column-shaped molded body in which a number of cells are formed in the longitudinal direction by removing the column body from the cured resin body obtained in the resin curing step and removing the entire mold body. A desorption step;
A degreasing step of removing organic matter contained in the molded body obtained in the mold body detaching step by heat degreasing;
A heat treatment step is performed in which the molded body degreased in the degreasing step is heat-treated at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particle C. The honeycomb structure of the present invention is manufactured.

The manufacturing method of the honeycomb structure of the fifth aspect of the present invention is a tank body, a mesh formed at the bottom of the tank body, and perpendicular to the mesh, and erected on the mesh in a lattice shape in plan view, Using a tank provided with a columnar mask for forming cells of a honeycomb structure, and a liquid filling part for charging the mixture, which is a space surrounded by the columnar mask with the mesh as a bottom surface A method for manufacturing a honeycomb structure, comprising:
A mixing step of mixing the inorganic fiber A and the inorganic fiber B and / or inorganic particles C that melt at a temperature at which the inorganic fiber A does not melt or sublime;
A mixture filling step of charging the mixture obtained in the mixing step into the liquid filling unit;
A dehydration step of draining the water in the mixture through the mesh to form a dehydrated body;
By removing the columnar mask from the dehydrated body, a mask detachment step for forming a columnar shaped body in which a large number of cells are formed in the longitudinal direction;
A heat treatment step of heat-treating the molded body formed in the mask detachment step at a temperature not higher than the heat resistance temperature of the inorganic fibers A and not lower than the softening temperature of the inorganic fibers B and / or the inorganic particles C. The honeycomb structure of the first aspect of the present invention is manufactured.

In the method for manufacturing a honeycomb structure according to the second to fifth aspects of the present invention, the inorganic fiber B and / or the inorganic particle C desirably contains silica, and the inorganic fiber A includes silicon carbide, It is desirable to be made of at least one selected from the group consisting of alumina, basalt, silica, silica-alumina, titania and zirconia.
Moreover, it is desirable that the compounding ratio of the inorganic fiber A to the inorganic fiber B and / or the inorganic particle C is (2: 8) to (8: 2).

It is desirable that the method for manufacturing a honeycomb structured body of the second to fifth inventions includes a step of acid-treating the columnar shaped body.
Moreover, it is preferable that the manufacturing method of the honeycomb structure of the second to fifth inventions includes a step of supporting an oxide catalyst on the inorganic fiber.

A honeycomb filter according to a sixth aspect of the present invention is characterized in that the cells of the honeycomb structure are sealed at one end thereof, and the honeycomb structure functions as a filter.

In the honeycomb filter according to the sixth aspect of the present invention, it is desirable that end-member laminated members mainly made of metal are laminated on both ends of the honeycomb structure.

In the honeycomb filter of the sixth aspect of the present invention, a honeycomb structure in which any one end of the cell is sealed, or an end laminated member mainly composed of the metal and the honeycomb structure is installed in a metal container. It is desirable that

A honeycomb filter manufacturing method according to a seventh aspect of the present invention includes an end laminate mainly made of metal at both ends of the honeycomb structure manufactured by any one of the second to fifth aspects of the honeycomb structure manufacturing method of the present invention. It includes a step of laminating members.

The manufacturing method of the honeycomb filter of the seventh aspect of the present invention preferably includes a step of installing the honeycomb structure and the end laminated member in a metal container.

The honeycomb structure of the first aspect of the present invention is mainly composed of inorganic fibers, and the inorganic fibers are integrally formed, so that there is no laminated interface. For this reason, since it is possible to obtain a structure in which the inorganic fibers are not relatively densely distributed in the honeycomb structure, the pressure loss is increased due to the relatively densely distributed portions of the inorganic fibers. It is possible to obtain a honeycomb structure without the above.

Further, in the method for manufacturing a honeycomb structure of the second aspect of the present invention, a mixture containing inorganic fibers is extruded through a die in which predetermined holes are formed to form a columnar shaped body, and heat treatment is performed. Without requiring a complicated process or expensive equipment, a honeycomb structure having a low pressure loss, mainly made of inorganic fibers, and integrally formed with the inorganic fibers can be manufactured.
Furthermore, by changing the shape of the dice, honeycomb structures having various outer shapes and cell shapes can be manufactured.

In the method for manufacturing a honeycomb structured body according to the third aspect of the present invention, the mixture of inorganic fibers and resin is filled in a container in which the cores are erected in a lattice shape in plan view, and the resin is cured. By removing the core and the resin, a pillar-shaped molded body is formed and heat-treated, so that complicated processes and expensive equipment are not required, and pressure loss is low, mainly from inorganic fibers. Thus, a honeycomb structure in which the inorganic fibers are integrally formed can be manufactured.
Further, since the shapes of the container and the core can be easily changed, a honeycomb structure having various outer shapes not limited to the column shape and cells having various shapes having steps in the bottomed holes, for example, is manufactured. be able to.

Further, in the method for manufacturing a honeycomb structured body according to the fourth aspect of the present invention, a mixture of inorganic fibers and resin is filled in a mold body in which pillars are erected in a plan view lattice shape, and the resin is cured. After forming the columnar shaped body by removing the formwork and heat-treating it, the pressure loss is low, mainly consisting of inorganic fibers, without requiring complicated steps or expensive equipment, etc. A honeycomb structure in which inorganic fibers are integrally formed can be manufactured.
Furthermore, honeycomb structures having various outer shapes and cell shapes can be manufactured by changing the shapes of the column and the outer frame.

In the method for manufacturing a honeycomb structured body according to the fifth aspect of the present invention, a mixture obtained by mixing inorganic fibers and inorganic fibers and / or inorganic particles is perpendicular to the bottom mesh and the bottom mesh and is planarly viewed. Filled into a tank equipped with a columnar mask standing on the mesh so as to form a lattice, drains the water in the mixture through the mesh to form a columnar shaped body made of inorganic fibers, and heat treatment By doing so, it is possible to manufacture a honeycomb structure in which the inorganic fibers are integrally formed with a low pressure loss and mainly composed of inorganic fibers, without requiring a complicated process or expensive equipment.

Further, the honeycomb filter of the sixth aspect of the present invention is mainly composed of inorganic fibers, the inorganic fibers are integrally formed, and any one of the cells of the honeycomb structure having no laminated interface is plugged. A honeycomb filter having a uniform and low pressure loss can be obtained.

Further, in the seventh method for manufacturing a honeycomb filter according to the present invention, a cell is formed by laminating a laminated member for an end portion made of metal on both ends of a honeycomb structure mainly made of inorganic fibers and integrally formed with the inorganic fibers. Can be plugged, so that a honeycomb filter having a uniform and low pressure loss can be manufactured.

(A) is a perspective view schematically showing a specific example of the honeycomb filter of the sixth aspect of the present invention, in which the end laminated members are laminated on both ends of the honeycomb structure of the first aspect of the present invention. b) is a cross-sectional view taken along line AA. It is sectional drawing which shows typically a part of inorganic fiber which comprises the honeycomb structure of 1st this invention. (A) is a perspective view showing a honeycomb structure and an end laminated member constituting the honeycomb filter of the sixth aspect of the present invention, and FIG. 3 (b) shows the honeycomb structure shown in FIG. It is a perspective view which shows a mode that the laminated member for edge parts is laminated | stacked and a honeycomb filter is produced. It is sectional drawing which shows typically the plunger type molding machine used for shaping | molding of a column-shaped molded object. (A) (I)-(VI) is the figure which represented typically the process from the core standing installation process to a core removal process in the manufacturing process of the honeycomb structure of 3rd this invention, ( (b) is a top view showing a state where the core is erected on the cylindrical container, and (c) is a perspective view showing an example of the shape of the core having a step. (A) (I)-(V) is the figure which represented typically the process from the mixture filling process to a mold body removal | desorption process in the manufacturing process of the honeycomb structure of 4th this invention, ( b) is a top view showing a state in which the columnar body is erected in the mold body. (A) is the figure which represented typically the tank used in the manufacturing process of the honeycomb structure of 5th this invention, (b) is a top view which represents typically the press board used for a press process. . It is sectional drawing which showed typically an example of the exhaust-gas purification apparatus of the vehicle by which the honeycomb filter of the 6th this invention was installed. It is explanatory drawing of a pressure loss measuring apparatus. (A) is the perspective view which showed typically the specific example of the lamination type honeycomb filter produced by laminating | stacking the lamination | stacking member which consists of a sheet-like inorganic fiber aggregate | assembly which has a through-hole, (b) It is the AA sectional view taken on the line. (C) is an enlarged sectional view of a portion indicated by B in (b).

First, the honeycomb structure of the first invention and the honeycomb filter of the sixth invention will be described.

The honeycomb structure of the first aspect of the present invention is a columnar honeycomb structure in which a plurality of cells are arranged in parallel in the longitudinal direction with a wall portion interposed therebetween, and the honeycomb structure is mainly composed of inorganic fibers, An inorganic fiber is integrally formed.

Here, being integrally formed means that the honeycomb structure is not formed by assembling several parts, but formed as a single indivisible member.

A honeycomb filter according to a sixth aspect of the present invention is characterized in that the honeycomb filter is sealed at one end of the cells of the honeycomb structure, and the honeycomb structure functions as a filter.
In the honeycomb filter of the sixth aspect of the present invention, it is desirable that end-member laminated members mainly made of metal are laminated on both ends of the honeycomb structure.
In the honeycomb filter of the sixth aspect of the present invention, a honeycomb structure in which one end of the cell is sealed, or an end laminated member mainly made of metal and the honeycomb structure is provided in a metal container. It is desirable that it is installed.

Hereinafter, the honeycomb structure of the first invention and the honeycomb filter of the sixth invention will be described with reference to the drawings.
FIG. 1 (a) is a perspective view schematically showing a specific example of the honeycomb filter of the sixth aspect of the present invention in which the end laminated members are laminated on both ends of the honeycomb structure of the first aspect of the present invention. (B) is the AA sectional view taken on the line.

The cylindrical honeycomb filter 1 is formed by laminating end laminated members 10b on both ends of a honeycomb structure 10a.
The honeycomb structure 10a is mainly composed of inorganic fibers, the inorganic fibers are integrally formed, and has a large number of cells 11 separated by wall portions (cell walls) 13. Each of the cells 11 has a honeycomb structure. It penetrates from one end of the body 10a to the other end.
Any one end of this cell is sealed by the end laminated member 10b. The end laminated member will be described later.

As shown in FIG. 1B, the cell 11 is sealed at either end corresponding to the inlet side or the outlet side of the exhaust gas, and the exhaust gas flowing into one cell 11 After passing through the cell wall 13 that separates the cells, it flows out from the other cells 11. That is, the cell wall 13 functions as a filter.

In the honeycomb filter 100 (see FIG. 10A) configured by laminating a large number of laminated members 110a made of inorganic fiber aggregates, a laminated interface in which inorganic fibers are densely distributed (see FIG. 10C). However, since the honeycomb structure of the first aspect of the present invention is not constituted by lamination, there is no lamination interface inside.
The inorganic fiber is densely distributed at the laminated interface, and it is difficult for exhaust gas to pass through, which causes an increase in pressure loss. However, in the honeycomb structure of the first invention, there is no laminated interface. Since the passage of the exhaust gas becomes easier, the increase in pressure loss does not occur, and the honeycomb structure has a low pressure loss. Therefore, the honeycomb filter manufactured using this also becomes a honeycomb filter with low pressure loss.

In addition, since the main constituent material of the honeycomb structure of the first aspect of the present invention is inorganic fibers, a honeycomb structure with a high porosity can be obtained. By making the porosity high, pressure loss can be lowered, PM can be taken into the wall, and the contact probability between the catalyst supported in the wall and PM can be increased. The energy for burning can be kept low.

In addition, since the honeycomb structure formed by integrally molding inorganic fibers with high porosity has a small heat capacity, it can be quickly raised to the activation temperature of the catalyst by exhaust heat discharged from the internal combustion engine. In particular, it is considered advantageous when the honeycomb filter is disposed directly under the engine and used in a form in which the exhaust heat is effectively used.

Note that the vertical cross-sectional shape of the honeycomb structure and the honeycomb filter is not particularly limited to a circle, and may be various shapes such as a rectangle. However, the shape may be a curve alone or a shape surrounded by a curve and a straight line. It is desirable to be.
As a specific example, besides a circle, for example, a shape in which a part of a simple closed curve such as an ellipse, an ellipse (race track shape), an ellipse, or an ellipse has a concave portion (concave shape) can be exemplified. .

The honeycomb structure according to the first aspect of the present invention is mainly composed of inorganic fibers and is formed of the inorganic fibers and an inorganic substance, and the inorganic fibers are fixed to each other via the inorganic substance.
Here, the portion where the inorganic fibers are fixed to each other is mainly at or near the intersection between the inorganic fibers, and the inorganic substance is localized at or near the intersection between the inorganic fibers. Is desirable.
Adhesion at or near the intersection means that the inorganic fibers are interspersed with an inorganic substance that is localized (exists) at the intersection between inorganic fibers (inorganic fibers may or may not be in contact). In a state where the inorganic fibers are fixed, a state in which the inorganic fibers are fixed through an inorganic substance that is localized (existing) in the vicinity of the intersection between the inorganic fibers, or the entire area in the vicinity of the intersection between the inorganic fibers and the vicinity thereof It means a state in which inorganic fibers are fixed to each other via an inorganic substance localized (existing).
Moreover, it is desirable that the inorganic material is melted and solidified to fix a crossing portion of the inorganic fibers or the vicinity thereof.
This will be described with reference to the drawings.

FIG. 2 is a cross-sectional view schematically showing a part of the inorganic fibers constituting the honeycomb structure of the first present invention. In addition, the cross-sectional view shown in FIG. 2 shows a cross section in which intersecting inorganic fibers are cut in the length direction.
The honeycomb structure according to the first aspect of the present invention is mainly composed of inorganic fibers and is formed from the inorganic fibers and an inorganic substance, and the inorganic fibers are fixed to each other via the inorganic substance. The fixing mode is not particularly limited, but the portion where the inorganic fibers are fixed is present at or near the intersection of the inorganic fibers, and the inorganic material is the intersection of the inorganic fibers. It is desirable to be localized at or near the part.
As shown in FIG. 2, when the inorganic substance 52 is fixed at or near the intersection between the inorganic fibers 51 forming the honeycomb structure, the inorganic substance 52 fixed at the intersection or in the vicinity thereof has two inorganic fibers simultaneously. It plays the role of joining at or near the intersection. The fixing part is not only one place for one inorganic fiber but also two or more sticking parts. Therefore, many inorganic fibers are entangled in a complicated manner. Is prevented. In addition, the strength of the honeycomb structure is improved.

When the inorganic substance 52 is localized at the intersection of the inorganic fibers 51 or in the vicinity thereof, many of the inorganic fibers 51 are covered with the inorganic substance 52 at the intersection of the other inorganic fibers 51 or in the vicinity thereof. For the most part, the inorganic substance is hardly fixed.
Here, the intersection of inorganic fibers or the vicinity thereof refers to a region having a distance within approximately 10 times the fiber diameter of the inorganic fibers from the portion where the inorganic fibers are closest to each other.

In the honeycomb structure according to the first aspect of the present invention, it is desirable that the inorganic substance 52 is melted and solidified to fix the crossing portion of the inorganic fibers or the vicinity thereof.
By fixing the inorganic fibers 51 by melting and solidifying the inorganic substance 52, the bonding strength between the inorganic fibers, which are the basic constituent elements of the honeycomb structure of the first aspect of the present invention, is increased, and the inorganic fibers are further defibrated. Thus, the strength of the honeycomb structure is further improved.

The tensile strength of the honeycomb structure is desirably 0.3 MPa or more, and more desirably 0.4 MPa or more.
If the tensile strength is less than 0.3 MPa, sufficient reliability may not be obtained when the honeycomb structure is used for a honeycomb filter.
The tensile strength can be measured with an Instron universal testing machine by processing the honeycomb structure into a sheet shape and fixing both ends with a jig.

In the above honeycomb structure, it is desirable that the intersection between the inorganic fibers to which the inorganic substance is fixed or the vicinity thereof is 20% or more of the intersection between the inorganic fibers or the entire vicinity thereof.
This is because if it is less than 20%, the honeycomb structure may have insufficient strength.
In addition, the ratio of the intersection between the inorganic fibers to which the inorganic substance is fixed or the vicinity thereof is obtained by observing a plurality of locations of the honeycomb structure under a microscope, and within each observation field, the intersection between the inorganic fibers or the vicinity thereof. It can be obtained by counting the number and the number of intersections between the inorganic fibers to which the inorganic substance is fixed or the number in the vicinity thereof to obtain the ratio, and calculating the average value.

The honeycomb structure is mainly composed of inorganic fibers, and is composed of the inorganic fibers and an inorganic substance.
Examples of the material of the inorganic fiber include oxide ceramics such as silica-alumina, mullite, alumina, silica, titania and zirconia, nitride ceramics such as silicon nitride and boron nitride, carbide ceramics such as silicon carbide, and basalt. Can be mentioned.
These may be used alone or in combination of two or more.

Among these, at least one selected from the group consisting of silicon carbide, alumina, basalt, silica, silica-alumina, titania and zirconia is desirable.
This is because a honeycomb structure using these is excellent in heat resistance.

A desirable lower limit of the fiber length of the inorganic fiber is 0.1 mm, and a desirable upper limit is 100 mm.
If the fiber length is less than 0.1 mm, it becomes difficult to fix the inorganic fibers to each other via an inorganic substance, and sufficient strength may not be obtained. On the other hand, if the fiber length exceeds 100 mm, the fibers are homogeneous. This is because it is difficult to produce a honeycomb structure having a sufficient strength and it may not be possible to obtain a honeycomb structure having sufficient strength.
A more desirable lower limit of the fiber length is 0.5 mm, and a more desirable upper limit is 50 mm.

A desirable lower limit of the fiber diameter of the inorganic fiber is 0.3 μm, and a desirable upper limit is 30 μm.
When the fiber diameter is less than 0.3 μm, the inorganic fibers themselves are easily broken, and as a result, the obtained honeycomb structure is easily eroded. On the other hand, when the fiber diameter exceeds 30 μm, the inorganic fibers are separated from each other by an inorganic substance. In some cases, it becomes difficult to fix the adhesive, and sufficient strength cannot be obtained. A more desirable lower limit of the fiber diameter is 0.5 μm, and a more desirable upper limit is 15 μm.

As said inorganic substance, what melt | dissolves at the temperature which the said inorganic fiber does not fuse | melt or sublime can be used, for example. The inorganic material is preferably melted at a temperature lower than the heat resistance temperature of the inorganic fiber.
And the said inorganic substance can use the inorganic substance fuse | melted at the temperature below the heat-resistant temperature of the said inorganic fiber, for example considering the temperature at which the inorganic fiber to combine fuses or sublimates, the heat-resistant temperature of the said inorganic fiber, etc. Specifically, for example, when alumina is used as the inorganic fiber, an inorganic material that melts at 1300 ° C. or lower can be used.
As said inorganic substance, what contains a silica is desirable, As an example, inorganic glass, such as silicate glass, silicate alkali glass, borosilicate glass, etc. are mentioned, for example.

As for the apparent density of the honeycomb structure, a desirable lower limit is 0.04 g / cm ³ and a desirable upper limit is 0.4 g / cm ³ .
If it is less than 0.04 g / cm ³ , the strength may be insufficient and breakage may easily occur. Moreover, 0.4 g / cm ³ or less is desirable because it is more suitable for continuously burning PM. In this specification, the apparent density means a value obtained by dividing the mass (g) of a sample by the apparent volume (cm ³ ) of the sample, and the apparent volume means a volume including the cell and pores of the sample. Say.

The desirable lower limit of the porosity of the honeycomb structure of the first invention is 75%, and the desirable upper limit is 95%.

When the porosity is less than 75%, the temperature in the filter is unlikely to rise to the temperature required for burning PM during filter regeneration, and the PM does not easily enter the pores. May decrease. On the other hand, when the porosity exceeds 95%, the proportion of the pores increases, and it becomes difficult to maintain the strength of the entire honeycomb structure.

Moreover, the average pore diameter in the honeycomb structure of the first aspect of the present invention is not particularly limited, and a desirable lower limit is 1 μm and a desirable upper limit is 100 μm. If the thickness is less than 1 μm, PM may not be filtered in the deep layer inside the cell wall and may not be able to contact the catalyst supported inside the cell wall. On the other hand, when it exceeds 100 μm, PM passes through the pores, and the PM cannot be sufficiently collected and may not function as a filter.
The porosity and average pore diameter can be measured by a conventionally known method such as a mercury intrusion method using a mercury porosimeter, an Archimedes method, or a measurement using a scanning electron microscope (SEM).

In the honeycomb structure of the first aspect of the present invention, the distance between adjacent cells (that is, the thickness of the cell wall) is preferably 0.2 mm or more. This is because if the thickness is less than 0.2 mm, the strength of the honeycomb structure may be lowered.

On the other hand, the desirable upper limit of the distance between adjacent cells (cell wall thickness) is 5.0 mm. If the cell wall is too thick, the cell aperture ratio and / or the filtration area may be reduced, and the pressure loss may increase accordingly. Further, the ash generated when PM is burned is deeply penetrated into the pores and is difficult to escape. Furthermore, when the range in which PM can be deeply filtered is the effective area of the wall against soot collection, the proportion of the effective area in the honeycomb structure is reduced.

In the honeycomb structure according to the first aspect of the present invention, the cell density in the plane perpendicular to the longitudinal direction of the cells is not particularly limited, and a desirable lower limit is desirably 0.16 cells / cm ² (1.0 cells / in ² ). The upper limit is 93 / cm ² (600 / in ² ), the more desirable lower value is 0.62 / cm ² (4.0 / in ² ), and the more desirable upper limit is 77.5 / cm ^2. (500 pieces / in ² ).

Further, in the honeycomb structure of the first aspect of the present invention, the size of the cell in the plane perpendicular to the longitudinal direction of the cell is not particularly limited, but the desirable lower limit is 0.8 mm × 0.8 mm, and the desirable upper limit is 16 mm × 16 mm. is there.

Further, when irregularities are formed on the inner surface of the cell constituting the honeycomb structure of the first invention, it is considered that the filtration area becomes large and the pressure loss when PM is collected can be further reduced. It is done. Moreover, since the flow of the exhaust gas can be made turbulent by the unevenness, it is considered that the temperature difference in the filter can be reduced and damage due to thermal stress can be effectively prevented.

The shape of the cell in plan view is not particularly limited to a quadrangle, and examples thereof include a triangle, a hexagon, an octagon, a dodecagon, a circle, an ellipse, and a star.

The desirable value of the aperture ratio of the honeycomb structure according to the first aspect of the present invention is a lower limit of 30% and an upper limit of 60%.
When the opening ratio is less than 30%, pressure loss when exhaust gas flows into and out of the honeycomb structure may increase, and when it exceeds 60%, the strength of the honeycomb structure may decrease.

In addition, the honeycomb structure according to the first aspect of the present invention preferably has a heat resistant temperature of 1200 ° C. or higher.
When the heat-resistant temperature is less than 1200 ° C., damage such as erosion may occur in the honeycomb structure when the regeneration process is performed, particularly when the regeneration process for burning a large amount of particulates at a time is performed. Because.

Next, the end laminated member for plugging one end of the cell provided in the honeycomb structure of the first present invention will be described.

Fig. 3 (a) is a perspective view showing a honeycomb structure and a laminated member for an end portion constituting the honeycomb filter of the sixth invention, and Fig. 3 (b) is a honeycomb structure shown in Fig. 3 (a). It is a perspective view which shows a mode that a body and the laminated member for edge parts are laminated | stacked and a honeycomb filter is produced.

In the honeycomb filter of the sixth aspect of the present invention, it is desirable that the end laminated member 10b having through holes formed in a checkered pattern is laminated on both ends of the honeycomb structure 10a.
By laminating the end laminate member, one end of the cell is sealed without sealing the end of the cell with a sealing material.

The end laminated member is made of the same material as the honeycomb structure, and the through holes may be formed in a checkered pattern, or the dense plate shape in which the through holes are formed in a checkered pattern. It may be a body.
In the present specification, dense means a material having a smaller porosity than the honeycomb structure, and specific materials include, for example, metals and ceramics.
When the dense plate-like body is used, the end laminated member can be thinned.
Further, the end laminated member is preferably made of a dense metal.

In addition, when a dense plate-like body is used as the end laminated member, it is possible to prevent soot from leaking from the sealing portion.

Further, when a metal laminated member having through holes formed in a checkered pattern or a plate-like body made of dense metal is laminated on both ends of the honeycomb structure, it is hard to be eroded even if used for a long time.

Subsequently, in the honeycomb filter of the sixth aspect of the present invention, it is possible to install a honeycomb structure in which any one end of the cell is sealed, or an end laminated member mainly composed of the honeycomb structure and a metal. The metal container which can be performed is demonstrated.

As the metal container, specifically, a cylindrical casing 123 having a pressing metal fitting on one side as shown in FIG. 3B can be used.
In FIG. 3B, the upper part of the cylindrical portion forming the casing 123 is omitted, and the casing 123 is cylindrical.
Examples of the material of the casing 123 include metals such as stainless steel (SUS), aluminum, and iron. Further, the shape is not particularly limited, but it is desirable that the shape be approximate to the outer shape of the installed honeycomb structure.
A specific installation method using the casing 123 will be described in the section of the manufacturing method described later.

Next, the catalyst that can be supported on the honeycomb structure of the first invention will be described.
In the honeycomb structure of the first aspect of the present invention, it is desirable that a catalyst is supported on at least a part of the inorganic fibers. Type of the catalyst is not particularly limited, it is preferable that an oxide catalyst containing at least CeO _2.
The oxide catalyst is not particularly limited as long as it can lower the combustion temperature of the particulates. For example, CeO ₂ , ZrO ₂ , FeO ₂ , Fe ₂ O ₃ , CuO, CuO ₂ , Mn ₂ O ₃ , MnO, composition formula _An B _1-n CO ₃ (wherein A is La, Nd, Sm, Eu, Gd or Y, B is an alkali metal or alkaline earth metal, and C is Mn , Co, Fe, or Ni).
These may be used alone or in combination of two or more, but preferably contain at least CeO ₂ .
By supporting such an oxide catalyst, the combustion temperature of the particulates can be lowered.

The supported amount of the catalyst with respect to the apparent volume of the honeycomb structure is preferably 10 to 200 g / l.
If the supported amount is less than 10 g / l, the portion where the catalyst is not supported on the wall portion of the honeycomb structure increases, and therefore a portion where the particulate does not contact the catalyst is generated. This is because the combustion temperature may not be lowered, and on the other hand, the contact between the particulates and the catalyst is not improved so much even if the combustion temperature exceeds 200 g / l.

The method for producing the honeycomb structure of the first invention is not particularly limited, and can be produced by various methods. For example, the honeycomb structures of the second to fifth inventions described below can be used. It can manufacture with the manufacturing method of a structure.

Next, a method for manufacturing the honeycomb structured body of the second invention will be described.
The manufacturing method of the honeycomb structure according to the second aspect of the present invention includes a mixing step of mixing inorganic fibers A and inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated,
Extruding the mixture obtained in the mixing step through a die in which predetermined holes are formed, thereby forming a columnar shaped body in which a large number of cells are formed in the longitudinal direction,
The honeycomb structure according to the first aspect of the present invention is subjected to a heat treatment step of heat-treating the molded body at a temperature not higher than the heat resistance temperature of the inorganic fibers A and not lower than the softening temperature of the inorganic fibers B and / or the inorganic particles C. It is characterized by manufacturing.
In the present specification, the method for manufacturing a honeycomb structure according to the second aspect of the present invention is also simply referred to as a manufacturing method by extrusion molding.

Hereinafter, the manufacturing method of the honeycomb structure of the second aspect of the present invention will be described in the order of steps.
First, a mixing step is performed in which the inorganic fibers A and the inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A do not melt are mixed to prepare a mixture.

As the inorganic fiber A, the same inorganic fiber as mentioned in the description of the honeycomb structure can be used, and it is selected from the group consisting of silicon carbide, alumina, basalt, silica, silica-alumina, titania and zirconia. Preferably, at least one kind is used.
The reason is that a honeycomb structure having excellent heat resistance can be manufactured.

The inorganic fiber B and / or the inorganic particle C are not particularly limited as long as the inorganic fiber A melts at a temperature at which the inorganic fiber A does not melt, and specific examples of the inorganic fiber B include, for example, silicate glass. And inorganic glass fibers made of alkali silicate glass, borosilicate glass, and the like. Examples of the inorganic particles C include inorganic glass particles made of silicate glass, alkali silicate glass, borosilicate glass, and the like.
The inorganic fibers B and / or the inorganic particles C are preferably melted at a temperature lower than the heat resistance temperature of the inorganic fibers A. These inorganic fibers B and / or the inorganic particles C are softened in a heat treatment step to be described later and become an inorganic substance in the honeycomb structure of the first invention.

A desirable lower limit of the fiber length of the inorganic fiber B is 0.1 mm, and a desirable upper limit is 100 mm.
If the fiber length is less than 0.1 mm, it becomes difficult to fix the inorganic fibers A to each other using an inorganic substance, and sufficient strength may not be obtained. On the other hand, if the fiber length exceeds 100 mm, the mixture When prepared, it is difficult to disperse uniformly, and in the subsequent step, when the heat treatment is performed, the inorganic fibers B and / or inorganic particles C are not uniformly dispersed. There may be a decrease in the number of sites that adhere to the intersection or the vicinity thereof.
A more desirable lower limit is 0.5 mm, and a more desirable upper limit is 50 mm.

A desirable lower limit of the fiber diameter of the inorganic fiber B is 0.3 μm, and a desirable upper limit is 30 μm.
When the fiber diameter is less than 0.3 μm, it becomes difficult to fix the inorganic fibers A to each other using an inorganic substance, and sufficient strength may not be obtained. When the fiber diameter exceeds 30 μm, There may be fewer sites that stick to the vicinity.

A desirable lower limit of the particle diameter of the inorganic particles C is 1 μm, and a desirable upper limit is 100 μm.
When the particle size is less than 1 μm, a flocculant is required and uniform dispersion may be difficult. When the particle size exceeds 100 μm, it is difficult to uniformly disperse the mixture when it is prepared. , The inorganic fibers B and / or the inorganic particles C are not uniformly dispersed, and there may be fewer sites that adhere to the intersections of the inorganic fibers A or in the vicinity thereof.

The mixing ratio (weight ratio) between the inorganic fiber A and the inorganic fiber B and / or the inorganic particle C when the inorganic fiber A and the inorganic fiber B and / or the inorganic particle C are mixed is as follows. It is desirable that they are (2: 8) to (8: 2).
If the blending ratio of the inorganic fibers A is less than (2: 8), the inorganic substance is likely to adhere so as to coat the entire surface of the inorganic fibers, and the resulting honeycomb structure may have insufficient flexibility. On the other hand, if the blending ratio of the inorganic fibers A is greater than (8: 2), the number of fixing sites between the inorganic fibers is small and the strength of the resulting honeycomb structure may be insufficient.

Moreover, when preparing the said mixture, the said inorganic fiber A, the said inorganic fiber B, and / or the said inorganic particle C are uniformly added by adding liquid media, such as water, and a dispersing agent as needed. May be mixed. Further, an organic binder may be added. By adding the organic binder, the inorganic fibers A, the inorganic fibers B and / or the inorganic particles C are surely entangled, and even before firing, the inorganic fibers B and / or the inorganic particles C are made of the inorganic fibers A. This is because the inorganic fibers A can be more reliably fixed to each other.

Examples of the organic binder include an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol. These organic binders may be used alone or in combination of two or more. Moreover, you may add a plasticizer, a lubrication agent, a shaping | molding adjuvant, a pore making material, etc. as needed. Conventional plasticizers and lubricants can be used.

The mixture thus obtained is desirably in a state in which a uniform composition state is maintained for a long period of time and inorganic fibers do not settle, and a predetermined shape is maintained in a subsequent molding step. It is desirable that the mixture has a viscosity as high as possible.

Next, by continuously extruding the mixture obtained in the above mixing step through a die in which predetermined holes are formed, a columnar shaped body in which a number of cells are formed in the longitudinal direction is formed. Perform an extrusion process.

The apparatus used for the present extrusion molding process is not particularly limited, and examples thereof include a single-screw extruder, a multi-screw extruder, and a plunger-type molding machine. Among these, a plunger type molding machine can be particularly preferably used.
Although the plunger type molding machine used in this step is not limited to the following type, the apparatus and its use example will be described with reference to the drawings.

FIG. 4 is a cross-sectional view schematically showing a plunger-type molding machine used for molding a columnar molded body.

This plunger type molding machine 70 is provided with a cylinder 73 and a piston 73 provided with a mechanism capable of reciprocating back and forth inside the cylinder (left and right in the drawing), and at the front end of the cylinder, and is provided with a large number in the longitudinal direction. A die 74 in which holes are formed so that a column-shaped formed body in which cells are formed can be extruded, and a mixture tank 72 that is located above the cylinder 71 and to which a pipe 75 from the cylinder 71 is connected. It is comprised including. A shutter 76 is provided immediately below the mixture tank 72 so that charging of the mixture from the mixture tank 72 can be blocked. The pipe 75 is provided with a screw 77 having blades 77 a and is rotated by a motor 78. Since the size of the blade 77a is substantially the same as the diameter of the pipe, the mixture 79 is difficult to flow backward. The mixture tank 72 is charged with the mixture obtained in the mixing step.

When a molded body is manufactured using the plunger-type molding machine 70, first, the shutter 76 is opened, and the mixture obtained in the above-described mixing step is rotated into the cylinder 71 from the mixture tank 72 by rotating the screw. . At this time, the piston 73 is moved to the end of the right cylinder 71 in FIG.
When the mixture is filled into the cylinder 71, the shutter 76 is closed and the rotation of the screw 77 is stopped simultaneously. When the piston 73 is pushed into the die side with the mixture 79 filled in the cylinder 71 in this way, the mixture is pushed out from the die 74 and a plurality of cells are formed in the longitudinal direction across the wall portion. Shaped compacts are formed continuously. At this time, cells having the shape are formed according to the shape of the hole formed in the die. By repeating this step, a molded body can be produced. Depending on the viscosity or the like, the molded body can be continuously produced by stopping the cylinder 73 and rotating the screw 77.
As the drive source for moving the piston 73, the plunger type molding machine 70 shown in FIG. 4 uses the oil cylinder 80. However, an air cylinder or a ball screw may be used. .

The shape of the cell formed by the extrusion process can be changed to a desired shape by changing the shape of the hole formed in the die.
The vertical cross-sectional shape of the cell is not particularly limited to a quadrangle, and examples thereof include an arbitrary shape such as a triangle, a hexagon, an octagon, a dodecagon, a circle, an ellipse, and a star.

Also, honeycomb structures having various outer shapes can be manufactured by changing the shape of the die. The vertical cross-sectional shape of the honeycomb structure is not limited to a circle, and may be various shapes such as a rectangle. However, it is desirable that the shape be surrounded by only a curve or a curve and a straight line. As a specific example, in addition to a circle, for example, a shape in which a part of a simple closed curve such as an ellipse, an ellipse (race track shape), an ellipse, or an ellipse has a concave portion (concave shape) can be exemplified. .

Next, a heat treatment step in which the molded body obtained in the extrusion molding step is heat-treated at a temperature not higher than the heat resistance temperature of the inorganic fiber A and not lower than the softening temperature of the inorganic fiber B and / or the inorganic particle C. By performing the above, it is possible to obtain a honeycomb structure that is mainly composed of inorganic fibers and in which the inorganic fibers are integrally formed.

By performing such heat treatment, the inorganic fibers A are fixed to each other through an inorganic material made of the same material as the inorganic fibers B and / or the inorganic particles C, and most of the fixed portions are inorganic fibers. A honeycomb structure in which an inorganic substance made of the same material as the inorganic fibers B and / or the inorganic particles C is located at or near the intersection A can be manufactured.
The heating temperature may be appropriately selected in consideration of the combination of the inorganic fiber A, the inorganic fiber B, and / or the inorganic particles C.
Examples of the heat resistant temperature of the inorganic fiber A are, for example, alumina> 1300 ° C., silica> 1000 ° C., silicon carbide> 1600 ° C., silica-alumina> 1200 ° C.

The specific heating temperature depends on the heat resistance temperature and softening temperature of the inorganic fibers and the inorganic particles, and thus cannot be generally specified. However, when inorganic glass is used as the inorganic fibers B and / or inorganic particles C, 900 is used. -1050C is considered desirable.
If the heating temperature is less than 900 ° C., the inorganic fibers may be fixed to a part of the surface of the inorganic fiber, but the inorganic fibers may not be fixed to each other. If the heating temperature exceeds 1050 ° C., cracks are generated in the fixed inorganic substance. Because there are things.

Before the heat treatment step, a cutting step for cutting the extruded molded body into a predetermined length, a drying step for removing moisture in the molded body, and a degreasing step for removing organic substances in the molded body are performed. desirable.

The cutting member used in the cutting step is not particularly limited, and examples thereof include a cutter, a laser, and a linear body in which a blade is formed at a cutting portion. It is also possible to use a cutter that cuts while the disk rotates.

In addition, a molded body cutting machine equipped with cutting means such as a laser and a cutter is provided in front of the molded body molded in the extrusion molding process, and the cutting means is synchronized with the molded body extrusion speed. A method of cutting the molded body with a cutting means while moving is desirable.
When a cutting apparatus having the above mechanism is used, a cutting process can be continuously performed, and mass productivity is improved.

Although it does not specifically limit as a drying apparatus used for a drying process, For example, a microwave heating dryer, a hot air dryer, an infrared dryer, etc. can be mentioned, You may combine a some apparatus.

For example, when a hot air dryer is used, the drying is desirably performed by drying at a set temperature of 100 to 150 ° C. in an air atmosphere for 5 to 60 minutes. In this case, it is desirable that the hot air is installed so as to be parallel to the longitudinal direction of the molded body so that the hot air can pass through the cells. When the hot air passes through the cells of the molded body, drying of the molded body proceeds efficiently.

The degreasing treatment is usually preferably performed in an oxidizing atmosphere such as an air atmosphere so that the organic matter can be oxidatively decomposed. The degreasing furnace is not particularly limited and may be a batch type degreasing furnace. However, it is desirable that the degreasing furnace be a continuous furnace provided with a belt conveyor so that the processing can be continuously performed. Degreasing is desirably performed by drying at a set temperature of 200 to 600 ° C. in an air atmosphere for 1 to 5 hours.

In the method for manufacturing a honeycomb structured body according to the second aspect of the present invention, a step of acid treatment may be performed on the columnar molded body manufactured by the above-described method.
This is because the heat resistance of the molded body is improved by performing the acid treatment.
The acid treatment can be performed, for example, by immersing the molded body in a solution such as hydrochloric acid or sulfuric acid.

As the acid treatment conditions, when inorganic glass is used as the inorganic substance, the concentration of the treatment solution is preferably 1 to 10 mol / l, the treatment time is preferably 0.5 to 24 hours, and the treatment temperature is 70 to 100. It is desirable to be at ° C.
By performing the acid treatment under such conditions, components other than silica are eluted, and as a result, the heat resistance of the molded body is improved.

The acid treatment step may be performed during the heat treatment step. Specifically, it is desirable that the primary baking step is performed at 950 ° C. for 5 hours, and then the acid treatment step is performed, and then the heat treatment at 1050 ° C. for 5 hours is performed again as the secondary baking step. This treatment can improve the heat resistance of the molded body.

In addition, the method for manufacturing a honeycomb structured body according to the second aspect of the present invention preferably includes a step of supporting an oxide catalyst on the inorganic fiber.

When the catalyst is supported, the oxide catalyst can be supported in advance on an inorganic fiber such as an alumina fiber which is a constituent material. By supporting the catalyst on the inorganic fiber before molding, the catalyst can be adhered in a more uniformly dispersed state.
Examples of the oxide catalyst include the same ones as those supported on the honeycomb structure described above.
Examples of the method of supporting the oxide catalyst on the inorganic fiber include a method of immersing the inorganic fiber in a slurry containing the oxide catalyst and then heating it by heating.

As another method, after manufacturing the columnar molded body through the above-described steps, the columnar molded body is impregnated with the slurry containing the oxide catalyst, and then pulled up and heated. You can also.

Next, a method for manufacturing the honeycomb structured body according to the third aspect of the present invention will be described.
The manufacturing method of the honeycomb structure of the third aspect of the present invention is a mixing step of mixing inorganic fibers A, inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated, and a resin. When,
The longitudinal direction of the cylindrical container for filling the mixture obtained in the mixing step and the long axis direction of the columnar core for forming the cells of the honeycomb structure are parallel to each other, and in a plan view lattice shape A core erecting step of erecting a plurality of the cores in the cylindrical container so as to be,
In the cylindrical container in which the core is erected in the core erecting step, the mixture filling step of filling the mixture,
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
By removing the core in the resin cured body obtained in the resin curing step, a core removing step for forming a columnar molded body in which a number of cells are formed in the longitudinal direction;
A degreasing step for removing the organic matter contained in the molded body obtained in the core removing step by heat degreasing;
A heat treatment step is performed in which the molded body degreased in the degreasing step is heat-treated at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particle C. The honeycomb structure of the present invention is manufactured.
In the present specification, the method for manufacturing a honeycomb structure according to the third aspect of the present invention is simply referred to as a manufacturing method by resin curing (core standing).
Here, the core is a mold that is inserted into a hollow part when a molded product (corresponding to a honeycomb structure in the present invention) having a hollow part (corresponding to a cell in the present invention) is produced. I mean.

Hereinafter, the manufacturing method of the honeycomb structure according to the third aspect of the present invention will be described with reference to the drawings.
FIGS. 5A to 5I are diagrams schematically showing processes from the core standing process to the core removal process in the manufacturing process of the honeycomb structure of the third aspect of the present invention. (B) is a top view showing a state where the core is erected on the cylindrical container, and (c) is a perspective view showing an example of the shape of the core having a step.

(1) First, before performing the steps of FIGS. 5A and 5I, the inorganic fiber A, the inorganic fiber B and / or inorganic particles C that melt at a temperature at which the inorganic fiber A does not melt or sublime, and heat A mixing step of mixing the curable resin is performed.
In the present invention, the inorganic fibers A, the inorganic fibers B, and the inorganic particles C are the same as those used in the method for manufacturing the honeycomb structure according to the second aspect of the present invention, so that details are omitted, but a resin is added to the inorganic substance. Is desirable. A cured resin body can be formed by curing the resin, and a honeycomb structure made of inorganic fibers can be manufactured by removing the resin in a subsequent degreasing step and further performing a heat treatment.
Although it does not specifically limit as said resin, It is desirable to use a thermosetting resin. The kind of the thermosetting resin is not particularly limited, and examples thereof include an epoxy resin, a phenol resin, a polyester resin, a urea resin, and a melamine resin. Of these, epoxy resins are particularly desirable because of their low cure shrinkage.

Moreover, when preparing the said mixture, the said inorganic fiber A, the said inorganic fiber B, and / or the said inorganic particle C are mixed uniformly by adding a solvent and a dispersing agent as needed. Also good.

(2) Next, a core standing step is performed.
A cylindrical container 20 and a plurality of columnar cores 21 are prepared (see FIGS. 5A and 5I), and the core 21 is placed in the cylindrical container 20 in the longitudinal direction of the cylindrical container 20 and the core 21. Are arranged so that the major axis directions thereof are parallel to each other (see FIGS. 5 (a) and (II)).
At this time, as shown in FIG. 5B, it is desirable to arrange the cores 21 in a lattice pattern in plan view.
As the core, core sand used for casting casting is preferably used, and resin materials, low melting point metals, high-pressure press-molded water-soluble salts, and the like can also be used.

(3) Next, a mixture filling step is performed.
The mixture 22 obtained in the mixing step is poured into the cylindrical container 20, and the cylindrical container is filled with the mixture (see FIGS. 5A and III). In addition, when hardening resin using a hardening | curing agent in a subsequent resin hardening process, a hardening | curing agent is added to a mixture just before a mixture filling process, and a mixture filling process is performed after that.
The type of curing agent is determined according to the type of resin.

(4) Next, a resin curing step is performed.
The curing method of the resin is not particularly limited, but when a curing agent is added before the mixture filling step, the resin is cured by the function of the curing agent, and a cured resin body 23 is formed ( FIG. 5 (a) (IV) reference).
Further, when a thermosetting resin is used without adding a curing agent, the thermosetting resin can be cured by heating to a temperature equal to or higher than the curing temperature of the thermosetting resin, and the cured resin body 23 is formed. Is done.
The heating temperature should be determined according to the type of the thermosetting resin used, but needs to be lower than the heat resistant temperature of the core. This is because a cell having a desired shape cannot be formed if the core is thermally deformed before the thermosetting resin is cured.

(5) Next, a core removal step is performed.
By removing the core, a cell is formed in a portion occupied by the core, and this can be used as a cell of the honeycomb structure (see FIGS. 5A and 5V).
The method for removing the core is not particularly limited, but examples include methods such as washing and elution, burnout, and heat fusion, and a removal method corresponding to the type of the installed core is used. be able to.
For example, when core sand or high-pressure press-molded water-soluble salts are used for the core, the core flows out by physically crushing the core or by applying hot water to the core part vigorously. Can be eluted.
Further, when the resin material is used for the core, the core can be burned down by baking at a high temperature. This firing step may be performed in combination with a later firing step.
When a low melting point metal is used for the core, the core can be thermally melted by heating to a temperature higher than the melting point.

Moreover, the shape of the cell formed in the present invention can be changed to a desired shape by changing the shape of the core.
The vertical cross-sectional shape of the cell is not particularly limited to a quadrangle, and examples thereof include an arbitrary shape such as a triangle, a hexagon, an octagon, a dodecagon, a circle, an ellipse, and a star.

When a core having a step as shown in FIG. 5C is used, cells having irregularities on the surface of the wall portion of the honeycomb structure can be formed. And it is thought by forming an unevenness | corrugation in the surface of a wall part that the filtration area increases and the pressure loss at the time of collecting a particulate can be reduced. Further, it is considered that the flow of exhaust gas becomes turbulent due to the unevenness, the temperature difference in the filter can be reduced, and damage such as cracks due to thermal stress can be prevented.

Before and after the core removal step, the cylindrical container 24 is removed to form a columnar shaped body 24 (see FIGS. 5A and 5I).
Moreover, the honeycomb structure of various external shapes can be manufactured by changing the shape of the cylindrical container. The vertical cross-sectional shape of the honeycomb structure is not limited to a circle, and may be various shapes such as a rectangle. However, it is desirable that the shape be surrounded by only a curve or a curve and a straight line. As a specific example, in addition to a circle, for example, a shape in which a part of a simple closed curve such as an ellipse, an ellipse (race track shape), an ellipse, or an ellipse has a concave portion (concave shape) can be exemplified. .

Next, a degreasing process for removing the resin in the molded body is performed.
Since the specific method is the same as the degreasing step described above, details thereof are omitted, but a degreased molded body can be obtained thereby.

Thereafter, the honeycomb structure can be manufactured in the same manner as the method for manufacturing the honeycomb structure of the second invention. Therefore, detailed description thereof is omitted here.

Next, a method for manufacturing a honeycomb structured body according to the fourth aspect of the present invention will be described.
The manufacturing method of the honeycomb structure according to the fourth aspect of the present invention includes a mixing step of mixing inorganic fibers A, inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated, and a resin. When,
A mold body for filling the mixture obtained in the above-mentioned mixing step, and pillars for forming cells of the honeycomb structure are erected in a lattice shape perpendicular to the main surface and in a plan view A mixture filling step of filling the mixture obtained in the mixing step into a mold body composed of the bottom plate body and an outer frame body provided so as to surround the bottom plate body and the column body;
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
A mold body that forms a column-shaped molded body in which a number of cells are formed in the longitudinal direction by removing the column body from the cured resin body obtained in the resin curing step and removing the entire mold body. A desorption step;
A degreasing step of removing organic matter contained in the molded body obtained in the mold body detaching step by heat degreasing;
A heat treatment step is performed in which the molded body degreased in the degreasing step is heat-treated at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particle C. The honeycomb structure of the present invention is manufactured.
In the present specification, the method for manufacturing a honeycomb structure according to the fourth aspect of the present invention is also simply referred to as a manufacturing method by resin curing (molding).

Hereinafter, the manufacturing method of the honeycomb structure according to the fourth aspect of the present invention will be described with reference to some drawings. However, since it includes many processes similar to those of the third aspect of the present invention described above, the description will focus on different processes. .

(1) First, a mixing process is performed.
Since this mixing step can be performed in the same manner as the third aspect of the present invention, detailed description thereof is omitted.

FIGS. 6 (a) to 6 (V) are diagrams schematically showing the steps from the mixture filling step to the mold body detachment step in the manufacturing process of the honeycomb structure of the fourth aspect of the present invention. (B) is a top view showing a state in which a columnar body is erected in the mold body.

(2) Next, a mixture filling step is performed.
As a mold body for filling the mixture, the column bodies 31 for forming the cells of the honeycomb structure are perpendicular to the main surface of the bottom plate body and have a lattice shape in plan view (FIG. 6A). (I) and FIG. 6 (b)), and an outer frame body 33 (FIG. 6 (a) provided so as to surround the bottom plate body 32 and the column body 31. ) (See (I)), the mold body 30 is formed (see FIGS. 6 (a) and (II)). The mold body may be integrated, or may be separable and connectable.
The material of each part constituting the mold body is preferably a metal. This is because it has high heat resistance, is suitable when the resin is cured by heating, and is easily separated from the cured resin.
And the mixture 22 is filled in the mold body 30 (refer Fig.6 (a) (III)). Since this step can be performed in the same manner as the third aspect of the invention except that the container to be filled is different, detailed description thereof will be omitted.

(3) Next, a resin curing step is performed.
Since the present resin curing step can be performed in the same manner as the third aspect of the present invention, detailed description thereof is omitted (see FIGS. 6A and IV).

(4) Next, a mold body detaching step is performed.
By detaching the column body 31, cells are formed at the site occupied by the column body until then, and this can be used as a cell of the honeycomb structure (see FIGS. 6A and 6V).
At this time, it is desirable that a post taper of about 2 ° is formed in the column body 31 in advance so that the column body 31 can be easily extracted from the cured resin body 23.
Moreover, the columnar shaped body 24 is formed by detaching the outer frame body 33.
The formwork can be used repeatedly.

Similarly to the third aspect of the present invention, honeycomb structures having various cell shapes and outer shapes can be manufactured by changing the shapes of the pillars and the outer frame.
However, unlike the third aspect of the present invention, it is not possible to form cells having irregularities on the surface of the wall portion of the honeycomb structure.

Thereafter, the honeycomb structure can be manufactured in the same manner as in the third method for manufacturing a honeycomb structure of the present invention. Therefore, detailed description thereof is omitted here.

Next, a method for manufacturing the honeycomb structured body according to the fifth aspect of the present invention will be described.
The manufacturing method of the honeycomb structure of the fifth aspect of the present invention is a tank body, a mesh formed at the bottom of the tank body, and perpendicular to the mesh, and erected on the mesh in a lattice shape in plan view, Using a tank provided with a columnar mask for forming cells of a honeycomb structure, and a liquid filling part for charging the mixture, which is a space surrounded by the columnar mask with the mesh as a bottom surface A method for manufacturing a honeycomb structure, comprising:
A mixing step of mixing the inorganic fiber A and the inorganic fiber B and / or inorganic particles C that melt at a temperature at which the inorganic fiber A does not melt or sublime;
A mixture filling step of charging the mixture obtained in the mixing step into the liquid filling unit;
A dehydration step of draining the water in the mixture through the mesh to form a dehydrated body;
By removing the columnar mask from the dehydrated body, a mask detachment step for forming a columnar shaped body in which a large number of cells are formed in the longitudinal direction;
A heat treatment step of heat-treating the molded body formed in the mask detachment step at a temperature not higher than the heat resistance temperature of the inorganic fibers A and not lower than the softening temperature of the inorganic fibers B and / or the inorganic particles C. The honeycomb structure of the first aspect of the present invention is manufactured.
In the present specification, the method for manufacturing a honeycomb structure of the fifth aspect of the present invention is also simply referred to as a manufacturing method by three-dimensional papermaking.

Hereinafter, the manufacturing method of the honeycomb structure of the fifth aspect of the present invention will be described with reference to some drawings.
First, the tank used in the fifth aspect of the present invention will be described with reference to the drawings. In addition, although a tank is not limited to the following types, it demonstrates as an example.

Fig.7 (a) is the figure which represented typically the tank used in the manufacturing process of the honeycomb structure of 5th this invention, (b) is a top view which represents typically the press board used for a press process. It is.

This tank 40 is erected on the mesh 42 so as to form a tank main body 47, a mesh 42 formed at the bottom of the tank main body, and a mesh in a plane view perpendicular to the mesh 42. A columnar mask 41 for forming cells of the honeycomb structure and a space surrounded by the columnar mask 41 with the mesh 42 as a bottom surface, and a liquid filling part 43 for introducing a mixture. is there.

The tank 40 has a press plate 44 made of a plate in which through holes 44a are formed in a lattice shape in a portion corresponding to the columnar mask 41, a cock 45 and a pump 46 for draining, and the press plate 44 as a tank body. You may provide the press drive part for pushing in, and the rocking | swiveling part which is not shown in figure for giving a vibration to a tank main body.

When manufacturing a honeycomb structure using the tank 40 configured in this way, the above-described mixing process, mixture filling process, dehydration process, mask desorption process, and heat treatment process are performed.
Moreover, you may perform a stirring process and / or a press process as needed.
Hereinafter, each step will be described.

(1) First, a mixing step is performed in which the inorganic fibers A, the inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A are not melted or sublimated, and water are mixed.
In the present invention, the inorganic fibers A, the inorganic fibers B, and the inorganic particles C are the same as those used in the method for manufacturing the honeycomb structure according to the second aspect of the present invention, so the details are omitted, but a large amount of water is added to the inorganic substance. In addition, it is desirable to reduce the viscosity of the mixture to the extent that it can be made.

Moreover, when preparing the said mixture, you may mix the said inorganic fiber A, the said inorganic fiber B, and / or the said inorganic particle C uniformly by adding a dispersing agent as needed. . Further, an organic binder may be added. By adding the organic binder, the inorganic fibers A and the inorganic fibers B and / or the inorganic particles C are surely entangled, and the inorganic fibers B and / or the inorganic particles C are difficult to come off from the inorganic fibers A before firing. This is because the inorganic fibers A can be more reliably fixed to each other.
Moreover, you may add a pore making material etc. as needed.

(2) Next, a mixture filling step is performed in which the mixture obtained in the mixing step is charged into the liquid filling unit 43. Note that the mixing step may be performed inside the tank 40.

In addition, you may perform the stirring process which stirs the mixture with which the liquid filling part 43 was filled after a mixture filling process. Stirring can be performed by operating a swinging portion (not shown) for applying vibration to the tank body. Specific examples of the swinging unit include an oscillator provided with an ultrasonic transducer, a vibrator, and the like, and can be installed on the side surface of the tank body 47. Moreover, you may install in the inside of the tank main body 47. FIG. By this stirring step, the mixture is stirred uniformly.

(3) Next, a dehydration step is performed in which moisture in the mixture is sucked and water in the mixture is discharged through the mesh 42.
At this time, the cock 45 provided below the mesh 42 is opened and the pump 46 is operated. As a result, the mixture filled in the liquid filling unit 43 is suction filtered, and moisture contained in the mixture falls down through the mesh 42 and is discharged through the cock 45. As a result, the water contained in the mixture is removed, and a dehydrated body having a predetermined height is formed from the bottom of the liquid filling portion.

Further, after the dehydration step, a press step may be performed in which the dehydrated body dehydrated in the dehydration step is pressed and compressed from above with the press plate. A compression body having a predetermined length, an appropriate density, and a porosity can be formed by pressure compression.

The apparatus and method used in the pressing process are not limited to the following, but the tank 40 shown in FIG. 7A is provided with a motor 49 and four ball screws 48 coupled to the motor 49 as a press driving unit. The four ball screws 48 are screwed into four screw holes 44b formed in the press plate 44, and the press plate 44 can be moved up and down by rotating the four ball screws 48 in synchronization. It can be done.
Further, the press plate 44 is a plate in which through holes are formed in a lattice shape in a portion corresponding to the columnar mask 41 as shown in FIG.

Accordingly, when the four motors 49 are driven while being synchronized, the press plate 44 descends downward, and the dewatering body is compressed at the tank body lower portion 47a to become a compression body. As shown in FIG. 7 (a), the tank body lower portion 47a has a honeycomb structure. When the press plate 44 is lowered to a portion where the motor 49 is disposed, a cylindrical compression body is formed. It is formed.
The tank main body lower portion 47a has a cylindrical shape, and the dehydrated body is compressed by the press plate 44 and filled into the tank main body lower portion 47a, thereby forming a honeycomb structure. Therefore, the shape of the honeycomb structure can be changed by changing the shape of the tank body lower portion 47a.

(4) Next, a mask detachment step is performed to remove the columnar mask from the dehydrated body, thereby forming a columnar shaped body in which a large number of cells are formed in the longitudinal direction. Thereby, the column-shaped molded object which has a cell of predetermined shape, a predetermined length, and a density can be obtained.

Moreover, the shape of the cell formed in the present invention can be changed to a desired shape by changing the shape of the columnar mask.
The vertical cross-sectional shape of the cell is not particularly limited to a quadrangle, and examples thereof include an arbitrary shape such as a triangle, a hexagon, an octagon, a dodecagon, a circle, an ellipse, and a star.

In addition, by changing the shape of the tank body 47, honeycomb structures having various outer shapes can be manufactured. The cross-sectional shape perpendicular to the cells of the honeycomb structure is not limited to a circle, and may be various shapes such as a rectangle, but may be a shape surrounded by only a curve or a curve and a straight line. Desirably, as a specific example, in addition to a circle, for example, a shape in which a part of a simple closed curve such as an ellipse, an ellipse (race track shape), an ellipse, or an ellipse has a concave portion (concave shape), etc. be able to. By setting the shape of the tank body 47 in plan view to the above shape, a honeycomb structure having a cross-sectional shape perpendicular to the cell as described above can be manufactured.

Thereafter, the honeycomb structure can be manufactured in the same manner as the manufacturing method of the honeycomb structure of the second to fourth inventions. Therefore, detailed description thereof is omitted here.

Next, a method for manufacturing the honeycomb filter of the seventh aspect of the present invention will be described.
A honeycomb filter manufacturing method according to a seventh aspect of the present invention is the end laminated member mainly made of metal at both ends of the honeycomb structure manufactured by the honeycomb structure manufacturing method according to any one of the second to fifth aspects of the present invention. Including a step of laminating the layers.
Moreover, it is preferable that the manufacturing method of the honeycomb filter of the seventh aspect of the present invention includes a step of installing the above-described honeycomb structure and the end laminated member mainly made of metal in a metal container.

In the method for manufacturing a honeycomb filter according to the seventh aspect of the present invention, the honeycomb structure manufactured by any one of the manufacturing methods according to the second to fifth aspects of the present invention and the laminated member for the end portion are stacked, thereby Either end is sealed, and a honeycomb filter that functions as a filter can be manufactured.
Specifically, as shown in FIG. 3B, a cylindrical casing 123 (metal container) having a pressing metal fitting on one side is used, and first, the end laminated member 10 b is laminated in the casing 123. Then, the honeycomb structure 10a manufactured by any one of the manufacturing methods of the second to fifth aspects of the present invention is installed. Finally, by laminating the end laminated member 10b, and then installing and fixing the pressing metal fitting on the other side, it is possible to produce a honeycomb filter that has been completed up to canning. Examples of the material of the casing include metals such as stainless steel (SUS), aluminum, and iron. The shape is not particularly limited, but is preferably a shape that approximates the outer shape of the honeycomb structure to be stored.

As the end laminated member, it is desirable to laminate an end laminated member made of metal having a predetermined through hole. Thereby, it is possible to manufacture a honeycomb filter in which the end laminated member mainly made of metal is laminated on both ends of the honeycomb structure.

Moreover, as the laminated member for an end portion, an laminated member for an end portion made of inorganic fibers may be laminated, and the laminated member for an end portion made of inorganic fibers is used in the method for manufacturing a honeycomb structure of the second aspect of the present invention. It is possible to manufacture a honeycomb structure having cells formed in a checkered pattern by changing the shape of the holes formed in the die in the extrusion molding process, and manufacturing the honeycomb structure by thinly cutting the honeycomb structure in the cutting process. it can.

In addition, the manufacturing method of the laminated member for edge parts which consists of metals is as follows.
First, a porous metal plate mainly made of metal having a thickness of 0.1 to 20 mm is laser-processed or punched to produce a laminated member for end portion in which through holes are formed in a checkered pattern.

Next, the oxide catalyst is supported on the end laminated member as necessary.
As a method for supporting the oxide catalyst, for example, the end laminated member is immersed for 5 minutes in a solution containing 10 g of CZ (nCeO ₂ · mZrO ₂ ), 1 l (liter) of ethanol, 5 g of citric acid and a pH adjusting agent. Then, the method etc. which perform a baking process at 500 degreeC are mentioned.
In this case, the amount of catalyst to be supported can be adjusted by repeating the dipping and firing steps described above.
The catalyst may be supported only on a part of the end laminated members, or may be supported on all the end laminated members.

Applications of the honeycomb structure of the first aspect of the present invention and the honeycomb filter of the sixth aspect of the present invention are not particularly limited, but it is desirable to use them in a vehicle exhaust gas purification device.
FIG. 8 is a cross-sectional view schematically showing an example of an exhaust gas purifying device for a vehicle in which the honeycomb filter of the sixth aspect of the present invention is installed.

As shown in FIG. 8, in the exhaust gas purification apparatus 200, the casing 123 covers the outside of the honeycomb filter 1 of the sixth aspect of the present invention, and the end of the casing 123 on the side where the exhaust gas is introduced is provided. An introduction pipe 124 connected to an internal combustion engine such as an engine is connected, and a discharge pipe 125 connected to the outside is connected to the other end of the casing 123. In FIG. 8, arrows indicate the flow of exhaust gas.

In the exhaust gas purifying apparatus 200 having such a configuration, exhaust gas discharged from an internal combustion engine such as an engine is introduced into the casing 123 through the introduction pipe 124 and is passed from the cell of the honeycomb filter 1 to the wall (cell wall). ), The particulates are collected and purified by this wall (cell wall), and then discharged through the discharge pipe 125 to the outside.

When a large amount of particulates accumulates on the wall portion (cell wall) of the honeycomb filter 1 and the pressure loss increases, the honeycomb filter 1 is regenerated by a predetermined means such as post-injection to regenerate the honeycomb filter 1. be able to.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
As a method for manufacturing a honeycomb structure, a honeycomb structure was manufactured using a manufacturing method by extrusion molding.
(1) Mixing step First, 12.3 parts by weight of alumina fiber (average fiber length: 0.3 mm, average fiber diameter: 5 μm) composed of 72% alumina and 28% silica, glass fiber (average fiber diameter: 9 μm, average) (Fiber length: 3 mm) 6.2 parts by weight, organic binder (methylcellulose) 11.7 parts by weight, pore former (acrylic) 7.1 parts by weight, plasticizer (Nippon Yushi Co., Ltd. Unilube) 8.1 parts by weight, The mixture was prepared by mixing 3.8 parts by weight of a lubricant (glycerin) and 50.9 parts by weight of water and stirring sufficiently.

(2) The mixture obtained in the extrusion molding step (1) is put into the cylinder from the mixture tank of the plunger type extruder, the piston is pushed into the die side, the mixture is pushed out from the die, and the longitudinal direction is 4.5 mm. A cylindrical shaped body (circle diameter: 160 mm) having x 4.5 mm cells at 2 mm intervals was produced.

(3) The cylindrical shaped product obtained in the cutting step (2) was cut to a length of 60 mm using a cutting device equipped with a cutting disk as a cutting member. As a result, a molded body having a diameter of 160 mm × length of 60 mm in the longitudinal direction was obtained.

(4) The cylindrical shaped product obtained in the drying step (3) is dried at 200 ° C. for 3 hours in an air atmosphere by a microwave dryer and a hot air dryer to remove moisture contained in the molded product. Removed.

(5) The columnar shaped body obtained in the degreasing step (4) was heat-treated in an electric furnace at 400 ° C. for 3 hours in an air atmosphere to remove organic substances contained in the shaped body.

(6) Heat treatment and acid treatment step The cylindrical shaped product obtained in the step (5) was heat-treated in a firing furnace at 950 ° C. for 5 hours in an air atmosphere.
Thereafter, the resulting molded body was subjected to an acid treatment by immersing it in an HCl solution at 90 ° C. and 4 mol / l for 1 hour, and further subjected to a heat treatment at 1050 ° C. for 5 hours to produce a honeycomb structure. .

(7) The honeycomb structure obtained in the catalyst supporting step (6) is immersed in a solution containing 10 g of CZ (nCeO ₂ · mZrO ₂ ), 40 ml of water and an appropriate amount of a pH adjuster for 5 minutes, and then fired at 500 ° C. By performing the treatment, CeO ₂ and ZrO ₂ were supported as oxide catalysts.

(8) Manufacturing process of laminated member for end portion After processing a Ni-Cr alloy metal plate into a disk shape having a diameter of 160 mm and a thickness of 1 mm, laser processing is performed to form a 4.5 mm x 4.5 mm hole. An end laminated member formed in a checkered pattern was manufactured. In this process, two end laminated members are produced, and when the end laminated member is laminated on each end laminated member in the following laminating step, the inlet side end face and the outlet of the honeycomb structure are formed. Holes were formed at positions different from each other so that the sealing locations were different on the side end surfaces.

(9) Canning Step First, a cylindrical casing (metal container) with a pressing metal fitting attached to one side was erected separately so that the side with the metal fitting attached was down. And after laminating | stacking one end laminated member obtained at the process of said (8), the process of said (7) so that the hole of this laminated member for end parts and the position of the cell of a honeycomb structure may match. The honeycomb structure obtained in the above is installed, and finally one end laminated member is laminated, and then a holding metal fitting is also installed and fixed on the other side, whereby a honeycomb filter having a length of 60 mm is obtained. Manufactured.
In this step, the end-portion laminate member is laminated so that the sealing location is different between the inlet-side end face and the outlet-side end face of the honeycomb filter (so that only one of the overlapping cells is sealed). did.
In this canning step, one honeycomb structure is installed in the casing, and the end laminated members are laminated (arranged) on both ends thereof. If this honeycomb structure is regarded as a laminated member, the state of the honeycomb filter after the end of the canning process corresponds to a state in which a total of three laminated members including the laminated member for the end portion are laminated and installed in the casing. The integrally formed honeycomb structure is represented as one laminated member.

(Example 2)
As a method for manufacturing a honeycomb structure, a honeycomb structure was manufactured using a manufacturing method based on resin curing (core erection).
(1) Mixing process First, 14.0 parts by weight of alumina fiber (average fiber length: 0.3 mm, average fiber diameter: 5 μm) composed of 72% alumina and 28% silica, glass fiber (average fiber diameter: 9 μm, average) (Fiber length: 3 mm) 7.1 parts by weight and thermosetting resin (epoxy resin) 78.9 parts by weight were mixed, and the mixture was prepared by sufficiently stirring.

(2) The mixture obtained in the core erecting step and the mixture filling step (1) is a plan view lattice of cores made of core sand (4.5 mm × 4.5 mm × 60 mm) at intervals of 2 mm. The mixture was poured into a cylindrical container (inner diameter: diameter 160 mm × longitudinal length 60 mm) standing upright.

(3) The cylindrical container filled with the mixture obtained in the resin curing step (2) was heat-treated at 120 ° C. for 30 minutes to cure the epoxy resin, thereby producing a cured resin body.

(4) Core removal step The cylindrical container was removed from the cured resin body, the core portion was struck with a thin rod-shaped body to break the core, and the core was removed from the cured resin body. As a result, a molded body having a diameter of 160 mm × length of 60 mm in the longitudinal direction was obtained.
Thereafter, the steps after the drying step were performed in the same manner as in Example 1 to manufacture a honeycomb structure and a honeycomb filter.

(Example 3)
10 parts by weight of a curing agent for epoxy resin is added to the mixture in advance, and then the mixture filling step is performed quickly, the epoxy resin is cured by the action of the curing agent, and heat treatment for resin curing is not performed. In the same manner as in Example 2, a honeycomb structure and a honeycomb filter were produced.

Example 4
A honeycomb structure and honeycomb as in Example 2, except that a polycarbonate (PC) core was used and the epoxy resin was degreased and the core removed simultaneously by heating in the degreasing step after the cured body was formed. A filter was manufactured.

(Example 5)
A honeycomb was formed in the same manner as in Example 2, except that a core made of tin, which is a low melting point metal, was used and the core was thermally melted and removed by heating to 240 ° C. above the melting point of tin after forming the cured body. A structure and a honeycomb filter were manufactured.

(Example 6)
Example 2 except that a core obtained by melt-molding sodium chloride (NaCl), which is a water-soluble salt, was used to dissolve and remove the core by dissolving sodium chloride in hot water at 60 ° C. after forming the cured body. In the same manner, a honeycomb structure and a honeycomb filter were produced.

(Example 7)
The same as Example 2 except that a core (4.5 mm × 4.5 mm part and 3.5 mm × 3.5 mm part, total length 60 mm) having a step as shown in FIG. Thus, a honeycomb structure and a honeycomb filter were manufactured.

(Example 8)
As a method for manufacturing a honeycomb structure, a honeycomb structure was manufactured by using a manufacturing method by resin curing (molding).
(1) Mixing step A mixture was prepared in the same manner as in Example 2.

(2) Mixture filling step A circular (diameter of 160 mm) bottom plate body made of Ni-Cr stainless steel, in which columnar columns (4.5 mm x 4.5 mm x 60 mm) are erected in a plan view lattice at intervals of 2 mm The mixture obtained in (1) was poured into a mold body consisting of a cylindrical (inner diameter: diameter 160 mm × longitudinal length 60 mm) container provided therearound, and filled with the mixture.

(3) Resin curing step A cured resin was produced in the same manner as in Example 2.

(4) Mold body detachment step The column body was pulled out from the cured resin body, and the outer frame body was also removed to remove the entire mold body from the cured resin body. As a result, a molded body having a diameter of 160 mm × length of 60 mm in the longitudinal direction was obtained.
Thereafter, the steps after the drying step were performed in the same manner as in Example 2 to manufacture a honeycomb structure and a honeycomb filter.

Example 9
As a method for manufacturing a honeycomb structure, a honeycomb structure was manufactured using a manufacturing method using three-dimensional papermaking.
(1) Mixing step First, 1.0 part by weight of alumina fiber (average fiber length: 0.3 mm, average fiber diameter: 5 μm) composed of 72% alumina and 28% silica, glass fiber (average fiber diameter: 9 μm, average) Fiber length: 3 mm) 0.5 part by weight, organic binder (polyvinyl alcohol) 0.08 part by weight, and water 50 part by weight were mixed and mixed sufficiently.

(2) Vibrator provided in the tank by charging the mixture obtained in the mixture filling process and the stirring process (1) into a liquid filling part in a tank having a volume of 50 liters and a liquid filling part having a height of 200 mm. Was stirred so that the mixture in the tank was uniform.

(3) Dehydration process and compression process (three-dimensional papermaking process)
The cock at the bottom of the tank was opened, the drainage pump was operated, the water in the mixture in the tank was discharged through the mesh, the mixture was dehydrated, and a dehydrated body was formed.
Subsequently, the press plate is placed by aligning the position of the through hole of the press plate and the columnar mask, the motor coupled to the ball screw is operated, and the press plate is pushed downward, so that the length of the dehydrator is reduced. Pressurized and compressed to 60 mm to form a compressed body.

(4) Mask Desorption Step The columnar mask was removed from the compressed body to obtain a molded body having a diameter of 160 mm × longitudinal length of 60 mm.
Thereafter, the steps after the drying step were performed in the same manner as in Example 1 to manufacture a honeycomb structure and a honeycomb filter.

(Comparative Example 1)
As a method for manufacturing a honeycomb structure, a honeycomb structure was manufactured by using a manufacturing method in which a large number of sheet-like laminated members were stacked.
(1) Preparation of papermaking slurry In the same manner as in Example 1, a mixture was prepared and sufficiently stirred to prepare a papermaking slurry.

(2) The slurry obtained in the paper making step (1) is made with a mesh having a diameter of 160 mm, and the obtained product is dried at 150 ° C., and then punched to give 4.5 mm × 4.5 mm. A sheet-like inorganic fiber aggregate having a thickness of 1 mm in which the cells were formed on the entire surface at intervals of 2 mm was obtained.

(3) The sheet-like inorganic fiber aggregate obtained in the catalyst supporting step (2) is immersed in a solution containing 10 g of CZ (nCeO ₂ · mZrO ₂ ), 40 ml of water and a pH adjuster for 5 minutes, and then By performing a baking treatment at 500 ° C., CeO ₂ and ZrO ₂ were supported as oxide catalysts.

(4) Laminating step And, as in Example 1, after laminating one end laminated member, the holes of the end laminated member and the through-holes of the sheet-like inorganic fiber aggregate are aligned. 68 sheet-like inorganic fiber aggregates are laminated, and finally one metal laminated member is laminated, and further pressed, and then the other side is provided with a holding metal fitting and fixed, so that the length is increased. A honeycomb filter made of a 60 mm laminate was obtained.
The metal laminated member was laminated so that the sealing location was different between the inlet side end face and the outlet side end face of the honeycomb filter (only one of the overlapping cells was sealed).

(Evaluation)
The pressure loss was measured using a pressure loss measuring device 170 as shown in FIG. FIG. 9 is an explanatory diagram of a pressure loss measuring device.
This pressure loss measuring device 170 is configured such that a honeycomb filter 1 is fixedly disposed in an exhaust gas pipe 177 of a blower 176 in a metal casing 171 and a pressure gauge 178 is attached so that the pressure before and after the honeycomb filter 1 can be detected. It is.
The blower 176 was operated so that the exhaust gas flow rate was 750 m ³ / h, and the differential pressure (pressure loss) after 5 minutes from the start of the operation was measured.
The results are as shown in Table 1.

As shown in Table 1, the initial pressure loss is as small as 13.5 to 14.6 in the honeycomb structure having one laminated sheet as shown in Examples 1 to 9.
In particular, the pressure loss is small in Example 10 in which unevenness is formed in the through hole.

On the other hand, when the number of stacked layers is 68 as in Comparative Example 1, the pressure loss is high because many stacked interfaces exist.
From the above, compared with a honeycomb structure in which a large number of sheet-like inorganic fiber aggregates are laminated, the number of laminated layers is one (ie, a honeycomb structure in which inorganic fibers are integrally formed). It has become clear that the pressure loss during the exhaust gas treatment can be reduced by using.

DESCRIPTION OF SYMBOLS 1,100 Honeycomb filter 10a Honeycomb structure 10b End part laminated member 11, 111 Cell 13, 113 Wall part 20 Tubular container 21 Core 22 Mixture 23 Resin hardened body 24 Column-shaped molded object 30 Mold frame 31 Column body 32 Bottom plate body 33 Outer frame body 40 Tank 41 Columnar mask 42 Mesh 43 Liquid filling part 47 Tank body 51 Inorganic fiber 52 Inorganic substance 74 Dice 123 Casing (metal container)

Claims (10)

A mixing step of mixing the inorganic fibers A and the inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A do not melt or sublime;
Extruding the mixture obtained in the mixing step through a die in which predetermined holes are formed, thereby forming a columnar shaped body in which a number of cells are formed in the longitudinal direction,
A heat treatment step of heat-treating the molded body at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particles C;
An acid treatment step of acid-treating the columnar shaped body,
The method for manufacturing a honeycomb structured body, wherein the inorganic fibers B and / or the inorganic particles C contain silica. A mixing step of mixing an inorganic fiber A, an inorganic fiber B and / or inorganic particles C that melt at a temperature at which the inorganic fiber A does not melt or sublime, and a resin;
The longitudinal direction of the cylindrical container for filling the mixture obtained in the mixing step and the long axis direction of the columnar core for forming the cells of the honeycomb structure are parallel to each other, and in a plan view lattice shape A core erecting step of erecting a plurality of the cores in the cylindrical container to be,
In the cylindrical container in which the core is erected in the core erecting step, the mixture filling step of filling the mixture,
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
By removing the core in the resin cured body obtained in the resin curing step, a core removal step of forming a columnar shaped body in which a number of cells are formed in the longitudinal direction;
A degreasing step of removing organic matter contained in the molded body obtained in the core removing step by heat degreasing;
A heat treatment step of heat-treating the molded body degreased in the degreasing step at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and a temperature equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particles C;
An acid treatment step of acid-treating the columnar shaped body,
The method for manufacturing a honeycomb structured body, wherein the inorganic fibers B and / or the inorganic particles C contain silica. A mixing step of mixing an inorganic fiber A, an inorganic fiber B and / or inorganic particles C that melt at a temperature at which the inorganic fiber A does not melt or sublime, and a resin;
A mold body for filling the mixture obtained in the mixing step, wherein pillars for forming cells of the honeycomb structure are erected in a lattice shape perpendicular to the main surface and in a plan view A mixture filling step of filling the mixture obtained in the mixing step into a mold body composed of the bottom plate body and an outer frame body provided so as to surround the bottom plate body and the column body;
A resin curing step of curing the resin in the mixture filled in the mixture filling step to form a resin cured body;
A mold body that forms a column-shaped molded body in which a large number of cells are formed in the longitudinal direction by removing the column body from the cured resin body obtained in the resin curing step and removing the entire mold body. A desorption step;
A degreasing step of removing the organic matter contained in the molded body obtained in the mold body detaching step by heat degreasing;
A heat treatment step of heat-treating the molded body degreased in the degreasing step at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and a temperature equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particles C;
An acid treatment step of acid-treating the columnar shaped body,
The method for manufacturing a honeycomb structured body, wherein the inorganic fibers B and / or the inorganic particles C contain silica. A tank body, a mesh formed at the bottom of the tank body, and a columnar mask that is perpendicular to the mesh and is erected on the mesh in a plan view lattice to form cells of the honeycomb structure; A method for manufacturing a honeycomb structure, wherein the mesh is a bottom surface and is a space surrounded by the columnar mask, and is performed using a tank provided with a liquid filling part for charging a mixture,
A mixing step of mixing the inorganic fibers A and the inorganic fibers B and / or inorganic particles C that melt at a temperature at which the inorganic fibers A do not melt or sublime;
A mixture filling step of charging the mixture obtained in the mixing step into the liquid filling unit;
A dehydration step of discharging moisture in the mixture through the mesh to form a dehydrated body;
By removing the columnar mask from the dehydrated body, a mask detachment step for forming a columnar shaped body in which a number of cells are formed in the longitudinal direction;
A heat treatment step in which the molded body formed in the mask detachment step is heat-treated at a temperature equal to or lower than a heat resistant temperature of the inorganic fiber A and equal to or higher than a softening temperature of the inorganic fiber B and / or the inorganic particles C;
An acid treatment step of acid-treating the columnar shaped body,
The method for manufacturing a honeycomb structured body, wherein the inorganic fibers B and / or the inorganic particles C contain silica. The method for manufacturing a honeycomb structure according to any one of claims 1 to 4, wherein the acid treatment step is a step of immersing the formed body in a treatment solution having a concentration of 1 to 10 mol / l. The method for manufacturing a honeycomb structure according to any one of claims 1 to 5, wherein a treatment time of the acid treatment step is 0.5 to 24 hours. The method for manufacturing a honeycomb structure according to any one of claims 1 to 6, wherein a treatment temperature in the acid treatment step is 70 to 100 ° C. The heat treatment step includes a primary firing step and a secondary firing step,
The manufacturing method of the honeycomb structure according to any one of claims 1 to 7, wherein the acid treatment step is performed after the primary firing step, and then the secondary firing step. The honeycomb structure according to any one of claims 1 to 8, wherein the inorganic fiber A is composed of at least one selected from the group consisting of silicon carbide, alumina, basalt, silica, silica-alumina, titania and zirconia. Method. The method for manufacturing a honeycomb structured body according to any one of claims 1 to 9, further comprising a step of supporting an oxide catalyst on the inorganic fibers.

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