WO2009118811A1 - Honeycomb structure - Google Patents

Abstract

A honeycomb structure that is adapted for preventing of any breakage caused by compressive force applied from outside the honeycomb structure and also adapted for relaxing of any stress generated within the honeycomb structure. The honeycomb structure comprises multiple columnar honeycomb fired bodies bonded together by means of bonding material layers. The honeycomb structure in its cross section is composed of a peripheral section constituting the peripheral side of the honeycomb structure and a central section lying inside the peripheral section and being quadrangular in the sectional configuration. The central section consists of one or multiple central honeycomb fired bodies. The peripheral section consists of, bonded together by means of the bonding material layers, multiple peripheral honeycomb fired bodies. In the cross section of the honeycomb structure, at least one of the bonding material layers of the peripheral section is provided in the direction from a corner portion of the central section toward the peripheral side face. Each of the bonding material layers provided in the direction from a corner portion of the central section toward the peripheral side face has an angle of 40° to 50° with reference to at least one of the bonding material layers provided in the direction from a non-corner portion of the central section toward the peripheral side face.

Description

Honeycomb structure

The present invention relates to a honeycomb structure.

A recent problem is that particulate matter (hereinafter also simply referred to as particulates or PM) contained in exhaust gas discharged from internal combustion engines such as buses and trucks and construction machinery and the like causes harm to the environment and the human body. It has become.
Therefore, various honeycomb structures made of porous ceramics have been proposed as diesel particulate filters (hereinafter also simply referred to as DPF) that can collect particulates in exhaust gas and purify the exhaust gas.

As such a honeycomb structure, for example, a honeycomb structure manufactured by binding a plurality of square pillar-shaped honeycomb fired bodies through an adhesive layer and then cutting them into a predetermined shape has been proposed. (For example, refer to Patent Document 1).
Further, there has been proposed a honeycomb structure manufactured by binding a plurality of honeycomb fired bodies, each of which has been previously extruded into a predetermined shape, through an adhesive layer (for example, Patent Document 2). reference).

WO01 / 23069 pamphlet JP 2004-154718 A

When the honeycomb structure is used as a DPF, it is necessary to hold the honeycomb structure in a predetermined case via a holding sealing material. In order to prevent the honeycomb structure from shifting in the case or part of the honeycomb fired body from falling out of the honeycomb structure due to exhaust gas, the honeycomb structure needs to be securely fixed in the case. .
However, in this case, the honeycomb structure may be damaged due to the compressive stress applied from the outside of the honeycomb structure.

The present inventors have studied to prevent the honeycomb structure from being damaged and completed the present invention. That is, the honeycomb structure according to claim 1
Columnar honeycomb fired bodies in which a large number of cells are arranged in parallel in the longitudinal direction across the cell wall are a honeycomb structure in which a plurality of cells are bound via an adhesive layer,
In the cross section perpendicular to the longitudinal direction of the honeycomb structure, the outer peripheral portion constituting the outer peripheral side of the honeycomb structure, the inner portion of the outer peripheral portion, the cross-sectional shape has a square central portion,
The central portion is composed of one central honeycomb fired body, or a plurality of central honeycomb fired bodies that are bound via the adhesive layer,
The outer peripheral portion is composed of a plurality of outer peripheral honeycomb fired bodies bound through the adhesive layer,
In a cross section perpendicular to the longitudinal direction of the honeycomb structure, at least one of the outer peripheral adhesive layers is formed in a direction from the corner of the central portion toward the outer peripheral side of the honeycomb structure. And
The adhesive layer formed in a direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure is formed in a direction toward the outer peripheral side surface of the honeycomb structure from other than the corner portion of the central portion. A honeycomb structure having an angle of 40 ° to 50 ° with at least one of the adhesive layers.

Hereinafter, in the present specification, among the adhesive layers in the outer peripheral portion, the adhesive layer formed in the direction from the corner portion in the central portion toward the outer peripheral side surface of the honeycomb structure is referred to as “first outer peripheral portion. Also referred to as an “adhesive layer”, the adhesive layer formed in a direction from the corner portion other than the central portion toward the outer peripheral side surface of the honeycomb structure is also referred to as a “second outer peripheral adhesive layer”.

In the present invention, the central portion in the cross section perpendicular to the longitudinal direction of the honeycomb structure is the center honeycomb fired body, the adhesive layer that binds the center honeycomb fired bodies, and the center honeycomb fired body. It refers to a region occupied by an adhesive layer that binds the outer peripheral honeycomb fired body. Further, the outer peripheral portion in the cross section perpendicular to the longitudinal direction of the honeycomb structure refers to a region occupied by the outer peripheral honeycomb fired body and an adhesive layer that binds the outer peripheral honeycomb fired bodies.

The honeycomb structure according to claim 1, wherein the honeycomb structure includes the central portion and the outer peripheral portion, and the outer peripheral portion located outside the central portion has an outer periphery constituting a part of an outer peripheral side surface of the honeycomb structure. A plurality of partial honeycomb fired bodies are bundled through an adhesive layer.
Here, in the cross section perpendicular to the longitudinal direction of the honeycomb structure, among the adhesive layers interposed between the outer peripheral honeycomb fired bodies, the direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure And an adhesive layer (second outer periphery) formed in a direction from the corner portion other than the central portion toward the outer peripheral side surface of the honeycomb structure. The angle formed by at least one of the partial adhesive layers is 40 to 50 °.
Therefore, it is possible to prevent the honeycomb structure from being damaged by the compressive stress applied from the outside of the honeycomb structure.

In addition, since the first outer peripheral adhesive layer is formed in a direction from the central corner to the outer peripheral side surface of the honeycomb structure, the central honeycomb firing is performed at the central corner. Two of the adhesive layers interposed between the body and the outer peripheral honeycomb structure and the first outer peripheral adhesive layer form a trident. In this way, if there is a portion where the adhesive layer has a trident in a cross section perpendicular to the longitudinal direction of the honeycomb structure, damage to the honeycomb structure can be prevented.

On the other hand, in the honeycomb structures described in Patent Documents 1 and 2, since the adhesive layer is formed in a lattice shape, the compressive stress applied in a specific direction (the direction in which the adhesive layer is formed) In contrast, although it has high strength, the strength is weak against compressive stress applied in other directions, for example, the direction of 45 ° with the adhesive layer, and the honeycomb structure is easily damaged.
In addition, in the honeycomb structures described in Patent Documents 1 and 2, since the adhesive layers cross each other in a cross shape, it is difficult to disperse the stress generated in the honeycomb structure, and the honeycomb structure is damaged. Cheap.

In the present invention, the center-portion honeycomb fired body refers to a honeycomb fired body that does not constitute the outer peripheral side surface of the honeycomb structure in a cross section perpendicular to the longitudinal direction of the honeycomb structure.
The angle formed by the first outer peripheral adhesive layer and the second outer peripheral adhesive layer is a straight line passing through the first outer peripheral adhesive layer and the other second outer peripheral adhesive. The angle formed by a straight line passing through the layer.

The invention according to claim 2 is the invention according to claim 1,
The central portion is composed of a plurality of central portion honeycomb fired bodies that are bound through the adhesive layer,
In a cross section perpendicular to the longitudinal direction of the honeycomb structure, the adhesive is interposed between the outer peripheral honeycomb fired bodies and is formed in a direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure. At least one of the material layers is linear with any one of the adhesive material layers interposed between the above-mentioned center-portion honeycomb fired bodies.
Such an adhesive layer can serve as a so-called beam for further improving the strength of the honeycomb structure.

Hereinafter, in the present specification, when simply referred to as a cross section of a honeycomb structure, a cross section of a honeycomb fired body, or a cross section of a honeycomb formed body, a cross section perpendicular to the longitudinal direction of the honeycomb structure, respectively, It refers to a cross section perpendicular to the longitudinal direction or a cross section perpendicular to the longitudinal direction of the honeycomb formed body.
Further, in this specification, when simply expressed as a cross-sectional area of a honeycomb fired body, it indicates a cross-sectional area of a cross section perpendicular to the longitudinal direction of the honeycomb fired body.

As described above, the honeycomb fired body constituting the honeycomb structure of the present invention includes the central honeycomb fired body and the outer peripheral honeycomb fired body. However, in the following description, when it is not necessary to distinguish between the two, it is simply expressed as a honeycomb fired body.

(First embodiment)
Hereinafter, a first embodiment which is an embodiment of a honeycomb structure of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view schematically showing the honeycomb structure of the first embodiment. FIG. 2A is a perspective view schematically showing the center-portion honeycomb fired body in the honeycomb structure of the first embodiment. FIG. 2B is a cross-sectional view taken along the line BB of FIG. FIG. 3 is a perspective view schematically showing the outer peripheral honeycomb fired body in the honeycomb structure of the first embodiment. 4 is a cross-sectional view taken along line AA in FIG.

In the honeycomb structure 100 shown in FIG. 1 and FIG. 4, the central honeycomb fired body 110 having the shape shown in FIGS. 2A and 2B and the outer peripheral honeycomb fired body 120 having the shape shown in FIG. Are bonded together via adhesive layers 101 (101A to 101D) to form a ceramic block 103, and a coat layer 102 is formed on the outer periphery of the ceramic block 103.
The shape of the cross section of the central honeycomb fired body 110 is a square.
The cross-sectional shape of the outer peripheral honeycomb fired body 120 is surrounded by three line segments 120a, 120b, and 120c and one arc 120d, and two corners (line lines) formed by two of the three line segments. The angle formed by the minute segment 120b and the line segment 120c and the angle formed by the line segment 120a and the line segment 120b) are 90 ° and 135 °, respectively.
The honeycomb fired bodies 110 and 120 are made of a porous silicon carbide sintered body.

In the central honeycomb fired body 110 shown in FIGS. 2 (a) and 2 (b), a large number of cells 111 are arranged in parallel in the longitudinal direction (in the direction of arrow a in FIG. 2 (a)) with a cell wall 113 therebetween. One end of the cell 111 is sealed with a sealing material 112. Therefore, the exhaust gas G (see the arrow in FIG. 2B) flowing into the cell 111 with one end face opened must pass through the cell wall 113 separating the cell 111, and then the other cell with the other end face opened. 111 is flowing out.
Therefore, the cell wall 113 functions as a filter for collecting PM and the like.

Similarly to the central honeycomb fired body 110, the outer peripheral honeycomb fired body 120 shown in FIG. 3 has a large number of cells 121 arranged in parallel in the longitudinal direction across the cell wall 123. Is sealed with a sealing material 122. Therefore, the exhaust gas that has flowed into the cell 121 having one open end face always passes through the cell wall 123 separating the cells 121 and then flows out from the other cell 121 having the other end face open.
That is, the outer peripheral honeycomb fired body 120 has the same function as the central honeycomb fired body 110, although the outer shape is different from the central honeycomb fired body 110.

In the honeycomb structure 100, as shown in FIGS. 1 and 4, four central honeycomb fired bodies 110 are located at the center of the cross section of the honeycomb structure 100, and eight peripheral honeycomb fired bodies are disposed around the central fired body. 120 is positioned, and the honeycomb structure 100 (ceramic block 103) is bound through the adhesive layer 101 so that the cross section of the honeycomb structure 100 (ceramic block 103) is circular.
The four central honeycomb fired bodies 110 bundled through the adhesive layer 101A constitute a central portion in the cross section of the honeycomb structure 100, and are bonded through the adhesive layers 101C and 101D. Each of the outer peripheral honeycomb fired bodies 120 constitutes an outer peripheral portion in the cross section of the honeycomb structure 100.
In the cross section of the honeycomb structure 100 having such a configuration (see FIG. 4), four central honeycomb fired bodies 110, an adhesive layer 101A for binding the central honeycomb fired bodies 110, and the central honeycomb fired body. The region occupied by the adhesive layer 101B that binds the body 110 and the outer peripheral honeycomb fired body 120 is the central portion, and the eight outer peripheral honeycomb fired bodies 120 and the outer peripheral honeycomb fired bodies 120 are bonded together. The area occupied by 101C and 101D is the outer periphery.

The honeycomb structure 100 has an adhesive layer (first layer) formed in a direction from the central corner to the outer peripheral side surface of the outer peripheral adhesive layers 101C and 101D in the cross section. One outer peripheral adhesive layer (101C) and an adhesive layer (second outer peripheral adhesive layer) 101D formed in a direction from the corner portion other than the central portion toward the outer peripheral side surface of the honeycomb structure 100 are 45. It has an angle of °.
As described above, when the first outer peripheral adhesive layer and the second outer peripheral adhesive layer form 45 °, it is possible to prevent the honeycomb structure from being damaged.

Further, in the honeycomb structure 100, the first outer peripheral adhesive layer 101C and the adhesive layer 101B that binds the central honeycomb fired body 110 and the outer peripheral honeycomb fired body 120 are formed at the corners of the central portion. It has a trident.
Thus, if there is a portion in which the adhesive layer has a trident in the cross section of the honeycomb structure, the honeycomb structure can be prevented from being damaged.

Further, in the honeycomb structure 100, in the cross section, the second outer peripheral adhesive layer 101D is linear with the adhesive layer 101A that binds the central honeycomb fired bodies 110 together.
Such an adhesive layer can serve as a so-called beam for further improving the strength of the honeycomb structure.

Next, a method for manufacturing the honeycomb structure of the present embodiment will be described.
(1) A forming step for producing a honeycomb formed body by extruding a wet mixture containing a ceramic powder and a binder is performed.
Specifically, first, a silicon carbide powder having a different average particle size as a ceramic powder, an organic binder, a liquid plasticizer, a lubricant, and water are mixed using a wet mixer to produce a honeycomb molded body. A wet mixture of is prepared.
Subsequently, the wet mixture is charged into an extruder. The wet mixture is put into an extruder and extruded to produce a honeycomb formed body having a predetermined shape.

Here, a honeycomb molded body having a square cross section, or a cross section surrounded by three line segments and one arc, two angles formed by two of the three line segments are 90 ° and 135 °, respectively. In order to produce a honeycomb molded body having a shape of 0 °, an extrusion mold corresponding to each shape is used.

(2) Next, the honeycomb formed body is cut into a predetermined length and dried using a microwave dryer, hot air dryer, dielectric dryer, vacuum dryer, vacuum dryer, freeze dryer, or the like. Then, a sealing step of filling a predetermined cell with a sealing material paste as a sealing material and sealing the cell is performed.
In addition, the conditions conventionally used when manufacturing a honeycomb fired body can be applied to the conditions of the cutting process, the drying process, and the sealing process.

(3) Next, a degreasing step of heating the organic matter in the honeycomb molded body in a degreasing furnace is performed, and the honeycomb fired body is transported to the firing furnace and the firing step is performed to produce a honeycomb fired body.
In addition, as conditions of a degreasing process and a baking process, the conditions conventionally used when manufacturing a honeycomb fired body are applicable.
Through the above steps, the central honeycomb fired body and the outer peripheral honeycomb fired body can be manufactured.

(4) Next, an adhesive paste layer is formed by applying an adhesive paste to the predetermined side surfaces of the center honeycomb fired body and the peripheral honeycomb fired body in which predetermined ends of each cell are sealed. Then, a step of laminating other honeycomb fired bodies sequentially on this adhesive paste layer is repeated to perform a binding step for producing a ceramic block in which a predetermined number of honeycomb fired bodies are bound.
Here, as the adhesive paste, for example, a paste made of an inorganic binder, an organic binder, and inorganic particles is used. The adhesive paste may further contain inorganic fibers and / or whiskers.

(5) Next, a coating layer forming step is performed in which a coating material paste is applied to the outer periphery of the cylindrical ceramic block, dried and solidified to form a coating layer.
Here, as the coating material paste, the same paste as the adhesive paste is used. In addition, you may use the paste of a different composition as a coating material paste.
Note that the coat layer is not necessarily provided, and may be provided as necessary.
Through the above steps, the honeycomb structure of the present embodiment can be manufactured.

Hereinafter, effects of the honeycomb structure of the present embodiment will be listed.
(1) In the honeycomb structure of the present embodiment, since the first outer peripheral adhesive layer and the second outer peripheral adhesive layer form 45 ° as described above, it is applied from the outside of the honeycomb structure. It is possible to prevent the honeycomb structure from being damaged by the compressive stress.

(2) In the honeycomb structure of the present embodiment, there is a portion where the adhesive layer has a trident in the cross section of the honeycomb structure, so that the honeycomb structure can be prevented from being damaged.

(3) In the honeycomb fired body constituting the honeycomb structure of the present embodiment, one end of each cell is sealed with a sealing material. Therefore, the honeycomb structure of the present embodiment can be suitably used as a diesel particulate filter.
(4) In the honeycomb structure of the present embodiment, since the coat layer is formed on the outer peripheral side surface of the ceramic block, leakage of particulates from the outer peripheral side surface of the honeycomb structure can be prevented.

Example 1
Examples that more specifically disclose the first embodiment of the present invention will be described below. In addition, this invention is not limited only to these Examples.

(1) 52.8% by weight of silicon carbide coarse powder having an average particle size of 22 μm and 22.6% by weight of fine powder of silicon carbide having an average particle size of 0.5 μm are mixed, and the resulting mixture is mixed. 2.1% by weight of acrylic resin, 4.6% by weight of organic binder (methyl cellulose), 2.8% by weight of lubricant (Unilube manufactured by NOF Corporation), 1.3% by weight of glycerin, and 13.8% by weight of water Was added and kneaded to obtain a wet mixture, followed by a molding step of extrusion molding.
In this step, a raw honeycomb molded body having substantially the same shape as the center-portion honeycomb fired body 110 shown in FIGS. 2A and 2B and having no cell plugged, and FIG. Further, a raw honeycomb molded body having substantially the same shape as the outer peripheral honeycomb fired body 120 and having no cell sealing was produced.

(2) Next, the raw honeycomb molded body is dried using a microwave dryer to obtain a dried honeycomb molded body, and then a predetermined cell is filled with a paste having the same composition as the wet mixture, and again It dried using the dryer.

(3) A degreasing step of degreasing the dried honeycomb formed body at 400 ° C. was performed, and further a firing step was performed at 2200 ° C. for 3 hours under an atmospheric pressure of argon atmosphere.
As a result, the porosity was 45%, the average pore diameter was 15 μm, the size was 34.5 mm × 34.5 mm × 150 mm, the number of cells (cell density) was 300 / inch ² , and the cell wall thickness was 0.1. A central honeycomb fired body 110 made of 25 mm (10 mil) porous silicon carbide sintered body;
The porosity, the average pore diameter, the number of cells (cell density), and the cell wall thickness are the same as those of the central honeycomb fired body 110, and the cross section is surrounded by three line segments and one arc. The outer periphery of the shape (line segment 120a = 20.8 mm, line segment 120b = 35.0 mm, line segment 120c = 35.7 mm) in which two angles formed by two line segments of the segment are 90 ° and 135 °, respectively. Part honeycomb fired body 120 was manufactured.

(4) Adhesive paste is applied to predetermined side surfaces of the central honeycomb fired body 110 and the peripheral honeycomb fired body 120, and four central honeycomb fired bodies 110 and the outer peripheral part are interposed through the adhesive paste. By bonding 8 honeycomb fired bodies 120 so that the arrangement shown in FIG. 1 is obtained, and further solidifying the adhesive paste at 180 ° C. for 20 minutes, the thickness of the adhesive layer is 1 mm and cylindrical. The ceramic block 103 was produced.
Here, the adhesive paste is composed of 30.0% by weight of silicon carbide particles having an average particle diameter of 0.6 μm, 21.4% by weight of silica sol, 8.0% by weight of carboxymethylcellulose, and 40.6% by weight of water. Adhesive paste was used.

(5) A coating material paste layer was formed on the outer periphery of the ceramic block 103 using a coating material paste having the same composition as the adhesive paste used in the step (4). Thereafter, this coating material paste layer was dried at 120 ° C. to produce a cylindrical honeycomb structure 100 having a diameter of 143.8 mm and a length of 150 mm, in which the coating layer 102 was formed on the outer periphery.

The cross-sectional shape of the honeycomb structure manufactured in Example 1 is as shown in FIG.
Therefore, in the honeycomb structure 100, in the cross section of the honeycomb structure 100, the angle formed by the first outer peripheral adhesive layer 101C and the second outer peripheral adhesive layer 101D is 45 °.
Further, in the cross section of the honeycomb structure 100, the first outer peripheral adhesive layer 101C and the adhesive layer 101B for binding the central honeycomb fired body 110 and the outer peripheral honeycomb fired body 120 form a trident. There is a part.

(Comparative Example 1)
(1) By performing the same steps as the steps (1) to (3) of Example 1, the porosity is 45%, the average pore diameter is 15 μm, the size is 34.3 mm × 34.3 mm × 150 mm, A honeycomb fired body made of a porous silicon carbide sintered body having a cell number (cell density) of 300 / inch ² and a cell wall thickness of 0.25 mm (10 mil) was produced.

(2) Adhesive paste is applied to the side face of the honeycomb fired body, 16 honeycomb fired bodies are bonded through the adhesive paste, and further, the adhesive paste is solidified at 180 ° C. for 20 minutes to bond. An aggregate of honeycomb fired bodies having a prism shape with a material layer thickness of 1 mm was manufactured.
Here, the same adhesive paste as the adhesive paste used in Example 1 was used as the adhesive paste.

Next, the outer periphery of the aggregate of the honeycomb fired bodies was ground using a diamond cutter to produce a cylindrical ceramic block.
Then, the coating material paste layer was formed in the outer peripheral part of the ceramic block using the coating material paste which consists of the same material as an adhesive material paste. And this coating material paste layer was dried at 120 degreeC, and the cylindrical honeycomb structure of diameter 143.8mm x length 150mm in which the coating layer was formed in the outer periphery was manufactured.

The cross-sectional shape of the honeycomb structure manufactured in Comparative Example 1 is as shown in FIG.
FIG. 5 is a cross-sectional view of the honeycomb structure 400 manufactured in Comparative Example 1. In FIG. 5, 410 is a central honeycomb fired body, 420 and 430 are outer peripheral honeycomb fired bodies, 401A to 401D are adhesive layers, Reference numeral 402 denotes a coating layer, and 403 denotes a ceramic block.
In the honeycomb structure 400, in the cross section, the first outer peripheral adhesive layer 401C and the second outer adhesive layer 401D are parallel or 90 °. Further, in the cross section of the honeycomb structure 400, there is no portion where the adhesive layer has a trident.

(Evaluation of honeycomb structure)
Example 1 and comparison in accordance with “Testing method of ceramic monolith carrier for automobile exhaust gas purification catalyst (JASO M 505-87)” prescribed by the Automotive Standards (Japan Automobile Standards Organization) established by the Japan Society for Automotive Engineers (Japan) With respect to the honeycomb structure manufactured in Example 1, isostatic strength was measured.

As a result of measuring the isostatic strength, the isostatic strength of the honeycomb structure of Example 1 was 9 MPa.
On the other hand, the isostatic strength of the honeycomb structure of Comparative Example 1 was 6 MPa.
As described above, the honeycomb structure of the first embodiment is suitable for preventing the honeycomb structure from being damaged as compared with the conventional honeycomb structure (the honeycomb structure of Comparative Example 1). Became clear.

(Second embodiment)
Hereinafter, a second embodiment, which is another embodiment of the honeycomb structure of the present invention, will be described with reference to the drawings.
FIG. 6 is a cross-sectional view of the honeycomb structure of the second embodiment.

In the honeycomb structure 200 of the present embodiment, as shown in FIG. 6, a plurality of central honeycomb fired bodies 210 and outer peripheral honeycomb fired bodies 220 and 230 are bonded together via adhesive layers 201A to 201D. A ceramic block 203 is configured, and a coat layer 202 is formed on the outer periphery of the ceramic block 203.
The cross-sectional shape of the central honeycomb fired body 210 is a square.
The cross-sectional shape of the outer peripheral honeycomb fired body 220 is surrounded by three line segments 220a, 220b, and 220c and one arc 220d, and two corners (line lines) formed by two of the three line segments. The angle formed by the segment 220a and the line segment 220b and the angle formed by the line segment 220b and the line segment 220c) are both 90 °.
The cross-sectional shape of the outer peripheral honeycomb fired body 230 is surrounded by three line segments 230a, 230b, and 230c and one arc 230d, and two corners (line lines) formed by two of the three line segments. The angle formed by the minute segment 230b and the line segment 230c and the angle formed by the line segment 230a and the line segment 230b) are 90 ° and 135 °, respectively.
That is, the center honeycomb fired body 210 is the same as the center honeycomb fired body 110 constituting the honeycomb structure of the first embodiment, and the outer peripheral honeycomb fired bodies 220 and 230 are the honeycomb structure of the first embodiment. Although the external shape is different from that of the center-portion honeycomb fired body 110 constituting the above, its function is the same.
The honeycomb fired bodies 210, 220, and 230 are made of a porous silicon carbide sintered body.

In the honeycomb structure 200, as shown in FIG. 6, nine central honeycomb fired bodies 210 are located at the center of the cross section of the honeycomb structure 100, and eight outer peripheral honeycomb fired bodies 220 around it, Eight outer peripheral honeycomb fired bodies 230 are located, and are bonded through adhesive layers 201A to 201D so that the honeycomb structure 200 (ceramic block 203) has a circular cross section.
The nine central honeycomb fired bodies 210 bundled through the adhesive layer 201A constitute the central portion in the cross section of the honeycomb structure 200, and the total bundled through the adhesive layers 201C and 201D. The 16 outer peripheral honeycomb fired bodies 220 and 230 constitute the outer peripheral portion in the cross section of the honeycomb structure 200.
In the cross section of the honeycomb structure 200 having such a configuration, eight central honeycomb fired bodies 210, an adhesive layer 201A for binding the central honeycomb fired bodies 210, and the central honeycomb fired body 210 and the outer peripheral portion. The area occupied by the adhesive layer 201B that binds the honeycomb fired body 220 is the central portion, and the 16 outer peripheral honeycomb fired bodies 220 and 230 and the outer peripheral honeycomb fired bodies 220 and 230 are bonded together. , 201D occupies the outer periphery.

The honeycomb structure 200 has an adhesive layer (first layer) formed in a direction from the corner of the central portion toward the outer peripheral side surface of the honeycomb structure 200 of the outer peripheral adhesive layers 201C and 201D in the cross section. One outer peripheral adhesive layer (201C) and an adhesive layer (second outer peripheral adhesive layer) 201D formed in a direction from the corner portion other than the central portion toward the outer peripheral side surface of the honeycomb structure 200 are 45. It has an angle of °.
As described above, when the first outer peripheral adhesive layer and the second outer peripheral adhesive layer form 45 °, it is possible to prevent the honeycomb structure from being damaged.

In the honeycomb structure 200, the first outer peripheral adhesive layer 201C and the adhesive layer 201B that binds the central honeycomb fired body 210 and the outer peripheral honeycomb fired body 220 are formed at the corners of the central portion. It has a trident.
Thus, if there is a portion in which the adhesive layer has a trident in the cross section of the honeycomb structure, the honeycomb structure can be prevented from being damaged.

Next, a method for manufacturing the honeycomb structure of the present embodiment will be described.
The manufacturing method of the honeycomb structure in the present embodiment is the same as the manufacturing method of the honeycomb structure in the first embodiment except for the following points.
That is, the shape of the honeycomb formed body produced in the forming step (1) of the manufacturing method of the first embodiment is the center portion shown in FIG. 6 except that either one end of the cell is not sealed. The honeycomb fired body 210 and the outer peripheral honeycomb fired bodies 220 and 230 have substantially the same shape, and when performing the binding step (4) of the manufacturing method of the first embodiment, it is shown in FIG. Thus, except that the honeycomb fired bodies are bundled so that the central honeycomb fired body 210 and the outer peripheral honeycomb fired bodies 220 and 230 are positioned, the method for manufacturing the honeycomb structure in the first embodiment is the same. By using the method, the honeycomb structure of the present embodiment can be manufactured.

In the honeycomb structure of the present embodiment, the same effects as the honeycomb structure of the first embodiment can be enjoyed.

(Example 2)
Examples that more specifically disclose the second embodiment of the present invention will be described below. In addition, this invention is not limited only to these Examples.

(1) Using the same method as in the forming step (1) of Example 1, the shape was substantially the same as that of the central honeycomb fired body 210 and the peripheral honeycomb fired bodies 220 and 230 shown in FIG. Thus, a raw honeycomb molded body without cell sealing was produced.

(2) Next, the raw honeycomb molded body is dried using a microwave dryer to obtain a dried honeycomb molded body, and then a predetermined cell is filled with a paste having the same composition as the wet mixture, and again It dried using the dryer.

(3) A degreasing step of degreasing the dried honeycomb formed body at 400 ° C. was performed, and further a firing step was performed at 2200 ° C. for 3 hours under an atmospheric pressure of argon atmosphere.
Accordingly, the porosity is 45%, the average pore diameter is 15 μm, the size is 34.5 mm × 34.5 mm × 200 mm, the number of cells (cell density) is 300 / inch ² , and the cell wall thickness is 0.00. A central honeycomb fired body 210 made of 25 mm (10 mil) porous silicon carbide sintered body;
The porosity, average pore diameter, number of cells (cell density), and cell wall thickness are the same as those of the central honeycomb fired body 210, and the cross section is surrounded by three line segments and one arc. Outer part honeycomb firing of a shape in which two corners made of two of the line segments are 90 ° (line segment 220a = 45.6 mm, line segment 220b = 26.8 mm, line segment 220c = 41.8 mm) A body 220;
The porosity, average pore diameter, number of cells (cell density), and cell wall thickness are the same as those of the central honeycomb fired body 210, and the cross section is surrounded by three line segments and one arc. The outer circumference of the shape (line segment 230a = 24.9mm, line segment 230b = 24.5mm, line segment 230c = 41.8mm) in which the two angles of two line segments are 90 ° and 135 °, respectively Part honeycomb fired body 230 was manufactured.

(4) Adhesive paste is applied to predetermined side surfaces of the central honeycomb fired body 210 and the outer peripheral honeycomb fired bodies 220 and 230, and nine central honeycomb fired bodies 210 are disposed through the adhesive paste. Adhering 8 outer peripheral honeycomb fired bodies 220 and 8 outer peripheral honeycomb fired bodies 230 so as to have the arrangement shown in FIG. 6, and further solidifying the adhesive paste at 180 ° C. for 20 minutes As a result, a cylindrical ceramic block 203 having an adhesive layer thickness of 1 mm was produced.
Here, the adhesive paste similar to Example (1) was used as an adhesive paste.

(5) A coating material paste layer was formed on the outer periphery of the ceramic block 203 using a coating material paste having the same composition as the adhesive paste used in the step (4). Thereafter, this coating material paste layer was dried at 120 ° C. to manufacture a cylindrical honeycomb structure 200 having a diameter of 203.2 mm and a length of 200 mm, on which the coating layer 202 was formed on the outer periphery.

The cross-sectional shape of the honeycomb structure manufactured in Example 2 is as shown in FIG.
Therefore, in the honeycomb structure 200, the angle formed by the first outer peripheral adhesive layer 201C and the second outer peripheral adhesive layer 201D in the cross section of the honeycomb structure 200 is 45 °.
Further, in the section of the honeycomb structure 200, the first outer peripheral adhesive layer 201C and the adhesive layer 201B for binding the central honeycomb fired body 210 and the outer peripheral honeycomb fired body 220 form a trident. There is a part.

The honeycomb structure manufactured in Example 2 was measured for isostatic strength by the same method as in Example 1.
As a result, the isostatic strength of the honeycomb structure of Example 2 was 8.5 MPa.
From the above, it has become clear that the honeycomb structure of the second embodiment is suitable for preventing the honeycomb structure from being damaged.

(Other embodiments)
In the method for manufacturing the honeycomb structure of the first and second embodiments, a honeycomb fired body formed in a predetermined shape is manufactured in advance, and the honeycomb structure is manufactured. However, the honeycomb structure of the embodiment of the present invention is manufactured. You may produce a structure using the following methods, for example.
Hereinafter, another method for manufacturing the honeycomb structure of the embodiment of the present invention will be described by taking as an example the case of manufacturing the honeycomb structure of the first embodiment.

FIGS. 7A and 7B are cross-sectional views for explaining another example of the method for manufacturing a honeycomb structure according to the embodiment of the present invention.
(1) Using the same method as in (1) to (3) of the first embodiment, a honeycomb fired body in which either one end of each cell is sealed is manufactured.
At this time, a central honeycomb fired body 310 having a square cross section and an outer peripheral honeycomb fired body 320 ′ having a trapezoidal cross section are manufactured (see FIG. 7A).

(2) Next, as in the case of (4) of the first embodiment, an adhesive is used so that the central honeycomb fired body 310 and the outer peripheral honeycomb fired body 320 ′ are positioned as shown in FIG. A bundle 303 'of honeycomb fired bodies is produced by binding the paste layers and solidifying the adhesive paste layer.

(3) Next, an outer periphery processing step is performed in which a side surface of the honeycomb fired body aggregate 303 ′ is processed into a cylindrical shape by using a diamond cutter or the like, and the central honeycomb fired body 310, the outer peripheral honeycomb fired body 320, Is manufactured through the adhesive layer 301 (see FIG. 7B).
Thereafter, if necessary, a coat layer (not shown) is formed on the outer peripheral side surface of the ceramic block 303 to complete the honeycomb structure.

The cross-sectional shape of the honeycomb structure according to the embodiment of the present invention is not limited to a circular shape, and may be, for example, an elliptical shape, an oval shape, a race track shape, or the like.

Moreover, in the honeycomb structure of the embodiment of the present invention, the number of the central honeycomb fired bodies is not limited to a plurality, and may be one.
Specifically, the cross-sectional shape of the honeycomb structure may be a shape as shown in FIG.
FIG. 8 is a cross-sectional view of a honeycomb structure according to another embodiment of the present invention.

The configuration of the honeycomb structure 700 shown in FIG. 8 is the same as that of the honeycomb structure 100 of the first embodiment, except that the number of central honeycomb fired bodies is different.
That is, in the honeycomb structure 700 shown in FIG. 8, instead of the four central honeycomb fired bodies 110 bound via the adhesive layer 101A of the honeycomb structure 100 shown in FIG. Partial honeycomb fired body 710 is provided.
Although the central honeycomb fired body 710 has a larger cross-sectional area than the central honeycomb fired body 110, its function is the same.

In such a honeycomb structure 700, the first outer peripheral adhesive layer 701C and the second outer peripheral adhesive layer 701D form an angle of 45 ° in the cross section.
Further, in the honeycomb structure 700, the first outer peripheral adhesive layer 701C and the adhesive layer 701B that binds the central honeycomb fired body 710 and the outer peripheral honeycomb fired body 720 are three-pronged at the central corner. I am doing.
Therefore, the honeycomb structure 700 can enjoy the same effects as the effects of the first embodiment.
In FIG. 8, 702 indicates a coat layer, and 703 indicates a ceramic block.

In the cross section of the honeycomb structure of the embodiment of the present invention, the angle formed by the first outer peripheral adhesive layer and the second outer peripheral adhesive layer is not limited to 45 °, It may be 50 °.
If the angle of the angle formed by the first outer peripheral adhesive layer and the second outer peripheral adhesive layer is within this range, the honeycomb structure may be affected by compressive stress generated in various directions on the outer peripheral surface of the honeycomb structure. This is because it is suitable for preventing damage.
Further, in the honeycomb structure of the embodiment described so far, the entire first outer peripheral adhesive layer forms 40 to 50 ° with the entire second outer peripheral adhesive layer. In the honeycomb structure of the embodiment, the first outer peripheral adhesive layer only needs to form 40 to 50 ° with at least one of the second outer peripheral adhesive layers.

In the honeycomb structure of the embodiment of the present invention, the cross-sectional area of the central honeycomb fired body is desirably 900 to 2500 mm ² .
This is because when the cross-sectional area of the central honeycomb fired body is in the above range, cracks are less likely to occur in the honeycomb structure when the honeycomb structure is subjected to a regeneration treatment.

In the honeycomb structure of the embodiment of the present invention, the end of the cell may not be sealed. Such a honeycomb structure can be used as a catalyst carrier.

Examples of the inorganic binder contained in the adhesive paste include silica sol and alumina sol. These may be used alone or in combination of two or more. Among inorganic binders, silica sol is desirable.

Examples of the inorganic particles contained in the adhesive paste include inorganic particles made of carbide, nitride, and the like. Specifically, inorganic particles made of silicon carbide, silicon nitride, boron nitride, and the like can be given. . These may be used alone or in combination of two or more. Among the inorganic particles, inorganic particles made of silicon carbide having excellent thermal conductivity are desirable.

Examples of the inorganic fibers and / or whiskers contained in the adhesive paste include inorganic fibers and / or whiskers made of silica-alumina, mullite, alumina, silica, and the like. These may be used alone or in combination of two or more. Among inorganic fibers, alumina fibers are desirable.

The porosity of the honeycomb fired body is not particularly limited, but is desirably 35 to 60%.
If the porosity is less than 35%, the honeycomb structure of the embodiment of the present invention may be clogged immediately. On the other hand, if the porosity exceeds 60%, the strength of the honeycomb fired body decreases. This is because they can be easily destroyed.

The average pore diameter of the honeycomb fired body is desirably 5 to 30 μm.
If the average pore diameter is less than 5 μm, the particulates may easily clog. On the other hand, if the average pore diameter exceeds 30 μm, the particulates pass through the pores and collect the particulates. This is because it may not be able to function as a filter.

The porosity and pore diameter can be measured by a conventionally known method such as a mercury intrusion method, an Archimedes method, or a measurement using a scanning electron microscope (SEM).

The cell density in the cross section of the honeycomb structure is not particularly limited, but a desirable lower limit is 31.0 / cm ² (200 / in ² ), and a desirable upper limit is 93 / cm ² (600 / in ² ). The more desirable lower value is 38.8 / cm ² (250 / in ² ), and the more desirable upper limit is 77.5 / cm ² (500 / in ² ).
The thickness of the cell wall of the honeycomb structure is not particularly limited, but is preferably 0.1 to 0.4 mm.

The main component of the constituent material of the honeycomb structure is not limited to silicon carbide, and other ceramic raw materials include, for example, nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, and titanium nitride, zirconium carbide, Examples thereof include carbide ceramics such as titanium carbide, tantalum carbide, and tungsten carbide, and oxide ceramics such as cordierite and aluminum titanate.
Of these, non-oxide ceramics are preferred, and silicon carbide is particularly preferred. It is because it is excellent in heat resistance, mechanical strength, thermal conductivity and the like. In addition, ceramic raw materials such as silicon-containing ceramics in which metallic silicon is blended with the above-described ceramics, ceramics bonded with silicon or a silicate compound can be cited as constituent materials, and among these, silicon carbide is blended with silicon carbide. (Silicon-containing silicon carbide) is desirable.
In particular, a silicon-containing silicon carbide ceramic containing 60 wt% or more of silicon carbide is desirable.

The particle size of the ceramic powder is not particularly limited, but it is preferable that the size of the honeycomb fired body manufactured through the subsequent firing step is small compared to the size of the degreased honeycomb formed body.

It does not specifically limit as an organic binder mixed with the said wet mixture, For example, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyethyleneglycol etc. are mentioned. Of these, methylcellulose is desirable. The amount of the organic binder is usually 1 to 10 parts by weight with respect to 100 parts by weight of the ceramic powder.
The plasticizer mixed with the wet mixture is not particularly limited, and examples thereof include glycerin.
The lubricant mixed in the wet mixture is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether. Specific examples include polyoxyethylene monobutyl ether and polyoxypropylene monobutyl ether.
In some cases, the plasticizer and the lubricant may not be contained in the wet mixture.

In preparing the wet mixture, a dispersion medium liquid may be used. Examples of the dispersion medium liquid include water, an organic solvent such as benzene, and an alcohol such as methanol.
Furthermore, a molding aid may be added to the wet mixture.
The molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol and the like.

Furthermore, a pore-forming agent such as balloons that are fine hollow spheres containing oxide-based ceramics, spherical acrylic particles, and graphite may be added to the wet mixture as necessary.
The balloon is not particularly limited, and examples thereof include an alumina balloon, a glass micro balloon, a shirasu balloon, a fly ash balloon (FA balloon), and a mullite balloon. Of these, alumina balloons are desirable.

The encapsulant paste for sealing the cells is not particularly limited, but it is desirable that the encapsulant produced through a subsequent process has a porosity of 30 to 75%. For example, a paste-like material similar to a wet mixture Can be used.

The honeycomb structure may support a catalyst for purifying exhaust gas. As the catalyst to be supported, for example, a noble metal such as platinum, palladium, rhodium or the like is desirable, and among these, platinum is more desirable. Further, as other catalysts, for example, alkali metals such as potassium and sodium, and alkaline earth metals such as barium can be used. These catalysts may be used alone or in combination of two or more.

The bundling step in the method for manufacturing a honeycomb structure according to the embodiment of the present invention includes, for example, a ceramic block (or an aggregate of honeycomb fired bodies) to be produced in addition to the method of applying the adhesive paste to the side surfaces of each honeycomb fired body. Alternatively, the honeycomb fired bodies may be temporarily fixed in a form having substantially the same shape as the shape, and an adhesive paste may be injected between the honeycomb fired bodies.

FIG. 1 is a perspective view schematically showing the honeycomb structure of the first embodiment. FIG. 2 (a) is a perspective view schematically showing a central honeycomb fired body in the honeycomb structure of the first embodiment, and FIG. 2 (b) is a cross-sectional view taken along line BB in FIG. 2 (a). FIG. FIG. 3 is a perspective view schematically showing an outer peripheral honeycomb fired body in the honeycomb structure of the first embodiment. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a cross-sectional view of the honeycomb structure manufactured in Comparative Example 1. FIG. 6 is a cross-sectional view of the honeycomb structure of the second embodiment. FIGS. 7A and 7B are cross-sectional views for explaining another example of the method for manufacturing a honeycomb structure according to the embodiment of the present invention. FIG. 8 is a cross-sectional view of a honeycomb structure according to another embodiment of the present invention.

Explanation of symbols

100, 200, 700 Honeycomb structure 101, 101A to 101D, 201A to 201D, 701B to 701D Adhesive layer 102, 202, 702 Coat layer 103, 203, 703 Ceramic block 110, 210, 710 Central honeycomb fired body 120, 220, 230, 720 Outer peripheral honeycomb fired body 111, 121 Cell 112, 122 Sealant 113, 123 Cell wall

Claims (2)

Columnar honeycomb fired bodies in which a large number of cells are arranged in parallel in the longitudinal direction across the cell wall are a honeycomb structure in which a plurality of cells are bound via an adhesive layer,
In the cross section perpendicular to the longitudinal direction of the honeycomb structure, the outer peripheral portion constituting the outer peripheral side of the honeycomb structure, the inner portion of the outer peripheral portion, the cross-sectional shape has a square central portion,
The central portion is composed of one central honeycomb fired body, or a plurality of central honeycomb fired bodies bound through the adhesive layer,
The outer peripheral portion is composed of a plurality of outer peripheral honeycomb fired bodies bound through the adhesive layer,
In a cross section perpendicular to the longitudinal direction of the honeycomb structure, at least one of the outer peripheral adhesive layers is formed in a direction from a corner of the central portion toward an outer peripheral side surface of the honeycomb structure. And
The adhesive layer formed in the direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure is formed in the direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure. A honeycomb structure having an angle of 40 to 50 ° with at least one of the adhesive layers. The center portion is composed of a plurality of center-portion honeycomb fired bodies bound through the adhesive layer,
In a cross section perpendicular to the longitudinal direction of the honeycomb structure, the adhesive is interposed between the outer peripheral honeycomb fired bodies and is formed in a direction from the corner of the central portion toward the outer peripheral side of the honeycomb structure. 2. The honeycomb structure according to claim 1, wherein at least one of the material layers is linear with any one of the adhesive layers interposed between the center-portion honeycomb fired bodies.

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