JP2005154202A - Honeycomb structure, its production method, and joining material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb structure in which a plurality of honeycomb segments are surely joined to each other without generating joining defects such as a crack, peeling an the like at the joining parts of the segments. <P>SOLUTION: In the honeycomb structure 1 comprising a ceramic, a plurality of honeycomb segments 12, each having a cell structure 5 with a plurality of cells 3 each of which is partitioned by a porous partition wall 2 and forms a passage for a fluid, and a porous outer wall 7 arranged at the outer periphery of the cell structure 5 are unified by joining the outer walls 7 to each other with a joining material. The joining material contains colloidal silica and/or colloidal alumina, and forms a joining layer 8 on each outer wall 7 after drying. Thereby, the outer walls 7 are joined to each other though the joining layer 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention is a honeycomb structure that can be suitably used for a catalyst carrier utilizing catalytic action such as an internal combustion engine, a boiler, a chemical reaction device, and a fuel cell reformer, or a particulate collection filter in exhaust gas, and the like, and More specifically, the manufacturing method and the bonding material, for example, a large-sized honeycomb structure in which a plurality of honeycomb segments are reliably bonded to each other, the manufacturing method thereof, and the manufacturing method are preferable. The present invention relates to a bonding material that can be used.

Ceramics such as internal combustion engines, boilers, chemical reaction equipment, and catalyst carriers that utilize catalytic action, such as fuel cell reformers, or collection filters (hereinafter referred to as DPF) for particulates in exhaust gas, especially diesel particulates. A honeycomb structure made of is used.

As shown in FIGS. 2A and 2B, a honeycomb structure used for such a purpose generally has a plurality of cells 23 serving as fluid flow paths partitioned by porous partition walls 24. And adjacent cells 23 are sealed at one end opposite to each other so that the end faces have a checkered pattern. In the honeycomb structure 21 having such a structure, the fluid to be treated flows into the cell 23 whose end face 25 on the inflow hole side is not sealed, that is, the cell 23 whose end is sealed with the end face 26 on the outflow hole side. Through the porous partition wall 24, the end portion is sealed by the adjacent cell 23, that is, the inflow hole side end surface 25, and the outflow hole side end surface 26 is discharged from the unsealed cell 23. At this time, the partition wall 24 serves as a filter. For example, when used as a DPF, soot discharged from a diesel engine is captured by the partition wall 24 and deposited on the partition wall 24.

The honeycomb structure 21 used in this way has a problem that the temperature distribution in the honeycomb structure 21 becomes non-uniform due to a sudden temperature change of the exhaust gas or local heat generation, and the honeycomb structure 21 is cracked. It was. In particular, when used as a DPF, it is necessary to burn off, remove, and regenerate the accumulated carbon fine particles. At this time, a local high temperature occurs, resulting in a decrease in regeneration efficiency due to uneven regeneration temperature. In addition, there is a problem that cracks due to large thermal stress are likely to occur.

For this reason, there has been proposed a method of joining a segment obtained by dividing a honeycomb structure into a plurality of pieces with a joining material. Specifically, there is a method for manufacturing a honeycomb structure in which a large number of honeycomb bodies are joined with discontinuous joining materials. It is disclosed (for example, see Patent Document 1).

Further, a matrix segment of a honeycomb structure made of a ceramic material is extruded, and after firing, the outer peripheral portion thereof is processed and smoothed, and then the mineral composition after firing is substantially the same as the matrix segment at the joint portion, and There has been proposed a thermal shock-resistant rotational heat storage type in which a ceramic bonding material having a difference in thermal expansion coefficient of 0.1% or less at 800 ° C. is applied and fired (see, for example, Patent Document 2).

Further, a ceramic honeycomb structure in which honeycomb segments of cordierite are joined with cordierite cement is disclosed (for example, see Non-Patent Document 1).

In a honeycomb structure in which such honeycomb segments are integrated using a bonding material, securing the bonding strength between the honeycomb segments is an important issue, but the coefficient of thermal expansion and firing between the bonding layer and the honeycomb segment are important. In some cases, bonding defects such as cracks in the bonding layer or peeling off of the bonding layer itself may occur due to a difference in shrinkage due to. In particular, in the case of a honeycomb structure having a large size, specifically, a flow path (cell) length of 50 mm or more, the difference between the thermal expansion amount and the shrinkage amount due to firing between the bonding layer and the honeycomb segment is significantly increased. There is a problem that it is difficult to obtain a honeycomb structure which is large but has no bonding defects in the bonding layer (bonding portion).
U.S. Pat. No. 4,335,783 Japanese Patent Publication No. 61-51240 SAE paper 860008 (1986)

The present invention has been made in view of such problems of the prior art, and the object of the present invention is that a plurality of honeycomb segments have a bonding failure such as cracking or peeling at these bonded portions. Honeycomb structure that is reliably bonded without generating, manufacturing method of honeycomb structure having such characteristics, and bonding of bonded objects without causing bonding defects such as cracks and peeling at the bonded portion It is in providing the joining material which can do.

That is, according to the present invention, a cell structure having a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and a porous outer wall disposed on the outer periphery of the cell structure are provided. A honeycomb structure made of ceramics, in which a plurality of the honeycomb segments are integrated by joining the outer walls with a bonding material, and the bonding material is colloidal silica and / or colloidal. There is provided a honeycomb structure (first invention) comprising alumina and dried to form a bonding layer on the outer wall, and the outer walls are bonded to each other via the bonding layer.

In the present invention (first invention), it is preferable that the maximum diameter in a cross section when cut along a plane orthogonal to the cell flow path direction is 300 mm or more, and the bonding layer on the outer wall of each honeycomb segment is The area of the formed part is preferably 2500 mm ² or more. In the present invention (first invention), it is preferable that two or more adjacent honeycomb segments have different thermal expansion coefficient values.

In the present invention (first invention), the bonding material preferably further comprises a ceramic powder having a tap bulk density of 1.3 g / cm ³ or more, and the bonding material has an average particle diameter of 20 to 20%. It is preferable to further include a ceramic powder having a content ratio of 28 μm and a particle component having a particle diameter of 44 μm or more to the entire powder of 80% by mass or less.

In the present invention (first invention), the ceramic powder is preferably a powder made of at least one selected from the group consisting of cordierite, silicon carbide, and alumina, and the main crystal phase of the honeycomb segment is cordier. It is preferably at least one selected from the group consisting of light, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, silicon nitride, and silicon carbide-metal silicon composite.

According to the present invention, there is provided a cell structure having a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and a porous outer wall disposed on the outer periphery of the cell structure. A method for manufacturing a honeycomb structure made of ceramics, including a joining step of integrating a plurality of the honeycomb segments by joining the outer walls with a joining material, wherein the colloidal silica, And / or applying the bonding material comprising colloidal alumina to the outer wall, drying the applied bonding material at 250 ° C. or less to form a bonding layer, and bonding the outer walls to each other via the bonding layer. A honeycomb structure manufacturing method (second invention) is provided.

In the present invention (second invention), it is preferable that the maximum diameter in a cross section when cut along a plane orthogonal to the cell flow path direction is 300 mm or more, and the bonding layer on the outer wall of each honeycomb segment The area of the portion to be formed is preferably 2500 mm ² or more. In the present invention (second invention), it is preferable that two or more adjacent honeycomb segments have different coefficients of thermal expansion.

In the present invention (second invention), the bonding material preferably further comprises ceramic powder having a tap bulk density of 1.3 g / cm ³ or more, and the bonding material has an average particle size of 20 to 20%. It is preferable to further include a ceramic powder having a content ratio of 28 μm and a particle component having a particle diameter of 44 μm or more to the entire powder of 80% by mass or less.

In the present invention (second invention), the ceramic powder is preferably a powder comprising at least one selected from the group consisting of cordierite, silicon carbide, and alumina, and the main crystal phase of the honeycomb segment is cordier. It is preferably at least one selected from the group consisting of light, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, silicon nitride, and silicon carbide-metal silicon composite.

Further, according to the present invention, colloidal silica and / or colloidal alumina, a powder having a tap bulk density of 1.3 g / cm ³ or more, an average particle diameter of 20 to 28 μm, and a particle diameter of 44 μm or less. There is provided a bonding material (third invention) comprising a ceramic powder having a content ratio of 80% by mass or less of the total component powder.

In the present invention (third invention), the ceramic powder is preferably a powder made of at least one selected from the group consisting of cordierite, silicon carbide, and alumina. In this invention (3rd invention), it is preferable to further contain an inorganic fiber, and it is preferable that an inorganic fiber is a ceramic fiber.

The bonding material of the present invention (third invention) is suitably used for bonding the outer walls of a plurality of honeycomb segments.

Since the ceramic honeycomb structure of the present invention (first invention) is formed by drying a bonding material containing a predetermined component to form a bonding layer, and bonding the outer walls through the bonding layer, There is an effect that the honeycomb segments are reliably bonded without causing a bonding failure such as cracking or peeling at the bonded portion.

Further, according to the method for manufacturing a ceramic honeycomb structure of the present invention (second invention), in the bonding step, a bonding material containing a predetermined component is applied to the outer wall of the honeycomb segment and substantially fired. Since the bonding layer is formed by drying at a temperature not to be bonded, and the outer walls are bonded to each other via the bonding layer, the honeycomb segments can be reliably bonded to each other without causing a bonding failure such as cracking or peeling. There is an effect that can be done.

The bonding material of the present invention (third invention) has colloidal silica and / or colloidal alumina, a tap bulk density of 1.3 g / cm ³ or more, an average particle size of 20 to 28 μm, and a particle size of The ceramic powder having a content ratio of 44 μm or less of the powder component with respect to the whole powder is 80% by mass or less, so that the bonded object can be bonded without causing any bonding failure such as cracking or peeling at the bonded portion. There exists an effect that it is possible to join.

Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and may be appropriately selected based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that design changes, improvements, etc. may be made.

FIG. 1 is a view for explaining an embodiment of a honeycomb structure (first invention) of the present invention. FIG. 1 (a) is a perspective view of a honeycomb segment, and FIG. 1 (b) is a perspective view of the honeycomb structure. FIG. 1 and FIG. 1C are top views of the honeycomb structure. A honeycomb structure 1 according to the present embodiment includes a cell structure 5 having a plurality of cells 3 serving as a fluid flow path partitioned by porous partition walls 2, and a porous structure disposed on the outer periphery of the cell structure 5. A plurality of honeycomb segments 12 having a plurality of outer walls 7 are integrated by joining the outer walls 7 with a bonding material, and the bonding material is colloidal silica and / or colloidal alumina. And a bonding layer 8 is formed on the outer wall 7 by drying, and the outer walls 7 are bonded to each other via the bonding layer 8.

The bonding material used for manufacturing the honeycomb structure 1 of the present embodiment includes at least one of colloidal silica and colloidal alumina, and the outer walls 7 of the plurality of honeycomb segments 12 are formed using this bonding material. When the members are joined, the joining material applied to the outer wall 7 is dried to form the joining layer 8. Here, in the present invention (first to third inventions), “drying” the bonding material means a temperature at which the components contained in the bonding material do not melt, that is, a temperature at which substantially no firing is performed. This means that the liquid component is evaporated and solidified (gelled). That is, in the honeycomb structure 1 of the present embodiment, since the bonding material is not fired, the bonding layer is formed only by drying and the outer walls 7 of the honeycomb segments 12 are bonded to each other. Bonding defects such as cracks in the bonding layer 8 or separation of the bonding layer 8 itself due to differences in the thermal expansion coefficient and shrinkage ratio between the honeycomb segment 12 and the honeycomb segment 12 are difficult to occur.

Further, the honeycomb structure 1 of the present embodiment has a particularly large honeycomb structure because the bonding material is not fired and a bonding layer is formed only by drying and the outer walls 7 of the honeycomb segments 12 are bonded to each other. In such a case, an effect that a bonding defect hardly occurs is remarkably exhibited. That is, in the first invention, the maximum diameter in a cross section when cut along a plane orthogonal to the cell flow path direction is preferably 300 mm or more, more preferably 330 mm or more, and 350 mm or more. It is particularly preferred. In the first invention, the upper limit value of the maximum diameter is not particularly limited, but may be 500 mm or less from the viewpoint of substantial manufacturability.

In the first invention, “the maximum diameter in a cross section when cut along a plane perpendicular to the cell flow direction” means a cross section when the honeycomb structure is cut along a plane perpendicular to the cell flow direction. (In an arbitrary cross section formed along the flow path), the diameter (maximum diameter) of the cross section having the maximum value. When the cross-sectional shape is a circle, the diameter of the circle, when the cross-sectional shape is an ellipse, when it is an ellipse, the length of the long axis, when the cross-sectional shape is a polygon, the length of the longest diagonal line, and when the cross-sectional shape is other irregular shapes Is the distance between the two longest points when two points on the outer periphery of the cross-sectional shape are taken.

In the first invention, in the outer wall of each honeycomb segment, the area of the portion where the bonding layer is formed, is preferably 2500 mm ² or more, further preferably 10000 mm ² or more, 15000 ² or more It is particularly preferred that In the first invention, the upper limit value of the area of the outer wall of each honeycomb segment where the bonding layer is formed is not particularly limited, but is 90000 mm ² or less from the viewpoint of substantial manufacturability and the like. If it is.

In the first invention, it is preferable that two or more adjacent honeycomb segments have different coefficients of thermal expansion. That is, the honeycomb structure according to the first aspect of the present invention is formed by bonding layers formed only by drying without firing the bonding material and bonding the outer walls of the honeycomb segments. Even when the honeycomb segments made of the material to be bonded are bonded to each other, bonding defects such as cracks in the formed bonding layer and peeling of the bonding layer itself are unlikely to occur.

In 1st invention, it is preferable that a joining material further contains the ceramic powder whose tap bulk density is 1.3 g / cm < ³ > or more. When a bonding material further containing such ceramic powder is applied to the porous outer wall, the bonding material comes into contact with the outer wall, and a coating layer is first formed. Immediately after this coating layer is formed, a part of the liquid (moisture) contained in the coating layer is absorbed by the porous outer wall, and along with this, fine components of the ceramic powder contained in the coating layer ( By the fine particles, a thin dense layer is formed in the immediate vicinity of the outer wall surface in contact with the coating layer.

The formed dense layer suppresses further moisture absorption to the outer wall, so that rapid moisture movement in the coating layer formed by the bonding material is suppressed, and the coating formed by the applied bonding material. Differences in liquid (water) content are unlikely to occur at each site in the layer. In addition, since the formed dense layer suppresses the absorption of liquid (water) by the outer wall, the deterioration of the coating property due to the rapid increase in the viscosity of the bonding material is suppressed, and the good coating property is maintained. Bonding material is applied. As a result, a difference in shrinkage at each site in the coating layer in the subsequent drying process is unlikely to occur, and cracks, peeling, and the like are unlikely to occur in the bonding layer formed by drying the coating layer. Therefore, the honeycomb structure according to the first aspect of the invention using this bonding material is more unlikely to cause bonding defects such as cracks and peeling at the bonded portion.

In addition, if the tap bulk density of the ceramic powder is less than 1.3 g / cm ³ , the effects obtained by further including the ceramic powder are difficult to be exhibited sufficiently. From the standpoint of more effectively suppressing the occurrence of the above, the tap bulk density of the ceramic powder is preferably 1.34 g / cm ³ or more, and more preferably 1.39 g / cm ³ or more. The upper limit value of the tap bulk density is not particularly limited, but is preferably 1.50 g / cm ³ or less in consideration of substantial handling properties. Here, the value of “tap bulk density” referred to in the present invention (first to third inventions) is obtained by measuring according to the constant volume measurement method of JIS R 1628-1997 “Method of measuring bulk density of fine ceramic powder”. Value.

Further, the amount of the ceramic powder having a tap bulk density of not less than a predetermined value included in the bonding material is preferably 50% by mass or more, more preferably 60% by mass or more, and 65% by mass or more. Is particularly preferred. This is because if it is less than 50% by mass, the effect obtained by further including the ceramic powder is hardly exhibited. The upper limit of the amount of the ceramic powder having a tap bulk density greater than or equal to a predetermined value included in the bonding material is not particularly limited, but if it exceeds 80% by mass, the pressure-bonding property at the time of bonding decreases. It is not preferable.

In the first invention, the bonding material has a content ratio of the powder component having an average particle diameter of 20 to 28 μm and a particle diameter of 44 μm or more (hereinafter referred to as “small particle diameter powder component ratio”). It is preferable to further include a ceramic powder having an average particle size of 21 to 27 μm and a small particle size powder component ratio of 80% by mass or less. It is more preferable to further comprise ceramic powder having an average particle diameter of 22 to 27 μm and a small particle diameter powder component ratio of 78% by mass or less. When such a ceramic powder is further included in the bonding material, absorption of moisture into the outer wall to which the bonding material has been applied is further effectively suppressed, and at each site in the coating layer in the subsequent drying step. The shrinkage difference is less likely to occur, and cracks, peeling, and the like are less likely to occur in the bonding layer formed by drying the coating layer. Therefore, the honeycomb structure according to the first aspect of the invention using this bonding material is more unlikely to cause bonding defects such as cracks and peeling at the bonded portion.

When the average particle size of the ceramic powder is less than 20 μm, it is preferable because the viscosity of the bonding material is increased and the coating property is deteriorated, or the amount of water needs to be increased in order to reduce the viscosity of the bonding material. If the thickness exceeds 28 μm, “nests” are likely to be generated in the bonding layer after the bonding material is dried. “Nest” refers to the portion that remains in the pores after water scatters, and if the ceramic powder particles are coarse, the fluidity of the ceramic powder deteriorates during drying shrinkage, which is considered to be the cause of “nest” generation. . It is not preferable that a large number of these “nests” are generated because it leads to a decrease in bonding strength. Moreover, since it becomes easy to produce joining malfunctions, such as a crack in a junction part and peeling, that a small particle size powder component ratio exceeds 80 mass%, it is unpreferable. In addition, although it does not specifically limit about the lower limit of a small particle size powder component ratio, It is preferable that it is about 50 mass% or more in general. Here, the content ratio of the powder component having an average particle diameter of 20 to 28 μm and a particle diameter of 44 μm or more (small particle diameter powder component ratio) referred to in the present invention (first to third inventions) "Means a value obtained by measurement according to JIS R 1629-1997" Method for measuring particle size distribution of fine ceramic raw material by laser diffraction / scattering method ".

The ceramic powder used in the first invention is a powder composed of ceramics such as cordierite, silicon carbide, silicon nitride, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, or titania, or a combination of two or more thereof. The affinity of the bonding material can be improved by selecting appropriately according to the material of the honeycomb segment to which the bonding material is applied (the type of ceramics), particularly from cordierite. Such a powder (cordierite powder) is preferably used. Cordierite powder is preferable because it has a small coefficient of thermal expansion and can form a bonding layer excellent in thermal shock resistance and mechanical strength.

In the first invention, the main crystal phase of the honeycomb segment is cordierite, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, silicon nitride, and silicon carbide-metal silicon composite from the viewpoint of strength, heat resistance, etc. However, when the honeycomb structure of the first invention is used for a DPF, silicon carbide or silicon carbide-metal silicon system is preferable in that the heat resistance is high. It is particularly preferable to use the composite as the main crystal phase, and it is particularly preferable to use cordierite as the main crystal phase because of its low thermal expansion coefficient and good thermal shock resistance. Here, the “main crystal phase” means a crystal phase constituting 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more in the crystal phase in the component forming the honeycomb segment. In the first invention, when the honeycomb segment is made of metal silicon (Si) and silicon carbide (SiC), the content of metal silicon (Si) defined by (Si) / (Si + SiC) of the honeycomb segment is small. If it is too high, the effect of adding metal silicon (Si) cannot be obtained, so the strength is weak, and if it exceeds 50% by mass, the effects of heat resistance and high thermal conductivity, which are the characteristics of silicon carbide (SiC), cannot be obtained. The metal silicon (Si) content is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass.

In the first invention, the thickness of the bonding layer is not particularly limited, but if it is too thick, the pressure loss when the exhaust gas passes becomes too large, and if it is too thin, the bonding material cannot exhibit sufficient bonding performance. It is not preferable. A preferable thickness range of the bonding layer is 0.1 to 3.0 mm.

In the first invention, the cell density of the honeycomb segment (the number of cells per unit cross-sectional area orthogonal to the flow path) is not particularly limited, but if the cell density is too small, the geometric surface area is insufficient and the cell density is large. If it is too high, the pressure loss becomes too large, which is not preferable. The cell density is preferably 0.9 to 310 cells / cm ² (6 to 2000 cells / in ² ). In addition, there is no particular limitation on the cross-sectional shape of the cell (cross-section perpendicular to the flow path), and it can be any shape such as a polygon such as a triangle, a quadrangle, and a hexagon, a circle, an ellipse, or a corrugated shape. From the viewpoint of production, a triangle, a quadrangle, or a hexagon is preferable. Also, the thickness of the partition walls is not particularly limited, but if the partition wall thickness is too thin, the strength as the honeycomb segment is insufficient, and if it is too thick, the pressure loss becomes too large, which is not preferable. The partition wall thickness is preferably in the range of 50 to 2000 μm.

Moreover, there is no restriction | limiting in particular also in the shape of a honeycomb segment, It can be set as all shapes. For example, a quadrangular prism as shown in FIG. 1A is used as a basic shape, and this is joined and integrated as shown in FIG. 1B, and the honeycomb segment 12 constituting the outermost peripheral surface of the honeycomb structure 1 is formed. The shape is preferably matched to the outer peripheral shape of the honeycomb structure 1. Moreover, the shape of the cross section orthogonal to the flow path of each honeycomb segment may be a fan shape.

In addition, the shape of the cross section of the honeycomb structure perpendicular to the flow path is not particularly limited, and any shape such as a perfect circle, an ellipse, an oval, a polygon such as a triangle, a rectangle, a pentagon, or an amorphous shape, etc. It can be a shape. Furthermore, when the honeycomb structure of the first invention is used as a catalyst carrier incorporated in an internal combustion engine, a boiler, a chemical reaction device, a fuel cell reformer, etc., a metal having catalytic ability is supported on the honeycomb structure. It is also preferable to do. Typical examples of the metal having catalytic ability include platinum (Pt), palladium (Pd), rhodium (Rd) and the like, and it is preferable to support at least one of these on the honeycomb structure. .

On the other hand, when the honeycomb structure of the first invention is used as a filter for collecting and removing particulate matter contained in exhaust gas such as DPF, the opening of a predetermined cell is sealed at one end face. The remaining cell opening is sealed at the other end surface, and adjacent cells are sealed at one end opposite to each other so that the end surface has a checkered pattern. preferable. By being sealed in this way, for example, exhaust gas containing particulate matter that has flowed in from one end face side of the honeycomb structure flows out from the other end face side through the partition wall, but the exhaust gas is separated from the partition wall. A porous partition acts as a filter as it passes through, and particulate matter can be collected. If the collected particulate matter accumulates on the partition wall, the pressure loss increases, which imposes a burden on the engine and reduces fuel consumption and drivability. The particulate matter is burned off and the filter function is regenerated. In order to promote combustion during this regeneration, the above-described metal having catalytic ability may be supported on the honeycomb structure.

Next, a method for manufacturing a honeycomb structure of the present invention (second invention) will be described. As shown in FIGS. 1A to 1C, the method for manufacturing a honeycomb structure according to the second invention has a plurality of cells 3 serving as fluid flow paths partitioned by porous partition walls 2. A plurality of honeycomb segments 12 each including a cell structure 5 and a porous outer wall 7 disposed on the outer periphery of the cell structure 5 are integrated by joining the outer walls 7 with a bonding material. A method for manufacturing a honeycomb structure 1 made of ceramics including a joining step, wherein a joining material containing colloidal silica and / or colloidal alumina is applied to the outer wall 7 in the joining step described above, and the applied joining material Is dried at 250 ° C. or lower to form the bonding layer 8, and the outer walls 7 are bonded to each other via the bonding layer 8. The details will be described below.

In the second invention, the method for manufacturing the honeycomb segment is not particularly limited, and generally a method for manufacturing a honeycomb structure (honeycomb body) can be adopted. Can be manufactured.

As raw materials, for example, silicon carbide, silicon carbide powder and metal silicon powder for forming a silicon carbide-metal silicon composite, other ceramic raw materials, binders such as methylcellulose, hydroxypropoxymethylcellulose, surfactants, water, etc. And kneaded to form a plastic clay. Next, the obtained kneaded material is extruded in a forming step, thereby forming a honeycomb-shaped formed body having a plurality of cells serving as fluid flow paths partitioned by partition walls. For extrusion molding, a plunger type extruder, a twin screw type continuous extruder, or the like can be used. When a twin-screw type continuous extruder is used, the clay forming step and the forming step can be performed continuously. The obtained honeycomb formed body 30 is dried by, for example, microwave, dielectric and / or hot air, and then fired to obtain a honeycomb fired body 30 as shown in FIG.

The obtained honeycomb fired body is shaped as necessary so as to form a honeycomb segment having a predetermined shape. For example, by processing the outer peripheral portion of a cylindrical honeycomb fired body 30 as shown in FIG. 3A using means such as a band saw or a metal saw, a joining surface 32 as shown in FIG. The square pillar-shaped honeycomb segment 12 can be obtained.

In the second invention, the honeycomb segments obtained are joined in a joining step to form a honeycomb structure. In this joining step, as shown in FIG. 3C, a predetermined joining material is applied to one, preferably both of the outer walls (joining surfaces 32) to be joined between the honeycomb segments 12. The bonding material to be applied includes at least one of colloidal silica and colloidal alumina, and may further include an organic binder such as methylcellulose and hydroxypropoxymethylcellulose. Moreover, there is no restriction | limiting in particular in the method of apply | coating a joining material, For example, the spraying method, the method of apply | coating with a brush, a brush, etc., the dipping method etc. are employable.

When applying the bonding material to the outer wall (bonding surface) of the honeycomb segment, as shown in FIG. 3 (c), a predetermined amount is used to prevent the bonding material from adhering to the cell opening end surface 33 of the honeycomb segment 12. It is preferable to attach a masking tape 34 having a size to a part of the cell opening end face 33. The average thickness of the bonding material to be applied may be 1 to 5 mm.

In order to avoid formation of a nest in the formed bonding layer, bonding is performed by applying an appropriate pressure while swinging the honeycomb segments 12 (FIG. 3C). Here, the average thickness of the final bonding material is preferably 1 to 3 mm from the viewpoint of exerting sufficient adhesive force and reducing the shrinkage stress of the bonding material. The excess bonding material 35 overflowing from the bonding surface 32 is removed by wiping or the like, but considering the shrinkage of the bonding material due to subsequent drying, the excessive bonding material 35 is removed so that an appropriate amount remains. It is preferable to do.

Thereafter, the bonding material applied on the outer wall is dried at a temperature that is not substantially fired, specifically at a temperature of 250 ° C. or lower to form a bonding layer, and the bonding layer formed between the outer walls is formed. Join through. That is, in the second invention, in the joining step, the joining material is applied to the outer wall of the honeycomb segment, and the joining material is dried at a predetermined temperature or less without substantially firing the joining material. Therefore, the bonding layer and the honeycomb segment are less likely to cause a bonding defect such as cracking of the bonding layer or separation of the bonding layer itself due to a difference in thermal expansion coefficient or shrinkage rate between the bonding layer and the honeycomb segment. Play.

Further, from the viewpoint of more effectively avoiding the occurrence of bonding defects, the temperature for drying the bonding layer is preferably 150 ° C. or lower, and more preferably 110 ° C. or lower. In the second invention, the lower limit of the drying temperature is not particularly limited, but may be approximately 50 ° C. or higher in consideration of the time required for drying. Moreover, it is also preferable to perform hot air drying (100-250 degreeC) for about 2 hours after natural drying (10-50 degreeC) for 10 hours or more.

In the second invention, the maximum diameter in a cross section when cut along a plane orthogonal to the flow direction of the cell is preferably 300 mm or more, more preferably 330 mm or more, and 350 mm or more. Particularly preferred. In the second invention, in the outer wall of each honeycomb segment, the area of the portion where the bonding layer is formed, is preferably 2500 mm ² or more, further preferably 10000 mm ² or more, 15000 ² or more It is particularly preferred that That is, particularly in the case of manufacturing a large-sized honeycomb structure, the effect of hardly causing a bonding defect is exhibited remarkably. The upper limit of the maximum diameter is not particularly limited, but may be 500 mm or less from the viewpoint of substantial manufacturability. Further, the upper limit value of the area of the outer wall of each honeycomb segment where the bonding layer is formed is not particularly limited, but may be 90000 mm ² or less from the viewpoint of substantial manufacturability.

In the second invention, it is preferable that two or more adjacent honeycomb segments have different coefficients of thermal expansion. That is, in the second invention, since the bonding layers are formed by simply drying and bonding the outer walls of the honeycomb segments without bonding the bonding material, the honeycomb segments made of materials having different coefficients of thermal expansion are bonded. Manufacturing a honeycomb structure having sufficient mechanical strength without causing bonding defects such as cracks in the formed bonding layer or separation of the bonding layer itself. Can do.

In the second invention, it is preferable that the bonding material further includes a ceramic powder having a tap bulk density of 1.3 g / cm ³ or more. When a bonding material further comprising such ceramic powder is applied to the porous outer wall, the bonding material comes into contact with the outer wall, and a coating layer is first formed. Immediately after this coating layer is formed, a part of the liquid (moisture) contained in the coating layer is absorbed by the porous outer wall, and along with this, fine components of the ceramic powder contained in the coating layer ( By the fine particles, a thin dense layer is formed in the immediate vicinity of the outer wall surface in contact with the coating layer.

The formed dense layer suppresses further moisture absorption to the outer wall, so that rapid moisture movement in the coating layer formed by the bonding material is suppressed, and the coating formed by the applied bonding material. Differences in liquid (water) content are unlikely to occur at each site in the layer. In addition, since the formed dense layer suppresses the absorption of liquid (water) by the outer wall, the deterioration of the coating property due to the rapid increase in the viscosity of the bonding material is suppressed, and the good coating property is maintained. A bonding material can be applied. As a result, a difference in shrinkage at each site in the coating layer in the subsequent drying process is unlikely to occur, and cracks, peeling, and the like are unlikely to occur in the bonding layer formed by drying the coating layer. Therefore, when this bonding material is used, it is possible to manufacture a honeycomb structure in which bonding defects such as cracks and peeling at the bonding portion are less likely to occur.

In addition, if the tap bulk density of the ceramic powder is less than 1.3 g / cm ³ , the effects obtained by further including the ceramic powder are difficult to be exhibited sufficiently. From the standpoint of more effectively suppressing the occurrence of the above, the tap bulk density of the ceramic powder is preferably 1.34 g / cm ³ or more, and more preferably 1.39 g / cm ³ or more. The upper limit value of the tap bulk density is not particularly limited, but is preferably 1.50 g / cm ³ or less in consideration of substantial handling properties.

Further, the amount of the ceramic powder having a tap bulk density of not less than a predetermined value included in the bonding material is preferably 50% by mass or more, more preferably 60% by mass or more, and 65% by mass or more. Is particularly preferred. This is because if it is less than 50% by mass, the effect obtained by further including the ceramic powder is hardly exhibited. The upper limit of the amount of the ceramic powder having a tap bulk density greater than or equal to a predetermined value included in the bonding material is not particularly limited, but if it exceeds 80% by mass, the pressure-bonding property at the time of bonding decreases. It is not preferable.

In the second invention, the bonding material preferably further comprises ceramic powder having an average particle size of 20 to 28 μm and a small particle size powder component ratio of 80% by mass or less. Is more preferably 21 to 27 μm, and a ceramic powder having a small particle size powder component ratio of 80% by mass or less, more preferably an average particle size of 22 to 27 μm and a small particle size powder component ratio of 78. It is particularly preferred to further comprise a ceramic powder having a mass% or less. When a bonding material comprising such ceramic powder is applied to the outer wall, the absorption of moisture into the outer wall is further effectively suppressed, and further shrinkage differences occur in each part in the coating layer in the subsequent drying process. It becomes difficult, and it becomes difficult to produce a crack, peeling, etc. in the joining layer formed by drying the coating layer. Therefore, when this bonding material is used, it is possible to manufacture a honeycomb structure in which bonding defects such as cracks and peeling at the bonding portion are less likely to occur.

When the average particle size of the ceramic powder is less than 20 μm, it is preferable because the viscosity of the bonding material is increased and the coating property is deteriorated, or the amount of water needs to be increased in order to reduce the viscosity of the bonding material. If the thickness exceeds 28 μm, “nests” are likely to be generated in the bonding layer after the bonding material is dried. Moreover, since it becomes easy to produce joining malfunctions, such as a crack in a junction part and peeling, that a small particle size powder component ratio exceeds 80 mass%, it is unpreferable. In addition, although it does not specifically limit about the lower limit of a small particle size powder component ratio, It is preferable that it is about 50 mass% or more in general.

In the second invention, the ceramic powder further contained in the bonding material includes powder made of ceramics such as cordierite, silicon carbide, silicon nitride, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, or titania, or these Although the powder which combines 2 or more types can be mentioned, the affinity of a joining material can be improved by selecting suitably according to the material (kind of ceramics) of the honeycomb segment to which a joining material is applied, In particular, a powder made of cordierite (cordierite powder) is preferably used. Cordierite powder is preferable because it has a small coefficient of thermal expansion and can form a bonding layer excellent in thermal shock resistance and mechanical strength.

In the second invention, the main crystal phase of the honeycomb segment is at least selected from the group consisting of cordierite, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, and a silicon carbide-metal silicon composite. Although it is preferable to use one type, when manufacturing a honeycomb structure used as a DPF, it is particularly preferable to use silicon carbide or a silicon carbide-metal silicon composite as the main crystal phase in terms of high heat resistance. It is also preferable to use cordierite as the main crystal phase because of its low thermal expansion coefficient and good thermal shock resistance.

When the honeycomb structure manufactured according to the second invention is used for a filter, particularly a DPF or the like, the opening of a predetermined cell is sealed with a plugging material at one end face, and the opening of the remaining cell is used. It is preferable that the other cell is sealed with a plugging material at the other end surface, and one end portion where adjacent cells are opposite to each other is alternately sealed so that the end surface has a checkered pattern. The plugging with the plugging material can be performed by masking the cells that are not plugged, immersing the plugging material in a slurry form or the like from the opening end face of the honeycomb segment to a predetermined depth, and drying and firing. The material of the plugging material to be used can be arbitrarily selected from the ceramic raw materials mentioned as the preferable honeycomb segment, but it is preferable to use the same ceramic raw material as the ceramic raw material used for the honeycomb segment.

In the second invention, a catalyst may be supported on the honeycomb structure. This method may be a method commonly performed by those skilled in the art. For example, the catalyst can be supported by washing a catalyst slurry, drying and calcining. This step may be performed at any time after the honeycomb segment is formed.

Note that at least a part of the outer periphery of the honeycomb structure (joined body) formed by joining the honeycomb segments may be removed as necessary. Specifically, as shown in FIG. 3D, for example, it is preferable to remove two or more cells 3 from the outermost periphery, and it is more preferable to remove two to four cells. Here, the removal of the cell means that at least a part of the partition wall forming the cell is removed so that the four sides are not completely surrounded by the partition wall. The removal can be performed, for example, by grinding the joined body 36 from the outer periphery thereof using a grinding means such as a diamond tool 42 and removing the removal portion 41 including the plurality of cells 3.

When at least a part of the outer periphery of the joined body 36 is removed, as shown in FIGS. 3E and 3F, a coating material 43 is applied to the part, and the honeycomb structure 1 An outer peripheral wall 50 is formed. The coating material 43 preferably includes at least one of colloidal silica, colloidal alumina, ceramic fibers, and ceramic particles. Examples of the ceramic particles include silicon carbide.

When applying the coating material, an outer peripheral wall having a uniform wall thickness can be formed by using an outer peripheral coater 48 as shown in FIG. Specifically, both end surfaces of the joined body 36 from which a part of the outer periphery has been removed are masked by a pressing jig 47 made of nylon, vinyl chloride or the like, and a shaft having a rotation handle 46 attached to one end thereof. The joined body 36 is held and fixed at 45. Next, while rotating the handle 46, the coating material 43 can be uniformly applied to the outer periphery of the joined body 36 by the leveling plate 44. The thickness of the outer peripheral wall to be formed can be set by appropriately adjusting the size of the pressing member 47 with respect to the size of the joined body 36.

The coating material preferably contains colloidal silica and / or colloidal alumina in addition to ceramic particles, more preferably contains ceramic fibers, particularly preferably contains an inorganic binder, and further contains an organic binder. Is more preferred. It is preferable to add a liquid component such as water to these raw materials to form a slurry, which is applied as a coating material. After applying the coating material, the honeycomb structure 1 as shown in FIG. 3F can be obtained by natural drying or heat drying.

In addition, in FIG. 3 (a)-FIG.3 (f), although the embodiment in case the shape of a final product is the cylindrical honeycomb structure 1 is demonstrated, in 2nd invention, it manufactures. The shape of the honeycomb structure, particularly the cross-sectional shape when cut along a plane orthogonal to the cell flow direction, is not particularly limited, and may be an ellipse, an oval, a polygon, other irregular shapes, etc. in addition to a circle. However, the honeycomb structure can be manufactured according to the above-described embodiment.

Next, the bonding material of the present invention (third invention) will be described. The bonding material of the third invention has colloidal silica and / or colloidal alumina, a tap bulk density of 1.3 g / cm ³ or more, an average particle size of 20 to 28 μm, and a particle size of 44 μm or less. Ceramic powder having a content ratio of the powder component to the whole powder of 80% by mass or less. The details will be described below.

Since the bonding material of the third invention comprises colloidal silica and / or colloidal alumina, the bonding material can be dried by using this, for example, when bonding objects to be bonded made of ceramics. A bonding layer is formed. Here, as described above, “drying” the bonding material means that the liquid component is evaporated and solidified at a temperature at which the components contained in the bonding material do not melt, that is, a temperature at which the bonding material is not substantially fired. Means gelation). That is, since the bonding material of the third invention can form a bonding layer by simply drying without bonding, and bonds the objects to be bonded, for example, bonded objects made of different materials can be bonded to each other. Assuming such a case, there is an effect that bonding defects such as cracks in the bonding layer or separation of the bonding layer itself due to differences in the thermal expansion coefficient and contraction rate are unlikely to occur.

In addition, since the bonding material of the third invention can be bonded to each other by forming a bonding layer only by drying without firing, the bonded material is particularly large (application of the bonding material). When the area is large), an effect that a bonding defect hardly occurs is remarkably exhibited.

Further, the bonding material of the third invention has a tap bulk density of 1.3 g / cm ³ or more together with the colloidal silica and / or colloidal alumina described above and an average particle diameter of 20 to 28 μm and particles. The ceramic powder whose content rate (small-particle-size powder component ratio) of the powder component whose diameter is 44 micrometers or less with respect to the whole powder is 80 mass% or less is included. When the joined body is a porous body and the joining material of the third invention is applied to the joining surface, a coating layer is first formed. Immediately after the formation of the coating layer, a part of the liquid (water) contained in the coating layer is absorbed by the porous bonding surface, and accordingly, fine components of the ceramic powder contained in the coating layer. A thin dense layer is formed by (fine particles) in the very vicinity of the joint surface in contact with the coating layer. The formed dense layer suppresses further absorption of moisture into the porous body, so that rapid moisture movement in the formed coating layer is suppressed, and liquid (moisture) is generated at each site in the coating layer. Differences in content are less likely to occur. In addition, since the formed dense layer suppresses the absorption of liquid (water) by the porous body, it suppresses the deterioration of the coating property due to the sudden increase in the viscosity of the bonding material, and maintains a good coating property. It can be applied in a state. As a result, a difference in shrinkage at each site in the coating layer in the subsequent drying process is unlikely to occur, and cracks, peeling, and the like are unlikely to occur in the bonding layer formed by drying the coating layer. Therefore, when the bonding material according to the third aspect of the invention is used, bonding problems such as cracks and peeling at the bonded portion are unlikely to occur, and the objects to be bonded can be bonded in a reliable state.

In addition, if the tap bulk density of the ceramic powder is less than 1.3 g / cm ³ , the effects obtained by further including the ceramic powder are difficult to be exhibited sufficiently. From the standpoint of more effectively suppressing the occurrence of the above, the tap bulk density of the ceramic powder is preferably 1.34 g / cm ³ or more, and more preferably 1.39 g / cm ³ or more. The upper limit value of the tap bulk density is not particularly limited, but is preferably 1.50 g / cm ³ or less in consideration of substantial handling properties.

In addition, if the average particle size of the ceramic powder is less than 20 μm, the viscosity of the bonding material is increased, the coating property is deteriorated, and it is necessary to increase the amount of water in order to reduce the viscosity. If it exceeds 28 μm, “nest” tends to occur in the bonding layer after drying, which is not preferable. “Nest” refers to the portion that remains in the pores after water scatters, and if the ceramic powder particles are coarse, the fluidity of the ceramic powder deteriorates during drying shrinkage, which is considered to be the cause of “nest” generation. . It is not preferable that a large number of these “nests” are generated because it leads to a decrease in bonding strength. Moreover, it is not preferable that the small particle size powder component ratio is more than 80% by mass because a bonding failure such as a crack or peeling at the bonded portion is likely to occur. In addition, although it does not specifically limit about the lower limit of a small particle size powder component ratio, It is preferable that it is about 50 mass% or more in general.

In addition, from the viewpoint of making cracks, peeling and the like less likely to occur in the bonding layer formed by drying, the bonding material of the third invention has an average particle size of 21 to 27 μm and a small particle size powder component It is preferable to include a ceramic powder having a ratio of 80% by mass or less, and further to include a ceramic powder having an average particle size of 22 to 27 μm and a small particle size powder component ratio of 78% by mass or less. Further preferred.

The ceramic powder contained in the bonding material of the third invention includes powder made of ceramics such as cordierite, silicon carbide, silicon nitride, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, or titania, or two of these. The powder which combines the above can be mentioned, and the affinity of the bonding material can be improved by appropriately selecting according to the material (for example, the type of ceramics) to which the bonding material is applied. In particular, a powder made of cordierite (cordierite powder) is preferably used. Cordierite powder is preferable because it has a small coefficient of thermal expansion and can form a bonding layer excellent in thermal shock resistance and mechanical strength.

Moreover, it is preferable that the bonding material of the third invention further includes an inorganic fiber because the inorganic fiber functions as a reinforcing material that suitably imparts toughness to the bonding layer to be formed. As an inorganic fiber, ceramic fibers, such as a silica, a mullite, an alumina, a silica-alumina, can be mentioned as a suitable example.

When the bonding material of the third invention is applied to the bonding surface when the object to be bonded is a porous body, a difference in shrinkage at each site in the formed bonding layer is hardly generated, and cracks in the bonding layer are not generated. There is an effect that defects such as generation and peeling are less likely to occur. Therefore, it is suitably used for joining the joining surfaces (outer walls) of a plurality of honeycomb segments made of ceramics, which are porous bodies, taking advantage of the feature of having such an effect. Examples of the ceramic constituting the porous body include cordierite, silicon carbide, silicon nitride, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, and titania.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Preparation of bonding material)
By blending each component of cordierite powder, colloidal silica, ceramic fiber, dispersion material, organic binder, preservative, raw material for cordierite, and water at a blending ratio (mass%) shown in Table 1, samples 1 to 1 are prepared. 5 bonding materials were prepared. In addition, the measuring method of the tap bulk density (g / cm < ³ >) of the used cordierite powder is shown below.

[Tap Bulk Density]: Measured according to the constant volume measuring method of JIS R 1628-1997 “Method of measuring bulk density of fine ceramic powder”.

(Examples 1-5)
1. Manufacture of honeycomb segment Talc, kaolin, alumina, silica, etc. are mixed with a cordierite raw material powder in which the composition after firing is the theoretical composition of cordierite (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ). Then, a pore forming agent and water were added and mixed and kneaded to prepare a plastic clay. The clay was extruded and dried with microwaves and hot air. Next, this was heated and degreased and fired in an air atmosphere, and then subjected to shape processing to manufacture a honeycomb segment 12 having a rectangular column shape (vertical 170 mm × horizontal 170 mm × height 170 mm) as shown in FIG. . The honeycomb segment had a partition wall thickness of 127 μm and a cell pitch of 1.47 mm.

2. Production of Honeycomb Structure As shown in FIG. 3 (c), four of the obtained honeycomb segments 12 were prepared, and a masking tape 34 was attached to a part of these cell opening end faces 33. Next, the bonding material of the above-described samples 1 to 3 is applied to the bonding surface 32 so as to have a predetermined thickness, and bonded to the bonding surface 32 and dried at 105 ° C. for 3 hours, whereby the bonding layer 8 having a thickness of 1 to 3 mm. To obtain a joined body 36.

Next, as shown in FIG. 3D to FIG. 3F, the cells 3 corresponding to about 5 mm from the outermost periphery of the obtained joined body 36 were removed by grinding using a diamond tool 42 at a machining center. Then, after processing the end face using a metal saw (to a predetermined height), after applying a predetermined coating material to cover the outer periphery of the joined body 36 using the outer peripheral coater 48, By drying for 10 hours, the applied coating material was cured to form the outer peripheral wall 50, and a honeycomb structure (outer diameter 320 mm × length 150 mm, outer peripheral wall thickness 3 mm) having a predetermined size was manufactured (Examples 1 to 3). 5).

(Comparative Examples 1-3)
As the bonding material, the bonding materials of Samples 4 and 5 were used, and the honeycomb segments were bonded and dried, and then fired at 1430 ° C. for 50 hours by the same method as in Examples 1 to 5 described above. A honeycomb structure having an outer diameter of 320 mm × a length of 150 mm and an outer peripheral wall thickness of 3 mm was manufactured (Comparative Examples 1 and 2).

(Evaluation of bonding material / bonding layer and honeycomb structure)
Table 2 shows the physical property evaluation results of the bonding layers obtained by drying the bonding materials of Samples 1 to 5 and drying Samples 1 to 3 and firing Samples 4 and 5. Moreover, the measurement results of the bending strength (four-point bending) and the bending strength (four-point bending) of the honeycomb structures (Examples 1 to 5 and Comparative Examples 1 and 2) obtained using the respective bonding materials. Table 3 shows the evaluation results of the crack generation position in the measurement test. Table 3 also shows the measurement results of the bending strength (four-point bending) of the unbonded honeycomb segments (Comparative Example 3). Measuring methods for various physical properties and evaluation methods are shown below.

[Folding strength (4-point bending)]: The strength at room temperature was measured according to the measurement method described in JIS R 1601 and JIS R 1624.

[Thermal diffusivity, thermal conductivity, specific heat capacity]: Measured by the laser flash method in accordance with the measuring method described in JIS R 1611.

[Density]: According to the measuring method described in JIS R 1634, the dried bonding material was measured at room temperature.

[Elastic modulus]: The elastic modulus at room temperature was measured according to the measurement method described in JIS R 1602.

[Evaluation of crack occurrence position]: The fracture mode in the measurement test of bending strength (4-point bending) was evaluated by the following method. That is, as a result of performing a four-point bending test using the test piece 60 shown in FIG. 4, a case where a crack occurred in the honeycomb structure 61 is “◯”, a case where the bonding surface 62 is peeled, or a case where the bonding layer 63 is broken Table 3 shows the evaluation results expressed as fractions where “×” is evaluated, the denominator is the number of tests (10 times), and the numerator is “×”.

(result)
From the results shown in Tables 2 and 3, the bending strength of the bonding layer made of the bonding materials of Samples 1 to 3 used for manufacturing the honeycomb structures of Examples 1 to 5 is more than the bending strength of the honeycomb structure portion. Was also found to be large. Moreover, it became clear that the elasticity modulus of the joining layer which consists of a joining material of the samples 1-3 is higher than the elasticity modulus of the conventional joining layer which consists of the samples 4 and 5 generally used. Furthermore, the thermal diffusivity of the bonding layer made of the bonding materials of Samples 1 to 3 was clearly lower than that of the conventional bonding layer.

Further, when focusing on the cordierite powder contained in the bonding material, as apparent from the evaluation result of the crack occurrence position (Table 3), if the tap bulk density is 1.3 g / cm ³ or more, the bonding material is used. In the honeycomb structure, the bonding layer has a higher bending strength than the honeycomb structure portion, so that the bonding layer hardly breaks and has an isostatic strength equal to or higher than that of the honeycomb segment of Comparative Example 3 which is a non-bonded carrier. It turned out that it is what has.

In the honeycomb structure of the present invention, a plurality of honeycomb segments are reliably bonded without causing a bonding failure such as cracking or peeling at these bonded portions, so that the internal combustion engine, boiler, chemical reaction It can be suitably used for a catalyst carrier utilizing catalytic action such as a device and a reformer for a fuel cell, or a particulate collection filter in exhaust gas.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one embodiment of the honeycomb structure (1st invention) of this invention, Fig.1 (a) is a perspective view of a honeycomb segment, FIG.1 (b) is a perspective view of a honeycomb structure, FIG. (C) is a top view of the honeycomb structure. FIG. 2A is a perspective view of a honeycomb structure, and FIG. 2B is a partially enlarged plan view of an end face of the honeycomb structure. Fig.3 (a)-FIG.3 (f) are explanatory drawings which show typically one Embodiment of the manufacturing method (2nd invention) of the honeycomb structure of this invention. It is a perspective view which shows the test piece used for evaluation of a crack generation position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Honeycomb structure, 2 ... Partition, 3 ... Cell, 5 ... Cell structure, 7 ... Outer wall, 8 ... Joining layer, 12 ... Honeycomb segment, 21 ... Honeycomb structure, 23 ... Cell, 24 ... Partition, 25 ... Inlet hole side end face, 26 ... Outlet hole side end face, 30 ... Honeycomb fired body, 31, 41 ... Removal part, 32 ... Joining surface, 33 ... Cell opening end face, 34 ... Masking tape, 35 ... Excess joining material, 36 ... Bonded body, 42 ... diamond tool, 43 ... coating material, 44 ... leveling plate, 45 ... shaft, 46 ... handle, 47 ... pressing jig, 48 ... outer periphery coating machine, 50 ... outer peripheral wall, 60 ... test piece, 61 ... Honeycomb structure part, 62 ... Joining surface, 63 ... Joining layer.

Claims (21)

A plurality of honeycomb segments each including a cell structure having a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and a porous outer wall disposed on an outer periphery of the cell structure, A honeycomb structure made of ceramics, which is integrated by bonding the outer walls with a bonding material,
A honeycomb structure in which the bonding material includes colloidal silica and / or colloidal alumina, is dried to form a bonding layer on the outer wall, and the outer walls are bonded to each other via the bonding layer. . The honeycomb structure according to claim 1, wherein a maximum diameter in a cross section when cut along a plane orthogonal to a flow path direction of the cell is 300 mm or more. The honeycomb structure according to claim 1 or 2, wherein an area of a portion where the bonding layer is formed on the outer wall of each honeycomb segment is 2500 mm ² or more. The honeycomb structure according to any one of claims 1 to 3, wherein two or more adjacent honeycomb segments have different values of coefficient of thermal expansion. The honeycomb structure according to any one of claims 1 to 4, wherein the bonding material further includes a ceramic powder having a tap bulk density of 1.3 g / cm ³ or more. The said joining material further contains the ceramic powder whose content rate with respect to the whole powder of the powder component whose average particle diameter is 20-28 micrometers and a particle diameter is 44 micrometers or more is 80 mass% or less. The honeycomb structure according to any one of the above. The honeycomb structure according to claim 5 or 6, wherein the ceramic powder is a powder made of at least one selected from the group consisting of cordierite, silicon carbide, and alumina. The main crystal phase of the honeycomb segment is at least one selected from the group consisting of cordierite, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, and silicon carbide-metal silicon composite. The honeycomb structure according to any one of the above. A plurality of honeycomb segments each including a cell structure having a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and a porous outer wall disposed on the outer periphery of the cell structure, A method for manufacturing a honeycomb structure made of ceramics, including a joining step in which these outer walls are integrated by joining together with a joining material,
In the joining step, the joining material comprising colloidal silica and / or colloidal alumina is applied to the outer wall, the applied joining material is dried at 250 ° C. or less to form a joining layer, and the outer walls are connected to each other. A method for manufacturing a honeycomb structure in which a structure is bonded through the bonding layer. The method for manufacturing a honeycomb structured body according to claim 9, wherein a maximum diameter in a cross section when cut along a plane orthogonal to the flow path direction of the cells is 300 mm or more. 11. The method for manufacturing a honeycomb structure according to claim 9, wherein an area of a portion where the bonding layer is formed on the outer wall of each honeycomb segment is 2500 mm ² or more. The method for manufacturing a honeycomb structure according to any one of claims 9 to 11, wherein two or more adjacent honeycomb segments have different coefficients of thermal expansion. The method for manufacturing a honeycomb structure according to any one of claims 9 to 12, wherein the bonding material further includes a ceramic powder having a tap bulk density of 1.3 g / cm ³ or more. The said joining material further contains the ceramic powder whose content rate with respect to the whole powder of the powder component whose average particle diameter is 20-28 micrometers and a particle diameter is 44 micrometers or more is 80 mass% or less. A method for manufacturing a honeycomb structured body according to any one of the above. The method for manufacturing a honeycomb structure according to claim 13 or 14, wherein the ceramic powder is a powder made of at least one selected from the group consisting of cordierite, silicon carbide, and alumina. The main crystalline phase of the honeycomb segment is at least one selected from the group consisting of cordierite, mullite, alumina, aluminum titanate, lithium aluminum silicate, silicon carbide, silicon nitride, and silicon carbide-metal silicon composite. The manufacturing method of the honeycomb structure according to any one of 9 to 15. Colloidal silica and / or colloidal alumina and the tap bulk density is 1.3 g / cm ³ or more, and the content ratio of the powder component having an average particle diameter of 20 to 28 μm and a particle diameter of 44 μm or less to the whole powder is And a ceramic powder that is 80% by mass or less. The bonding material according to claim 17, wherein the ceramic powder is a powder made of at least one selected from the group consisting of cordierite, silicon carbide, and alumina. The bonding material according to claim 17 or 18, further comprising inorganic fibers. The bonding material according to claim 19, wherein the inorganic fiber is a ceramic fiber. The bonding material according to any one of claims 17 to 20, which is used for bonding outer walls of a plurality of honeycomb segments.

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