JP2019177368A - Plugged honeycomb segment and plugged honeycomb structure - Google Patents

Abstract

A plugged honeycomb segment capable of increasing thermal shock resistance while suppressing an increase in pressure loss. SOLUTION: The honeycomb segment 4 includes a honeycomb segment 4 and a plugged portion 5, and the honeycomb segment 4 has four hexagonal cells 2a surrounding a square cell 2b in a cross section orthogonal to a direction in which the cells 2 extend. The square cell 2b has an end on the first end face side plugged with a plugging portion 5, and the hexagonal cell 2a has an end on the second end face side. , The hexagonal cell 2ab is located at the corner 6 of the peripheral edge of the honeycomb segment 4, and one vertex of the hexagon of the hexagonal cell 2ab is connected to the peripheral edge of the honeycomb segment 4. Are formed so as to face the apex of the corner portion 6 of the honeycomb segment 4, and are formed of a porous material disposed at a portion including one apex inside the hexagonal cell 2 ab at the corner 6 of the peripheral edge of the honeycomb segment 4. It has a thick portion 7. [Selection] Figure 2

Description

  The present invention relates to a plugged honeycomb structure including a plugged honeycomb segment and a plugged honeycomb segment joined body in which a plurality of plugged honeycomb segments are joined. More specifically, the present invention relates to a plugged honeycomb segment and a plugged honeycomb structure capable of increasing the thermal shock resistance while suppressing an increase in pressure loss.

  In various industries, an internal combustion engine is used as a power source. On the other hand, particulate matter such as soot and ash (hereinafter sometimes referred to as “PM”) is released into the atmosphere together with toxic gases such as nitrogen oxides as exhaust gas discharged by the internal combustion engine when fuel is burned. . In particular, regulations regarding the removal of PM discharged from diesel engines and the like have become stricter worldwide, and plugged honeycomb as an exhaust gas purification filter (hereinafter sometimes simply referred to as “filter”) for removing PM. A structure is used.

  The plugged honeycomb structure includes a honeycomb structure in which a plurality of cells serving as a fluid flow path are formed by porous partition walls, and a plugging disposed on one of the plurality of cells on the end surface side. Part. The plugged honeycomb structure has a structure in which porous partition walls serve as a filter for removing PM.

  The exhaust gas purification filter using the plugged honeycomb structure has a problem in that PM accumulates on the partition wall with the inflow of exhaust gas and closes the end portion on the inflow end face side of the cell. Therefore, in order to suppress such blockage of the cell, a wall flow type gas purification filter that can keep the opening diameter of the outflow cell large while increasing the filtration area and opening ratio of the inflow cell has been proposed. (For example, refer to Patent Document 1).

  In the wall flow type gas purification filter described in Patent Document 1, the shape of the inlet opening cell is hexagonal and the shape of the outlet opening cell is square in the cross section orthogonal to the central axis direction of the honeycomb structure portion. . And this wall flow type gas purification filter has a structure in which four inlet opening cells surround the periphery of one outlet opening cell.

  Conventionally, a technique has been proposed in which a plugged honeycomb structure is not manufactured by a single honeycomb structure, but a plurality of segments having a honeycomb structure are bonded via a bonding material (for example, patents). Reference 2). Hereinafter, the “segment having a honeycomb structure” may be referred to as a “honeycomb segment”. A “honeycomb structure in which a plurality of honeycomb segments are bonded by a bonding layer” may be referred to as a “segment structure honeycomb structure”.

Japanese Unexamined Patent Publication No. 2014-200741 JP 2003-340224 A

  A plugged honeycomb structure used as a filter or the like for removing PM may generate a large thermal stress due to a sudden temperature change of exhaust gas or local heat generation. For this reason, excellent thermal shock resistance is required for the plugged honeycomb structure.

  In order to improve the thermal shock resistance of the plugged honeycomb structure, one of the methods is to increase the volume of partition walls constituting the honeycomb structure and increase the heat capacity of the honeycomb structure. Conceivable. However, when the volume of the partition walls of the honeycomb structure is increased, the pressure loss of the plugged honeycomb structure using the honeycomb structure increases. When used as a filter for removing PM, a plugged honeycomb structure having a large pressure loss may cause a reduction in engine output and fuel consumption. For this reason, development of a honeycomb structure capable of increasing the thermal shock resistance while suppressing an increase in pressure loss has been demanded.

  The present invention has been made in view of such problems of the prior art. The present invention provides a plugged honeycomb segment and a plugged honeycomb structure capable of increasing the thermal shock resistance while suppressing an increase in pressure loss.

  According to the present invention, the following plugged honeycomb segment and plugged honeycomb structure are provided.

[1] A porous partition wall having a quadrangular prism shape having a first end surface and a second end surface and defining a plurality of cells extending from the first end surface to the second end surface, and an outer segment wall disposed on the outermost periphery Honeycomb segments having
A plugging portion disposed on the end face side in any one of the cells,
The honeycomb segment has a cell structure configured such that four hexagonal cells surround a square cell in a cross section perpendicular to the cell extending direction,
The square cell has an end portion on the first end face side plugged by the plugging portion,
In the hexagonal cell, the end portion on the second end face side is plugged by the plugging portion,
In the cross section, the hexagonal cells are arranged at the corners of the periphery of the honeycomb segment so that the hexagonal cells are located, and the hexagonal cells arranged at the corners are hexagonal. Is arranged so that one apex of the end faces the apex of the corner of the peripheral edge of the honeycomb segment,
Inside the hexagonal cell disposed at each corner, a porous material is disposed at a portion including the one apex of the hexagon,
A plugged honeycomb segment having a thick portion made of the porous material at the corner of the periphery of the honeycomb segment.

[2] In the cross section, the ratio of the area S1 of the thick part to the area S0 of the triangle including two sides of the hexagonal cell located at the corner of the peripheral edge of the honeycomb segment is 0.125 to The plugged honeycomb segment according to [1], which is 2.0.

[3] The plugged honeycomb segment according to [2], wherein in the cross section, a ratio of the area S1 of the thick part to the area S0 is 0.5 to 1.0.

[4] The plugged honeycomb segment according to any one of [1] to [3], wherein the honeycomb segment has a cell density of 15 to 78 cells / cm ² .

[5] The plugged honeycomb segment according to any one of [1] to [4], wherein a thickness of the partition wall of the honeycomb segment is 100 to 450 μm.

[6] In any one of the above [1] to [5], in the cross section, a ratio of the area A1 of the hexagonal cell to the area B1 of the square cell is 0.5 to 1.5. The plugged honeycomb segment as described.

[7] The plugged honeycomb segment according to any one of [1] to [6], wherein the honeycomb segment has a rectangular cross-sectional shape orthogonal to the cell extending direction.

[8] The plugged honeycomb segment according to any one of [1] to [7], wherein the hexagonal shape has an inner angle of 90 ° between two opposing vertices.

[9] A plugging having a plurality of the plugged honeycomb segments according to any one of [1] to [8], and a bonding layer that joins side surfaces of the plurality of plugged honeycomb segments. A bonded honeycomb segment assembly,
A plugged honeycomb structure comprising: an outer peripheral wall disposed on an outer peripheral surface of the plugged honeycomb segment assembly.

  The plugged honeycomb segment of the present invention can increase thermal shock resistance while suppressing an increase in pressure loss. This plugged honeycomb segment has a cell structure configured such that four hexagonal cells surround a square cell in a cross section perpendicular to the cell extending direction. And in the said cross section, it arrange | positions so that a predetermined | prescribed hexagonal cell may be located in each corner | angular part of the periphery of a honeycomb segment. Further, the hexagonal cells arranged at the respective corners are arranged so that one vertex of the hexagon faces the corner vertex of the peripheral edge of the honeycomb segment. In addition, a porous material is disposed inside the hexagonal cell disposed at each corner at a portion including one vertex of the hexagon. The plugged honeycomb segment of the present invention has a thick portion made of the porous material described above at the corners of the periphery of the honeycomb segment. The plugged honeycomb segment of the present invention has an effect that the thermal shock resistance can be increased while effectively suppressing an increase in pressure loss. That is, the hexagonal cells arranged so as to be located at the corners of the periphery of the honeycomb segment are filtered as filters at the site (predetermined two sides of the hexagon) forming the wall surface of the corner of the honeycomb segment. It has few functions. For this reason, by increasing the thickness of the plugged honeycomb segment by placing a porous material inside the hexagonal cells arranged at the corners of the periphery of the honeycomb segment to make it thick, Thermal shock resistance can be increased while suppressing. Moreover, since the plugged honeycomb segment of the present invention has a thick portion at the corner of the honeycomb segment, the occurrence of defects such as chipping at the corner can be effectively suppressed.

  The plugged honeycomb structure of the present invention is a plugged honeycomb structure including a plugged honeycomb segment bonded body in which a plurality of the plugged honeycomb segments are bonded by a bonding layer. The plugged honeycomb structure of the present invention can increase the thermal shock resistance while suppressing an increase in pressure loss.

1 is a perspective view schematically showing a first embodiment of a plugged honeycomb segment of the present invention as viewed from the first end face side. FIG. FIG. 2 is a plan view of the plugged honeycomb segment shown in FIG. 1 viewed from the first end face side. FIG. 3 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 2 is enlarged. It is sectional drawing which shows the A-A 'cross section of FIG. 2 typically. FIG. 3 is an enlarged plan view in which a part of a plugged honeycomb segment shown in FIG. 2 is enlarged, and is an explanatory diagram for explaining a method for calculating an area of a thick portion. FIG. 2 is a perspective view schematically showing a plugged honeycomb structure using the plugged honeycomb segment shown in FIG. 1 as viewed from the first end face side. FIG. 7 is a plan view of the plugged honeycomb structure shown in FIG. 6 as viewed from the first end face side. It is the top view seen from the 1st end surface side which shows typically a second embodiment of the plugged honeycomb segment of the present invention. FIG. 9 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 8 is enlarged. It is the top view seen from the 1st end surface side which shows typically 3rd embodiment of the plugged honeycomb segment of this invention. FIG. 11 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 10 is enlarged. It is the top view seen from the 1st end surface side which shows typically 4th embodiment of the plugged honeycomb segment of this invention. FIG. 13 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 12 is enlarged. It is the top view seen from the 1st end surface side which shows typically 5th embodiment of the plugged honeycomb segment of this invention. FIG. 15 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 14 is enlarged.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. Accordingly, it is understood that modifications, improvements, and the like to the following embodiments are also included in the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

(1) Plugged honeycomb segment (first embodiment):
The first embodiment of the plugged honeycomb segment of the present invention is a plugged honeycomb segment 100 shown in FIGS. As shown in FIG. 1 to FIG. 4, the plugged honeycomb segment 100 has a first end face 11 and a second end face 12, and has a square pillar-shaped honeycomb segment 4 and a cell 2 on the end face side. The plugging portion 5 is provided. Here, FIG. 1 is a perspective view schematically showing the first embodiment of the plugged honeycomb segment of the present invention as seen from the first end face side. FIG. 2 is a plan view of the plugged honeycomb segment shown in FIG. 1 as viewed from the first end face side. FIG. 3 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 2 is enlarged. FIG. 4 is a cross-sectional view schematically showing the AA ′ cross section of FIG. 2.

  The honeycomb segment 4 includes a porous partition wall 1 that defines a plurality of cells 2 extending from the first end surface 11 to the second end surface 12, and a segment outer wall 3 disposed on the outermost periphery of the honeycomb segment 4. The honeycomb segment 4 has four hexagonal cells (hereinafter referred to as “hexagonal cells 2a”) around a square cell (hereinafter also referred to as “square cell 2b”) in a cross section perpendicular to the extending direction of the cells 2. ) Has a cell structure configured to surround. That is, the honeycomb segment 4 has a cell structure in which square cells 2b and hexagonal cells 2a are regularly arranged at a predetermined cycle on a plane orthogonal to the extending direction of the cells 2 as one repeating pattern. By having such a cell structure, when the first end surface 11 is an inflow end surface into which exhaust gas flows, the opening ratio of the square cells 2b is increased and the number of the square cells 2b is compared with the number of the hexagonal cells 2a. Can be less. For this reason, the pressure loss in the initial state of the plugged honeycomb segment 100 can be reduced. The honeycomb segment 4 preferably has a rectangular cross-sectional shape orthogonal to the cell 2 extending direction.

  The cell structure of the honeycomb segment 4 has four sides around one square cell 2b so that one side of a predetermined hexagonal cell 2a and one side of an adjacent square cell 2b have the same length and are parallel to each other. It is preferable that the two hexagonal cells 2a surround the structure. Moreover, it is preferable that the shape in the cross section orthogonal to the extension direction of the said square cell 2b is the square of the square cell 2b. In the plugged honeycomb segment 100 of the present embodiment, with respect to the cells 2 arranged on the outermost periphery of the honeycomb segment 4, the hexagonal cells 2a may not be arranged so as to surround the square cells 2b. That is, at the outermost periphery of the honeycomb segment 4, the cell structure described above is divided by the segment outer wall 3, and a part of the cell structure partially exists. The shapes of the square cells 2b and the hexagonal cells 2a in the plane perpendicular to the cell 2 extending direction of the honeycomb segment 4 are preferably the same as each other except for the cells 2 arranged on the outermost periphery.

  In the plugged honeycomb segment 100 of the present embodiment, the square cell 2b is plugged at the end on the first end surface 11 side by the plugged portion 5, and the hexagonal cell 2a is on the second end surface 12 side. Are plugged by the plugging portion 5. For this reason, the honeycomb segment 4 is used as an exhaust gas purification filter in which the first end surface 11 is an inflow end surface into which exhaust gas flows and the second end surface 12 is an outflow end surface from which exhaust gas that has passed through the honeycomb segment 4 flows out. it can. Note that the plugged honeycomb segment 100 of the present embodiment is manufactured by joining a plurality of plugged honeycomb segment assemblies to form a plugged honeycomb structure 600 as shown in FIGS. 6 and 7. Can be used as A specific configuration of the plugged honeycomb structure 600 as shown in FIGS. 6 and 7 will be described later.

  In the honeycomb segment 4, predetermined hexagonal cells 2 ab are arranged at the respective corners 6 on the peripheral edge of the honeycomb segment 4 in a plane orthogonal to the extending direction of the cells 2. As shown in FIGS. 1 to 3, in the corner portion 6 of the peripheral edge of the honeycomb segment 4, two sides constituting one corner of the hexagonal cell 2 ab become a part of two sides constituting the corner portion 6. In addition, hexagonal cells 2ab are arranged. Hereinafter, the hexagonal cells 2a arranged at the respective corners 6 of the peripheral edge of the honeycomb segment 4 are referred to as “hexagonal cells 2ab”, and the hexagonal cells 2a arranged other than the peripheral corners 6 of the honeycomb segment 4 are referred to as “hexagonal cells 2aa” " And this hexagon cell 2ab is arrange | positioned so that one vertex of a hexagon may face the vertex of the corner | angular part 6 of the periphery of the honeycomb segment 4. FIG. Further, in the hexagonal cell 2ab, a porous material is disposed at a portion including the apex facing the apex of the corner portion 6 on the periphery of the honeycomb segment 4.

  The plugged honeycomb segment 100 of the present embodiment has a thick portion 7 made of the porous material described above at the corner portion 6 on the periphery of the honeycomb segment 4. That is, the thick portion 7 is a portion where a portion including one apex of the hexagonal cell 2ab is blocked with a porous material. The thick portion 7 may be integrated with the segment outer wall 3 of the honeycomb segment 4 or formed by filling a part of the hexagonal cell 2ab with a porous material separate from the segment outer wall 3. It may be. The “integrated with the segment outer wall 3” means that there is no interface between the thick portion 7 and the segment outer wall 3, and a part of the segment outer wall 3 can be regarded as the thick portion 7. It means the state.

  The plugged honeycomb segment 100 of the present embodiment can increase the thermal shock resistance while suppressing an increase in pressure loss. That is, in the hexagonal cell 2ab arranged so as to be located at the corner 6 on the periphery of the honeycomb segment 4, the portion forming the wall surface of the corner 6 has little filtration function as a filter. For this reason, by increasing the pressure loss of the plugged honeycomb segment 100 by arranging the porous material inside the hexagonal cells 2ab arranged at the corners 6 of the peripheral edge of the honeycomb segment 4 to form the thickened portion 7. The thermal shock resistance can be increased while effectively suppressing. Moreover, since the plugged honeycomb segment 100 of the present embodiment has the thick portions 7 at the corner portions 6 of the honeycomb segments 4, the occurrence of defects such as chipping of the corner portions 6 can be effectively suppressed. .

  There is no restriction | limiting in particular about the magnitude | size of the said thick part 7 in the cross section orthogonal to the direction where the cell 2 of the honeycomb segment 4 is extended. For example, as shown in FIG. 5, in the cross section, the ratio (S1) of the area S1 of the thick part 7 to the area S0 of the triangle including the two sides of the hexagonal cell 2ab located at the corner part 6 of the peripheral edge of the honeycomb segment 4 / S0) is preferably 0.125 to 2.0. By comprising in this way, a thermal shock resistance can be increased favorably, suppressing the raise of a pressure loss effectively. Here, FIG. 5 is an enlarged plan view in which a part of the plugged honeycomb segment shown in FIG. 2 is enlarged, and is an explanatory diagram for explaining a method of calculating the area of the thick portion.

  The ratio (S1 / S0) of the area S1 of the thick portion 7 to the area S0 of the triangle including the two sides of the hexagonal cell 2ab is more preferably 0.5 to 1.0, and is 1.0. Is particularly preferred. By comprising in this way, a thermal shock resistance can be improved more favorably, suppressing the raise of a pressure loss more effectively. Here, “the area S0 of the triangle including two sides of the hexagonal cell 2ab” and “the area S1 of the thick portion 7” are cross sections orthogonal to the extending direction of the cell 2 of the honeycomb segment 4, for example, an image analysis device It can obtain | require by analyzing the image imaged by. “Area S0 of a triangle including two sides of the hexagonal cell 2ab” is an area of a triangle having two sides parallel to the peripheral edge of the corner 6 of the honeycomb segment 4 among the six sides of the hexagonal cell 2ab. Can be obtained as In other words, the “area S0” is defined as one vertex located on the most corner 6 side of the honeycomb segment 4 among the six vertices of the hexagonal cell 2ab as a vertex P1, and two vertices adjacent to the vertex P1. When the vertices are P2 and P3, the area is surrounded by the vertices P1, P2 and P3. The “area S1 of the thick portion 7” can be obtained as the area of the porous material occupied in the hexagonal cell 2ab. The “area S1 of the thick portion 7” may be larger than the area surrounded by the vertices P1, P2, and P3 (that is, the area S0), but is equal to or less than the area surrounded by the vertices P1, P2, and P3. It is more preferable that In the measurement of “triangular area S0 including two sides of hexagonal cell 2ab” and “area S1 of thick portion 7”, when thick portion 7 and segment outer wall 3 are integrated, Thus, each value can be calculated. First, extrapolate two sides in contact with the corner 6 of the hexagonal cell 2ab arranged at the corner 6 of the peripheral edge of the honeycomb segment 4, and a point where these two sides intersect is defined as a vertex P4. Next, let two vertices adjacent to the vertex P4 be a vertex P5 and a vertex P6. “A triangular area S0 including two sides of the hexagonal cell 2ab” is an area surrounded by the vertex P4, the vertex P5, and the vertex P6. Further, “the area S1 of the thick portion 7” is an area of a portion where the porous material is disposed inside the hexagonal cell 2ab starting from the vertex P4. Note that when “area S0” and “area S1” are obtained, they are arranged other than “the hexagonal cell 2ab whose opening is not closed by the porous material” and “the corner 6 on the periphery of the honeycomb segment 4”. It is assumed that the hexagonal cell 2aa "has the same cross-sectional shape. As the image analysis apparatus, for example, “NEXIV, VMR-1515 (trade name)” manufactured by Nikon Corporation can be used.

  In the plugged honeycomb segment 100 shown in FIGS. 1 to 4, the thickness of the partition walls 1 and the cell density are not particularly limited. The thickness of the partition wall 1 is preferably 100 to 450 μm, more preferably 150 to 305 μm, and particularly preferably 150 to 205 μm. If the thickness of the partition wall 1 is less than 100 μm, the mechanical strength of the plugged honeycomb segment 100 may be lowered. On the other hand, when the thickness of the partition wall 1 exceeds 450 μm, the pressure loss of the plugged honeycomb segment 100 may increase.

Cell density of the honeycomb segment 4 is preferably 15 to 78 pieces / cm ^2, further preferably from 31 to 62 pieces / cm ^2, and particularly preferably 47 to 62 pieces / cm ^2. When the cell density is less than 15 cells / cm ² , the filtration area as the exhaust gas purification filter becomes small, and sufficient collection performance may not be obtained. On the other hand, when the cell density exceeds 78 cells / cm ² , the pressure loss of the plugged honeycomb segment 100 may increase.

  In the cross section orthogonal to the extending direction of the cell 2, there is no particular limitation on the individual sizes of the square cell 2b and the hexagonal cell 2aa. The ratio (A1 / B1) of the area A1 of the hexagonal cell 2aa to the area B1 of the square cell 2b is preferably 0.5 to 1.5, more preferably 1.0 to 1.5, It is especially preferable that it is 1.0-1.2. By comprising in this way, the pressure loss of the initial state of the plugged honeycomb segment 100 can be reduced favorably. In addition, as for the hexagon of the hexagon cell 2a, it is preferable that the magnitude | size of the internal angle of two opposing vertices is 90 degrees, respectively.

  The porosity of the partition wall 1 is preferably 35 to 70%, and more preferably 40 to 50%. When the porosity of the partition wall 1 is less than 35%, the pressure loss of the plugged honeycomb segment 100 may increase. When the porosity of the partition wall 1 exceeds 70%, the mechanical strength of the plugged honeycomb segment 100 may be lowered. The porosity of the partition wall 1 is a value measured by a mercury porosimeter. An example of the mercury porosimeter is Autopore 9500 (trade name) manufactured by Micromeritics.

  There is no restriction | limiting in particular about the material of the partition 1. FIG. For example, it is preferable that the main component is ceramic. Specifically, at least one selected from the group consisting of silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide-cordierite based composite material. Preferably there is. Here, the “main component” means a component contained in the material constituting the partition wall 1 at a ratio of 50% by mass or more. In addition, it is preferable that this main component is contained in the material which comprises the partition 1 in the ratio of 70 mass% or more, and it is still more preferable that it is contained in the ratio of 80% or more.

  The thick part 7 is made of the same porous material as that of the partition wall 1. For example, the partition wall 1 and the thick part 7 may be formed integrally or separately from the partition wall 1 (that is, integrally formed). Not).

  There is no restriction | limiting in particular about the material of the plugging part 5. FIG. For example, it is preferable that the main component is ceramic, and materials exemplified as the material of the partition wall 1 can be suitably used.

(2) Manufacturing method of plugged honeycomb segment:
Next, a method for manufacturing the plugged honeycomb segment of the present invention will be described. In addition, the manufacturing method demonstrated below is an example of the method of manufacturing the plugged honeycomb segment of this invention, and is not limited to the manufacturing method demonstrated below.

  First, a plastic clay for producing a honeycomb segment is prepared. The method for preparing the kneaded material can be performed according to a conventionally known method for manufacturing a honeycomb segment.

  Next, the formed clay is extruded to obtain a quadrangular prism-shaped honeycomb formed body having partition walls for partitioning a plurality of cells. In extrusion molding, as the die for extrusion molding, there can be used one in which a slit that is an inverted shape of the honeycomb molded body to be molded is formed on the extruded surface of the clay. For example, it is preferable that the slit of the die has a space for forming a thick portion at the corner of the periphery of the honeycomb segment. The honeycomb formed body obtained by extrusion molding may be dried with, for example, microwaves and hot air.

  Next, plugged portions are formed in the dried honeycomb formed body. Specifically, first, a mask is applied to the first end surface of the honeycomb formed body so as to cover the opening of the hexagonal cell. At this time, the openings of the square cells are not covered with the mask on the first end surface of the honeycomb formed body. As described above, the first end face of the honeycomb formed body provided with the mask is immersed in the plugging slurry, and the opening of the square cells is filled with the plugging slurry. In this manner, plugged portions are formed in the opening portions of the square cells on the first end face side of the honeycomb formed body. Similarly, plugging portions are formed in the opening portions of the hexagonal cells on the second end surface side on the second end surface of the honeycomb formed body.

  Next, by firing the obtained honeycomb formed body, a honeycomb segment having porous partition walls can be obtained. The firing temperature and firing atmosphere vary depending on the material used to manufacture the honeycomb formed body, and those skilled in the art can select the optimum firing temperature and firing atmosphere for the selected material. As described above, the plugged honeycomb segment of the present embodiment can be manufactured.

(3) Plugged honeycomb segment (second embodiment to fifth embodiment):
Next, second to fifth embodiments of the plugged honeycomb segment of the present invention will be described with reference to FIGS. Here, FIG. 8, FIG. 10, FIG. 12 and FIG. 14 are plan views seen from the first end face side, schematically showing the second embodiment to the fifth embodiment of the plugged honeycomb segment of the present invention. . 9, 11, 13, and 15 are enlarged plan views in which a part of each plugged honeycomb segment shown in FIGS. 8, 10, 12, and 14 is enlarged.

  As shown in FIGS. 8 and 9, the plugged honeycomb segment of the second embodiment includes a honeycomb segment 24 having a quadrangular column shape and a plugged portion 25 disposed on the end face side in either one of the cells 22. And. The honeycomb segment 24 includes a porous partition wall 21 that defines a plurality of cells 22 extending from a first end surface 31 to a second end surface (not shown), and a segment outer wall 23 disposed on the outermost periphery of the honeycomb segment 24. Have. The honeycomb segment 24 has a cell structure configured such that the four hexagonal cells 22a surround the square cells 22b in a cross section orthogonal to the extending direction of the cells 22.

  In the plugged honeycomb segment 200 of the second embodiment, the square cell 22b is plugged at the end on the first end surface 11 side by the plugged portion 25, and the hexagonal cell 22a is connected to the second end surface ( An end portion on the side (not shown) is plugged with a plugging portion 25. And in the surface orthogonal to the extending direction of the cells 22, the predetermined hexagonal cells 22 ab are arranged so as to be positioned at the corners 26 on the peripheral edge of the honeycomb segment 24. The plugged honeycomb segment 200 of the second embodiment also has a thick portion 27 made of a porous material disposed inside the hexagonal cell 22ab at the corner portion 26 of the peripheral edge of the honeycomb segment 24.

  In the plugged honeycomb segment 100 of the first embodiment shown in FIG. 1 to FIG. 4, the porous material of the hexagonal cell 2ab extends to the vicinity of the midpoint of each of the two sides extending from the apex on the corner 6 side of the hexagonal cell 2ab. As a result, the thick portion 7 was formed. As shown in FIGS. 8 and 9, in the plugged honeycomb segment 200 of the second embodiment, the thickness of the segment outer wall 23 is approximately twice as thick in the vicinity of the corner portion 6 of the honeycomb segment 24. It is comprised so that it may become. And the part which the thickness of the segment outer wall 23 mentioned above increased becomes the thick part 27 in the plugged honeycomb segment 200 of 2nd embodiment. The plugged honeycomb segment 200 thus configured has an advantage in that the thermal shock resistance can be increased while effectively suppressing an increase in pressure loss.

  8 and 9, an example is shown in which the thickness of the segment outer wall 23 is partially doubled in the vicinity of the corner 6 of the honeycomb segment 24. The thickness is not limited to the example shown in FIGS. For example, in the vicinity of the corner portion 6 of the honeycomb segment 24, the thickness of the segment outer wall 23 is preferably 1 to 4 times that of other portions, and is 2 to 3 times as thick. More preferably. When obtaining the area S1 of the thick portion 27, it can be obtained as the area of the portion where the thickness of the segment outer wall 23 is thick.

  As shown in FIGS. 10 and 11, the plugged honeycomb segment of the third embodiment includes a honeycomb segment 44 having a quadrangular prism shape and a plugged portion 45 disposed on one of the end faces of the cells 42. And. The honeycomb segment 44 includes a porous partition wall 41 defining a plurality of cells 42 extending from a first end surface 51 to a second end surface (not shown), and a segment outer wall 43 disposed on the outermost periphery of the honeycomb segment 44. Have. The honeycomb segment 44 has a cell structure configured such that the four hexagonal cells 42a surround the square cells 42b in a cross section orthogonal to the extending direction of the cells 42.

  In the plugged honeycomb segment 300 of the third embodiment, the square cell 42b is plugged at the end on the first end surface 51 side by the plugged portion 45, and the hexagonal cell 42a is formed on the second end surface ( An end portion on the side (not shown) is plugged with a plugging portion 45. And in the plane orthogonal to the extending direction of the cells 42, the predetermined hexagonal cells 42 ab are arranged so as to be positioned at the corners 46 on the peripheral edge of the honeycomb segment 44. The plugged honeycomb segment 300 of the third embodiment also has a thick portion 47 made of a porous material arranged inside the hexagonal cell 42ab at the corner 46 on the periphery of the honeycomb segment 44. In the plugged honeycomb segment 300, the flesh is within a triangular range surrounded by three points of one vertex P1 located on the corner 46 side of the hexagonal cell 42ab and two vertices P2 and P3 adjacent to the vertex P1. A thick portion 47 is formed. The plugged honeycomb segment 300 configured in this way can effectively increase the thermal shock resistance while effectively suppressing an increase in pressure loss.

  As shown in FIGS. 12 and 13, the plugged honeycomb segment of the fourth embodiment includes a honeycomb segment 64 having a quadrangular column shape and a plugged portion 65 disposed on the end face side in either one of the cells 62. And. The honeycomb segment 64 includes a porous partition wall 61 that defines a plurality of cells 62 extending from a first end surface 71 to a second end surface (not shown), and a segment outer wall 63 disposed on the outermost periphery of the honeycomb segment 64. Have. The honeycomb segment 64 has a cell structure configured such that the four hexagonal cells 62a surround the square cell 62b in a cross section orthogonal to the extending direction of the cells 62.

  In the plugged honeycomb segment 400 of the fourth embodiment, the square cell 62b is plugged at the end on the first end surface 71 side by the plugged portion 65, and the hexagonal cell 62a is connected to the second end surface ( The end on the side (not shown) is plugged with a plugging portion 65. And in the plane orthogonal to the extending direction of the cells 62, the predetermined hexagonal cells 62ab are arranged so as to be positioned at the corners 66 on the peripheral edge of the honeycomb segment 64. The plugged honeycomb segment 400 of the fourth embodiment also has a thick portion 67 made of a porous material disposed inside the hexagonal cell 62ab at the corner 66 of the periphery of the honeycomb segment 64. In the plugged honeycomb segment 400, the thick portion 67 is formed so that the vicinity of the apex located on the corner 46 side of the hexagonal cell 62ab has an R shape. In the plugged honeycomb segment 400 configured in this way, the surface of the thick portion 67 (that is, the surface facing the inside of the hexagonal cell 62ab) is rounded, and the plugged honeycomb segment 400 is thermally expanded. The generated stress can be relaxed more effectively. For this reason, it can be made more excellent in thermal shock resistance.

  As shown in FIGS. 14 and 15, the plugged honeycomb segment of the fifth embodiment includes a honeycomb segment 84 having a quadrangular column shape and a plugged portion 85 disposed on one of the end faces of the cells 82. And. The honeycomb segment 84 includes a porous partition wall 81 that defines a plurality of cells 82 extending from a first end surface 91 to a second end surface (not shown), and a segment outer wall 83 disposed on the outermost periphery of the honeycomb segment 84. Have. The honeycomb segment 84 has a cell structure configured such that the four hexagonal cells 82a surround the square cells 82b in a cross section orthogonal to the extending direction of the cells 82.

  In the plugged honeycomb segment 500 of the fifth embodiment, the square cell 82b is plugged at the end on the first end surface 91 side by the plugged portion 85, and the hexagonal cell 82a has a second end surface ( The end on the side (not shown) is plugged with a plugging portion 85. And, in a plane orthogonal to the extending direction of the cells 82, the predetermined hexagonal cells 82ab are arranged at the corners 86 on the peripheral edge of the honeycomb segment 84. The plugged honeycomb segment 500 of the fifth embodiment also has a thick portion 87 made of a porous material disposed inside the hexagonal cell 82ab at the corner 86 on the periphery of the honeycomb segment 84. In the plugged honeycomb segment 500, it exceeds the range of a triangle surrounded by three points of one vertex P1 located on the corner 86 side of the hexagonal cell 82ab and two vertices P2 and P3 adjacent to this vertex P1. A thick portion 87 is formed. The plugged honeycomb segment 300 configured in this manner is excellent in the effect of increasing the thermal shock resistance, although the suppression of the increase in pressure loss is slightly reduced.

(4) Plugged honeycomb structure:
Next, an embodiment of the plugged honeycomb structure of the present invention will be described with reference to FIGS. Here, FIG. 6 is a perspective view schematically showing a plugged honeycomb structure using the plugged honeycomb segment shown in FIG. 1 as viewed from the first end face side. FIG. 7 is a plan view of the plugged honeycomb structure shown in FIG. 6 as viewed from the first end face side.

  As shown in FIGS. 6 and 7, the plugged honeycomb structure 600 of the present embodiment includes a plugged honeycomb segment assembly 610 and an outer periphery disposed on the outer peripheral surface of the plugged honeycomb segment assembly 610. And a wall 611.

  The plugged honeycomb segment bonded body 610 includes a plurality of plugged honeycomb segments 100 and a bonding layer 612 that bonds side surfaces of the plurality of plugged honeycomb segments 100 to each other. The plugged honeycomb structure 600 of the present embodiment is characterized in that the plugged honeycomb segment 100 of the first embodiment described so far is used as the plugged honeycomb segment 100. The plugged honeycomb segment 100 used for the plugged honeycomb segment assembly 610 is any one of the plugged honeycomb segments 200, 300, 400, 500 of the second to fifth embodiments described so far. It may be. Since the plugged honeycomb structure 600 of the present embodiment includes the plugged honeycomb segment assembly 610 using the plugged honeycomb segment 100 of the first embodiment, while suppressing an increase in pressure loss, Thermal shock resistance can be increased.

  The plugged honeycomb structure 600 of the present embodiment is a so-called segmented plugged honeycomb structure, and has, for example, a conventional segmented structure except that the structure of the plugged honeycomb segment 100 is characteristic. A configuration of a plugged honeycomb structure can be employed. Further, as for the manufacturing method of the plugged honeycomb structure 600, a manufacturing method according to a conventionally known manufacturing method may be adopted except that the plugged honeycomb segment 100 is manufactured by the method described so far. it can.

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

Example 1
As a ceramic raw material, a mixed raw material in which silicon carbide (SiC) powder and metal silicon (Si) powder were mixed at a mass ratio of 80:20 was prepared. The average particle diameter of the silicon carbide (SiC) powder was in the range of 3 to 40 μm. To this mixed raw material, hydroxypropylmethylcellulose as a binder and a water-absorbing resin as a pore former were added, and water was added to prepare a molding raw material. The obtained forming raw material was kneaded using a kneader to obtain a clay.

  Next, the obtained clay is molded using an extrusion molding machine, and a rectangular column-shaped honeycomb segment molded body having the same cell structure as the honeycomb segment 4 shown in FIG. Sixteen pieces were produced. Note that the “cell structure similar to the honeycomb segment shown in FIG. 2” is a cell structure in which cells are arranged around a square cell having a square cross-sectional shape so as to surround four hexagonal cells having a hexagonal cross-sectional shape. That's it.

  Next, the obtained honeycomb segment formed body was dried by high-frequency dielectric heating and then further dried using a hot air dryer.

  Plugged portions were formed in the dried honeycomb segment formed body. First, a mask was applied to the first end surface of the honeycomb segment formed body. Next, the end portion (end portion on the first end face side) where the mask is applied is immersed in the plugging slurry, and the opening portion of the cell (square cell) where the mask is not applied is filled with the plugging slurry. . In this way, a plugged portion was formed on the first end face side of the honeycomb segment formed body. The plugged portions were also formed in the hexagonal cells in the same manner for the second end face of the dried honeycomb segment formed body.

  Then, the honeycomb segment formed body in which the plugged portions were formed was degreased and fired to obtain plugged honeycomb segments. The degreasing conditions were 550 ° C. for 3 hours, and the firing conditions were 1450 ° C. and 2 hours in an argon atmosphere.

  The obtained plugged honeycomb segment is arranged such that the hexagonal cells are located at the corners of the periphery of the honeycomb segment, and the corners are constituted by the porous material disposed inside the hexagonal cells. It has a thick part.

The obtained plugged honeycomb segment had a square cross section perpendicular to the cell extending direction, and the length (segment size) of one side of the square was 36 mm. Further, the plugged honeycomb segment had a length in the cell extending direction of 152.4 mm. Table 1 shows the partition wall thickness (μm) and cell density (pieces / cm ² ) of the plugged honeycomb segment. The porosity of the partition walls was 48%. The porosity of the partition walls was measured by Autopore 9500 (trade name) manufactured by Micromeritics.

  The obtained plugged honeycomb segment had a thick portion made of a porous material disposed inside the hexagonal cell at the corner of the periphery of the honeycomb segment. The ratio (S1 / S0) of the area S1 of the thick part to the area S0 of the triangle including two sides of the hexagonal cell located at the corner of the peripheral edge of the plugged honeycomb segment was 0.25. Table 1 shows the value of the area ratio (S1 / S0) of the thick part.

  Next, the produced 16 plugged honeycomb segments were joined and integrated using a joining material (ceramic cement). The bonding material was mainly composed of inorganic particles and an inorganic adhesive, and contained an organic binder, a surfactant, a foamed resin, water and the like as subcomponents. The outer periphery of the plugged honeycomb segment joined body in which the 16 plugged honeycomb segments are integrally joined is ground into a columnar shape, and a coating material is applied to the outer peripheral surface. A honeycomb structure was obtained. The plugged honeycomb structure of Example 1 had an end face diameter of 143.8 mm.

  Next, the obtained plugged honeycomb structure was evaluated for “mechanical strength”, “thermal shock resistance (heat capacity)”, “pressure loss”, and “thermal stress” by the following methods. The evaluation results are shown in Table 1.

[Mechanical strength]
The mechanical strength was evaluated by the following method. First, the isostatic strength of the honeycomb structure was measured by an isostatic strength test stipulated in the JASO standard (Japan Automobile Engineering Association standard). The isostatic strength is a compressive fracture strength when an isotropic hydrostatic pressure load is applied, and is indicated by a pressure value when fracture occurs. The obtained measurement results were evaluated based on the following evaluation criteria. In addition, the ratio (percentage) in the following evaluation criteria is a ratio when the measurement result of Comparative Example 1 is 100%.
Evaluation A: It is set as evaluation A when it improves + 15% or more from the comparative example 1.
Evaluation B: When the improvement is + 10% or more and less than + 15% from Comparative Example 1, it is set as Evaluation B.
Evaluation C: When the improvement is + 5% or more and less than + 10% from Comparative Example 1, the evaluation is C.
Evaluation D: When the improvement from Comparative Example 1 is less than + 5% or no improvement is observed, the evaluation is D.

[Thermal shock resistance (heat capacity)]
In the evaluation of the thermal shock resistance (heat capacity), the following thermal shock test using an electric furnace was performed. In the thermal shock test, first, a plugged honeycomb structure as a sample was placed in an electric furnace maintained at 400 ° C. and heated for 1 hour. After 1 hour, the plugged honeycomb structure was taken out into the room, and the outer surface of the plugged honeycomb structure was lightly tapped with a thin metal rod over the entire circumference while visually observing the appearance until it cooled. At this time, if no cracks were observed in the plugged honeycomb structure and the hit sound was a metal sound, the test was accepted. In the case of passing, the temperature of the electric furnace was further raised by 25 ° C., and the same process was repeated until the cracking sound was observed in the plugged honeycomb structure or the sound hitting became muddy. The highest temperature at which the pass was confirmed was taken as the evaluation value of the thermal shock resistance of the plugged honeycomb structure to be measured. The obtained results were evaluated based on the following evaluation criteria. In addition, the ratio (percentage) in the following evaluation criteria is a ratio when the evaluation value of Comparative Example 1 is 100%.
Evaluation A +: In the case of + 100 ° C. or higher from Comparative Example 1, the evaluation is A +.
Evaluation A: In the case of + 75 ° C. from Comparative Example 1, it is set as Evaluation A.
Evaluation B: From Comparative Example 1, when the temperature is + 50 ° C., the evaluation is B.
Evaluation C: From Comparative Example 1, in the case of + 25 ° C., the evaluation is C.
Evaluation D: Evaluation D is equivalent to or less than that of Comparative Example 1.

[Pressure loss]
The pressure loss was evaluated by the following method. The pressure loss of the plugged honeycomb structure was measured with a pressure loss measuring device described in Japanese Patent Application Laid-Open No. 2005-172652 (Japanese Patent Application No. 2003-414291). The obtained measurement results were evaluated based on the following evaluation criteria.
Evaluation A: When it is equivalent to Comparative Example 1, it is set as Evaluation A
Evaluation B: When a value higher than that of Comparative Example 1 is indicated, it is determined as Evaluation B.

[Thermal stress]
The thermal stress was evaluated by the following method. First, a plugged honeycomb structure was put in an electric furnace. Next, the temperature distribution of the plugged honeycomb structure when the atmosphere in the electric furnace was changed from room temperature to 600 ° C. was obtained. Next, thermal stress analysis was performed on the acquired temperature distribution, and the maximum stress value generated in the plugged honeycomb structure was obtained. The result of the maximum stress value generated was evaluated based on the following evaluation criteria. In addition, the ratio (percentage) in the following evaluation criteria is a ratio when the evaluation value of Comparative Example 1 is 100%.
Evaluation A: When it is + 5% or more from Comparative Example 1, it is set as Evaluation A.
Evaluation B: When it is less than + 5% compared with Comparative Example 1, it is set as Evaluation B.

(Examples 2 to 5, Comparative Example 1)
As shown in Table 1, the ratio (S1 / S0) of the area S1 of the thick part to the area S0 of the triangle including two sides of the hexagonal cell located at the corner of the peripheral edge of the plugged honeycomb segment is changed. A plugged honeycomb segment was produced in the same manner as in Example 1 except that this was done. Then, using the obtained plugged honeycomb segment, a plugged honeycomb structure was produced in the same manner as in Example 1. The obtained plugged honeycomb structure was evaluated for “mechanical strength”, “thermal shock resistance (heat capacity)”, “pressure loss”, and “thermal stress”. The evaluation results are shown in Table 1. Example 2 has a cell structure as shown in FIG. 8, Example 3 has a cell structure as shown in FIG. 10, and Example 4 has a cell structure as shown in FIG. 5 had a cell structure as shown in FIG. The column of “reference drawing” in Table 1 indicates the number of the drawing that refers to the cell structure in each embodiment.

(result)
The plugged honeycomb structures of Examples 1 to 5 can obtain superior results in the evaluation of mechanical strength and thermal shock resistance (heat capacity) as compared with the plugged honeycomb structure of Comparative Example 1. did it. Moreover, regarding the evaluation of the pressure loss, the plugged honeycomb structures of Examples 1 to 4 and the plugged honeycomb structure of Comparative Example 1 showed substantially the same value. For this reason, it turned out that the plugged honeycomb structures of Examples 1 to 4 can effectively suppress the reduction in pressure loss. In addition, the plugged honeycomb structure of Example 5 also has an extremely small increase in pressure loss, and in view of the excellent thermal shock resistance (heat capacity) evaluation, the pressure loss evaluation is also good. It can be said that it is a result.

  The plugged honeycomb structure of Example 4 was able to obtain excellent results in the evaluation of thermal stress. The plugged honeycomb structure of Example 4 uses the plugged honeycomb segment 400 shown in FIGS. 12 and 13. The plugged honeycomb segment 400 as shown in FIGS. 12 and 13 is generated at the time of thermal expansion because the surface of the thick portion 67 (that is, the surface facing the inside of the hexagonal cell 62ab) is rounded. It is considered that the stress was relaxed and good results were obtained in the thermal stress evaluation.

  The plugged honeycomb segment and the plugged honeycomb structure of the present invention can be used as a filter for purifying exhaust gas.

1, 2, 41, 61, 81: partition wall, 2, 22, 42, 62, 82: cell, 2a, 22a, 42a, 62a, 82a: hexagonal cell, 2aa, 22aa, 42aa, 62aa, 82aa: hexagonal cell ( Hexagonal cells arranged at other than corners), 2ab, 22ab, 42ab, 62ab, 82ab: Hexagonal cells (hexagonal cells arranged at the corners), 2b, 22b, 42b, 62b, 82b: square cells, 3, 23 , 43, 63, 83: Segment outer wall, 4, 24, 44, 64, 84: Honeycomb segment, 5, 25, 45, 65, 85: Plugged portion, 6, 26, 46, 66, 86: Corner portion 7, 27, 47, 67, 87: Thick part, 11, 31, 51, 71, 91: First end surface, 12: Second end surface, 100, 200, 300, 400, 500: Plugged honeycomb segment , 60 : Plugged honeycomb structure, 610: plugged honeycomb segment assembly, 611: outer peripheral wall, 612: bonding layer, S0: area (two sides of the hexagonal cell located at the corner of the periphery of the honeycomb segment) , S1: area (thickness area).

Claims (9)

A honeycomb having a quadrangular prism shape having a first end face and a second end face, defining a plurality of cells extending from the first end face to the second end face, and a segment outer wall disposed on the outermost periphery Segments,
A plugging portion disposed on the end face side in any one of the cells,
The honeycomb segment has a cell structure configured such that four hexagonal cells surround a square cell in a cross section perpendicular to the cell extending direction,
The square cell has an end portion on the first end face side plugged by the plugging portion,
In the hexagonal cell, the end portion on the second end face side is plugged by the plugging portion,
In the cross section, the hexagonal cells are arranged at the corners of the periphery of the honeycomb segment so that the hexagonal cells are located, and the hexagonal cells arranged at the corners are hexagonal. Is arranged so that one apex of the end faces the apex of the corner of the peripheral edge of the honeycomb segment,
Inside the hexagonal cell disposed at each corner, a porous material is disposed at a portion including the one apex of the hexagon,
A plugged honeycomb segment having a thick portion made of the porous material at the corner of the periphery of the honeycomb segment.   In the cross section, the ratio of the area S1 of the thick part to the area S0 of the triangle including two sides of the hexagonal cell located at the corner of the peripheral edge of the honeycomb segment is 0.125 to 2.0. The plugged honeycomb segment according to claim 1, wherein   The plugged honeycomb segment according to claim 2, wherein a ratio of the area S1 of the thick part to the area S0 is 0.5 to 1.0 in the cross section. Cell density of the honeycomb segment is 15 to 78 pieces / cm ^2, plugged honeycomb segment according to any one of claims 1 to 3.   The plugged honeycomb segment according to any one of claims 1 to 4, wherein a thickness of the partition wall of the honeycomb segment is 100 to 450 µm.   The plugging according to any one of claims 1 to 5, wherein, in the cross section, a ratio of an area A1 of the hexagonal cell to an area B1 of the square cell is 0.5 to 1.5. Stop honeycomb segment.   The plugged honeycomb segment according to any one of claims 1 to 6, wherein the honeycomb segment has a rectangular cross-sectional shape perpendicular to the cell extending direction.   The plugged honeycomb segment according to any one of claims 1 to 7, wherein each of the hexagons has an inner angle of 90 ° between two opposing vertices. Plugged honeycomb segment bonding comprising a plurality of the plugged honeycomb segments according to any one of claims 1 to 8 and a bonding layer for bonding side surfaces of the plurality of plugged honeycomb segments. Body,
A plugged honeycomb structure comprising: an outer peripheral wall disposed on an outer peripheral surface of the plugged honeycomb segment assembly.

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