JP2010227847A - Honeycomb structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb structure that can effectively prevent its damage resulting from its melting caused by the overheating arising in the operation (regeneration) of combusting and removing particulate matter collected thereby. <P>SOLUTION: The honeycomb structure 100 includes a plurality of honeycomb segments 10 each comprising a plurality of separation walls 3 demarcating and forming a plurality of cells 2, of which a plurality of first cells 2a each opening at one end 8 and plugged at the other end 9 and a plurality of second cells 2b each plugged at one end 8 and opening at the other end 9 are alternately disposed one after the other, with the opposing side faces of the plurality of the honeycomb segments 10 mutually bonded by a bonding member 14, and with the thickness (Tv) of each of the separation walls 3Y disposed along one direction (Y direction) being greater than the thickness (Th) of each of the separation walls 3X disposed along the other direction (X direction) intersecting the one direction at right angles, on a cross section intersecting the direction of the center axis thereof at right angles (namely a cross section vertical to the axial direction of the cells 2) in at least one honeycomb segment 10a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a honeycomb structure. More specifically, the present invention relates to a honeycomb structure capable of effectively preventing melting damage due to overheating when an operation (regeneration) for burning and removing collected particulate matter is performed.

  Ceramic honeycomb structure with excellent heat resistance and corrosion resistance is used as a carrier or filter for catalyst devices used for environmental measures and recovery of specific materials in various fields such as chemistry, electric power, steel, etc. Has been. In particular, recently, a honeycomb structure has a plugged honeycomb structure by alternately plugging the cell openings on both end faces, and particulate matter (PM: particulate matter) discharged from a diesel engine or the like. It is actively used as a diesel particulate filter (DPF) that collects water. As a material for the honeycomb structure used in a high temperature and corrosive gas atmosphere, silicon carbide (SiC), cordierite, aluminum titanate (AT), etc. excellent in heat resistance and chemical stability are suitable. It is used for.

  Since silicon carbide has a relatively high coefficient of thermal expansion, a honeycomb structure formed using silicon carbide as an aggregate may have a defect due to thermal shock during use when a large structure is formed. In addition, defects may occur due to thermal shock when the collected particulate matter is removed by combustion. Therefore, in the case of manufacturing a honeycomb structure formed of silicon carbide as an aggregate, a plurality of segments of a small plugged honeycomb structure (hereinafter referred to as “honeycomb segments”) are usually used when manufacturing a structure having a predetermined size or more. And the segments are joined to produce one large joined body, and the outer periphery thereof is roughly processed and ground to form a plugged honeycomb structure having a desired shape such as a cylindrical shape ( For example, see Patent Document 1). And joining of a segment is performed using a joining material, a joining material is apply | coated to the side surface (outer peripheral surface) of a predetermined segment, and the several segment is joined by the side surfaces. Thereby, a honeycomb structure in which a plurality of segments are bonded via the bonded portion is obtained.

JP 2003-291054 A

  However, such a honeycomb structure has a problem that it melts due to overheating when the collected particulate matter is burned and removed, and a defect occurs due to thermal shock.

  The present invention has been made in view of the above-described problems, and can provide a honeycomb structure that can effectively prevent melting damage due to overheating when an operation (regeneration) for burning and removing the collected particulate matter is performed. Is to provide.

  In order to solve the above-described problems, the present invention provides the following honeycomb structure.

[1] A first partition having partition walls for partitioning a plurality of cells extending from one end face to the other end face to be a fluid flow path, one end being opened and the other end being plugged. And a plurality of honeycomb segments in which the one end portion is plugged and the other end portion is opened, and the plurality of honeycomb segments are connected to each other. Are disposed adjacent to each other so that the side surfaces of the plurality of honeycomb segments are opposed to each other, and the opposed side surfaces are bonded to each other by a bonding portion, and at least one of the plurality of honeycomb segments is orthogonal to the central axis direction. In the cross section, the thickness (Tv) of the partition wall arranged along one direction (Y direction) has a thickness (Tv) of the partition wall arranged along another direction (X direction) orthogonal to the one direction. Greater than thickness (Th) There honeycomb structure.

[2] The honeycomb structure according to [1], wherein at least the one honeycomb segment is configured such that an area of the first cell is larger than an area of the second cell in a cross section orthogonal to the central axis direction. body.

[3] The honeycomb structure according to [1] or [2], wherein the relationship between Th and Tv is “1.05 ≦ Tv / Th ≦ 2.00”.

[4] The honeycomb structure according to any one of [1] to [3], wherein the Th is “0.25 mm ≦ Th ≦ 0.38 mm”.

[5] In the plurality of honeycomb segments, the other adjacent honeycomb segment is arranged in a state of being rotated 90 degrees about the central axis with respect to one of the adjacent honeycomb segments. [4] The honeycomb structure according to any one of [4].

  When the honeycomb structure of the present invention is used as a diesel particulate filter that collects particulate matter discharged from a diesel engine or the like, when the operation (regeneration) of removing the collected particulate matter is performed (regeneration) It is possible to effectively prevent melting damage due to overheating.

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. FIG. 2 is a plan view schematically showing an enlarged area A in FIG. 1. FIG. 3 is a plan view schematically showing the honeycomb structure in FIG. 2 further enlarged. FIG. 2 is a plan view schematically showing an enlarged portion corresponding to a region A in FIG. 1 in another embodiment of the honeycomb structure of the present invention. Fig. 5 is a plan view schematically showing the honeycomb structure in Fig. 4 further enlarged. FIG. 6 is an enlarged plan view schematically showing a portion corresponding to a region A in FIG. 1 in still another embodiment of the honeycomb structure of the present invention. FIG. 7 is a plan view schematically showing the honeycomb structure in FIG. 6 further enlarged. It is a side view which shows typically the measuring method of breaking strength (%). It is a side view which shows typically the measuring method of outer periphery minimum temperature (degreeC).

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and those skilled in the art do not depart from the spirit of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge.

[1] Honeycomb structure:
As shown in FIGS. 1 to 3, one embodiment of the honeycomb structure of the present invention has partition walls 3 for partitioning and forming a plurality of cells 2 extending from one end face serving as a fluid flow path to the other end face. The first cell 2a in which one end portion 8 is opened and the other end portion 9 is plugged, and the first cell 8a in which one end portion 8 is plugged and the other end portion 9 is opened. Two cells 2b are alternately arranged, and a plurality of honeycomb segments 10 are arranged adjacent to each other so that the side surfaces thereof are opposed to each other. The at least one honeycomb segment 10a of the plurality of honeycomb segments 10 joined by the joint portion 14 is in one direction in a cross section orthogonal to the central axis direction (that is, a cross section perpendicular to the axial direction of the cells 2). Arranged along (Y direction) In the honeycomb structure 100, the thickness (Tv) of the formed partition wall 3Y is larger than the thickness (Th) of the partition wall 3X arranged along another direction (X direction) orthogonal to the one direction. is there. The honeycomb segment 10 is surrounded by an outer wall 15 located on the outermost periphery.

  With this configuration, when the honeycomb structure of the present embodiment is used as a diesel particulate filter that collects particulate matter discharged from a diesel engine or the like, the collected particulate matter is burned and removed. It is possible to effectively prevent melting damage due to overheating when the operation (regeneration) is performed. That is, the amount of particulate matter to be processed per unit volume (in other words, the amount of particulate matter that can be regenerated per unit volume) can be increased. Further, for example, since the temperature at which melting damage occurs in filter regeneration becomes high, breakage in filter regeneration can be effectively prevented.

  Further, the honeycomb structure of the present embodiment can improve the compressive strength in the specific direction of at least one honeycomb segment. For this reason, by appropriately selecting the arrangement of the honeycomb segments, the compressive strength can be changed between one direction of the honeycomb structure and the other direction, for example, selective to the direction in which the compressive strength is required. It is possible to impart strength to the.

  Furthermore, by increasing the thickness of the partition wall arranged along one direction (Y direction), the direction of the heat flow rate can be controlled, and a portion that does not want to become high temperature can be arbitrarily set. it can. For example, this is effective when the clearance with other parts is narrow, or when there is a fuel pipe or electrical part that does not need to be heated in a specific direction nearby, such as when it is mounted on an automobile.

  Here, FIG. 1 is a perspective view schematically showing an embodiment of the honeycomb structure of the present invention, and FIG. 2 is a plan view schematically showing an enlarged region A in FIG. FIG. 3 is a plan view schematically showing the honeycomb structure in FIG. 2 further enlarged.

  The thickness (Tv) of the partition walls 3Y arranged along one direction (Y direction) means the thickness of any partition wall 3Y extending in parallel with the Y direction in one honeycomb segment. The thickness (Th) of the partition walls 3X arranged along the direction (X direction) means the average thickness of all the partition walls 3X extending in parallel with the X direction in one honeycomb segment.

  In the honeycomb structure of the present embodiment, the relationship between Th and Tv described above is preferably “1.05 ≦ Tv / Th ≦ 2.00”, and “1.11 ≦ Tv / Th ≦ 1. 80 ”is more preferable, and“ 1.28 ≦ Tv / Th ≦ 1.80 ”is particularly preferable. If Tv / Th is less than 1.05, the effect of improving the temperature causing melting loss in filter regeneration cannot be obtained. On the other hand, if Tv / Th exceeds 2.00, Tv becomes thick and pressure loss occurs. Is unfavorable because it increases.

  There is no particular limitation on the thickness (Th) of the partition wall 3X arranged along the other direction (X direction), but if it is too thin, extrusion may be difficult when manufacturing the honeycomb segment, If it is too thick, the pressure loss may become too large. More specifically, the preferable range of the thickness (Th) of the partition wall 3X is 50 μm or more, more preferably 100 μm or more, particularly preferably 250 μm or more, 500 μm or less, more preferably 450 μm or less, particularly preferably 380 μm or less. It is.

  The cell shape of the cells 2 formed on one honeycomb segment 10a (that is, the cell shape in a cross section perpendicular to the central axis direction of the honeycomb structure (the direction in which the cells extend)) is not particularly limited. For each of the cells and the second cell, for example, a triangle, a quadrangle, a hexagon, an octagon, a circle, or a combination thereof can be given. 1 to 3 show examples in which the cell shape is a quadrangle. Further, as shown in FIG. 3, in the cross section orthogonal to the central axis direction of the honeycomb segment 10a, the width (Wx) of the opening portion in the other direction of the opening portion of the cell 2 and the one direction of the opening portion of the cell The relationship with the width (Wy) of the opening is preferably 1 ≦ Wy / Wx ≦ 2, more preferably 1 ≦ Wy / Wx ≦ 1.7.

  Further, in the honeycomb structure of the present embodiment, if the partition wall thickness in at least one of the plurality of honeycomb segments is configured to be thick in one direction as described above, for example, the honeycomb structure The partition wall thicknesses in all the honeycomb segments constituting the body may be configured as described above, or the partition wall thicknesses in some of the plurality of honeycomb segments may be configured as described above. The remaining honeycomb segments may be configured such that the partition walls have the same thickness in one direction (Y direction) and the other direction (X direction). 2 and 3, all the honeycomb segments 10 in the region A are constituted by the one honeycomb segment 10a described above.

  Furthermore, in the honeycomb structure of the present invention, for example, as shown in FIG. 4 and FIG. 5, the other honeycomb segment 10 b of the plurality of honeycomb segments 10 has one honeycomb segment as its center axis. It may be rotated 90 degrees. That is, one honeycomb segment 10a having a large thickness (Tv) of partition walls 3Y arranged along one direction (Y direction), and another honeycomb segment 10b obtained by rotating one honeycomb segment by 90 degrees May be a honeycomb structure 101 formed by mixing the two.

  Here, FIG. 4 is a plan view schematically showing an enlarged portion corresponding to the region A in FIG. 1 in another embodiment of the honeycomb structure of the present invention, and FIG. 5 is a honeycomb view in FIG. It is a top view which expands a structure further and shows typically. 4 and 5, the honeycomb segment 10 on the right side of the paper surface in the region A is constituted by the one honeycomb segment 10 a described above, and the honeycomb segment 10 on the left side of the paper surface rotates one honeycomb segment by 90 degrees as described above. It is constituted by the other honeycomb segment 10b. That is, in FIGS. 4 and 5, one honeycomb segment 10 a and the other honeycomb segment 10 b are orthogonal to each other in a direction (one direction) in which the thickness of the partition walls 3 increases.

  As described above, one honeycomb segment 10a in which the thickness (Tv) of the partition walls 3Y arranged along one direction (Y direction) is large, and another honeycomb segment obtained by rotating one honeycomb segment by 90 degrees. By mixing 10b, the temperature distribution of the honeycomb structure 101 that is an aggregate of the honeycomb segments 10 can be freely adjusted. For this reason, since the site | part which reduces the temperature of outer periphery can be created, the part which does not want to become high temperature can be set arbitrarily, for example.

  Needless to say, the size of Tv and Th may be changed for each honeycomb segment. However, since many types of honeycomb segments are manufactured correspondingly, the cost becomes expensive.

  Further, when a honeycomb structure is constituted by such one honeycomb segment and another honeycomb segment, as in the honeycomb structure 101 shown in FIG. 4, one honeycomb segment 10a and another honeycomb segment are formed. 10b are preferably arranged alternately so that the side surfaces are adjacent to each other. As described above, the honeycomb structure 101 is configured by alternately arranging the one honeycomb segment 10a and the other honeycomb segment 10b, thereby performing an operation (regeneration) for removing the collected particulate matter by combustion. Overheating at the time can be satisfactorily suppressed, and melting damage during regeneration can be more effectively prevented.

  As the material of the honeycomb segment constituting the honeycomb structure of the present embodiment, ceramic is preferable, and since it is excellent in strength and heat resistance, silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, More preferably, it is at least one selected from the group consisting of silicon carbide-cordierite composite material, lithium aluminum silicate, aluminum titanate, and iron-chromium-aluminum alloy. Among these, silicon carbide or silicon-silicon carbide based composite material is particularly preferable. Since silicon carbide has a relatively high coefficient of thermal expansion, a honeycomb structure formed using silicon carbide as an aggregate may cause defects due to thermal shock when used, but the honeycomb structure of the present invention The structure is a structure in which a plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposing side surfaces are bonded together by a bonded portion, so that stress due to thermal expansion of silicon carbide is bonded. It is relieved by the part, and the occurrence of defects in the honeycomb structure can be prevented.

  The honeycomb segment constituting the honeycomb structure of the present embodiment (more specifically, the partition walls constituting the honeycomb segment) is preferably porous. The porosity of the honeycomb segment is preferably 30 to 80%, and more preferably 40 to 65%. By setting the porosity in such a range, the pressure loss can be reduced while maintaining the strength. If the porosity is less than 30%, the pressure loss may increase. When the porosity exceeds 80%, the strength may decrease or the thermal conductivity may decrease. The porosity is a value measured with a mercury porosimeter.

  The honeycomb segment constituting the honeycomb structure of the present embodiment preferably has an average pore diameter of 5 to 50 μm, more preferably 7 to 35 μm. By setting the average pore diameter in such a range, particulate matter (PM) can be effectively collected. If the average pore diameter is less than 5 μm, clogging may easily occur due to particulate matter (PM). When the average pore diameter exceeds 50 μm, particulate matter (PM) may pass through without being collected by the filter. The average pore diameter is a value measured with a mercury porosimeter.

  When the material of the honeycomb segment constituting the honeycomb structure of the present embodiment is silicon carbide, the average particle diameter of the silicon carbide particles is preferably 5 to 100 μm. By setting it as such an average particle diameter, there exists an advantage that it is easy to control to the porosity and pore diameter suitable for a filter. When the average particle size is smaller than 5 μm, the pore diameter becomes too small, and when it is larger than 100 μm, the porosity becomes too large. If the pore diameter is too small, clogging may easily occur due to particulate matter (PM), and if the porosity is too large, pressure loss may increase. The average particle diameter of the raw material is a value measured according to JIS R 1629.

  The cell shape of the honeycomb segment constituting the honeycomb structure of the present embodiment (cell shape in a cross section perpendicular to the central axis direction (cell extending direction) of the honeycomb structure) is not particularly limited. For both the cell and the second cell, for example, a triangle, a quadrangle, a hexagon, an octagon, a circle, or a combination thereof can be given.

The cell density of the honeycomb segments is not particularly limited, preferably 0.9 to 311 cells / cm ^2, more preferably 7.8 to 62 cells / cm ^2.

  Further, in the honeycomb structure of the present invention, as shown in FIGS. 6 and 7, the area (cross-sectional area) of the first cell 2a in the cross section orthogonal to the central axis direction is the area (cut-off area) of the second cell 2b. The honeycomb structure 102 may be configured to be larger than (area). By comprising in this way, waste gas flows in from the opening edge part side (one edge side) of the 1st cell 2a, permeate | transmits the porous partition 3, and the opening edge part of the 2nd cell 2b The exhaust gas can be discharged from the side (the other end side), and particulate matter in the exhaust gas can be collected on the surface of the partition wall 3 having a large surface area inside the first cell 2a. For this reason, obstruction | occlusion of the inflow side cell by a particulate matter can be suppressed.

  Here, FIG. 6 is a plan view schematically showing an enlarged portion corresponding to the region A of FIG. 1 in still another embodiment of the honeycomb structure of the present invention, and FIG. Fig. 3 is a plan view schematically showing the honeycomb structure further enlarged.

  “The area of the first cell (cross-sectional area)” or “the area of the second cell (cross-sectional area)” refers to “a cross section perpendicular to the central axis direction (cell extending direction) of the honeycomb structure”. "Area". In the honeycomb structure of the present embodiment, the cross-sectional area of the first cell is preferably 120 to 300%, more preferably 140 to 250% with respect to the cross-sectional area of the second cell. preferable. When the cross-sectional area of the first cell is smaller than 120% of the cross-sectional area of the second cell, the blocking effect of the inflow side cell (first cell) may be reduced, and the cross-sectional area of the first cell may decrease. Is larger than 300% of the cross-sectional area of the second cell, the cross-sectional area of the cell on the outflow side (second cell) becomes small, and the pressure loss may increase.

  The cell shape of the honeycomb structure (cell shape in a cross section perpendicular to the central axis direction of the honeycomb structure (cell extending direction)) is not particularly limited, and any of the first cell and the second cell is used. For example, a triangle, a quadrangle, a hexagon, an octagon, a circle, or a combination thereof can be given. Among these, as shown in FIGS. 6 and 7, it is preferable that the first cell 2a having a large cross-sectional area is an octagon and the second cell 2b having a small cross-sectional area is a quadrangle. In addition, it is also preferable that the first cell is a quadrangle with rounded corners and the second cell is a quadrangle.

  Further, in such a honeycomb structure 102, the width (W1x) of the opening portion in the other direction of the opening portion of the first cell 2a and the opening of the first cell 2b in the cross section orthogonal to the central axis direction. The relationship with the width (W1y) of the opening in one direction of the portion is preferably 1 ≦ W1y / W1x ≦ 2, and more preferably 1 ≦ W1y / W1x ≦ 1.55. If W1y / W1x is more than 2, the ratio of the width of the opening portion in one direction to the width of the opening portion in the other direction becomes too large, and the strength of the honeycomb structure may be lowered. More specifically, the width W1x of the first cell 2a is preferably 0.2 to 3 mm, and the width W1y of the first cell 2a is preferably 0.2 to 3 mm.

  Further, in the cross section orthogonal to the central axis direction, the width (W2x) of the opening portion in the other direction of the opening portion of the second cell 2b and the width of the opening portion in one direction of the opening portion of the second cell 2b The relationship with (W2y) is preferably 1 ≦ W2y / W2x ≦ 2, and more preferably 1 ≦ W2y / W2x ≦ 1.7. More specifically, the width W2x of the second cell 2b is preferably 0.2 to 3 mm, and the width W2y of the second cell 2b is preferably 0.2 to 3 mm.

  Further, as shown in FIG. 7, the thickness Ts of the inclined partition wall 3s is preferably the same as Tv. As shown in FIG. 7, the “inclined partition wall” is inclined with respect to the direction in which the first cells 2a and the second cells 2b are alternately arranged in a cross section orthogonal to the central axis of the honeycomb structure 102. The barrier ribs extend in the direction in which the diagonal lines of the first cells (or the second cells) extend, and extend in the direction in which the diagonal lines are extended.

  In FIG. 4, one honeycomb segment 10 a and another honeycomb segment 10 b rotated by 90 degrees about the central axis are arranged alternately so that the side surfaces thereof are adjacent to each other. Although an example of the case is shown, all of the honeycomb segments constituting the honeycomb structure may be constituted by one honeycomb segment, or one honeycomb segment and one honeycomb segment are arranged at 90 degrees. Other honeycomb segments that have been rotated may be arranged irregularly or with a certain regularity. Furthermore, another honeycomb segment having the same partition wall thickness in one direction and the other direction may be further provided.

In the cross section perpendicular to the central axis direction of the honeycomb structure 100 of the present embodiment as shown in FIGS. 1 to 3, the number of the honeycomb segments 10 arranged is preferably 4 to 144, 16 to More preferably, the number is 100. The size of the honeycomb segment 10, the area of the cross section perpendicular to the central axis is preferably 3～16Cm ^2, and still more preferably 7~13cm ^2. If it is smaller than 3 cm ² , the pressure loss when the gas flows through the honeycomb structure 100 may increase, and if it exceeds 16 cm ² , the damage prevention effect of the honeycomb segment 10 may be reduced.

  The honeycomb structure of the present embodiment has a plugged portion 5 at one end 8 of the second cell 2b and the other end 9 of the first cell 2a of the honeycomb segment 10, The first cells 2 a and the second cells 2 b are alternately arranged so that a checkered pattern is formed on the end face of the honeycomb segment 10.

  The joint portions 14 constituting the honeycomb structure 100 of the present embodiment are disposed between adjacent honeycomb segments 10, and the honeycomb segments 10 are joined by the joint portions 14. It is preferable that the joint portion 14 is disposed on the entire side surfaces of the adjacent honeycomb segments 10 that face each other. The material of the joint portion 14 is preferably a slurry obtained by adding water to an inorganic raw material such as inorganic fiber, colloidal silica, clay, or SiC particles, and adding an additive such as an organic binder, a foamed resin, or a dispersant, and kneading. .

  As shown in FIG. 1, the honeycomb structure of the present embodiment preferably includes an outer peripheral wall 4 formed so as to surround the plurality of honeycomb segments 10 as a whole. By providing the outer peripheral wall 4, there are effects such as improvement of the roundness of the outer shape. The thickness of the outer peripheral wall 4 of the honeycomb structure of the present embodiment is preferably 0.1 to 4.0 mm, and more preferably 0.3 to 1.0 mm. If it is thinner than 0.1 mm, cracks may easily occur when the outer periphery coating for forming the outer peripheral wall 4 is performed. If it is thicker than 4.0 mm, the pressure may increase. The thickness of the outer peripheral portion refers to the distance from the outer peripheral surface (front surface) of the outer peripheral wall 4 to the closest cell.

Further, the thermal expansion coefficient at 40 to 800 ° C. of the honeycomb segment constituting the honeycomb structure of the present embodiment is preferably 1 × 10 ⁻⁶ / ° C. or more, and 2 × 10 ^{−6 to} 7 × 10 ^−6. More preferably, the temperature is / ° C. The honeycomb structure of the present embodiment is a honeycomb structure having high thermal shock resistance because it is formed by bonding honeycomb segments even when the thermal expansion coefficient is large.

  The overall shape of the honeycomb structure of the present embodiment is not particularly limited, and can be a desired shape such as a cylindrical shape or an oval shape. Moreover, as for the magnitude | size of a honeycomb structure, it is preferable that the diameter of a bottom face is 50-450 mm in the case of a cylindrical shape, for example, and it is still more preferable that it is 100-350 mm. The length of the honeycomb structure in the central axis direction is preferably 50 to 450 mm, and more preferably 100 to 350 mm.

[2] Manufacturing method of honeycomb structure:
Next, a manufacturing method of an embodiment of the honeycomb structure of the present invention will be described.

[2-1] Production of honeycomb segment:
First, a binder, a surfactant, a pore former, water and the like are added to a ceramic raw material to form a forming raw material. Ceramic raw materials include silicon carbide, silicon-silicon carbide composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite composite material, lithium aluminum silicate, aluminum titanate, iron-chromium-aluminum alloy It is preferably at least one selected from the group consisting of Among these, silicon carbide or silicon-silicon carbide based composite material is preferable. When a silicon-silicon carbide based composite material is used, a mixture of silicon carbide powder and metal silicon powder is used as a ceramic raw material. The content of the ceramic raw material is preferably 30 to 90% by mass with respect to the entire forming raw material.

  Examples of the binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder content is preferably 2 to 20% by mass with respect to the entire forming raw material.

  The water content is preferably 5 to 50 mass% with respect to the entire forming raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the surfactant is preferably 0 to 5% by mass with respect to the entire forming raw material.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include starch, foamed resin, water absorbent resin, silica gel and the like. The pore former content is preferably 0 to 20% by mass with respect to the entire forming raw material.

  Next, the forming raw material is kneaded to form a clay. The method of kneading the forming raw material to form the kneaded material is not particularly limited, and examples thereof include a method using a kneader, a vacuum kneader or the like.

  Next, the clay is extruded to form a plurality of honeycomb formed bodies. As the honeycomb formed body to be formed, the honeycomb formed body has a porous partition wall that partitions and forms a plurality of cells serving as fluid flow paths and an outer peripheral wall located at the outermost periphery, and is orthogonal to the central axis direction. In the cross section, the thickness (Tv) of the barrier ribs arranged along one direction (Y direction) is equal to the thickness of the barrier ribs (X direction) perpendicular to the one direction (X direction) ( One or more honeycomb formed bodies that are larger than Th) are formed. That is, in addition to a honeycomb molded body having a thick partition wall disposed along one direction (Y direction), a honeycomb molded body having the same partition wall thickness as one direction and the other direction. It may be formed by extruding separately, or all of the honeycomb formed bodies may have a thick partition wall arranged along one direction (Y direction). That is, the shape of the formed honeycomb body can be appropriately selected according to the structure of the honeycomb structure formed by combining the honeycomb segments.

  In addition, as the honeycomb formed body to be extruded, the first cells having a large area in the cross section orthogonal to the central axis and the second cells having a small area in the cross section orthogonal to the central axis are alternately arranged. There may be.

  In extrusion molding, it is preferable to use a die having a desired segment shape, segment arrangement, cell shape, partition wall thickness, cell density, and the like. As the material of the die, a cemented carbide which does not easily wear is preferable.

  The partition wall thickness, cell density, outer peripheral thickness, etc. of the honeycomb molded body can be appropriately determined in accordance with the structure of the honeycomb structure of the present invention to be manufactured in consideration of shrinkage during drying and firing. it can.

  The obtained honeycomb formed body is preferably dried before firing. The drying method is not particularly limited, and examples thereof include an electromagnetic heating method such as microwave heating drying and high-frequency dielectric heating drying, and an external heating method such as hot air drying and superheated steam drying. Among these, the entire molded body can be dried quickly and uniformly without cracks, and after drying a certain amount of moisture with an electromagnetic heating method, the remaining moisture is dried with an external heating method. It is preferable to make it. As drying conditions, it is preferable to remove moisture of 30 to 90% by mass with respect to the amount of moisture before drying by an electromagnetic heating method, and then to make the moisture to 3% by mass or less by an external heating method. As the electromagnetic heating method, dielectric heating drying is preferable, and as the external heating method, hot air drying is preferable.

  Next, when the length of the honeycomb formed body in the central axis direction is not a desired length, it is preferable to cut both end faces (both end portions) to a desired length. The cutting method is not particularly limited, and examples thereof include a method using a circular saw cutting machine.

  Next, the honeycomb fired body is preferably fired to produce a honeycomb fired body. In order to remove the binder or the like before firing, it is preferable to perform temporary firing. Pre-baking is preferably performed at 400 to 500 ° C. for 0.5 to 20 hours in an air atmosphere. The method of temporary baking and baking is not particularly limited, and baking can be performed using an electric furnace, a gas furnace, or the like. Firing conditions are preferably heated at 1300 to 1500 ° C. for 1 to 20 hours in an inert atmosphere such as nitrogen or argon.

  Next, the obtained honeycomb fired body was plugged at one end portion of the second cell and the other end portion of the first cell (forming a plugged portion), and the honeycomb segment was formed. Is made. A method for forming the plugged portion is not particularly limited, and examples thereof include the following methods. After the sheet is attached to one end face of the honeycomb fired body, a hole is opened at a position corresponding to a cell (second cell) where a plugging portion of the sheet is to be formed. Then, in the plugging slurry in which the constituent material of the plugging portion is slurried, the honeycomb fired body is immersed in the end face on which the sheet is pasted, and an attempt is made to form the plugging portion through holes formed in the sheet. The plugging slurry is filled into the open end of the cell (second cell) to be performed. And about the other end surface of a honeycomb fired body, about the cell (1st cell) which was not plugged in one end surface, it is the method similar to the method of forming the plugging part in the said one end surface. A plugging portion is formed (filled with a plugging slurry). As the constituent material of the plugged portion, the same material as that of the honeycomb formed body is preferably used. After forming the plugged portion, it is preferable to perform baking under the same conditions as the above baking conditions. The plugging portion may be formed before firing the honeycomb formed body.

[2-2] Production of honeycomb structure:
A honeycomb segment in which a predetermined number of honeycomb segments are bonded with a bonding material, and a plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposite side surfaces are bonded to each other by a bonding portion A joined body is formed. The honeycomb segment bonded body may be a honeycomb structure finally obtained. It is preferable that the joining portion is disposed on the entire side surfaces facing each other. The joined portion plays a role of buffering (absorbing) a volume change when the honeycomb segments are thermally expanded and contracted, and also serves to join the honeycomb segments. When forming a bonded honeycomb segment assembly, the unit in the resulting honeycomb structure is adjusted by adjusting the position and orientation of the one honeycomb segment having a thick partition wall in one direction. It becomes possible to increase the amount of particulate matter to be processed per volume and to improve the compressive strength in a specific direction.

  The method for applying the bonding material to the side surfaces of the honeycomb segments is not particularly limited, and a method such as brush coating can be used.

  Examples of the bonding material include a slurry obtained by adding water to an inorganic raw material such as inorganic fiber, colloidal silica, clay, and SiC particles and adding an additive such as an organic binder, a foamed resin, and a dispersant, and kneading. it can.

  After forming the joined honeycomb segment assembly, the outer peripheral portion can be cut into a desired shape. For example, when the honeycomb structure shown in FIG. 1 is manufactured, a honeycomb segment bonded body is manufactured by bonding 16 square columnar honeycomb segments, and the outer periphery of the honeycomb segment bonded body is cut to form a cylindrical honeycomb. A segment bonded body is provided, and an outer peripheral portion (outer peripheral wall) is disposed to form a honeycomb structure.

  After forming the joined honeycomb segment assembly, it is preferable to perform an outer periphery coating treatment to dispose the outer periphery on the outermost periphery of the joined honeycomb segment assembly. By performing the outer periphery coating process, there is an advantage that the roundness of the outer shape is improved. Examples of the outer periphery coating treatment include a method in which an outer periphery coating material is applied to the outermost periphery of the joined honeycomb segment assembly and dried. As the outer periphery coating material, a mixture of inorganic fiber, colloidal silica, clay, SiC particles, organic binder, foamed resin, dispersant, water, or the like can be used. The content of each raw material is preferably in the same range as the preferable range of the content of the raw material of the bonding material. Moreover, the method of applying the outer periphery coating material is not particularly limited, and examples thereof include a method of coating the honeycomb structure with a rubber spatula while rotating on the potter's wheel.

  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 ceramic raw materials, SiC powder and metal Si powder are mixed at a mass ratio of 80:20. To this, methylcellulose and hydroxypropoxymethylcellulose are formed as molding aids, starch and water-absorbing resin, surfactant and water are used as pore formers. The kneaded material was added and kneaded, and a square columnar kneaded material was produced with a vacuum kneader.

  The obtained square columnar clay is extruded using an extruder and has a porous partition wall that forms a plurality of cells that serve as fluid flow paths and an outer wall located at the outermost periphery, and is orthogonal to the central axis direction. A honeycomb formed body having a structure in which the first cells having a large area and the second cells having a small area are alternately arranged in the cross section is formed. The obtained honeycomb formed body was dried by high-frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both end surfaces were cut by a predetermined amount.

  The obtained honeycomb formed body was dried at 120 ° C. for 5 hours using a hot air dryer, and then degreased at about 450 ° C. for 5 hours using an air furnace equipped with a deodorizing apparatus in an air atmosphere. Firing at about 1450 ° C. for 5 hours in an inert atmosphere yielded a porous honeycomb fired body in which SiC crystal particles were bonded with Si. The honeycomb fired body had an average pore diameter of 13 μm and a porosity of 41%. The average pore diameter and porosity are values measured with a mercury porosimeter.

  About the obtained honeycomb fired body, plugged portions were formed at one end portion of the second cell and the other end portion of the first cell. As the plugging filler, the same material as that of the honeycomb formed body was used. After forming the plugged portions in the honeycomb fired body, the honeycomb fired body was fired under the same conditions as the above firing conditions to form a plurality of honeycomb segments. The obtained honeycomb segment had a square bottom surface, a side of 36 mm, and a central axis direction length of 160 mm.

  Table 1 shows the width of the opening portion of each cell constituting the honeycomb segment and the thickness of the partition wall. Specifically, the width (W1x) of the opening in the other direction (X direction) of the first cell is 1.06 mm, and the width (W1y) of the opening in one direction (Y direction) of the first cell. ) Is 1.08 mm, and the width (W2x) of the opening in the other direction (X direction) of the second cell is 1.06 mm, and the opening in one direction (Y direction) of the second cell is The width (W2y) of the part is 1.08 mm.

  Further, the thickness (Tv) of the partition wall arranged along one direction (Y direction) is 0.40 mm, and the thickness (Th) of the partition wall arranged along the other direction (X direction) is 0. .38 mm and Tv / Th is 1.05. The cell pitch in the X direction and the Y direction of this honeycomb structure is 1.46 mm.

  The obtained honeycomb segments were joined with a joining material in a manner of 4 × 4 as in the honeycomb structure 100 shown in FIG. 1 to obtain a joined honeycomb segment. As a bonding material, a mixture of aluminosilicate inorganic fibers and SiC particles was used. In addition, the arrangement | sequence at the time of joining a honeycomb segment shall be the partition arranged along the one direction (Y direction) where the thickness of a partition is thick arranged in the same direction in all the honeycomb segments. Such an arrangement is indicated as “one direction” in the “segment arrangement” in Table 1.

  The outer periphery of the obtained joined honeycomb segment assembly was ground to form a cylindrical shape. Thereafter, an outer periphery coating process is performed, and an outer periphery coat portion is disposed on the outermost periphery of the joined honeycomb segment assembly to produce a bonded honeycomb structure having a structure of 144 mm in diameter and 160 mm in the length in the central axis direction as shown in FIG. did. The bonded honeycomb structure was subjected to outer periphery coating, and an outer peripheral wall was disposed on the outermost periphery of the bonded honeycomb structure to obtain a honeycomb structured body. The outer periphery coating material used was a mixture of inorganic fiber, colloidal silica, clay, SiC particles, organic binder, foamed resin, dispersant and water.

  The obtained honeycomb structure was evaluated for “breaking strength (%)”, “regeneration limit value (g / liter)” and “minimum outer peripheral temperature (° C.)” by the following methods. The results are shown in Table 2. The columns of “Fracture strength (%)”, “Regeneration limit value (g / liter)” and “Minimum outer temperature (° C.)” in Tables 2 and 4 are Comparative Examples 1 to Examples 1-31. The increase / decrease relative to the comparative example 1 is shown based on the result of the above, and the examples 32 to 53 show the increase / decrease relative to the comparative example 2 based on the result of the comparative example 2.

〔destruction strength(%)〕
As shown in FIG. 8, the honeycomb structure 100 is placed sideways on the iron plate 111 having a thickness of 10 mm so that the end faces (one end face and the other end face) of the honeycomb structure 100 face the horizontal direction. Above the honeycomb structure 100, an iron plate 112 having a thickness of 10 mm, a width of 30 mm, and a length of the honeycomb structure +20 mm (ie, 180 mm) was further placed. Thereafter, a load was applied to the honeycomb structure 100 by moving the plate 112 downward at 0.5 mm / min, and the load was increased until damage to the honeycomb structure 100 was confirmed. The load when the breakage of the honeycomb structure 100 was confirmed was measured, and the increase amount (%) when the load in the corresponding comparative example was 100% was defined as “breaking strength (%)”. Here, FIG. 8 is a side view schematically showing a method for measuring the breaking strength (%).

  In each example, when the honeycomb structure 100 is placed on the iron plate 111, the honeycomb structure 100 is arranged so that one direction (Y direction) faces the vertical direction. Further, the breakage of the honeycomb structure 100 was regarded as occurrence of cracks on the appearance.

[Regeneration limit value (g / liter)]
The amount of regenerated particulate matter (for example, soot) per unit volume (liter) of the honeycomb structure was measured. The volume of the honeycomb structure is a volume (liter) measured from the outer shape of the honeycomb structure. The “regeneration limit value (g / liter)” in each example represents an increase (g / liter) from the regeneration limit value (g / liter) in the corresponding comparative example. As a specific measuring method, the honeycomb structure is used as a DPF, and the amount of soot accumulation is sequentially increased and regeneration (combustion of soot) is performed to confirm the limit of occurrence of cracks. First, a ceramic non-thermally expandable mat is wound around the outer periphery of the obtained honeycomb structure as a holding material, and is pushed into a canning body made of SUS409 to obtain a canning structure. Thereafter, the combustion gas containing soot generated by the combustion of diesel fuel (light oil) is introduced from the end face of the honeycomb structure on the side where the first cell is opened, and the soot is discharged from the other end face, so that the soot is produced in the honeycomb structure. Deposit in the body. Then, after cooling to room temperature, a combustion gas containing oxygen at a constant rate flows at 680 ° C. from the one end face of the honeycomb structure, and when the pressure loss of the honeycomb structure decreases, the flow rate of the combustion gas By reducing the above, the soot is rapidly burned, and the presence or absence of cracks in the subsequent plugged honeycomb structure is confirmed. In this test, the amount of soot accumulated was 2.5 g per liter of honeycomb structure (hereinafter referred to as 2.5 g / liter, etc.), and 0.5 (g / liter) until cracks were observed. Repeatedly increasing each time. For each honeycomb structure, it is obtained from the measurement result (average value when each of the five honeycomb structures is measured (N = 5)) of the regeneration limit value (the amount of soot at the time of initial crack occurrence) (g / liter). It was.

[Minimum outer temperature (℃)]
As shown in FIG. 9, a K thermocouple 113 having a wire diameter of 0.2 mm is provided at a position equally divided into four in the axial direction (that is, three locations in the axial direction of the honeycomb structure 100) in the outer peripheral portion of the honeycomb structure 100. The temperature was measured at four points at equal intervals in the outer circumferential direction (measured at a total of 12 points). At the time of measuring the outer peripheral temperature, the exhaust gas at 350 ° C. was vented from one end face side of the honeycomb structure 100, and the temperature after steady state was measured. Among the temperatures measured at 12 points, the lowest temperature (minimum temperature (° C.)) was obtained, and the difference from the lowest temperature (° C.) in the corresponding comparative example was defined as “outer peripheral minimum temperature (° C.)”. Here, FIG. 9 is a side view schematically showing a measuring method of the lowest outer peripheral temperature (° C.). In FIG. 9, a point indicated by “x” in the outer peripheral portion of the honeycomb structure 100 is a point at which temperature measurement was performed.

(Examples 2 to 8)
Except that the width (W1x, W1y, W2x, W2y) and the partition wall thickness (Tv, Th) of each cell constituting the honeycomb structure were changed as shown in Table 1, the same as Example 1 Thus, a honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 2.

(Examples 9 to 13)
When the widths (W1x, W1y, W2x, W2y) and the partition wall thicknesses (Tv, Th) of the cells constituting the honeycomb structure are changed as shown in Table 1, and the honeycomb segments are joined. Are arranged in one direction (Y direction), and one honeycomb segment having a thick partition wall and another honeycomb segment obtained by rotating this one honeycomb segment by 90 ° are arranged on the side surfaces of each other. A honeycomb structure was manufactured in the same manner as in Example 1 except that the layers were alternately arranged so as to be adjacent to each other. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 2. Such an array of honeycomb segments is indicated as “different direction” in the “segment array” in Table 1.

(Examples 14 to 25)
Except that the width (W1x, W1y, W2x, W2y) and the partition wall thickness (Tv, Th) of each cell constituting the honeycomb structure were changed as shown in Table 1, the same as Example 1 Thus, a honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 2. In Examples 14 to 25, the area of the first cell is configured to be larger than the area of the second cell in the cross section orthogonal to the central axis direction of the honeycomb segment.

(Examples 26 to 31)
The width (W1x, W1y, W2x, W2y) of the opening portion of each cell constituting the honeycomb structure and the thickness (Tv, Th) of the partition walls are changed as shown in Table 1, and the above “segment arrangement” A honeycomb structure was manufactured in the same manner as in Example 1 except that “different direction” was set. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 2. Also in Examples 26 to 31, the area of the first cell is configured to be larger than the area of the second cell in the cross section orthogonal to the central axis direction of the honeycomb segment.

(Examples 32-41)
The same as Example 1 except that the width (W1x, W1y, W2x, W2y) of the opening portion of each cell constituting the honeycomb structure and the thickness (Tv, Th) of the partition walls were changed as shown in Table 3. Thus, a honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 4. Also in Examples 32 to 41, the area of the first cell is configured to be larger than the area of the second cell in the cross section orthogonal to the central axis direction of the honeycomb segment.

(Examples 42 to 46)
The width (W1x, W1y, W2x, W2y) of the opening part of each cell constituting the honeycomb structure and the thickness (Tv, Th) of the partition wall are changed as shown in Table 3, and the above “segment arrangement” A honeycomb structure was manufactured in the same manner as in Example 1 except that “different direction” was set. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 4. Also in Examples 42 to 46, the area of the first cell is configured to be larger than the area of the second cell in the cross section orthogonal to the central axis direction of the honeycomb segment.

(Examples 47-53)
The width (W1x, W1y, W2x, W2y) of the opening portion of each cell constituting the honeycomb structure and the thickness (Tv, Th) of the partition walls are changed as shown in Table 3, and as shown in Table 3 In the same manner as in Example 1 except that the width of the cell opening was made the same, the thickness of the partition wall was changed, and the “segment arrangement” was changed to “different direction” in Examples 51 to 53. A honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed. The results are shown in Table 4.

(Comparative Example 1)
Example 1 except that the partition walls constituting the honeycomb structure have the same thickness in one direction (Y direction) and the other direction (X direction) as shown in Table 1. In the same manner as in Example 1, a honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed.

(Comparative Example 2)
Example 3 except that the partition walls constituting the honeycomb structure are configured to have the same thickness in one direction (Y direction) and the other direction (X direction) as shown in Table 3. In the same manner as in Example 1, a honeycomb structure was produced. In the same manner as in Example 1, evaluation of “breaking strength (%)”, “regeneration limit value (g / liter)”, and “minimum outer temperature (° C.)” was performed.

  From Tables 1 to 4, the honeycomb structures of Examples 1 to 53 have a high regeneration limit value, and even when more particulate matter is collected per unit volume, when they are removed by combustion ( That is, it can be seen that it is difficult to melt due to overheating when the filter is regenerated. In addition, the honeycomb structure of each example has a lower outer peripheral temperature (° C.) than that of the corresponding comparative example, and heat transfer from the inside is performed in one direction (Y direction) and the other direction. (X direction) can be changed, and it can be seen that an excessive temperature rise in the outer peripheral portion can be suppressed.

  In addition, the honeycomb structures of Examples 1 to 8, 14 to 25, 32 to 41, and 47 to 50 in which the segment arrangement is “one direction”, the breaking strength in one direction (Y direction) is the thickness of the partition wall. It can be seen that the length is improved compared to the comparative example configured to have the same thickness in one direction (Y direction) and the other direction (X direction). Further, the outer peripheral minimum temperature (° C.) also has a greater effect than the example in which the segment arrangement is “different direction”.

  The method for manufacturing a honeycomb structure of the present invention is suitably used as a carrier for a catalytic device or a filter used for environmental measures or recovery of specific materials in various fields such as chemistry, electric power, and steel. be able to.

2: cell, 2a: first cell, 2b: second cell, 3: partition, 3X: partition (a partition arranged along the other direction (X direction)), 3Y: partition (one direction ( Partition wall arranged along the Y direction), 3s: partition wall (inclined partition wall), 4: outer peripheral wall, 5: plugging portion, 8: one end portion, 9: other end portion, 14: joint portion , 15: outer wall, Th: thickness of the partition wall arranged along the other direction (X direction), Ts: thickness of the inclined partition wall, Tv: thickness of the partition wall arranged along one direction (Y direction) Thickness, 100, 101, 102: honeycomb structure, 111: iron plate, 112: plate, 113: thermocouple, X: other direction (X direction), Y: one direction (Y direction).

Claims (5)

A first cell having a partition that partitions and forms a plurality of cells extending from one end face to the other end face to be a fluid flow path, wherein one end is open and the other end is plugged; A plurality of honeycomb segments alternately arranged with the second cells whose one end is plugged and the other end is opened,
A plurality of the honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposing side surfaces are joined by a joint portion,
At least one honeycomb segment of the plurality of honeycomb segments has a thickness (Tv) of the partition walls arranged along one direction (Y direction) in a cross section perpendicular to the central axis direction. A honeycomb structure having a thickness greater than a thickness (Th) of the partition walls arranged along another direction (X direction) orthogonal to the direction.   2. The honeycomb structure according to claim 1, wherein at least one of the honeycomb segments is configured such that an area of the first cell is larger than an area of the second cell in a cross section orthogonal to the central axis direction.   The honeycomb structure according to claim 1 or 2, wherein the relationship between Th and Tv is "1.05 ≦ Tv / Th ≦ 2.00”.   The honeycomb structure according to any one of claims 1 to 3, wherein the Th is "0.25 mm ≤ Th ≤ 0.38 mm".   The plurality of honeycomb segments, wherein one adjacent honeycomb segment is disposed in a state where the other adjacent honeycomb segment is rotated 90 degrees about the central axis. The honeycomb structure according to one item.

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