HONEYCOMB STRUCTURE

Abstract

Honeycomb structure (100, 200, 300, 400), comprising a honeycomb structure body (4, 24, 44) with porous partitions (1, 21, 41) arranged to surround a plurality of cells (2, 22, 42) extending from a first end face (11, 31, 51) to a second end face (12, 52) and forming passage channels for a fluid, where a value of a porosity of the partition (1, 21, 41) in a partition part between the two cells (2, 22, 42) is defined as a porosity A, a porosity value of the partition wall (1, 21, 41) in a crossing part (15, 35), which is an area connecting two or more wall parts (16, 36), is defined as a porosity B, a value of A / B obtained by dividing porosity A by porosity B lies in a range of 0.5 to 0.95 and the porosity A lies in a range of 10 to 40%, the porosity B lies in a range of 20 to 37.2%, and the thickness of the partition walls (1, 21, 41) is in a range of 40 to 115 µm.

Description

[0001] The present application is based on JP-2017-225577, filed on 24.11.2017, and JP2018-196101, filed on 17.10.2018 with the Japanese Patent Office, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION Area of ​​the invention

[0002] The present invention relates to a honeycomb structure and in particular to a honeycomb structure with excellent temperature shock resistance. Description of the state of the art

[0003] In recent years, environmental awareness has increased throughout society, and various technologies have been developed in the technical field of combustion, where fuel is burned to generate power, to remove toxic components such as nitrogen oxides from the exhaust gas produced during combustion. For example, various technologies have been developed to remove toxic components like nitrogen oxides from the exhaust gas emitted by a motor vehicle engine. In such a process, it is common to use a catalyst to initiate a chemical reaction within the toxic component, thereby converting it into a different, comparatively non-toxic component. Furthermore, a honeycomb structure has been used as the catalyst carrier, which is impregnated with the catalyst for exhaust gas purification.

[0004] Previously, honeycomb structures were proposed which each contained a honeycomb structure body with a multitude of honeycombs extending from an inlet end face to an outlet end face and forming passage channels for a fluid, and defined porous partitions (see, for example, patent documents 1 to 4).

[0005] Further prior art is also known from patent document 5. [Patent document 1] WO 2002 / 011 884 A1 [Patent document 2] JP 2004- 270 569 A [Patent document 3] JP 2004- 289 925 A [Patent Document 4] JP 2010-227 818 A [Patent Document 5] JP 2013- 184 836 A BRIEF DESCRIPTION OF THE INVENTION

[0006] Patent document 1 discloses a honeycomb structure in which the thickness of partition walls in a circumferential part is greater than that in a central part of a cross-section of the honeycomb structure, which is perpendicular to a honeycomb expansion direction. Patent document 1 explains that this honeycomb structure has disadvantages due to an increase in pressure loss and a decrease in thermal shock resistance, but can achieve a balanced harmony with advantages resulting from improved isostatic strength and high accuracy of the partition wall shape and the outer shape of the honeycomb structure.

[0007] Here, the honeycomb structure, for example when used as a catalyst carrier for exhaust gas purification, can be employed in a state where the structure is housed within a can-like element such as a metal casing. In the following, housing the honeycomb structure within a can-like element such as the metal casing will sometimes be referred to as "canning." The metal casing can be called a metal can. With the honeycomb structure described in patent document 1, the strength of the circumferential portion of the honeycomb structure is improved, and therefore it can be assumed that this improvement has a lasting effect, for example, in preventing damage to the circumferential portion during the aforementioned canning process or the like.However, in the honeycomb structure described in patent document 1, the configuration of the partitions in the middle part of the cross-section is not changed compared to that of a conventional honeycomb structure, and therefore the problem was that the improvement could not be a countermeasure to prevent the generation of cracks as a result of temperature shock stress.

[0008] Patent document 2 describes a honeycomb structure with a relationship Pi < Po, where Pi is the porosity of partitions in a central part of a cross-section of the honeycomb structure perpendicular to an axial direction, and Po is the porosity of partitions in a circumferential part of the aforementioned cross-section. In this honeycomb structure, the porosity of the central part is set lower than the porosity of the circumferential part, thus increasing the heat capacity of the central part. However, considering only the central part, the problem remains that, in a case where cracks are generated by thermal shock, a partition in a partition section between two honeycombs becomes the starting point for crack generation.

[0009] Patent document 3 discloses a honeycomb structure in which the shape of the honeycombs is essentially square, the intersection of partitions has an R-shape or a C-shape, the ratio of the diagonal distance between the intersections to the average thickness of the partitions is greater than or equal to 1.6, and the proportion of an open end face of the honeycombs is greater than or equal to 55%. The problem with this honeycomb structure was that, insofar as the partition in a partition section between two honeycombs becomes a starting point for crack generation, even though the intersection of the partitions is reinforced, the issue remains unresolved.

[0010] Patent document 4 discloses a honeycomb structure in which the ratio of a cross-section porosity to an intermediate-section porosity is in the range of 0.5 to 0.95, where the cross-section porosity is the porosity in a partition-crossing section containing a cross-section where partitions intersect, and the intermediate-section porosity is the porosity in a partition-intersection. Furthermore, this honeycomb structure presented the problem that, despite the reinforcement of the partition-crossing section, the partition-intersection between adjacent partition-crossing sections can become a starting point for crack initiation. In particular, when the honeycomb structure described in patent document 4 is subjected to thermal shock, the strength of a partition-intersection that essentially separates two honeycombs decreases further.Therefore, it can be assumed that if a temperature shock of the entire honeycomb structure is taken into account, its temperature shock resistance will be impaired.

[0011] The present invention was developed in consideration of these problems of conventional methods. According to the present invention, a honeycomb structure with excellent resistance to thermal shock is provided.

[0012] According to the present invention, the following honeycomb structure is provided. [1] A honeycomb structure comprising a honeycomb structure body with porous partitions arranged to surround a plurality of honeycombs extending from a first end face to a second end face and forming passage channels for a fluid, where a value of a porosity of the partition wall in a partition wall section between the two honeycombs is defined as a porosity A, a porosity value of the partition wall in a crossing part, which is an area connecting two or more wall parts, is defined as a porosity B, a value of A / B obtained by dividing porosity A by porosity B lies in a range of 0.5 to 0.95 and the porosity A is in a range of 10 to 40%, the porosity B is in a range of 20 to 37.2%, and the thickness of the partition walls is in a range of 40 to 115 µm. [2] The honeycomb structure according to point [1] above, wherein an arithmetic mean of porosity A and porosity B lies in a range of 15 to 38.6%. [3] The honeycomb structure according to point [1] or [2] above, wherein one shape of the honeycomb in a cross-section of the honeycomb structure body, which is perpendicular to a direction of extension of the honeycomb, is square or hexagonal.

[0013] A honeycomb structure of the present invention exhibits excellent resistance to thermal shock. This means that, compared to a conventional honeycomb structure with approximately the same degree of porosity, the honeycomb structure of the present invention is able to effectively prevent the formation of cracks as a result of thermal shock. In particular, if the porosity of the partition walls is set to 10 to 40% and the porosity B of the partition wall in a cross-section connecting two or more wall sections is appropriately reduced, the thermal shock resistance of the entire honeycomb structure can be improved. Specifically, if the porosity of the partition walls is less than or equal to 40%, for example, a catalyst for exhaust gas purification will hardly penetrate the pores formed in the partition walls.Consequently, in a case where the conventional honeycomb structure is used as a catalyst support under harsh thermal conditions, for example, directly beneath a motor vehicle engine, cracks are generated at an early stage in the wall sections of the partitions because the thickness of the wall section of each partition is less than that of the intersection section. Furthermore, there are concerns that the cracks generated in the wall sections of the partitions can easily develop into larger cracks, exacerbating defects in the honeycomb structure. For example, while increasing the thickness of the wall section of the partition might improve the thermal shock resistance of the honeycomb structure, it could also lead to an increase in the pressure drop across the honeycomb structure.In the honeycomb structure of the present invention, the porosity A of the partition walls in the wall sections where cracks are more likely to form is set relatively low, and the aforementioned A / B ratio is set to 0.5 to 0.95, thus effectively preventing crack formation in both the wall section and the partition wall intersection. Furthermore, in a cross-section of the honeycomb structure of the present invention that is perpendicular to an expansion direction of the honeycomb, it is not necessary to partially change the thickness of the partition walls or partially alter the honeycomb shape, and therefore a secondary problem such as an increase in pressure loss hardly occurs. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective view which schematically shows a first embodiment of a honeycomb structure of the present invention, viewed from the side of a first end face; Fig. 2 is a top view, which shows the first end face of the in Fig. The honeycomb structure shown in section 1 is shown schematically; Fig. 3 is an enlarged top view, in which part of the first end face of the in Fig. The honeycomb structure shown in 2 is enlarged; Fig. 4 is a sectional view showing a cross-section along line AA' in Fig. 2 schematically shows; Fig. 5 is a top view which schematically shows a second embodiment of the honeycomb structure of the present invention and shows part of its first end face; Fig. Figure 6 is a perspective view which schematically shows a third embodiment of the honeycomb structure of the present invention, viewed from the side of a first end face; Fig.7 is a top view which schematically shows a first end face of a fourth embodiment of the honeycomb structure of the present invention; and Fig. Figure 8 is a diagram showing a relationship between the operating time (seconds) of a motor and the motor speed (rpm) during a temperature shock resistance test. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0014] The following describes embodiments of the present invention. However, the present invention is not limited to the following embodiments. Therefore, it is self-evident that, based on the average knowledge of a person skilled in the art, modifications, improvements, and the like can be expediently made to the following embodiments without departing from the core of the present invention. (1) Honeycomb structure (first embodiment):

[0015] As in Fig. 1 to Fig. Figure 4 shows a first embodiment of a honeycomb structure of the present invention, a honeycomb structure 100 containing a honeycomb structure body 4 with porous partitions 1. Here, Fig. 1 a perspective view which schematically shows the first embodiment of the honeycomb structure of the present invention, as seen from the side of a first end face. Fig. 2 is a top view, which shows the first end face of the in Fig. The honeycomb structure shown in Figure 1 is shown schematically. Fig. 3 is an enlarged top view, in which part of the first end face of the in Fig. The honeycomb structure shown in 2 is enlarged. Fig. 4 is a sectional view showing a cross-section along line AA' in Fig. 2 shows schematically.

[0016] The partitions 1 of the honeycomb structure 4 are arranged such that they surround a plurality of honeycombs 2, which extend from a first end face 11 to a second end face 12 and become passage channels for a fluid. That is, the plurality of honeycombs 2 is defined by the porous partitions 1. The honeycomb structure 4 can further have a circumferential wall 3 in its circumferential part, which is arranged such that it surrounds the partitions 1.

[0017] The honeycomb structure 100 of the present embodiment is suitable for use as a catalyst carrier, which is to be impregnated with a catalyst for exhaust gas purification. The catalyst carrier is a porous structure that carries particles of the catalyst. Therefore, no honeycomb 2 formed in the honeycomb structure body 4 is closed at its open ends on the sides of the first end face 11 and the second end face 12 with a closure element or the like, and the side of the first end face 11 is in contact with the side of the second end face 12 via the respective honeycomb 2.

[0018] As in Fig. 2 and Fig.As shown in Figure 3, the honeycomb structure 4 is characterized by the fact that the porosity A of the partition wall 1 in a partition wall section 16 between two cells 2 and the porosity B of the partition wall 1 in a crossover section 15, which is an area connecting two or more wall sections 16, have different values. More specifically, a value of the porosity of the partition wall 1 in the partition wall section 16 between two cells 2 is defined as porosity A. Furthermore, a value of the porosity of the partition wall 1 in the crossover section 15 connecting two or more wall sections 16 is defined as porosity B. In this case, "porosity A / porosity B", which is a value obtained by dividing porosity A by porosity B, lies in a range from 0.5 to 0.95. In the following, "porosity A / porosity B" can simply be referred to as "A / B".Here is an example of the “intersection part 15 connecting two or more wall sections 16” – an intersection part of the partitions 1 in a case where the partitions 1 are configured in the form of grids on a surface of the honeycomb structure body 4, which is perpendicular to an extension direction of the honeycombs 2. Furthermore, for example, although not shown in the drawing, an area where two wall sections are connected in such a way that they form a kink also becomes the intersection part connecting two or more wall sections. As in . Fig. 2 and Fig. As shown in Figure 3, the wall part 16 and the intersection part 15 are elements that form the partition wall 1 and can appropriately be referred to, for example, as the "wall part 16 of the partition wall 1" and the "intersection part 15 of the partition wall 1".

[0019] The honeycomb structure 100 of the present embodiment has excellent thermal shock resistance. That is, the honeycomb structure 100 of the present invention is able to effectively prevent the formation of cracks as a result of thermal shock compared to a conventional honeycomb structure with approximately the same degree of porosity. In particular, if the porosity of the partitions 1 is set to a value of less than or equal to 40% and the porosity B of the partition 1 in the intersection 15 connecting two or more wall sections 16 is appropriately reduced, the thermal shock resistance of the entire honeycomb structure 100 can be improved. Specifically, if the porosity of the partitions 1 is less than or equal to 40%, a catalyst for exhaust gas purification, for example, hardly penetrates the pores formed in the partitions 1.For example, in a case where the conventional honeycomb structure is used as a catalyst support under harsh thermal conditions, such as directly beneath a motor vehicle engine, cracks are generated at an early stage in the wall sections of the partitions because the thickness of the wall section is less than that of the intersection section. Furthermore, there are concerns that the cracks generated in the wall sections of the partitions can easily develop into larger cracks, exacerbating defects in the honeycomb structure. For instance, increasing the thickness of the wall section of the partition might improve the thermal shock resistance of the honeycomb structure, but this could also lead to an increase in the pressure drop within the structure.In the honeycomb structure 100 of the present embodiment, the porosity A of the partition walls 1 in the wall sections 16, where cracks are more likely to form, is set relatively low, and the aforementioned A / B value is set to 0.5 to 0.95, so that it is possible to effectively prevent the formation of cracks in both the wall section 16 and the intersection section 15 of the partition wall 1. Additionally, in a cross-section of the honeycomb structure 100 of the present embodiment that is perpendicular to an expansion direction of the honeycomb 2, it is not necessary to partially change the thickness of the partition walls 1 or to partially change the shape of the honeycomb 2, and therefore a secondary problem such as an increase in pressure loss hardly occurs.

[0020] In the following description, a value of the porosity of the partition wall 1 in the partition wall section 16 between two cells 2 can simply be referred to as "porosity A". Furthermore, a value of the porosity of the partition wall 1 in the intersection section 15 connecting two or more wall sections 16 can simply be referred to as "porosity B". The "partition wall section 16 between two cells 2", for example, in a case where the cross-sectional shape of the two cells 2 is polygonal, is a part forming each side of a cross-sectional shape of each cell.

[0021] In the present invention, it is assumed that both the porosity A and the porosity B of the partition walls 1 are values ​​obtained by the following method. First, a test piece, for which the porosity A and the porosity B are to be measured, is cut out of the honeycomb structure 100. The corresponding areas from which the test pieces are to be cut out are five areas on both the side of the first end face 11 and on the side of the second end face 12 of the honeycomb structure 100, i.e., a total of ten areas. With regard to an area to be cut out on each end face, the center point of each end face is considered the first cut-out area.Then, in each end face, four intermediate points between the center point and a circumferential edge of the honeycomb structure 100 on an X-axis and a Y-axis, which pass through this center point and are perpendicular to each other, are considered as four remaining cut-out areas.

[0022] The sample for which the porosity A is to be measured is cut from each of the ten areas mentioned above such that it contains a central part of the partition wall section 16 between two combs 2. One side of the sample for which the porosity A is to be measured is considered to be the thickness of the wall section 16 forming the partition wall 1, another side is set to 100 µm in the direction of expansion of the partition walls 1 on each end face, and yet another side is set to 20 mm in the direction of expansion of the combs 2.

[0023] The sample for which the porosity B is to be measured is cut from each of the ten areas mentioned above such that it contains a central part of the intersection section 15 of the partition wall 1. The sample for which the porosity B is to be measured is considered to be an end face of a square, where the length of one side is set to 100 µm, with the central part of the intersection section 15 connecting two or more wall sections 16 being assumed to be its center point, and the length of the sample in an axial direction is set to 20 mm in the direction of expansion of the honeycomb 2.

[0024] The sample, cut from the honeycomb structure 100 and thus prepared, is embedded in an epoxy resin to harden, and then its surface is polished. Each sample is then trimmed by 5 mm along its entire length, and its cut surface is used for observation with a scanning electron microscope (SEM). For example, a scanning electron microscope model no. S3200-N manufactured by Hitachi High-Technologies Corporation can be used.

[0025] The surface of the manufactured sample is then observed with the SEM, and an SEM image is acquired. During the measurement of the porosity A of partitions 1, the above SEM image is acquired with respect to partition 1 on the surface of each of the ten samples. The SEM image is magnified 100 times and observed. Furthermore, during the measurement of the porosity B of partition 1, the above SEM image is acquired with respect to the intersection 15 of partitions 1 on each surface of the ten samples. Then, in each image, an "area S1 of partition 1" and an "area S2 of a pore portion (empty portion)" are calculated using image analysis software. The porosity of the depicted partition 1 in each image is then calculated according to "Formula (1): S2 / (S1+S2)". Average porosity values ​​of the respective ten regions are used as the values ​​for S1 and S2.

[0026] Regarding the honeycomb structure 100, for which the porosity is to be measured, in a case where the surfaces of the partitions 1 and the interior of the pores of the partitions 1 are impregnated with a catalyst for exhaust gas purification (not shown), the portion impregnated with the catalyst is considered the pore fraction of the partition 1, and the porosity is obtained. That is, in a method for measuring the aforementioned porosity A and the aforementioned porosity B, after obtaining the SEM image, an area in which the presence of the catalyst in the obtained SEM image is inferred from color information is identified as the pore fraction of the partition 1, and its porosity is then obtained.

[0027] If the value of A / B obtained by dividing porosity A by porosity B is less than 0.5, there is concern that the cracks may penetrate into the intersection sections 15 of the partition walls 1 and that the cracks may sometimes develop into continuous cracks across two or more areas. If the above value of A / B exceeds 0.95, the cracks may also penetrate into the partition wall 1 in the wall section 16 separating the two honeycomb cells 2.

[0028] The value of A / B obtained by dividing the porosity A by the porosity B preferably lies in the range of 0.50 to 0.95 and more preferably in the range of 0.55 to 0.90. With such a property, it is possible to prevent the formation of cracks more effectively.

[0029] There are no particular restrictions regarding the value of the porosity B, but the value preferably lies in the range of 20 to 50% and more preferably in the range of 20 to 45%. If the porosity B is less than 20%, it could be difficult to impregnate the partitions 1 with the catalyst. Furthermore, if the porosity B is greater than 50%, the isostatic strength of the honeycomb structure 100 could deteriorate.

[0030] The arithmetic mean of porosity A and porosity B preferably lies in the range of 15 to 45% and more preferably in the range of 15 to 40%. If the arithmetic mean of porosity A and porosity B is less than 15%, it could be difficult to impregnate the partitions 1 with the catalyst. Furthermore, if the arithmetic mean of porosity A and porosity B exceeds 45%, the isostatic strength of the honeycomb structure 100 could deteriorate.

[0031] There are no particular restrictions regarding the shape of each honeycomb 2 (hereinafter simply referred to as the "honeycomb shape") in the cross-section of the honeycomb structure body 4, which is perpendicular to the direction of extension of the honeycombs 2. For example, the shape of the honeycombs 2 is preferably polygonal and more preferably quadrilateral or hexagonal. Furthermore, the shape of each honeycomb 2 can be a shape obtained by forming corner parts of a polygon in a rounded shape, for example, a substantially quadrilateral shape obtained by forming corner parts of a quadrilateral in a rounded shape.

[0032] The thickness of the partitions 1 is preferably 40 to 200 µm, more preferably 45 to 185 µm, and particularly preferably 50 to 170 µm. If the thickness of the partitions 1 is less than 40 µm, the isostatic strength of the honeycomb structure 100 could be reduced. If the thickness of the partitions 1 is greater than 200 µm, pressure loss could increase, potentially leading to a decrease in engine performance or a deterioration in fuel consumption. The thickness of the partitions 1 is a value measured using an optical microscope by examining a cross-section of the honeycomb structure 100 perpendicular to an axial direction.

[0033] There are no particular restrictions regarding the overall shape of the honeycomb structure 100. An example of the overall shape of the in Fig. 1 to Fig.The honeycomb structure 100 shown in Figure 4 is a round column shape, in which the first end face 11 and the second end face 12 are round. Another example of the overall shape of the honeycomb structure 100 can be a column shape, in which the first end face 11 and the second end face 12 have an essentially round shape, such as an elliptical shape, a racetrack shape, or an elongated shape. Alternatively, the overall shape of the honeycomb structure 100 can be a prismatic column shape, in which the first end face 11 and the second end face 12 have a polygonal shape, such as a square shape or a hexagonal shape.

[0034] There are no particular restrictions regarding the material forming the partitions 1, but from the perspectives of strength, heat resistance, durability, and the like, it is preferable that a type of ceramic made of an oxide or non-oxide, a metal, or the like be a major component. Specifically, cordierite, mullite, aluminum oxide, spinel, silicon carbide, silicon nitride, and aluminum titanate are considered examples of ceramics. An Fe-Cr-Al-based metal and metallic silicon are considered examples of metals. It is preferable to use at least one material selected from this group as the major component.From the perspectives of high strength, high heat resistance, and the like, it is particularly preferable to use at least one material selected from the group consisting of aluminum oxide, mullite, aluminum titanate, cordierite, silicon carbide, and silicon nitride as the main component. Furthermore, from the perspectives of high thermal conductivity, high heat resistance, and the like, silicon carbide or a silicon-silicon carbide composite is particularly suitable. Here, "main component" means a component comprising 50% or more by mass of the partitions 1. The above component is preferably present in the material forming the partitions 1 at a concentration of 70% or more by mass, and more preferably at a concentration of 80% or more by mass.

[0035] In the honeycomb structure 100 of the present embodiment, at least one of the respective surfaces of the partition walls 1 of the honeycomb structure body 4 and each pore of the partition walls 1 can be impregnated with a catalyst for exhaust gas purification. Thanks to this composition, CO, NO x HC and similar substances in the exhaust gas are converted into harmless compounds through a catalytic reaction.

[0036] When the honeycomb structure 100 of the present embodiment is impregnated with the catalyst, it is preferred that the catalyst comprises at least one of the following: a three-way catalyst, an SCR catalyst, an NO catalyst x The three-way catalyst consists of a storage catalyst and an oxidation catalyst. It is primarily used for the removal of hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). x). An example of a three-way catalyst is a catalyst containing platinum (Pt), palladium (Pd), and rhodium (Rh). The SCR catalyst is a catalyst for the selective reduction of components to be removed. In particular, it is preferable that the aforementioned SCR catalyst selectively reduces NO. x Reducing SCR catalyst for the selective reduction of NO x in the exhaust gas. A prime example of NO x A selective reducing SCR catalyst is a catalyst for the selective reduction and removal of NO. xin the exhaust gas. Furthermore, an example of an SCR catalyst is a metal-substituted zeolite. Examples of metals in metal-substituted zeolites include iron (Fe) and copper (Cu). A suitable example of zeolite is beta-zeolite. Additionally, the SCR catalyst can be a catalyst containing at least one component selected from the group consisting of vanadium and titanium dioxide as a main component. Examples of NO x Storage catalysts include alkali metals and alkaline earth metals. Examples of alkali metals are potassium, sodium, and lithium. An example of an alkaline earth metal is calcium. An example of an oxidation catalyst is a catalyst containing a noble metal. It is particularly preferable that the oxidation catalyst contains at least one metal selected from the group consisting of platinum, palladium, and rhodium. (2) Honeycomb structure (second to fourth embodiment):

[0037] Now, based on the Fig. 5 to 7 embodiments two to four of the honeycomb structure of the present invention are described. Fig. Figure 5 is a top view which schematically shows the second embodiment of the honeycomb structure of the present invention and shows part of its first end face. Fig. Figure 6 is a perspective view which schematically shows the third embodiment of the honeycomb structure of the present invention, as seen from the side of a first end face. Fig. Figure 7 is a top view which schematically shows a first end face of the fourth embodiment of the honeycomb structure of the present invention.

[0038] As in Fig.As shown in Figure 5, the second embodiment of the honeycomb structure of the present invention is a honeycomb structure 200 comprising a honeycomb structure body 24 with porous partitions 21. In the honeycomb structure 200 of the second embodiment, one shape of the honeycombs 22 is a "hexagon". Furthermore, if a porosity value of a partition 21 in a partition section 36 between two honeycombs 22 is defined as a porosity A, and a porosity value of a partition 21 in a cross-section 35 connecting two or more wall sections 36 is defined as a porosity B, the value of A / B obtained by dividing porosity A by porosity B lies in a range of 0.5 to 0.95. The honeycomb structure 200 of the second embodiment with such characteristics can produce technological effects similar to those of the honeycomb structure 100 of the first embodiment described so far (see Figure 5). Fig. 1 to Fig.4) achieve. It is preferable that the honeycomb structure 200 of the second embodiment, apart from the fact that the shape of the honeycombs 22 is different, be one of those of the honeycomb structure 100 of the first embodiment (see Fig. 1 to Fig. 4) has the same characteristics. Fig. Reference numeral 31 designates a first end face of the honeycomb structure body 24.

[0039] As in Fig.As shown in Figure 6, the third embodiment of the honeycomb structure of the present invention is a honeycomb structure 300 containing a honeycomb structure body 44 of a segmented structure. That is, in the honeycomb structure 300, each honeycomb structure body 44 consists of columnar honeycomb segments 46, and side surfaces of a plurality of honeycomb segments 46 are connected to one another by a connecting layer 47. In this way, in the honeycomb structure 300 of the present embodiment, each of the plurality of honeycomb segments 46 corresponds to the honeycomb structure body 44 of the honeycomb structure 300. Here, the “honeycomb structure of the segmented structure” is referred to as a honeycomb structure formed by connecting the plurality of individually manufactured honeycomb segments 46. It should be noted that the honeycomb structure 100, in which all partition walls 1 of the honeycomb structure body 4 are formed monolithically as in Figure 6, is a honeycomb structure formed by connecting the plurality of individually manufactured honeycomb segments 46. Fig. 1 to Fig.Figure 4 shows a “monolithic honeycomb structure”. The honeycomb structure of the present invention can be the “segmented honeycomb structure” or the “monolithic honeycomb structure”.

[0040] In the case of the honeycomb structure 300, it is preferred that at least one honeycomb segment 46 has a structure identical to that of the honeycomb structure body of the previously described honeycomb structure of the first embodiment. Furthermore, the honeycomb structure 300 can achieve technological effects similar to those of the previously described honeycomb structure of the first embodiment. The plurality of honeycomb segments 46 can have the same honeycomb structure or can each have different honeycomb structure shapes. Fig. Reference numeral 6 designates a first end face and reference numeral 52 designates a second end face.

[0041] It is preferable that a circumferential wall 43 of the honeycomb structure 300 is a circumferential coating layer consisting of a circumferential coating material. The circumferential coating material is a coating material for application to a perimeter of a composite body obtained by connecting the plurality of honeycomb segments 46, thereby forming the circumferential coating layer. Furthermore, it is preferable that the composite body in which the plurality of honeycomb segments 46 are connected to one another is produced by grinding a circumferential portion of the composite body and applying the aforementioned circumferential coating layer to it. Furthermore, also with regard to the in Fig. 1 to Fig. As regards the monolithic honeycomb structure 100 shown in Figure 4, a circumferential wall 3 arranged on a perimeter of the honeycomb structure body 4 may be a circumferential coating layer formed from a circumferential coating material as described above.

[0042] In the Fig.In the honeycomb structure 300 shown in Figure 6, the honeycomb cells 42 are square. However, the shape of each honeycomb cell 42 in each honeycomb segment 46 is not limited to the square, and the shape of the honeycomb cells in the honeycomb structure of the second embodiment described so far can be used.

[0043] As in Fig. As shown in Figure 7, the fourth embodiment of the honeycomb structure of the present invention is a honeycomb structure 400 containing a honeycomb structure body 4 whose cross-sectional shape is elliptical. Therefore, the overall shape of the honeycomb structure 400 is a column shape, both end faces of which are elliptical. It is preferable that the honeycomb structure 400 of the fourth embodiment, apart from the fact that its overall shape differs, is one of those of the honeycomb structure 100 of the first embodiment (see Figure 7). Fig. 1 to Fig. 4) has the same characteristics.

[0044] In the Fig.The honeycomb structure 400 shown in Figure 7 is a square form of honeycomb 2. However, the shape of honeycomb 2 is not limited to the square. (3) Manufacturing process of the honeycomb structure:

[0045] A method for producing the honeycomb structure of the present invention is now described. An example of the manufacturing method for the honeycomb structure of the present invention is a method comprising a step of producing a honeycomb mold and a step of drying and firing the resulting honeycomb mold. (3-1) Shaping step:

[0046] The forming step involves extruding a kneadable material, obtained by kneading a molding raw material, into a honeycomb shape to produce the honeycomb body. The honeycomb body has partitions that define honeycombs extending from one end face to the other, and a perimeter wall that surrounds the outermost perimeter of the partitions. A portion of a honeycomb structure consisting of partitions corresponds to a honeycomb body. In the forming step, the molding raw material is first kneaded to obtain the kneadable material. This kneadable material is then extruded, resulting in the honeycomb body in which the partitions and the perimeter wall are formed monolithically.

[0047] It is preferable that the molding material be a ceramic material to which a dispersing medium and an additive have been added. Examples of additives include an organic binder, a pore-forming agent, and a wetting agent. An example of a dispersing medium is water. A material similar to that used in a previously known honeycomb structure manufacturing process can be used as the molding material.

[0048] An example of a method for kneading the mold raw material to form the kneading material is a method in which a kneader, a vacuum kneading machine or the like is used.

[0049] Extrusion can be carried out using an extrusion die in which slots corresponding to a cross-sectional shape of the honeycomb body are formed. For example, it is preferable to use a die in which slots corresponding to the shape of the honeycombs in each of the honeycomb structures of embodiments one to four described so far.

[0050] In extrusion, it is preferable to increase the extrusion speed and pressure during the forming process. This allows the extrusion process to be carried out in such a way that the partition wall in the section between two honeycombs is denser than the partition wall in the intersection section. This means that the porosity B of the partition wall in the intersection section can be relatively higher in the resulting honeycomb structure. Consequently, the A / B value, obtained by dividing the porosity A of the partition wall in the wall section by the porosity B of the partition wall in the intersection section, can be adjusted to a range of 0.5 to 0.95. (3-2) Firing step:

[0051] The firing step is a stage in the firing process of the honeycomb-shaped body obtained through the forming step, in order to preserve the honeycomb structure. The resulting honeycomb-shaped body can be dried, for example, using microwaves and hot air before firing.

[0052] The firing temperature for the honeycomb mold can be appropriately determined according to the material of the honeycomb mold. For example, if the material of the honeycomb mold is cordierite, the firing temperature is preferably 1380 to 1450 °C and more preferably 1400 to 1440 °C. Furthermore, it is preferred that the firing time during which the highest temperature is maintained is approximately 4 to 6 hours. Examples

[0053] The present invention is described below in accordance with examples of more specific inventions, but the present invention is not limited to these examples. Example 1

[0054] To 100 parts by mass of cordierite molding raw material, 0.5 parts by mass of a pore-forming agent, 33 parts by mass of a dispersing medium, and 5.6 parts by mass of an organic binder were added, and the mixture was blended and kneaded to produce a modeling material. The cordierite molding raw material consisted of aluminum oxide, aluminum hydroxide, kaolin, talc, and silicon dioxide. Water was used as the dispersing medium, a water-absorbing polymer with an average particle diameter of 10 to 50 µm was used as the pore-forming agent, methylcellulose was used as the organic binder, and dextrin was used as the dispersing agent.

[0055] The kneadable material was then extruded using a predefined die to obtain a honeycomb-shaped body, in which one honeycomb cell was rectangular and the overall shape was a round column. Additionally, during extrusion, a die was used in which slots corresponding to the cross-sectional shape of the honeycomb-shaped body were formed. Furthermore, compared to the extrusion process described later in Example 1, the extrusion speed and pressure were increased to achieve this shape.

[0056] The honeycomb molded body was then dried in a hot air dryer. During drying, the ambient temperature was set to 95 to 145°C.

[0057] The dried honeycomb mold was then fired to produce a honeycomb structure as shown in Example 1. The ambient temperature during firing was set to 1350 to 1440°C, and the firing time was set to 10 hours.

[0058] In the honeycomb structure of example 1, the partition wall thickness was 70 µm and the honeycomb density was 139.5 honeycombs / cm³. 2 A honeycomb shape in a cross-section of the honeycomb structure, perpendicular to a honeycomb expansion direction, was a quadrilateral. Table 1 lists the thickness of the partitions, the honeycomb density, and the honeycomb shape in a column entitled "Honeycomb Structure".

[0059] In the honeycomb structure of Example 1, one cross-sectional shape perpendicular to an axial direction was a circle with a diameter of 105.7 mm and a length (total length) in the direction of expansion of the honeycomb cells of 81.2 mm. Table 1 lists the shape of the honeycomb structure of Example 1 in columns "Cross-sectional shape", "Diameter" and "Total length".

[0060] Regarding the honeycomb structure of Example 1, the porosity A of the partition wall in a partition section between two cells 2 and the porosity B of the partition wall in a crossing section connecting two or more wall sections were measured using the following methods. Furthermore, an average porosity and a porosity ratio were obtained from the values ​​of porosity A and porosity B. The average porosity is a value of the arithmetic mean of porosity A and porosity B (i.e., (A+B) / 2). The porosity ratio is a value of porosity A to porosity B (i.e., A / B). Table 2 shows the corresponding results. Porosity measurement methods

[0061] First, a sample piece, for which porosity A and porosity B were to be measured, was cut out of the honeycomb structure. The corresponding areas from which the samples were to be cut out were five areas on one side of a first end face (e.g., one side of an inflow end face) and on one side of a second end face (e.g., one side of an outflow end face) of the honeycomb structure, i.e., a total of ten areas. The areas to be cut out on each end face were defined as a center point (one area) and four intermediate points (areas two to five) between the center point and a circumferential edge of the honeycomb structure on an X-axis and a Y-axis that passed through this center point and were perpendicular to each other.The sample for which porosity A was to be measured was cut from each of the ten areas mentioned above such that it contained a central portion of the partition wall between two combs. One side of the sample for which porosity A was to be measured was considered to be the thickness of the partition wall portion; another side was set to 100 µm in the direction of partition expansion on each end face; and yet another side was set to 20 mm in the direction of comb expansion. The sample for which porosity B was to be measured was cut from each of the ten areas mentioned above such that it contained a central portion of the junction of the partition wall.The test piece for which the porosity B is to be measured is considered to be an end face of a square, in which a length of one side is set to 100 µm, with the middle part of the intersection being assumed to be its center point, and a length of the test piece in an axial direction is set to 20 mm in the expansion direction of the honeycomb 2.

[0062] The prepared specimen was then embedded in a curing epoxy resin, and its surface was polished. Each specimen was then trimmed by 5 mm along its entire length, and the cut surface was examined using a scanning electron microscope (SEM). The SEM used was a model S3200-N manufactured by Hitachi High-Technologies Corporation. During porosity measurement A, a 100x magnified SEM image was acquired showing the central portion of the partition on each of the ten specimens. Similarly, during porosity measurement B, a 100x magnified SEM image was acquired showing the intersection of the partition on each of the ten specimens.Subsequently, for each image, an "area S1 of the partition" and an "area S2 of a pore portion (empty portion)" were calculated using image analysis software, and the porosity of the depicted partition in each image was calculated according to "Formula (1): S2 / (S1+S2)". Average porosity values ​​of the respective ten areas were used as the values ​​for S1 and S2. Table 1 material honeycomb structure cross-sectional shape Diameter (mm) Long diameter (mm) Short diameter (mm) Total length (mm) Partition wall thickness (µm) Honeycomb density (honeycombs / cm²) 2 ) honeycomb shape Example 1 Cordierite 70 139,5 square around 105,7 - - 81,2 Example 2 Cordierite 70 139,5 square around 105,7 81,2 Example 3 Cordierite 90 93 square around 129 - - 100,0 Example 4 Cordierite 90 93 square around 129 - - 100,0 Example 5 Cordierite 115 62 hexagonal around 118,4 - - 118,0 Example 6 Cordierite 115 62 hexagonal around 118,4 - - 118,0 Example 7 Cordierite 88 93 square elliptical - 228,6 137,2 152,4 Example 8 Cordierite 88 93 square elliptical - 228,6 137,2 152,4 Example 9 Cordierite 65 93 square around 93 - - 110,0 Example 10 Cordierite 65 93 square around 93 - - 110,0 Example 11 Cordierite 90 62 square around 105,7 - - 95,0 Example 12 Cordierite 90 62 square around 105,7 - - 95,0 Example 13 Cordierite 92 93 hexagonal around 110 - - 100,0 Example 14 Cordierite 92 93 hexagonal around 110 - - 100,0 Example 15 Cordierite 68 139,5 square around 129 - - 95,0 Example 16 Cordierite 68 139,5 square around 129 - - 95,0 Example 17 Cordierite 115 62 square around 266,7 - - 200,0 Example 18 Cordierite 115 62 square around 266,7 - - 200,0 Example 19 SiC 165 46,5 square around 143,8 - - 127,0 Example 20 SiC 165 46,5 square around 143,8 - - 127,0 Table 2 Porosity (%) Porosity ratio [A / B] Porosity A (wall section) Porosity B (crossing section) Average porosity [(A+B) / 2] Example 1 17,2 22,9 20,1 0,75 Example 2 25,0 31,0 28,0 0,81 Example 3 20,0 26,0 23,0 0,77 Example 4 29,8 36,3 33,1 0,82 Example 5 21,1 29,2 25,2 0,72 Example 6 31,0 39,2 35,1 0,79 Example 7 25,7 28,3 27,0 0,91 Example 8 36,1 39,9 38,0 0,90 Example 9 14,5 23,3 18,9 0,62 Example 10 25,1 28,9 27,0 0,87 Example 11 23,2 25,2 24,2 0,92 Example 12 31,0 39,2 35,1 0,79 Example 13 22,5 26,6 24,6 0,85 Example 14 33,3 36,6 35,0 0,91 Example 15 18,3 30,8 24,6 0,59 Example 16 33,0 37,0 35,0 0,89 Example 17 23,0 26,0 24,5 0,88 Example 18 33,0 37,2 35,1 0,89 Example 19 22,9 30,1 26,5 0,76 Example 20 35,0 41,1 38,1 0,85 Examples 2 to 20

[0063] The honeycomb structure, cross-sectional shape, and porosity A and porosity B of partition walls were modified as shown in Table 1 and Table 2 to produce the honeycomb structures of Examples 2 to 20. In Examples 5, 6, 13, and 14, the honeycomb shape was a hexagon. Furthermore, in Examples 7 and 8, the cross-sectional shape of the honeycomb structure was an ellipse. The honeycomb structure according to Examples 6, 8, 12, and 20 is not covered by the patent claims.

[0064] In Examples 19 and 20, silicon carbide (SiC) was used as the material for creating the honeycomb structure. The honeycomb structure of each of Examples 19 and 20 was a segmented honeycomb structure.

[0065] During the production of the honeycomb structures of examples 2 to 20, an extrusion pressure was set during extrusion and values ​​of a porosity A and a porosity B of partition walls were set.

[0066] Regarding the honeycomb structures of examples 1 to 20, assessments of "temperature shock resistance (robustness)" were carried out using the following procedure. Table 3 shows the results. Temperature shock resistance (robustness)

[0067] Each honeycomb structure, housed in a metal can, was connected to the exhaust port of a 2.0-liter, four-cylinder, in-line gasoline engine. Additionally, for the temperature shock resistance assessment, the honeycomb structure of each sample and comparison sample was impregnated with a three-way catalyst at a concentration of 150 g / l. Then, a sample of the honeycomb structure, acting as a support and impregnated with the three-way catalyst, was connected directly below the engine. Then, as described in Fig.Figure 8 shows the motor being operated under conditions where high-speed rotation and idling were repeatedly performed. In each instance, a temperature was set so that the carrier temperature of a central part at a 5 mm position in the honeycomb structure on one inlet side ranged between a maximum temperature of 1050°C and a minimum temperature of 100°C. Additionally, on the side with the highest temperature, the motor's high-speed rotation was regulated to achieve temperature adjustment, and on the side with the lowest temperature, air was supplied during cooling to achieve temperature adjustment. This 20-minute operation of the motor was considered one cycle, and this operation was repeated over 300 cycles to perform a temperature shock resistance test.For each comparison example, the test was conducted under conditions where the engine speed was set to the same speed as the example with the same number, and the amount of air supplied during cooling was set to the same amount as the example with the same number. After completion of the test, the metal can was removed from the gasoline engine. The honeycomb structure forming the support was then also removed from the metal can to visually observe the presence or absence of cracks in the "wall section of the partition" and the "intersection section." To confirm the presence or absence of cracks, all areas of an inlet face where the temperature had risen most sharply were examined in the aforementioned test. The thermal shock resistance was then evaluated based on the following assessment standards.Table 3 shows the respective observation results for each wall section of the partitions and the respective observation results for each intersection section of the partitions. Here is . Fig. 8 a diagram showing a relationship between the operating time (seconds) of the motor and the motor speed (rpm) during the temperature shock resistance test. Rating A: There are no cracks. Rating C: Cracks are present.

[0068] Furthermore, a comprehensive assessment of temperature shock resistance was carried out using the following procedure, based on the evaluation results of the two parts mentioned above. Table 3 shows the results. It should be noted that in this comprehensive assessment, rating A is considered "Pass" and rating C is considered "Fail".

[0069] Rating A: there are no cracks whatsoever, neither in the wall section nor in the intersection section of any partition wall.

[0070] Rating C: there are cracks either in the wall section or in the intersection section or in both sections of each partition wall. Table 3 Temperature shock resistance (robustness) wall section Intersection section Comprehensive assessment Example 1 A A A Example 2 A A A Example 3 A A A Example 4 A A A Example 5 A A A Example 6 A A A Example 7 A A A Example 8 A A A Example 9 A A A Example 10 A A A Example 11 A A A Example 12 A A A Example 13 A A A Example 14 A A A Example 15 A A A Example 16 A A A Example 17 A A A Example 18 A A A Example 19 A A A Example 20 A A A Comparative examples 1 to 22

[0071] The honeycomb structure, cross-sectional shape, and porosity A and porosity B of partition walls were modified as shown in Tables 4 and 5 to produce the honeycomb structures of comparison examples 1 to 22. Furthermore, the procedure for example 1 was repeated for the honeycomb structures of comparison examples 1 to 22 to evaluate their "temperature shock resistance (robustness)." Table 6 shows the results.

[0072] Additionally, in comparison examples 5, 6, 13, and 14, a honeycomb shape was formed in the form of a hexagon. Furthermore, in comparison examples 7 and 8, the cross-sectional shape of the honeycomb structure was formed in the form of an ellipse. In comparison examples 19 and 20, silicon carbide (SiC) was used as the material for creating the honeycomb structure. Each of the honeycomb structures in comparison examples 19 and 20 was a segmented honeycomb structure. The honeycomb structures in comparison examples 1 to 20 were constructed identically to the honeycomb structures of examples 1 to 20, except that porosity A and porosity B had different values.Furthermore, each of the honeycomb structures in comparison examples 21 and 22 had the same structure (a square honeycomb shape) as the honeycomb structure in comparison example 1, except that porosity A and porosity B had different values. Additionally, the aforementioned temperature shock resistance (robustness) of each of the honeycomb structures in comparison examples 21 and 22 was measured under the same conditions as in example 1. Table 4 material honeycomb structure cross-sectional shape Diameter (mm) Long diameter (mm) Short diameter (mm) Total length (mm) Partition wall thickness (µm) Honeycomb density (honeycombs / cm²) 2 ) honeycomb shape Comparative example 1 Cordierite 70 139,5 square around 105,7 - - 81,2 Comparative example 2 Cordierite 70 139,5 square around 105,7 - - 81,2 Comparative example 3 Cordierite 90 93 square around 129 - - 100,0 Comparative example 4 Cordierite 90 93 square around 129 - - 100,0 Comparative example 5 Cordierite 115 62 hexagonal around 118,4 - - 118,0 Comparative example 6 Cordierite 115 62 hexagonal around 118,4 - - 118,0 Comparative example 7 Cordierite 88 93 square elliptical - 228,6 137,2 152,4 Comparative example 8 Cordierite 88 93 square elliptical - 228,6 137,2 152,4 Comparative example 9 Cordierite 65 93 square around 93 - - 110,0 Comparative example 10 Cordierite 65 93 square around 93 - - 110,0 Comparative example 11 Cordierite 90 62 square around 105,7 - - 95,0 Comparative example 12 Cordierite 90 62 square around 105,7 - - 95,0 Comparative example 13 Cordierite 92 93 hexagonal around 110 - - 100,0 Comparative example 14 Cordierite 92 93 hexagonal around 110 - - 100,0 Comparative example 15 Cordierite 68 139,5 square around 129 - - 95,0 Comparative example 16 Cordierite 68 139,5 square around 129 - - 95,0 Comparative example 17 Cordierite 115 62 square around 266,7 - - 200,0 Comparative example 18 Cordierite 115 62 square around 266,7 - - 200,0 Comparative example 19 SiC 165 46,5 square around 143,8 - - 127,0 Comparative example 20 SiC 165 46,5 square around 143,8 - - 127,0 Comparative example 21 Cordierite 70 139,5 square around 105,7 - - 81,2 Comparative example 22 Cordierite 70 139,5 square around 105,7 - - 81,2 Table 5 Porosity (%) Porosity ratio [A / B] Porosity A (wall section) Porosity B (crossing section) Average porosity [(A+B) / 2] Comparative example 1 19,9 20,1 20,0 0,99 Comparative example 2 27,8 28,2 28,0 0,99 Comparative example 3 24,1 21,9 23,0 1,10 Comparative example 4 32,8 33,2 33,0 0,99 Comparative example 5 25,3 24,5 24,9 1,03 Comparative example 6 35,5 34,7 35,1 1,02 Comparative example 7 26,8 27,3 27,1 0,98 Comparative example 8 38,8 39,1 39,0 0,99 Comparative example 9 10,3 27,0 18,7 0,38 Comparative example 10 15,6 38,3 27,0 0,41 Comparative example 11 15,0 33,3 24,2 0,45 Comparative example 12 21,0 49,2 35,1 0,43 Comparative example 13 24,3 24,7 24,5 0,98 Comparative example 14 34,8 35,3 35,1 0,99 Comparative example 15 24,3 24,8 24,6 0,98 Comparative example 16 34,8 35,2 35,0 0,99 Comparative example 17 14,0 35,0 24,5 0,40 Comparative example 18 20,3 49,8 35,1 0,41 Comparative example 19 26,4 26,7 26,6 0,99 Comparative example 20 37,8 38,2 38,0 0,99 Comparative example 21 41,0 47,0 44,0 0,87 Comparative example 22 41,0 41,3 41,2 0,99 Table 6 Temperature shock resistance (robustness) wall section Intersection section Comprehensive assessment Comparative example 1 C A C Comparative example 2 C A C Comparative example 3 C A C Comparative example 4 C A C Comparative example 5 C A C Comparative example 6 C A C Comparative example 7 C A C Comparative example 8 C A C Comparative example 9 A C C Comparative example 10 A C C Comparative example 11 A C C Comparative example 12 A C C Comparative example 13 C A C Comparative example 14 C A C Comparative example 15 C A C Comparative example 16 C A C Comparative example 17 A C C Comparative example 18 A C C Comparative example 19 C A C Comparative example 20 C A C Comparative example 21 C C C Comparative example 22 C C C Result

[0073] The honeycomb structures of examples 1 to 20 achieved a rating of "A", fulfilling the criteria for passing the comprehensive assessment of temperature shock resistance. Specifically, no cracks were generated in either the wall section or the intersection section of the partition wall during the temperature shock resistance assessment of the honeycomb structures of examples 1 to 20.

[0074] The honeycomb structures of comparison examples 1 to 22 achieved a "C" rating, which indicated failure in the comprehensive assessment of temperature shock resistance. Specifically, cracks were generated in the honeycomb structures of comparison examples 1 to 22 during the temperature shock resistance assessment, either in the wall section, in the intersection section, or in both sections of the partition.

[0075] A honeycomb structure of the present invention can be used as a catalyst carrier, which is to be impregnated with a catalyst for exhaust gas purification. Reference symbol list

[0076] 1, 21 and 41: partition wall, 2, 22 and 42: honeycomb, 3 and 43: perimeter wall, 4, 24 and 44: honeycomb structure body, 11, 31 and 51: first end face, 12 and 52: second end face, 15 and 35: crossing part, 16 and 36: wall part, 46: honeycomb segment, 47: connecting layer, and 100, 200, 300 and 400: honeycomb structure

Claims

[1] Honeycomb structure (100, 200, 300, 400), comprising a honeycomb structure body (4, 24, 44) with porous partitions (1, 21, 41) arranged to surround a plurality of cells (2, 22, 42) extending from a first end face (11, 31, 51) to a second end face (12, 52) and forming passage channels for a fluid, where a value of a porosity of the partition (1, 21, 41) in a partition part between the two cells (2, 22, 42) is defined as a porosity A, a porosity value of the partition wall (1, 21, 41) in a crossing part (15, 35), which is an area connecting two or more wall parts (16, 36), is defined as a porosity B, a value of A / B obtained by dividing porosity A by porosity B lies in a range of 0.5 to 0.95 and the porosity A lies in a range of 10 to 40%, the porosity B lies in a range of 20 to 37.2%, and the thickness of the partition walls (1, 21, 41) is in a range of 40 to 115 µm. [2] Honeycomb structure (100, 200, 300, 400) according to claim 1, wherein an arithmetic mean of the porosity A and the porosity B is in a range of 15 to 38.6%. [3] Honeycomb structure (100, 200, 300, 400) according to claim 1 or 2, wherein a shape of the cells (2, 22, 42) in a cross-section of the honeycomb structure body (4, 24, 44) which is perpendicular to an extension direction of the cells (2, 22, 42) is square or hexagonal.

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