HONEYCOMB STRUCTURE

Abstract

Honeycomb structure (100), containing: a columnar honeycomb structure body (4) which contains a porous partition (1) arranged in such a way as to surround a plurality of cells (2) which function as fluid passage channels extending from a first end face (11) to a second end face (12), wherein, if a thickness (µm) of the partition (1) is defined as T1 and, for pores formed in the partition (1), a value of an average pore diameter (µm) of certain pores, whose pore diameters measured by means of a mercury injection method are 20 to 100 µm, is defined as D (20 bis 100) is defined T1 / D (20 bis 100) , which is obtained by dividing T1 by D (20 bis 100) The value obtained is between 2.4 and 4.0. a ratio of the pore volume of the specific pores to a total pore volume PV all the partition wall (1) is 5 to 45% and a PV2 / PV ratio alla sum pv2 of pore volume of large pores whose pore diameter is greater than or equal to 100 µm, to the total pore volume PV all the partition (1) is less than or equal to 5%.

Description

[0001] This application is based on JP 2018-057065, filed with the Japan Patent Office on March 23, 2018, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTIONField of the invention

[0002] The present invention relates to a honeycomb structure. More particularly, the present invention relates to a honeycomb structure that can suppress the decline in isostatic strength while maintaining a desired catalyst loading ratio. Description of the state of the art

[0003] Currently, industrialized countries are drawing stronger NO x Regulations for diesel passenger and commercial vehicles are being considered. Various technologies for the treatment of NO x in an exhaust gas were for such NO x-regulations proposed For example, such technologies include, as an example, a technology for impregnating a honeycomb structure having a porous partition wall with a catalyst for selective catalytic reduction (hereinafter also referred to as “SCR catalyst”), etc., and purifying an exhaust gas of NO x by means of the honeycomb structure (see, for example, Patent Document 1).

[0004] The NO x Treatment using the honeycomb structure as described above can improve the purification performance by increasing the amount of catalyst to be incorporated into the honeycomb structure. On the other hand, when performing NO xTreatment after incorporation of a catalyst-impregnated honeycomb structure into the exhaust system of a diesel vehicle, etc., may cause an increase in pressure loss. In particular, if the amount of catalyst used to improve purification performance is increased, the increase in pressure loss of the honeycomb structure may become more significant. In other words, in the NO xTreatment using a honeycomb structure involves a trade-off between improving purification performance and preventing an increase in pressure loss. Therefore, a technology for increasing the porosity of the honeycomb partition wall has been proposed to overcome this trade-off. Furthermore, a thin-wall technology for thinning the honeycomb partition wall has also been proposed. For example, it is believed that increasing the porosity of the partition wall and making the honeycomb partition wall thinner can prevent an increase in pressure loss, even if the amount of catalyst incorporated is increased.

[0005] Furthermore, Patent Document 2 discloses a ceramic honeycomb filter with a ceramic honeycomb structure in which flow channels for a fluid are defined via porous partition walls. To improve the mechanical properties of the honeycomb structure, Patent Document 2 teaches a varying pore ratio for different pore sizes in the partition wall, with the total pore volume in the porous partition wall being 0.55-0.80 cm 3 / g and the volume of pores with a pore size of 100 µm or more 0.02-0.10 cm 3 / g.

[0006] Furthermore, another honeycomb structure is known from Patent Document 3, the partition walls of which also define flow channels whose thickness is between about 0.2 mm and about 0.3 mm. Patent document 1: JP 2013- 052 367 A Patent document 2: JP 2004- 322 082 A Patent document 3: US 2011 / 0 085 941 A1

[0007] However, the honeycomb structure in which the porosity of the partition wall is increased has the problem of a decrease in isostatic strength. Furthermore, the honeycomb structure in which the partition wall is made thinner also has the problem of a decrease in isostatic strength.

[0008] The present invention was conceived in view of the problems of the above conventional technology. According to the present invention, a honeycomb structure is provided that can suppress the decline in isostatic strength. BRIEF DESCRIPTION OF THE INVENTION

[0009] According to the present invention, there is provided a honeycomb structure as defined in claim 1. Preferred embodiments of the honeycomb structure are defined in claims 2 to 5. Effects of the invention

[0010] The honeycomb structure according to the present invention can suppress the decrease in isostatic strength compared to a conventional honeycomb structure with the same porosity. In other words, the honeycomb structure according to the present invention has, when the thickness (μm) of the partition wall is defined as T1 and the value of an average pore diameter (μm) of certain pores whose pore diameters are 20 to 100 μm is defined as D (20 bis 100) is defined, a value of T1 / D (20 bis 100)which is greater than or equal to 2.4. By adopting such a configuration, it is possible to effectively suppress the decrease in isostatic strength. For this reason, it is possible to realize the high porosity of the partition wall, which can maintain a desired catalyst filling ratio, while effectively suppressing the decrease in isostatic strength. For example, the high porosity of the partition wall makes it possible to increase the filling ratio of a catalyst in the pores of the partition wall and also effectively suppress the increase in pressure loss of the honeycomb structure. In particular, the honeycomb structure according to the present invention can effectively suppress the decrease in isostatic strength while maintaining a catalyst filling ratio in pores, which is advantageous in terms of pressure loss. BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 is a perspective view schematically showing an embodiment of a honeycomb structure according to the present invention; Fig. 2 is a plan view showing a first end face of the Fig. 1 shows the honeycomb structure; Fig. 3 is a sectional view showing a section along the line AA' in Fig. 2 shows schematically. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Embodiments of the present invention will be explained below, but the present invention is not limited to the following embodiments. Therefore, it goes without saying that those in which modifications, improvements, etc., are appropriately made to the following embodiments based on the average knowledge of those skilled in the art without departing from the spirit of the present invention are within the scope of the present invention. 1. Honeycomb structure

[0012] One embodiment of a honeycomb structure according to the present invention is a honeycomb structure 100 as shown in the Fig. 1 to 3. Herein is Fig. 1 is a perspective view schematically showing an embodiment of the honeycomb structure according to the present invention. Fig. 2 is a plan view showing a first end face of the Fig. 1 shows the honeycomb structure. Fig. 3 is a sectional view showing a section along the line AA' in Fig. 2 shows schematically.

[0013] As in the Fig.1 to 3, the honeycomb structure 100 according to the present embodiment includes a columnar honeycomb structural body 4 having a first end face 11 and a second end face 12. The honeycomb structural body 4 includes a porous partition wall 1 arranged to surround a plurality of honeycombs 2 that function as fluid passageways extending from the first end face 11 to the second end face 12. In the honeycomb structure 100 according to the present embodiment, the honeycomb structural body 4 is configured to have a circular columnar shape and further includes a peripheral wall 3 on its peripheral surface. In other words, the peripheral wall 3 is arranged to surround the partition wall 1 arranged in a lattice pattern.

[0014] The honeycomb structure 100 according to the present embodiment has a technical feature related to the thickness of the partition wall 1 and the pore diameter and pore volume of pores formed in the partition wall 1. Hereinafter, the thickness (μm) of the partition wall 1 is defined as "T1." "T1" may be referred to as "thickness T1." Moreover, among the pores formed in the partition wall 1, pores whose pore diameters measured by a mercury injection method are 20 to 100 μm are defined as "specific pores." Herein, the value of an average pore diameter (μm) of the specific pores is referred to as "D (20 bis 100) “ defined. “D (20 bis 100) ” can be defined as “average pore diameter D (20 bis 100) The “average pore diameter of specific pores” means an average pore diameter for which the values ​​of the pore diameters of specific pores (ie

[0015] Pores with pore diameters between 20 and 100 µm are described as a single population. Furthermore, pores with pore diameters greater than 100 µm, measured using the mercury injection method, are defined as "large pores."

[0016] The honeycomb structure 100 according to the present embodiment has a feature that T1 / D (20 bis 100) , obtained by dividing T1 by D (20 bis 100), has a value greater than or equal to 2.4. Moreover, a ratio of the pore volume of certain pores to the total pore volume (total pore volume) of the partition wall 1 is 5 to 45%. Further, a ratio of the pore volume of large pores to the total pore volume (total pore volume) of the partition wall 1 is less than or equal to 5%. By adopting such a configuration, the decrease in isostatic strength can be effectively suppressed compared with a conventional honeycomb structure having the same porosity. For this reason, it is possible to realize the high porosity of the partition wall 1, which can effectively suppress the decrease in isostatic strength and also maintain a desired catalyst filling ratio.For example, thanks to the high porosity of the partition wall 1, the filling degree of a catalyst in the pores of the partition wall 1 can be increased and, in addition, the increase in pressure loss of the honeycomb structure 100 can be effectively prevented.

[0017] The specific pores, whose pore diameters are 20 to 100 μm, and the large pores, whose pore diameters are larger than 100 μm, are pores mainly formed from a pore-forming agent added to the ceramic raw material powder in a manufacturing step for the ceramic porous partition wall 1. On the other hand, the pores, whose pore diameters are smaller than 20 μm, are micropores mainly formed from the ceramic raw material powder in the ceramic porous partition wall 1. The honeycomb structure 100 according to the present embodiment can be manufactured by adjusting the particle diameters of the pore-forming agent added to the ceramic raw material powder in the manufacturing step so that "T1 / D (20 bis 100) " is greater than or equal to 2.4. For example, "T1 / D (20 bis 100)“ may take a value greater than or equal to 2.4 by making the average particle diameter of the pore former smaller than the thickness T1 of the partition wall 1 in the manufacturing step.

[0018] The average pore diameter of the partition wall 1 can be measured, for example, using the Autopore 9500 (product name) manufactured by Micromeritics. The measurement of the average pore diameter can be performed after cutting out a portion of the partition wall 1 from the honeycomb structure 100 as a sample using the sample thus obtained. A method for calculating the average pore diameter D (20 bis 100)The method for determining the pores is to first create a pore size distribution graph from the measurement result of a summed pore volume of the partition wall 1, which will be described later. A horizontal axis corresponds to a pore diameter and a vertical axis corresponds to a log-differential pore volume. Then, a mean diameter in a range in which the pore diameters lie between 20 µm and 100 µm in the created pore size distribution graph is used as the average pore diameter D. (20 bis 100) of the specific pores.

[0019] The total pore volume of the partition wall 1 and the pore volume of the specific pores and large pores can be calculated from the total pore volume of the partition wall 1 measured by the mercury injection method. The measurement of the total pore volume of the partition wall 1 can be performed using, for example, the Autopore 9500 (product name) produced by Micromeritics. The measurement of the total pore volume of the partition wall 1 can be performed using the following method. First, a part of the partition wall 1 is cut out of the honeycomb structure 100 to obtain a sample for measuring a total pore volume. The size of the sample is not particularly limited, but preferably the sample should be a rectangular solid whose dimensions in length, width, and height are, for example, approximately 10 mm, approximately 10 mm, and approximately 10 mm, respectively.The area of ​​the partition wall 1 from which a sample is cut out is not particularly limited, but it is preferable to obtain the sample by cutting it out from the vicinity of the center in the axial direction of the honeycomb structural body 4. The obtained sample is placed in a measuring cell of a measuring device, and the measuring cell is depressurized. Then, mercury is introduced into the measuring cell. Then, the mercury introduced into the measuring cell is pressurized, and a volume of mercury forced into the pores in the sample is measured during the pressurization. In this case, as a pressure applied to the mercury is increased, the mercury is gradually forced from pores whose pore diameters are large into pores whose pore diameters are small.Therefore, a relationship between the "pore diameters of pores formed in the sample" and the "total pore volume" can be calculated from a relationship between the "pressure applied to the mercury" and the "volume of mercury forced into the pores." The "total pore volume" is a value obtained by summing the pore volumes from the minimum pore diameter to the specified pore diameter. For example, a "pore volume fraction with a pore diameter less than or equal to 20 µm" is a percentage (pv1 / PV). all · 100%) of a ratio of a pore volume p v1 of pores with a pore diameter of less than or equal to 20 µm to a total pore volume PV given by the summed pore volume all Accordingly, a “pore volume fraction with a pore diameter greater than or equal to 100 µm” is a percentage (pv2 / PV all· 100%) of a ratio of a pore volume pv2 of pores whose pore diameters are greater than or equal to 100 µm to the total pore volume PV given by the summed pore volume all meant.

[0020] The thickness T1 of the partition wall 1 can be measured, for example, using a scanning electron microscope or a microscope. The thickness T1 of the partition wall 1 is preferably 60 to 140 μm, more preferably 60 to 114 μm, and particularly preferably 60 to 90 μm. Since the honeycomb structure 100 according to the present embodiment can effectively suppress the decrease in isostatic strength, it is possible to reduce the wall thickness of the partition wall 1 as described above. For this reason, according to the honeycomb structure 100 of the present embodiment, the low pressure loss of the honeycomb structure 100 can also be realized. If the thickness T1 of the partition wall 1 is less than 60 μm, the thickness T1 of the partition wall 1 is far too thin, and thus sufficient strength may not be obtained. On the other hand, if the thickness T1 of the partition wall 1 is greater than 140 μm, the pressure loss of the honeycomb structure 100 may increase.

[0021] If T1 / D (20 bis 100)less than 2.4, the isostatic strength decreases compared to the honeycomb structure with the same porosity. Preferably, T1 / D (20 bis 100) 2.40 to 4.0.

[0022] If the ratio of the pore volume of the specific pores to the total pore volume of the partition wall 1 is less than 5%, this is undesirable in terms of the catalyst filling ratio in the pores. Hereinafter, the ratio of the pore volume of the specific pores to the total pore volume of the partition wall 1 may be simply referred to as a "pore volume ratio of the specific pores." The pore volume ratio of the specific pores is preferably 5 to 45%, and more preferably 10 to 45%.

[0023] If the ratio of the pore volume of the large pores to the total pore volume of the partition wall 1 is greater than 5%, this is undesirable in terms of the strength of the honeycomb structure 100. Hereinafter, the ratio of the pore volume of the large pores to the total pore volume of the partition wall 1 may be simply referred to as a "large pore volume ratio." Preferably, the large pore volume ratio should be less than or equal to 4%. The lower limit of the large pore volume ratio is 0%.

[0024] Although the porosity of the partition wall 1 is not particularly limited, the porosity is preferably 45 to 65%, and more preferably 45 to 55%. If the porosity of the partition wall 1 is less than 45%, there is a fear that a pore volume that can be filled with a catalyst cannot be sufficiently ensured. If the porosity of the partition wall 1 is greater than 65%, it is undesirable because of the deterioration of the strength of the honeycomb structure 100. The porosity of the partition wall 1 can be measured using, for example, the Autopore 9500 (product name) produced by Micromeritics. The porosity measurement can be performed after cutting out a part of the partition wall 1 from the honeycomb structure 100 as a sample using the thus obtained sample.

[0025] The honeycomb structure 100 according to the present embodiment allows the filling ratio of a catalyst in the pores of the partition wall 1 to be increased thanks to the high porosity of the partition wall 1. For this reason, it is also possible to suppress the increase in pressure loss after impregnation with a catalyst for exhaust gas purification. Therefore, even if, for example, the amount of catalyst incorporated is increased, it is possible to suppress the increase in pressure loss of the honeycomb structure 100, and thus it is possible to achieve the compatibility of "improving purification performance" with "suppressing the increase in pressure loss."

[0026] The shape of the honeycombs 2 formed in the honeycomb structural body 4 is not particularly limited. For example, a polygonal shape, a circular shape, an elliptical shape, and the like are possible shapes of the honeycombs 2 in a cross-section orthogonal to the extension direction of the honeycombs 2. Polygonal shapes include a triangle, a square, a pentagon, a hexagon, an octagon, and the like. Furthermore, the shape of the honeycombs 2 should preferably be a triangle, a square, a pentagon, a hexagon, and / or an octagon. Furthermore, regarding the shape of the honeycombs 2, the shapes of all the honeycombs 2 may be the same or different. For example, although not shown, honeycombs may be a mixture of square honeycombs and octagonal honeycombs. Furthermore, regarding the size of the honeycombs 2, the sizes of all the honeycombs 2 may be the same or different from each other.For example, although not shown, the size of some of the plurality of honeycombs may be made larger, and the size of other honeycombs may be made relatively smaller. Furthermore, in the present invention, a honeycomb refers to a space surrounded by the partition wall.

[0027] The honeycomb density of the honeycombs 2 defined by the partition wall 1 is preferably 46.5 to 116.3 pcs. / cm 2 and preferably 62 to 93 pcs. / cm 2 By employing such a configuration, the honeycomb structure 100 according to the present embodiment can be preferably used as a purification member (e.g., catalyst carrier and filter) for purifying an exhaust gas discharged from an engine of an automobile.

[0028] The peripheral wall 3 of the honeycomb structural body 4 may be configured integrally with the partition wall 1, or may be a peripheral coating layer formed by applying an outer coating material surrounding the partition wall 1. Although not shown, during manufacturing, after a partition wall and a peripheral wall are integrally formed and then the formed peripheral wall is removed by a well-known method such as grinding, the peripheral coating layer may be applied to the outer peripheral side of the partition wall.

[0029] The shape of the honeycomb structural body 4 is not particularly limited. Possible shapes of the honeycomb structural body 4 include a columnar shape, in which the shape of the first end face 11 and the second end face 12 is a circular shape, an elliptical shape, a polygonal shape, or the like.

[0030] The dimensions of the honeycomb structural body 4, for example, the length from the first end face 11 to the second end face 12 and the size of a cross section of the honeycomb structural body 4 orthogonal to the extension direction of the honeycombs 2, are not particularly limited. When the honeycomb structure 100 according to the present embodiment is used as a purification element for exhaust gas purification, only the above dimensions need to be appropriately selected to achieve optimal purification performance. For example, the length from the first end face 11 to the second end face 12 of the honeycomb structural body 4 is preferably 76 to 254 mm, and more preferably 101.6 to 203 mm. Furthermore, the area of ​​the cross section of the honeycomb structural body 4 orthogonal to the extension direction of the honeycombs 2 is preferably 24828.7 to 99314.7 mm. 2 and preferably 41043.3 to 72965.9 mm 2 .

[0031] Preferably, the material of the partition wall 1 should contain at least one material selected from a group consisting of cordierite, silicon carbide, silicon-silicon carbide composite, cordierite-silicon carbide composite, silicon nitride, mullite, aluminum oxide, and aluminum titanate. The material constituting the partition wall 1 is preferably a material in which the materials listed in the group are contained by at least 30 mass%, more preferably a material in which the materials are contained by at least 40 mass%, and particularly preferably a material in which the materials are contained by at least 50 mass%. Furthermore, a silicon-silicon carbide composite is a composite material formed from silicon carbide as an aggregate and silicon as a bonding material.Furthermore, a cordierite-silicon carbide composite is a composite material formed from silicon carbide as an aggregate and cordierite as a bonding material. In the honeycomb structure 100 according to the present embodiment, the material forming the partition wall 1 should particularly preferably be cordierite.

[0032] In the honeycomb structure 100 according to the present embodiment, the partition wall 1 defining the plurality of honeycombs 2 may be impregnated with a catalyst for exhaust gas purification. Impregnating the partition wall 1 with a catalyst means applying a catalyst to the surface of the partition wall 1 and into the pores formed in the partition wall 1. Since the honeycomb structure 100 according to the present embodiment can suppress the decrease in isostatic strength, it is possible to increase the amount of catalyst to be applied and thus achieve an improvement in purification performance thanks to the high porosity and the thinner partition wall. (2) Manufacturing process of the honeycomb structure

[0033] A method for producing the honeycomb structure according to the present invention is not particularly limited and may, for example, include the following method. First, a plastic wrought material for producing a honeycomb structural body is prepared. The wrought material for the honeycomb structural body can be prepared by appropriately adding an additive such as a binder, a pore-forming agent, and water to a material selected from the preferred materials of the honeycomb structural body described above as the raw material powder. The raw material powder may, for example, contain a cordierite raw material. The cordierite raw material is a raw material that becomes cordierite by firing, and is specifically a raw material mixed to have a chemical composition having a silica content of 42 to 56 mass%, an alumina content of 30 to 45 mass%, and a magnesia content of 12 to 16 mass%.

[0034] During the preparation of the kneaded material, the pore diameter distribution of the partition wall can be adjusted by adjusting the particle diameters of the pore-forming agents. For example, it is preferable to make the average particle diameter of the pore-forming agent smaller than the thickness T1 of the partition wall. The honeycomb structure in which "T1 / D (20 bis 100) " is greater than or equal to 2.4, the "pore volume ratio of the specific pores" is 5 to 45%, and the "pore volume ratio of the large pores" is less than or equal to 5% can be advantageously produced using such a pore former.

[0035] Then, by extruding the thus obtained wrought material, a columnar honeycomb formed body is produced, which includes the partition wall defining the plurality of honeycombs and the peripheral wall arranged to surround the partition wall. Furthermore, regarding the thickness of the partition wall of the honeycomb formed body, the thickness of the partition wall of the honeycomb structure after firing should preferably be equal to the desired thickness T1 according to the average particle diameter of the pore-forming agent added to the raw material powder.

[0036] The resulting honeycomb body is then dried, for example, using microwaves and hot air. The honeycomb structure is then produced by firing the honeycomb body. Firing temperatures and atmospheres vary depending on the raw material. Experts can select the firing temperature and atmosphere most suitable for the selected material. Examples

[0037] In the following, the present invention will be explained more specifically by means of examples, but the present invention is not limited to these examples. Example 1

[0038] A kneading material was prepared by adding 10 parts by mass of a pore-forming agent, 30 parts by mass of a dispersing medium, and 1 part by mass of an organic binder to 100 parts by mass of cordierite raw material, followed by mixing and kneading. Alumina, aluminum hydroxide, kaolin, talc, and silica were used as the cordierite raw material. Water was used as the dispersing medium. Methylcellulose was used as the organic binder. Dextrin was used as the dispersing agent. Hollow resin particles with an average particle diameter of 70 µm were used as the pore-forming agent.

[0039] Then, a honeycomb molded body with an overall circular column shape was obtained by extruding the wrought material using a honeycomb molding die. The honeycomb shape of the honeycomb molded body was quadrangular.

[0040] Then, the honeycomb body was adjusted to a predefined size by drying it with a microwave dryer, further drying it completely with a hot air dryer, and then trimming both end faces of the honeycomb body. The honeycomb structure of Example 1 was then manufactured by degreasing and firing the dried honeycomb body.

[0041] The honeycomb structure according to Example 1 had a round column shape, and the first and second end faces were circular. The diameter of the first and second end faces was 266.7 mm. Furthermore, the total length of the honeycomb in the extension direction of the honeycomb structure was 152.4 mm. In the honeycomb structure according to Example 1, the thickness T1 of the partition wall was 88.9 µm, and the honeycomb density was 93 pcs / cm. 2 . Table 1 shows the thickness T1 of the partition wall and the honeycomb density in the honeycomb structure. Table 1 Diameter (mm) Total length (mm) Partition thickness T1 (µm) Honeycomb density (combs / cm 2 ) Porosity (%) D (20 bis 100) (µm) Ratio (%) of pore volume of specific pores Ratio (%) of pore volume of large pores T1 / D (20 bis 100) Example 1 266,7 152,4 88,9 93 50 34,0 32,5 3,5 2,6 Example 2 266,7 152,4 88,9 93 50 37,1 36,7 3,7 2,4 Example 3 266,7 152,4 88,9 93 50 30,9 24,2 3,2 2,9 Example 4 266,7 152,4 88,9 93 50 27,9 15,8 2,8 3,2 Example 5 266,7 152,4 88,9 93 50 27,8 15,0 2,8 3,2 Example 6 266,7 152,4 88,9 93 50 27,2 13,8 2,8 3,3 Example 7 266,7 152,4 88,9 62 50 26,5 11,7 2,7 3,4 Example 8 266,7 152,4 88,9 62 50 25,3 7,5 2,5 3,5 Example 9 266,7 152,4 114,3 62 50 43,5 45,0 4,0 2,6 Example 10 266,7 152,4 114,3 62 50 37,1 36,7 3,7 3,1 Example 11 266,7 152,4 114,3 62 50 34,0 32,5 3,5 3,4 Example 12 266,7 152,4 114,3 62 50 27,9 15,8 2,8 4,1 Example 13 266,7 152,4 114,3 62 50 26,5 11,7 2,7 4,3 Comparison example 1 266,7 152,4 88,9 93 50 43,5 45,0 4,0 2,0 Comparison example 2 266,7 152,4 88,9 93 50 39,7 40,8 3,8 2,2 Comparison example 3 266,7 152,4 114,3 62 50 49,0 57,5 4,5 2,3 In addition, a “Porosity (%)”, “D (20 bis 100) (µm)”, a “ratio (%) of the pore volume of certain pores”, a “ratio (%) of the pore volume of large pores” and “T1 / D (20 bis 100) “ was calculated with respect to the honeycomb structure according to Example 1. The results are shown in Table 1.

[0042] The porosity of the partition wall was measured using the Autopore 9500 (product name) manufactured by Micromeritics. The porosity measurement was performed after cutting out a portion of the partition wall from the honeycomb structure as a sample using the obtained sample. The sample was a rectangular solid with dimensions of approximately 10 mm in length, width, and height, respectively. Furthermore, the sample was obtained by cutting out the area near the center in the axial direction of the honeycomb structure.

[0043] The total pore volume of the partition wall was measured using the Autopore 9500 (product name) manufactured by Micromeritics. The sample used for porosity measurement was also used to measure the total pore volume. When measuring the total pore volume, the summed pore volume of the partition wall was measured, and the "pore volume of specific pores with pore diameters of 20 to 100 µm" and the "pore volume of large pores with pore diameters greater than 100 µm" described above were simultaneously measured. Based on the measurement results, the average pore diameter D was also calculated. (20 bis 100) of the specific pores.

[0044] In the honeycomb structure according to Example 1, the porosity of the partition wall was 50% and the average pore diameter D (20 bis 100)of the determined pores was 34.0 µm. The pore volume ratio of the determined pores was 32.5%, and the pore volume ratio of the large pores was 3.5%.

[0045] The partition wall of the honeycomb structure according to Example 1 was impregnated with a catalyst using the following method. First, a catalyst slurry containing zeolite with an average particle diameter of 5 µm was prepared. This catalyst slurry was used to impregnate the honeycomb structure so that the impregnation amount per unit volume after drying was 148 g / L. Upon introduction of the catalyst, the honeycomb structure was subjected to an immersion bath for impregnation, and excess catalyst slurry was blown off with air. Then, by drying the honeycomb structure at a temperature of 120°C and subjecting it to a heat treatment at 500°C for 3 hours, a catalyst-impregnated honeycomb structure was obtained. The impregnation amount of the catalyst introduced into the honeycomb structure according to Example 1 was 148 g / L. Table 2 Isostatic strength (MPa) Catalyst filling level (%) Comprehensive evaluation Example 1 2,3 60 A Example 2 1,6 65 A Example 3 2,4 60 A Example 4 2,9 55 A Example 5 2,8 55 A Example 6 3,0 55 A Example 7 3,2 55 A Example 8 3,4 50 A Example 9 2,30 65 A Example 10 2,40 55 A Example 11 2,40 55 A Example 12 2,50 45 B Example 13 2,60 45 B Comparison example 1 0,90 65 C Comparison example 2 1,40 65 C Comparison example 3 1,40 65 C

[0046] The measurement of "isostatic strength (MPa)" was performed on the honeycomb structure according to Example 1 using the following method. Furthermore, the "catalyst filling ratio (%)" was calculated using the following method. Furthermore, based on the results of "isostatic strength (MPa)" and "catalyst filling ratio (%)," a "comprehensive evaluation" was performed based on the following evaluation criteria. The results are shown in Table 2. Isostatic strength (MPa)

[0047] The isostatic strength measurement was conducted based on an isostatic fracture test regulated by M505-87 of the Japanese Automobile Standards (JASO) issued by the Society of Automotive Engineers of Japan, Inc. The isostatic fracture test is a test in which the honeycomb structure is placed in a tubular rubber container sealed with an aluminum plate and then subjected to isostatic compression pressure underwater. The isostatic strength measured by the isostatic fracture test is indicated by the compression pressure value (MPa) at which the honeycomb structure breaks. The case where the isostatic strength is greater than or equal to 1.5 MPa is defined as "pass," and the case where it is less than 1.5 MPa is defined as "fail." Catalyst filling level (%)

[0048] A sample piece for measurement of 20 mm in length, 20 mm in width, and 20 mm in height was cut out from the honeycomb structural body of the honeycomb structure according to Example 1. After polishing the partition wall of the sample piece, SEM images were randomly acquired using a scanning electron microscope (SEM) in three fields of view. One of the image acquisition fields had a size corresponding to the thickness (µm) of a piece of the partition wall in the X direction and 600 µm in the Y direction. Then, with the honeycomb structure impregnated with the catalyst, a ratio (percentage) of a volume (V1) of the pores actually filled with the catalyst to a volume (V0) of all the pores formed in the partition wall was calculated. Specifically, the volume (V0) of all the pores formed in the partition wall was calculated from pore proportions extracted by binarization through image analysis (i.e.,The volume V1 was calculated by impregnating the honeycomb structure with the catalyst and performing binarization through image analysis to extract the proportion of pores into which the catalyst penetrated. The catalyst filling ratio (%) was then calculated using these values. Here, the catalyst filling ratio (%) value in Table 2 is an arithmetic mean of catalyst filling ratios from SEM images of three fields of view. Furthermore, the catalyst filling ratio is defined as "passing" if it is greater than or equal to 40%. Comprehensive evaluation

[0049] Rating A: The case where the isostatic strength is “Pass” and the catalyst filling ratio is greater than or equal to 50% is defined as Rating A.

[0050] Rating B: The case where the isostatic strength is “Pass” and the catalyst filling ratio is greater than or equal to 40% and less than 50% is defined as Rating B.

[0051] Rating C: The case where the isostatic strength results in “failure” or the catalyst filling ratio is less than 40% is defined as rating C. Examples 2 to 13

[0052] By changing the “Thickness T1 (µm) of the partition wall”, the “Honeycomb density (pcs. / cm 2 )”, from “D (20 bis 100) (µm)”, the “ratio (%) of the pore volume of the specific pores”, the “ratio (%) of the pore volume of the large pores” and “T1 / D (20 bis 100) “ Honeycomb structures were prepared as shown in Table 1. The setting of “D (20 bis 100)(µm)”, “ratio (%) of pore volume of specific pores” and “ratio (%) of pore volume of large pores” was determined by adjusting the particle diameters of a pore former to be added to a molding raw material.

[0053] In Example 2, a pore former with an average particle diameter of 80 µm was used.

[0054] In Example 3, a pore former with an average particle diameter of 50 µm was used.

[0055] In Example 4, a pore former with an average particle diameter of 30 µm was used.

[0056] In Example 5, a pore former with an average particle diameter of 28 µm was used.

[0057] In Example 6, a pore former with an average particle diameter of 25 µm was used.

[0058] In Example 7, a pore former with an average particle diameter of 20 µm was used.

[0059] In Example 8, a pore former with an average particle diameter of 10 µm was used.

[0060] In Example 9, a pore former with an average particle diameter of 100 µm was used.

[0061] In Example 10, a pore former with an average particle diameter of 80 µm was used.

[0062] In Example 11, a pore former with an average particle diameter of 70 µm was used.

[0063] In Example 12, which is not covered by the claim, a pore former with an average particle diameter of 30 µm was used.

[0064] In Example 13, which does not fall within the scope of the claim, a pore former with an average particle diameter of 20 µm was used. Comparative examples 1 to 3

[0065] By changing the “Thickness T1 (µm) of the partition wall”, the “Honeycomb density (pcs. / cm 2 )”, from “D (20 bis 100) (µm)”, the “ratio (%) of the pore volume of the specific pores”, the “ratio (%) of the pore volume of the large pores” and “T1 / D (20 bis 100) “ Honeycomb structures were prepared as shown in Table 1. The setting of “D (20 bis 100) (µm)”, “ratio (%) of pore volume of specific pores” and “ratio (%) of pore volume of large pores” was determined by adjusting the particle diameters of a pore former to be added to a molding raw material.

[0066] In Comparative Example 1, a pore former with an average particle diameter of 100 µm was used.

[0067] In Comparative Example 2, a pore former with an average particle diameter of 90 µm was used.

[0068] In Comparative Example 3, a pore former with an average particle diameter of 130 µm was used.

[0069] The measurement of "isostatic strength (MPa)" was performed on the honeycomb structures of Examples 2 to 13 and Comparative Examples 1 to 3 in the same manner as in Example 1. Furthermore, the "catalyst filling ratio (%)" was calculated in the same manner as in Example 1, and a "comprehensive evaluation" was conducted based on these results. The results are shown in Table 2, with Examples 12 and 13 not falling within the scope of the claim. Result

[0070] The honeycomb structures of Examples 1 to 13 had high isostatic strength and also met a test criterion regarding the "catalyst filling ratio (%)." The honeycomb structures of Comparative Examples 1 to 3 had exceptionally low isostatic strength. Industrial applications

[0071] The honeycomb structures according to the present invention can be used as a catalyst carrier to be impregnated with a catalyst for exhaust gas purification. List of reference symbols 1 partition wall 2 honeycombs 3 Perimeter wall 4 honeycomb structural bodies 11 first front side 12 second front side 100 honeycomb structure

Claims

[1] Honeycomb structure (100) containing: a columnar honeycomb structural body (4) containing a porous partition wall (1) arranged to surround a plurality of cells (2) which function as fluid passageways extending from a first end face (11) to a second end face (12), wherein, when a thickness (µm) of the partition wall (1) is defined as T1 and, for pores formed in the partition wall (1), a value of an average pore diameter (µm) of certain pores whose pore diameters measured by a mercury injection method are 20 to 100 µm is defined as D (20 bis 100) is defined, T1 / D (20 bis 100) , which is a function calculated by dividing T1 by D (20 bis 100) obtained value is 2.4 to 4.0, a ratio of a pore volume of the specific pores to a total pore volume PV all the partition wall (1) is 5 to 45% and a ratio pv2 / PV alla sum pv2 of pore volume of large pores with pore diameters greater than or equal to 100 µm to the total pore volume PV all the partition wall (1) is less than or equal to 5%. [2] The honeycomb structure (100) according to claim 1, wherein T1 is 60 to 140 µm. [3] Honeycomb structure (100) according to one of claims 1 to 2, wherein a porosity of the partition wall (1) is 45 to 65%. [4] A honeycomb structure according to any one of claims 1 to 3, wherein a honeycomb density of the honeycomb structural body is 46.5 to 116.3 pcs / cm 2 amounts. [5] The honeycomb structure according to claim 4, wherein a honeycomb density of the honeycomb structural body is 62 to 93 pcs / cm 2 amounts.

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