Honeycomb structure, honeycomb filter, catalyst carrier honeycomb filter, and method for manufacturing a honeycomb structure

Abstract

The present invention provides a honeycomb structure, a honeycomb filter, a catalyst support honeycomb filter, and a method for manufacturing a honeycomb structure that can suppress the occurrence of cracks during catalyst coating or firing while maintaining a low Young's modulus. [Solution] A honeycomb structure 1 comprising a plurality of honeycomb segments 10 having an outer peripheral wall 103 and partition walls 101 disposed inside the outer peripheral wall 103 that partition and form a plurality of cells 100 which become fluid flow paths extending from an inlet end face 14 to an outlet end face 15, and a bonding layer 11 that joins the surfaces of the outer peripheral wall 103 of the plurality of honeycomb segments 10, wherein the bonding layer 11 contains siloxane, has a compressive Young's modulus of 100 MPa or less, a porosity of 68 to 85%, and a bonding strength of 400 to 1700 kPa.

Description

[Technical Field]

[0001] The present invention relates to a honeycomb structure, a honeycomb filter, a catalyst carrier honeycomb filter, and a method for manufacturing a honeycomb structure. [Background technology]

[0002] Porous ceramic filters with columnar honeycomb structures, such as diesel particulate filters (DPFs) and gasoline particulate filters (GPFs), are known for removing particulate matter (PM) from exhaust gases emitted from internal combustion engines of automobiles and other vehicles. In order to use such filters continuously for a long period of time, regeneration treatment is necessary to burn and remove the PM accumulated inside the filter. However, during filter regeneration, the heat of PM combustion generates significant thermal stress on the filter, which can cause defects such as cracks in the filter.

[0003] As one measure to prevent such filter defects, attempts are being made to improve impact resistance by forming a segment joint by joining multiple honeycomb segments with a bonding material, thereby dispersing and mitigating the thermal stress generated during filter regeneration.

[0004] For example, Patent Document 1 describes a honeycomb structure in which multiple honeycomb segments are joined with a bonding material having a ratio of shear strength σ to compressive Young's modulus E (σ / E) of 5 to 50. Patent Document 2 describes a honeycomb structure in which multiple honeycomb segments are joined with a bonding material containing colloidal silica and / or colloidal alumina. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-187044 [Patent Document 2] Japanese Patent Publication No. 2005-154202 [Overview of the project] [Problems that the invention aims to solve]

[0006] In response to the increasing demand for larger products in recent years, honeycomb structures have also been enlarged. To ensure the robustness of honeycomb structures in large products, it is necessary to impart functions to the honeycomb structure that alleviate thermal stress during use, and therefore, a low compressive Young's modulus of the bonding material is desirable. One way to lower the compressive Young's modulus is to increase the porosity of the bonding material. However, increasing the porosity of the bonding material reduces the bonding strength, which leads to the problem of cracks being more likely to occur during catalyst coating or firing.

[0007] In view of the above problems, the present invention provides a honeycomb structure, a honeycomb filter, a catalyst carrier honeycomb filter, and a method for manufacturing a honeycomb structure that can suppress the occurrence of cracks during catalyst coating or firing while maintaining a low Young's modulus. [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that by employing a bonding layer having predetermined properties as the bonding layer for joining multiple honeycomb segments, the occurrence of cracks during the firing of the catalyst coating can be suppressed. That is, the present invention is defined as follows.

[0009] [Aspect 1] In one embodiment, the present invention provides a honeycomb structure comprising: a plurality of honeycomb segments having an outer peripheral wall and partition walls disposed inside the outer peripheral wall that partition a plurality of cells which form fluid flow paths extending from an inlet end face to an outlet end face; and a bonding layer that joins the surfaces of the outer peripheral walls of the plurality of honeycomb segments, wherein the bonding layer contains siloxane, has a compressive Young's modulus of 100 MPa or less, a porosity of 68 to 85%, and a bonding strength of 400 to 1700 kPa.

[0010] [Aspect 2] In another embodiment, the present invention provides a honeycomb structure comprising: a plurality of honeycomb segments having an outer peripheral wall and partition walls disposed inside the outer peripheral wall that partition and form a plurality of cells which are fluid flow paths extending from an inlet end face to an outlet end face; and a bonding layer that joins the surfaces of the outer peripheral walls of the plurality of honeycomb segments, wherein the compressive Young's modulus of the bonding layer is 100 MPa or less, and when heated gas mass spectrometry of the bonding layer is performed at a heating rate of 10°C / min, the rate of water generation due to the desorption of OH groups at 200 to 400°C is 1.7 wt ppm / sec or less.

[0011] [Aspect 3] In yet another embodiment, the present invention is a honeycomb structure according to Embodiment 2, wherein the porosity of the bonding layer is 68 to 85%.

[0012] [Aspect 4] In yet another embodiment, the present invention is a honeycomb structure according to Embodiment 2, wherein the bonding strength of the bonding layer is 400 to 1700 kPa.

[0013] [Aspect 5] In yet another embodiment, the present invention is a honeycomb structure according to any of embodiments 1 to 4, wherein the bonding layer contains 15.0 to 35.0 wt% of SiO2.

[0014] [Aspect 6] In yet another embodiment, the present invention is a honeycomb structure according to any one of embodiments 1 to 5, wherein the bonding layer contains 45.0 to 65.0 wt% SiC, 15.0 to 35.0 wt% SiO2, 5.0 to 25.0 wt% Al2O3, and 0 to 3.0 wt% MgO.

[0015] [Aspect 7] In yet another embodiment, the present invention is a honeycomb structure according to any one of embodiments 1 to 6, further comprising an outer periphery coating layer disposed to surround the outermost periphery surface of a plurality of honeycomb segments joined via a bonding layer.

[0016] [Aspect 8] In yet another embodiment, the present invention is a honeycomb filter comprising the honeycomb structure according to any one of aspects 1 to 7.

[0017] [Aspect 9] In yet another embodiment, the present invention is a catalyst-carrying honeycomb filter, wherein a catalyst is carried on the honeycomb filter according to aspect 8.

[0018] [Aspect 10] In yet another embodiment, the present invention is a method for manufacturing a honeycomb structure, comprising: preparing a plurality of honeycomb segments each having an outer peripheral wall and partition walls disposed inside the outer peripheral wall, the partition walls defining and forming a plurality of cells serving as fluid flow paths extending from an inflow end face to an outflow end face; applying a bonding material containing amorphous particles including Si to outer peripheral walls of the plurality of honeycomb segments, and performing heat treatment at 200°C or lower to form a bonding layer that bonds surfaces of the outer peripheral walls of the plurality of honeycomb segments to each other, this being a first heat treatment step; and applying an outer peripheral coating material so as to surround the outermost peripheral surface of the plurality of honeycomb segments bonded via the bonding layer, and performing heat treatment at 350°C or higher and lower than 700°C, this being a second heat treatment step. Effects of the Invention

[0019] According to the present invention, there can be provided a honeycomb structure, a honeycomb filter, a catalyst-carrying honeycomb filter, and a method for manufacturing a honeycomb structure, which are capable of suppressing the occurrence of cracks during catalyst coating calcination while maintaining a low Young's modulus. Brief Description of the Drawings

[0020] [Figure 1] It is a perspective view showing a honeycomb structure according to an embodiment of the present invention. [Figure 2] It is a perspective view showing a honeycomb segment according to an embodiment of the present invention. [Figure 3] It is a perspective view showing a honeycomb segment provided with plugging portions. [Figure 4]This graph shows the water vapor generation rate when the bonding layer of a honeycomb structure is heated and the resulting gas is mass-spectrometrically at a heating rate of 10°C / min. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments shown below are illustrative examples of devices and methods for realizing the technical concept of this invention, and the technical concept of this invention is not limited to the structure, arrangement, etc., of the components described below.

[0022] <Honeycomb structure> Figure 1 is a perspective view showing a honeycomb structure 1 according to an embodiment of the present invention, and Figure 2 is a perspective view showing honeycomb segments 10 constituting the honeycomb structure 1. The honeycomb structure 1 according to an embodiment of the present invention comprises a plurality of honeycomb segments 10 having an outer peripheral wall 103 and partition walls 101 disposed inside the outer peripheral wall 103 that partition a plurality of cells 100 which form fluid flow paths extending from an inlet end face 14 to an outlet end face 15, and a joining layer 11 that joins the surfaces of the outer peripheral wall 103 of the plurality of honeycomb segments 10 together.

[0023] The external shape of the honeycomb structure 1 is not particularly limited, but the cross-section perpendicular to the direction in which the cells 100 extend may be cylindrical, oval, or a columnar shape with polygons (quadrilateral, pentagon, hexagon, heptagon, octagon, etc.). Figure 1 shows an example of a honeycomb structure 1 in which the cross-section perpendicular to the direction in which the cells 100 extend is circular.

[0024] The diameter of the end face of the honeycomb structure 1 can be set appropriately according to the application and required performance. If the diameter of the end face of the honeycomb structure 1 is too large, the manufacturing difficulty increases, so the diameter of the end face is preferably 30 to 600 mm, and more preferably 50 to 500 mm. Note that the diameter of the end face of the honeycomb structure 1 refers to the diameter if the outer shape is circular, and to the equivalent diameter if the outer shape is not circular. If the end face of the honeycomb structure 1 is square, the length of one side of the inlet end face 14 and the outlet end face 15 is preferably 35 to 500 mm, and more preferably 100 to 200 mm.

[0025] As shown in Figure 2, the honeycomb segment 10 has a plurality of cells 100 and a porous partition wall 101 and an outer peripheral wall 103 that divide the plurality of cells 100, which form a fluid flow path extending from the inlet end face 14 to the outlet end face 15. In addition, as shown in Figure 3, a blind seal 104 may be formed on the cell 100 to exhibit a complementary checkerboard pattern at the inlet end face 14 and the outlet end face 15. By forming the blind seal 104 on the cell 100 to exhibit a complementary checkerboard pattern at the inlet end face 14 and the outlet end face 15, the exhaust gas flows in from the cell 100 where the blind seal 104 is not formed on the inlet end face 14, passes through the porous partition wall 101 at least once, and is discharged from the cell 100 where the blind seal 104 is not formed on the outlet end face 15. PM contained in the exhaust gas is removed when it passes through the porous partition wall 101. To minimize the difference in thermal expansion coefficient between the eye seal 104 and the honeycomb segment 10, the same material as the honeycomb segment 10 can be used for the eye seal 104.

[0026] The surfaces of the outer walls 103 of multiple honeycomb segments 10 are joined to each other via a bonding layer 11. By joining multiple honeycomb segments 10 via the bonding layer 11, thermal stress is relieved, and the occurrence of cracks that may occur when exposed to rapid temperature changes or localized heat generation of exhaust gas, resulting in an uneven temperature distribution inside, can be suppressed.

[0027] The number of honeycomb segments 10 is not particularly limited, but for example, it is preferable to have 4 to 100 honeycomb segments in the honeycomb structure 1, and may also be 9 to 81 or 16 to 64. Of the multiple honeycomb segments 10 constituting the honeycomb structure 1, the proportion of honeycomb segments 10 having a rectangular parallelepiped shape can be, for example, 0 to 60%, typically 10 to 55%, and more typically 25 to 50%.

[0028] The material of the honeycomb segment 10 is not particularly limited, but porous ceramics can be used. Examples of ceramics include cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide, silicon-silicon carbide composites (e.g., Si-bonded SiC), cordierite-silicon carbide composites, zirconia, spinel, indialite, sapphirin, corundum, titania, and silicon nitride. These ceramics may be contained individually or in combination of two or more. Other materials for the honeycomb segment 10 include porous sintered metals containing alloy components mainly composed of one or more elements selected from the group consisting of Fe, Cr, Mo, and Ni.

[0029] Among porous ceramics, silicon-silicon carbide composites are suitable for filter applications due to their excellent heat resistance, thermal shock resistance, and oxidation resistance. Silicon-silicon carbide composites contain silicon carbide particles as aggregate and silicon as a binder to hold the silicon carbide particles together. Preferably, in this silicon-silicon carbide composite, multiple silicon carbide particles are bound together by silicon in such a way that pores are formed between the silicon carbide particles.

[0030] Furthermore, when the material of the honeycomb segment 10 is mainly composed of a carbon-silicon carbide composite material, it is preferable that the carbon-silicon carbide composite material be present in an amount of 70% by mass or more of the total, more preferably 75% by mass or more, and even more preferably 80% by mass or more. The blending ratio of silicon and silicon carbide in the honeycomb segment 10, the type of firing aid and its blending ratio can be appropriately adjusted according to the required dimensions and application.

[0031] The porosity of the honeycomb segment 10 is not particularly limited, but is preferably 70% or less, more preferably 65% ​​or less, and even more preferably 60% or less. If the porosity of the honeycomb segment 10 is too high, the required strength and thermal conductivity may not be obtained. The porosity of the honeycomb segment 10 is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. In one embodiment, the porosity of the honeycomb segment 10 is preferably 30 to 70%, more preferably 35 to 65%, and even more preferably 40 to 60%.

[0032] The porosity of the honeycomb segment 10 is given as the average value obtained when multiple samples of the partition walls 101 constituting the honeycomb segment 10 are taken without bias from the honeycomb segment 10 and the porosity of each sample is measured by the mercury intrusion method. Specifically, the porosity is given as the total pore volume (unit: cm) measured by the mercury intrusion method (in accordance with JIS R 1655:2003). 3 It is calculated as ( / g).

[0033] The thickness of the partition wall 101 of the honeycomb segment 10 is not particularly limited, but is preferably 0.1 mm to 0.5 mm. By making the thickness of the partition wall 101 preferably 0.1 mm or more, more preferably 0.2 mm or more, the strength of the honeycomb segment 10 can be ensured. Furthermore, by making the thickness of the partition wall 101 preferably 0.5 mm or less, more preferably 0.4 mm or less, the pressure loss when exhaust gas is passed through the honeycomb segment 10 can be kept low. Note that the thickness of the partition wall 101 refers to the length over which a line segment connecting the centroids of adjacent cells 100 in a cross section perpendicular to the direction in which the cell 100 extends crosses the partition wall 101, and refers to the average value of the thickness of all partition walls 101 in each honeycomb segment 10 constituting the honeycomb structure 1.

[0034] The shape of the cell 100 is not particularly limited, but in a cross section perpendicular to the direction in which the cell 100 extends, it may have any shape such as a triangle, square, pentagon, hexagon, octagon, or other polygon, a circle, or an ellipse, or it may be irregular in shape. By providing cells 100 of such shape, the pressure loss when air flows can be reduced. Figure 2 shows an example of a honeycomb segment 10 in which the shape of the cell 100 is square in a cross section perpendicular to the direction in which the cell 100 extends.

[0035] The cell density of the honeycomb segment 10 is not particularly limited, but is 15 to 77 cells / cm². 2 It is preferable to set the range to 20-62 cells / cm². 2 It is more preferable to set the range to 23-54 cells / cm². 2 It is even more preferable to set it within this range. The cell density is the value obtained by dividing the number of cells 100 in the honeycomb segment 10 in a cross section perpendicular to the direction in which the cells 100 extend.

[0036] The thickness of the outer periphery wall 103 of the honeycomb segment 10 is not particularly limited, but from the viewpoint of ensuring strength, it can be, for example, 0.1 mm to 0.7 mm, and preferably 0.3 mm to 0.6 mm. The thickness of the outer periphery wall 103 refers to the average value obtained when the thickness of multiple locations on the outer periphery wall 103 is measured without bias in a cross section perpendicular to the direction in which the cell 100 extends.

[0037] The bonding layer 11 is interposed in a layered manner between the outer peripheral walls 103 of adjacent honeycomb segments 10. In order to suppress the occurrence of cracks during catalyst coating or firing and to improve impact resistance, the compressive Young's modulus of the bonding layer 11 must be 100 MPa or less. Preferably, the compressive Young's modulus of the bonding layer 11 is 80 MPa or less, more preferably 60 MPa or less, and even more preferably 50 MPa or less. If the compressive Young's modulus of the bonding layer 11 is too low, cracks may occur in the bonding portion of the bonding layer 11 that joins the honeycomb segments 10 together during catalyst coating or firing. Preferably, the compressive Young's modulus of the bonding layer 11 is 5 MPa or more, more preferably 20 MPa or more, and even more preferably 25 MPa or more. That is, in one embodiment, the compressive Young's modulus of the bonding layer 11 is preferably 5 to 100 MPa, more preferably 5 to 80 MPa, even more preferably 25 to 60 MPa, and even more preferably 25 to 50 MPa.

[0038] The compressive Young's modulus of the bonding layer 11 is calculated as follows: A test specimen of predetermined dimensions (planar dimensions 10mm × 10mm to 30mm × 30mm, thickness 0.5 to 3mm) including the bonding layer 11 is cut from the honeycomb structure 1, and a compression test is performed in the Z-axis direction. Here, "Z-axis direction" refers to the direction perpendicular to the bonding surface of the bonding layer 11. In this test, a part of the honeycomb segment 10 may be attached to the test specimen. Then, the slope of the stress-strain curve when a load of 0 to 3 MPa is applied to the sample in the Z-axis direction is calculated as the compressive Young's modulus using the following formula (1).

[0039] E = (W / S) × (t / Δt) ... (1) E: Compression Young's modulus (MPa) W: Load (N) S: Specimen area (mm²) 2 ) t: Test specimen thickness (mm) Δt: Change in specimen thickness

[0040] The bonding layer 11 is porous, and as its porosity increases, its compressive Young's modulus tends to decrease, and as its porosity decreases, its compressive Young's modulus tends to increase. From the viewpoint of maintaining a sufficiently low compressive Young's modulus of the bonding layer 11 and ensuring the necessary bonding strength even for large product applications, the porosity of the bonding layer 11 is set to 85% or less. Preferably, the porosity of the bonding layer 11 is 80% or less, more preferably 77% or less, and even more preferably 75% or less. Also, the porosity of the bonding layer 11 is 68% or more, preferably 70% or more, more preferably 71% or more, and even more preferably 72% or more. In one embodiment, the porosity of the bonding layer 11 is 68-85%, preferably 70-80%, more preferably 71-77%, and even more preferably 72-75%.

[0041] The porosity of the bonding layer 11 refers to the value calculated by taking multiple samples of the bonding layer 11 without bias from a filter and using the mercury intrusion method (in accordance with JIS R1655:2003) or the Archimedes method in water. Here, porosity refers to the porosity before the catalyst is supported on the honeycomb segment 10.

[0042] The bonding strength (shear strength) of the bonding layer 11 is 400 to 1700 kPa, preferably 500 to 1600 kPa, more preferably 1000 to 1500 kPa, even more preferably 1100 to 1500 kPa, and even more preferably 1200 to 1400 kPa. If the bonding strength of the bonding layer 11 is within the above range, it is possible to ensure the adhesive strength of the honeycomb structure 1 required for various applications such as DPF and GPF while easing stress and suppressing the occurrence of cracks during catalyst coating or firing.

[0043] In this specification, the bonding strength of the bonding layer 11 is calculated as follows. First, a sample is cut from the honeycomb structure 1 in which two honeycomb segments 10 are bonded together. Next, a shear load is applied to the bonding layer 11 of this sample in the Y-axis direction (the direction in which the cell 100 extends). Then, the shear strength is calculated using the following formula (1) with respect to the fracture load and the area of ​​the bonding layer 11.

[0044] σ = (W / S) × 1000 ... (2) σ: Shear strength (kPa) W: Breaking load (N) S: Area of ​​the bonding layer (mm²) 2 )

[0045] The thickness of the bonding layer 11 (length in the direction perpendicular to the bonding surface of the honeycomb segment 10) is not particularly limited, but can be appropriately selected within the range of 0.5 to 3.0 mm, for example. The thickness of the bonding layer 11 can be 0.8 mm to 2.0 mm, and 1.0 mm to 1.5 mm is preferred. The thickness of the outer peripheral wall 103 refers to the average value obtained when the thickness of multiple locations on the outer peripheral wall 103 is measured without bias in a cross section perpendicular to the direction in which the cell 100 extends.

[0046] The bonding layer 11 contains siloxane. By containing siloxane in the bonding layer 11, the strength of the bonding layer 11 can be improved by siloxane bonding, thereby suppressing the occurrence of cracks in the bonding layer 11 due to catalyst coating or heat treatment during firing, and the occurrence of cracks in the bonding layer 11 due to thermal stress during use. In one embodiment, the bonding layer 11 preferably contains 15.0 to 35.0 wt% of SiO2. In a further embodiment, the bonding layer 11 preferably contains 45.0 to 65.0 wt% of SiC, 15.0 to 35.0 wt% of SiO2, 5.0 to 25.0 wt% of Al2O3, and 0 to 3.0 wt% of MgO.

[0047] The amount of SiO2 is preferably 16.0 to 25.0 wt%, more preferably 17.0 to 23.0 wt%, and even more preferably 18.0 to 22.0 wt%. The amount of SiC is preferably 53.0 to 63.0 wt%, more preferably 54.0 to 62.0 wt%, and even more preferably 56.0 to 60.0 wt%. The amount of Al2O3 is preferably 17.0 to 24.0 wt%, more preferably 18.0 to 23.0 wt%, and even more preferably 19.0 to 22.0 wt%. The amount of MgO is preferably 0 to 2.8 wt%, more preferably 0.5 to 2.5 wt%, and even more preferably 1.0 to 2.0 wt%.

[0048] The SiC, SiO2, Al2O3, and MgO content in the bonding layer 11 is calculated as follows. First, the bonding layer 11 is cut from the honeycomb structure 1 and pulverized into a powder to prepare an observation sample. The total Si content: A (wt%), total Al content: B (wt%), and total Mg content: C (wt%) of the observation sample are measured using the X-ray fluorescence method. The total C content: D (wt%) of the observation sample is measured using the resistance heating infrared absorption method.

[0049] When the SiC content is F (wt%), the Al2O3 content is G (wt%), the MgO content is H (wt%), and the SiO2 content is I (wt%), F, G, H, and I are calculated using the following formula. F = D × 40 / 12 ... (3) G = B × 10² / 54 ... (4) H = C × 40 / 24 ... (5) I = (A / 28 - F / 40) × 60 ... (6) After calculating the content F, G, H, and I of SiC, Al2O3, MgO, and SiO2 according to equations (3) to (6), calculate the ratio of each component according to the following equation so that the total amount of these components is 100%. F'={F / (F+G+H+I)}×100 ···(7) G'={G / (F+G+H+I)}×100 ···(8) H'={H / (F+G+H+I)}×100 ···(9) I'={I / (F+G+H+I)}×100 ···(10) Analysis using X-ray fluorescence is performed using a simultaneous X-ray fluorescence analyzer for multiple elements (manufactured by Rigaku Corporation) with a tube voltage of 50kV and a current of 70mA. Analysis using resistance heating infrared absorption spectroscopy is calculated according to the method conforming to JIS R 1616 "Chemical analysis method for silicon carbide fine powder for fine ceramics".

[0050] When the bonding layer 11 of the honeycomb structure 1 according to an embodiment of the present invention was subjected to thermal generated gas mass spectrometry (TPD / MS) to evaluate the rate of moisture generation, it was found that it exhibits a characteristic trend in the 200-400°C range. Specifically, in the bonding layer 11 according to this embodiment, the compressive Young's modulus of the bonding layer 11 is 100 MPa or less, and in thermal generated gas mass spectrometry of the bonding layer 11, when performed under the condition of a heating rate of 10°C / min, the rate of moisture generation due to the detachment of OH groups in the 200-400°C range is 1.7 wt ppm / sec or less.

[0051] More typically, the rate of water generation due to the elimination of OH groups at 200-400°C is 1.5 wtppm / sec or less, even more typically, it is 1.4 wtppm / sec or less, and even more typically, it is 1.3 wtppm / sec or less. The lower limit of the rate of water generation is typically 0.9 wtppm / sec or more, and more typically, 1.0 wtppm / sec or more.

[0052] The rate of water generation due to the detachment of OH groups at 200-400°C is calculated as follows. First, the bonding layer 11 cut from the honeycomb structure 1 is crushed into a powder, which is used as the measurement sample. This measurement sample is then measured using thermal generated gas mass spectrometry (TPD-MS). TPD-MS is a method in which a mass spectrometer (MS) (manufactured by Shimadzu Corporation) is directly connected to a special heating device with a temperature controller, and the concentration change of the gas generated from the heated sample for each mass number is tracked as a function of temperature or time according to a predetermined heating program. In this measurement, after setting the measurement sample in the electric furnace of the thermal generated gas mass spectrometer, a carrier gas (He) is flowed for 15 minutes or more. Then, under atmospheric pressure and a He atmosphere, the water generation rate curve is obtained when the measurement sample is heated from room temperature to 100°C at a heating rate of 10°C / min, and from this, the water generation rate [wtppm / sec] due to the detachment of OH groups at 200-400°C is calculated.

[0053] As shown in Figure 1, it is preferable for the honeycomb structure 1 to have an outer peripheral coating layer 12 on its outer peripheral surface 13, which is arranged to surround the outermost surface of a plurality of honeycomb segments 10 joined via a bonding layer 11, in order to improve mechanical strength.

[0054] The outer periphery coating layer 12 is formed to have a predetermined thickness so as to surround the outer periphery of the multiple honeycomb segments 10. This outer periphery coating layer 12 can be formed by applying a slurry-like outer periphery coating material, which is composed of a ceramic material, to the outer periphery surface of the honeycomb segments 10. The outer periphery coating layer 12 is formed after the honeycomb segments 10 are joined together.

[0055] The material of the outer periphery coating layer 12 is not particularly limited, but is usually made of a ceramic material. For example, cordierite, silicon carbide, or titanium oxide can be used as materials for the outer periphery coating layer 12. It is preferable to use the same material for the outer periphery coating layer 12 as the main component of the material constituting the honeycomb segment 10, as this reduces the difference in thermal expansion coefficients between the honeycomb segment 10 and the outer periphery coating layer 12. In addition to the ceramic material mentioned above, the outer periphery coating layer 12 may also include a binder, dispersion medium, additives, etc.

[0056] The thickness of the outer periphery coating layer 12 is not particularly limited, but by setting it to 0.1 to 3.0 mm, improvements in thermal shock resistance and other properties can be achieved. The thickness of the outer periphery coating layer 12 is preferably, for example, 0.15 to 2.5 mm, and more preferably 0.2 to 2.0 mm. The thickness of the outer periphery coating layer 12 refers to the length in the normal direction from the boundary between the partition wall 101 of the outermost cell 100 and the outer periphery coating layer 12 to the outer surface 13 of the honeycomb structure 1, in a cross section perpendicular to the direction in which the cell 100 extends.

[0057] The porosity of the outer coating layer 12 is not particularly limited, but is preferably 30-60%, more preferably 35-55%, and even more preferably 40-50%. The porosity is measured by the total pore volume (unit: cm³) measured by the mercury intrusion method (in accordance with JIS R 1655:2003). 3 It is calculated as ( / g).

[0058] (Honeycomb filters and catalyst carrier honeycomb filters) The honeycomb structure 1 according to an embodiment of the present invention can be used, for example, as a honeycomb filter such as a DPF and GPF that collects soot and is installed in the exhaust gas line from a combustion device, typically an engine mounted in a vehicle. The honeycomb filter can be installed, for example, inside an exhaust pipe. A buffer mat can be interposed between the inner surface of the exhaust pipe and the honeycomb filter to hold the honeycomb filter inside the exhaust pipe.

[0059] This honeycomb filter may be loaded with a suitable catalyst in accordance with the application. Exemplary methods for loading a catalyst onto the filter include: introducing a catalyst slurry into cells by a conventionally known suction method or the like, allowing the catalyst slurry to adhere to the surfaces of partition walls and pores, then performing high-temperature treatment to bake the catalyst contained in the catalyst slurry onto the partition walls.

[0060] Examples of the catalyst include, but are not limited to: diesel oxidation catalysts (DOC) for oxidatively combusting hydrocarbons (HC) and carbon monoxide (CO) to raise exhaust gas temperature, PM combustion catalysts that assist the combustion of PM such as soot, nitrogen oxide (NO x )) SCR catalysts and NSR catalysts for removing x, and three-way catalysts capable of simultaneously removing hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NO x )x). The catalyst may appropriately contain, for example, noble metals (Pt, Pd, Rh, etc.), alkali metals (Li, Na, K, Cs, etc.), alkaline earth metals (Ca, Ba, Sr, etc.), rare earths (Ce, Sm, Gd, Nd, Y, La, Pr, etc.), transition metals (Mn, Fe, Co, Ni, Cu, Zn, Zr, Sc, Ti, V, Cr, etc.) and the like.

[0061] In particular, for DPFs for passenger vehicles, in order to provide both soot collection and NO x x purification functions at the same time, SCR catalysts such as Cu-substituted zeolite and Fe-substituted zeolite are loaded on the DPF. In this case, NO x x purification can be performed using ammonia obtained by decomposing urea on-board the vehicle.

[0062] (Method for Manufacturing Honeycomb Structure) A method for manufacturing a honeycomb structure 1 according to an embodiment of the present invention includes: a step (step 1) of first preparing a plurality of honeycomb segments 10 having an outer peripheral wall 103 and partition walls 101 disposed inside the outer peripheral wall 103 that partition a plurality of cells 100 which form fluid flow paths extending from an inlet end face 14 to an outlet end face 15; a first heat treatment step (step 2) of applying a bonding material containing amorphous particles containing Si to the outer peripheral walls 103 of the plurality of honeycomb segments 10 and heat-treating it at 200°C or less to form a bonding layer 11 that bonds the surfaces of the outer peripheral walls 103 of the plurality of honeycomb segments 10; and a second heat treatment step (step 3) of applying an outer peripheral coating material so as to surround the outer peripheral walls 103 of the plurality of honeycomb segments 10 that have been bonded via the bonding layer 11 and heat-treating it at 350°C or more and less than 700°C.

[0063] In step 1, multiple honeycomb segments 10 are prepared as shown in Figure 2. The honeycomb segments 10 can be manufactured in accordance with known methods for manufacturing honeycomb structures.

[0064] First, a raw material composition containing ceramic raw materials, a dispersion medium, a pore-forming material, and a binder is kneaded to prepare a clay body. Then, the clay body is extruded and dried to produce a honeycomb molded body. Additives such as dispersants can be added to the raw material composition as needed. When extruding, a die having the desired overall shape, cell shape, partition wall thickness, cell density, etc., can be used.

[0065] In the drying process, conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze-drying can be used. Among these, a drying method combining hot air drying with microwave drying or dielectric drying is preferred because it can dry the entire molded body quickly and uniformly. The eye seals 104 can be formed by forming them at predetermined positions on the inlet end face 14 and outlet end face 15 of the dried honeycomb molded body and then drying the eye seals 104.

[0066] Examples of ceramic raw materials include cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide, silicon-silicon carbide composites (e.g., Si-bonded SiC), cordierite-silicon carbide composites, zirconia, spinel, indialite, sapphirin, corundum, titania, and silicon nitride. Specifically, though not limited to these, examples include silicon carbide, silicon, silica, talc, alumina, kaolin, serpentine, pyroferrite, brucite, boehmite, mullite, magnesite, and aluminum hydroxide. In addition, silicon oxide, strontium oxide, and aluminum oxide added as firing aids are also types of ceramic raw materials. Ceramic raw materials may be used individually or in combination of two or more types.

[0067] Examples of dispersion media include water, or a mixed solvent of water and an organic solvent such as alcohol, but water is particularly suitable. The pore-forming material is not particularly limited as long as it becomes porous after firing, and examples include wheat flour, starch, foamed resin, superabsorbent resin, silica gel, carbon (e.g., graphite, coke), ceramic balloons, polyethylene, polystyrene, polypropylene, nylon, polyester, acrylic, phenol, etc. The pore-forming material may be used alone or in combination of two or more types.

[0068] Examples of binders include organic binders such as methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, and polyvinyl alcohol. In particular, the combined use of methylcellulose and hydroxypropylmethylcellulose is preferred. The binder may be used alone or in combination of two or more types.

[0069] Dispersants that can be used include ethylene glycol, dextrin, fatty acid soap, and polyether polyol. The dispersant may be used individually or in combination of two or more types.

[0070] The honeycomb segment 10 is manufactured by performing a degreasing process and a firing process on the dried honeycomb molded body. The conditions for the degreasing process and the firing process can be those known, depending on the material composition of the honeycomb molded body.

[0071] In step 2, a bonding material containing amorphous particles including Si is applied to the outer periphery walls 103 of the multiple honeycomb segments 10, and the surfaces of the outer periphery walls 103 of the multiple honeycomb segments 10 are bonded together via the bonding material. The multiple honeycomb segments 10 bonded together via this bonding material are bonded together by heat treatment at 200°C or below, forming a bonding layer 11 between the multiple honeycomb segments 10.

[0072] As bonding materials containing amorphous particles including Si, for example, anisotropic inorganic powder, aggregate, and materials prepared by mixing amorphous particles containing Si with a dispersion medium such as water can be used.

[0073] As the anisotropic inorganic powder, natural minerals or artificial ceramic fibers may be used. Suitable natural minerals include needle-shaped or plate-shaped natural minerals such as volastonite, mica, talc, sepiolite, palygoskite, and attapulgite. Suitable artificial ceramic fibers include RCF (amorphous refractory ceramic fiber mainly composed of alumina and silica), alumina fiber, mullite fiber, carbon fiber, silicon carbide fiber, boron nitride fiber, potassium titanate fiber, and zinc oxide fiber. The anisotropic inorganic powder may be used alone or in combination of two or more types.

[0074] Examples of aggregates include ceramics such as cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide, silicon-silicon carbide composites (e.g., Si-bonded SiC), cordierite-silicon carbide composites, zirconia, spinel, indialite, sapphirin, corundum, titania, and silicon nitride. Among these, silicon-silicon carbide composites are preferably used as the bonding material.

[0075] Preferred amorphous particles containing Si include, for example, silicone oil, silicone varnish, silicate alkoxy oligomer, colloidal silica, colloidal alumina, or mixtures thereof. Among these, colloidal silica is preferred as the bonding material.

[0076] Either an inorganic binder or an organic binder may be used as the bonding material. Examples of organic binders include methylcellulose, hydroxypropoxylmethylcellulose, carboxymethylcellulose, polyvinyl alcohol, and methylcellulose. Examples of inorganic binders include clay minerals such as bentonite, montmorillonite, sepiolite, and attapulgite. One type of binder may be used, or two or more types may be used in combination.

[0077] The bonding material preferably contains 0.1 to 15 wt% of a pore-forming agent as an external compounding component, when the total content of the main component of the bonding material is 100 wt%. The pore-forming agent can be the same as that used in the manufacture of honeycomb molded bodies. The pore-forming agent content is more preferably 1 to 10 wt%, even more preferably 2 to 9 wt%, and even more preferably 5 to 8 wt%. The porosity of the bonding layer 11 can be controlled by appropriately controlling the pore-forming agent content.

[0078] If the solid content concentration of the bonding material is too low, the joint width will be thin, while if it is too high, the joint width will be thick. For this reason, the solid content concentration of the bonding material is preferably 50-90 wt%, more preferably 60-80 wt%, and even more preferably 65-75 wt%.

[0079] There are no particular restrictions on the method of applying the bonding material; for example, spraying, applying with a brush or similar, or dipping can be used. When applying the bonding material to the outer periphery wall 103 of the honeycomb segment 10, it is preferable to apply masking tape of a predetermined size to prevent the bonding material from adhering to the inlet end face 14 and outlet end face 15 of the honeycomb segment 10.

[0080] The bonding material applied to the outer peripheral wall 103 of the honeycomb segment 10 is heat-treated at a temperature that does not substantially cause firing, specifically at a temperature of 200°C or lower. According to this step 2, the bonding layer 11 is formed by drying the bonding material at a predetermined temperature or lower without substantially causing firing. Therefore, according to this step 2, it is possible to suppress the occurrence of bonding defects such as cracks in the bonding layer 11 or delamination of the bonding layer 11 itself due to differences in thermal expansion and contraction rates between the bonding layer 11 and the honeycomb segment 10.

[0081] From the viewpoint of more effectively suppressing the occurrence of bonding defects, the heat treatment temperature of the bonding material is more preferably 150°C or lower, and even more preferably 110°C or lower. There is no particular limit to the lower limit of the drying temperature, but considering the time required to dry the bonding material, it is generally acceptable to have a temperature of 50°C or higher. It is also preferable to perform natural drying for 10 hours or more (10-50°C) followed by hot air drying for about 2 hours (100-200°C).

[0082] In step 3, the outer periphery of the segment joint, formed by joining multiple honeycomb segments 10 in the above procedure, is ground to a desired shape (for example, cylindrical), an outer periphery coating material is applied to surround the outer periphery walls 103 of the multiple honeycomb segments 10, and then dried and heat-treated at 350°C to less than 700°C to form an outer periphery coating layer 12 and obtain a honeycomb structure 1.

[0083] Examples of outer coating materials include those prepared by mixing inorganic raw materials such as inorganic fibers, colloidal silica, clay, and ceramic particles with additives such as organic binders, foaming resins, and dispersants, along with water, to form a slurry. Furthermore, the application method for the outer coating material is not particularly limited, and known methods can be used.

[0084] The drying and heat treatment of the outer periphery coating layer 12 is preferably performed at a temperature of, for example, 350°C or higher and less than 700°C, more preferably 370 to 650°C, and even more preferably 400 to 600°C. The drying and heat treatment of the outer periphery coating layer 12 can be performed by heating in an air atmosphere for 0.5 to 3 hours, preferably 0.5 to 1 hour. This heat treatment at 350°C or higher and less than 700°C causes the OH groups that have been hydrogen-bonded between the silanol groups of the bonding layer 11 to detach, forming siloxane bonds. This imparts bonding strength and is effective in improving the ability to coat large products with catalysts and suppressing cracks caused by thermal stress during automotive use. On the other hand, if the heat treatment temperature in step 3 is too high, the strength will improve, but the sintering of the bonding layer 11 may proceed too much, and the desired properties may not be obtained. According to this embodiment, a honeycomb structure 1 can be obtained that can suppress the occurrence of cracks during catalyst coating or firing while maintaining a low Young's modulus. If the outer periphery coating layer 12 is not formed, the bonding layer 11 of the honeycomb structure 1 can be adjusted to desired properties by performing a heat treatment on the segment joint, to which the honeycomb segments 10 are joined, at a temperature of 350°C or higher and less than 700°C.

[0085] The honeycomb structure 1 is supported with a catalyst appropriate to the application. An example of a method for supporting the catalyst on the honeycomb structure 1 is to introduce a catalyst slurry into the cell by a conventionally known suction method or the like, allow it to adhere to the surface and pores of the partition walls, and then, for example, calcinate it at 400-600°C to bake the catalyst contained in the catalyst slurry onto the partition walls. [Examples]

[0086] Examples and comparative examples of the present invention are described below, but the technical scope of the present invention is not intended to be limited by these examples.

[0087] SiC powder and metallic Si powder were mixed in a mass ratio of SiC powder:metallic Si powder = 80:20. A pore-forming agent, organic binder, surfactant, and water were added to this mixture to obtain a plastic clay. This clay was extruded through a predetermined die and dried to produce a columnar honeycomb molded body. This honeycomb molded body was degreased in an air atmosphere at approximately 400°C and fired in an Ar atmosphere at approximately 1450°C to bond the SiC particles in the molded body with Si. The result was a porosity of 41%, a side length of 36 mm at the inlet and outlet ends, a partition wall thickness of 260 μm, an outer wall thickness of 0.6 mm, and a cell density of 47 cells / cm². 2 Multiple honeycomb segments with a length of 177.8 mm were fabricated.

[0088] SiC powder, alumina fiber, colloidal silica, and cordierite powder were mixed in proportions of 55 wt%, 15 wt%, 22 wt%, and 8 wt%, respectively. An organic binder (carboxymethylcellulose), an inorganic binder (bentonite), a pore-forming agent (foamed resin), and water were added to this mixture, and the mixture was kneaded with a mixer for 30 minutes to prepare a bonding material (solid content concentration 75 wt%) for coating the outer wall of honeycomb segments. The bonding materials of Examples 1 to 4 were prepared so that, when the total content of the main components (SiC powder, alumina fiber, colloidal silica) is taken as 100%, the content of the pore-forming agent as an external compound was in the range of 3 to 8 mass% relative to the main components (see Table 1). The bonding material of Comparative Example 1 consisted of SiC powder and colloidal silica as the main components (69 mass% SiC powder, 31 mass% colloidal silica) without the addition of alumina fiber, and no pore-forming agent was added. The bonding materials for Comparative Examples 2-5 were prepared with the same main components as in Examples 1-4, with a pore-forming agent content in the range of 0-9% by mass.

[0089] The bonding materials of Examples 1-4 and Comparative Examples 1-5 were applied to the outer periphery walls of honeycomb segments, and another honeycomb segment prepared using the same procedure as above was placed on top. This process was repeated to produce a total of 16 segment joints, each consisting of 4x4 combinations. These segment joints were then dried at 140°C for 2 hours to create segment joints with bonding layers between the honeycomb segments. The outer periphery of these segment joints was ground to create a cylindrical shape, and then the outer periphery coating material was applied to the ground surface to form an outer periphery coating layer. The joints were then dried and cured in an atmospheric environment at the heat treatment temperature (maximum temperature) shown in Table 1 to produce a honeycomb structure (143.8 mmφ × 177.8 mmL). The thickness of the bonding layer of the obtained honeycomb structure was 1.0 mm, and the thickness of the outer periphery coating layer was 0.1 mm.

[0090] (Compression Young's modulus, porosity, bonding strength, moisture generation rate, chemical composition) The compression Young's modulus, porosity, bonding strength, and moisture generation rate due to OH group detachment at 200-400°C of the bonding layers of the honeycomb filters in Examples 1-4 and Comparative Examples 1-5 were measured using the measurement method described above. Furthermore, the chemical composition of the bonding layer obtained in Example 1 was chemically analyzed based on the method using equations (3) to (10) described above, and it was found to be 58.0 wt% SiC, 20.5 wt% Al2O3, 20.0 wt% SiO2, and 1.5 wt% MgO.

[0091] (Ring crack initiation temperature) The method for measuring the ring crack initiation temperature is as follows. First, exhaust gas from the gas burner was introduced into the honeycomb filters of Examples 1-4 and Comparative Examples 1-5, which were mounted on a gas burner, at a flow rate of 2500 ± 500 l / min. The mass of the honeycomb filter was measured at regular intervals, and PM was deposited while calculating the amount of PM. After a predetermined amount of PM had accumulated on the honeycomb filter, the flammable gas was increased while the exhaust gas flow rate was set to 2500 ± 500 l / min, and combustion gas containing a certain percentage of oxygen at 600°C was introduced into the honeycomb filter. After a certain period of time with an exhaust gas flow rate of 350 ± 50 l / min, the flammable gas was stopped to burn and remove the PM. At that time, the highest temperature on the honeycomb filter outlet side and the presence or absence of ring cracks were checked. The presence or absence of ring cracks was determined by identifying cracks extending radially in the honeycomb filter as ring cracks in the CT images obtained by an X-ray computed tomography (CT) scanner. The highest temperature at which ring cracks were observed on the surface of the honeycomb filter during PM combustion removal treatment, when the amount of PM accumulation was gradually increased, was defined as the ring crack initiation temperature.

[0092] (Crack resistance and evaluation during firing) Samples of honeycomb filters from Examples 1-4 and Comparative Examples 1-5, coated with a catalyst, were heated in an electric furnace at a set temperature of 400°C for 2 hours to achieve a uniform temperature. Afterward, each sample was removed from the electric furnace and rapidly cooled at room temperature. Following rapid cooling, the crack initiation temperature of each sample was evaluated by visually observing the crack initiation while measuring the sample temperature. Samples with a crack initiation temperature of 450°C or higher were classified as "A," those between 350°C and 450°C as "B," and those below 350°C as "C." Furthermore, for the honeycomb filters of Examples 1-4 and Comparative Examples 1-5, filters with a compressive Young's modulus of 100 MPa or less, a ring crack initiation temperature of 1200°C or higher, and a crack initiation temperature during calcination of 450°C or higher were evaluated as "◎", filters with a compressive Young's modulus of 100 MPa or less, a ring crack initiation temperature of 1200°C or higher, and a crack initiation temperature during calcination of 350°C or higher were evaluated as "〇", and filters that did not meet the requirements of "◎" and "〇" were evaluated as "×". The results are shown in Table 1.

[0093] [Table 1]

[0094] (Water generation rate curve) A filter from Example 1, a filter from Comparative Example 1 that did not contain alumina fiber as a raw material for the bonding layer, a filter from Comparative Example 2 in which the outer periphery coating layer was formed at a heat treatment temperature of 400°C on a segment bond body dried at room temperature, and a filter from Comparative Example 3 in which the outer periphery coating layer was formed at a heat treatment temperature of 120°C on a segment bond body prepared in the same manner as in Example 1. Samples containing the bonding layer were cut from these filters and powdered to be used as the measurement sample. The measurement sample was placed in the electric furnace of a heating-generated gas mass spectrometer, and the measurement sample was heated from room temperature to 1000°C at a heating rate of 10°C / min under atmospheric pressure and a He atmosphere using the TPD-MS method described above. The moisture generation rate curve at this time was obtained. The results are shown in Figure 4.

[0095] In Examples 1 to 4, where the bonding material was dried at 140°C and the heat treatment temperature of the outer coating layer was in the range of 350°C to less than 700°C, there was almost no generation of moisture due to the desorption of OH groups between 200 and 400°C, with a generation rate of 1.7 wtppm / sec or less. On the other hand, Comparative Example 1 showed almost no generation of moisture due to the desorption of OH groups between 200 and 400°C, which is thought to be because amorphous particles (siloxane) containing Si were not used in the bonding material. In Comparative Example 2, where the heat treatment temperature of the outer coating layer was 400°C, but the bonding layer of the honeycomb segment bond was formed by drying the bonding layer at room temperature before the heat treatment of the outer coating layer, a peak was observed around 300°C, with a generation rate of 1.9 wtppm / sec. Comparative Example 3, in which the segmented joint was not subjected to heat treatment between 350°C and 700°C, showed the generation of moisture due to OH desorption at 200-400°C, with a generation rate of 4.0 wtppm / sec.

[0096] From the above results, it can be seen that, according to Examples 1 to 4, a siloxane-containing bonding layer with a low compressive Young's modulus of 100 MPa or less, a porosity of 45 to 80%, and a bonding strength of 400 to 1700 MPa is obtained. When gas gravimetric analysis of the bonding layer is performed at a heating rate of 10°C / min, the rate of moisture generation due to the desorption of OH groups at 200 to 400°C is small. As shown in Table 1, the honeycomb structures of Examples 1 to 4, which have a low rate of moisture generation, have a higher temperature at which ring cracks occur (1200°C or higher) compared to the honeycomb structures of Comparative Examples 1 to 5, demonstrating durability in high-temperature processing, and the crack resistance evaluation results during catalyst coating or firing are also good. In other words, the honeycomb structure according to this example maintains a low Young's modulus while having durability in high-temperature processing, making it possible to suppress the occurrence of cracks during catalyst coating or firing. [Explanation of Symbols]

[0097] 1: Honeycomb structure 10: Honeycomb segment 11: Bonding layer 12: Outer coating layer 13: Outer surface 14:Inflow end face 15:Outflow end face 100: Cell 101: Bulkhead 103:Outer wall 104: Eye sealing

Claims

1. A plurality of honeycomb segments having an outer periphery wall and partition walls disposed inside the outer periphery wall, which divide and form a plurality of cells that serve as fluid flow paths extending from the inlet end face to the outlet end face, A bonding layer that joins the surfaces of the outer walls of the plurality of honeycomb segments, A honeycomb structure comprising, The aforementioned bonding layer is a honeycomb structure containing siloxane, having a compressive Young's modulus of 100 MPa or less, a porosity of 68-85%, a bonding strength of 400-1700 kPa, and containing 15.0-35.0 wt% SiO2.

2. A plurality of honeycomb segments having an outer periphery wall and partition walls disposed inside the outer periphery wall, which divide and form a plurality of cells that serve as fluid flow paths extending from the inlet end face to the outlet end face, A bonding layer that joins the surfaces of the outer walls of the plurality of honeycomb segments, A honeycomb structure comprising, A honeycomb structure in which the compressive Young's modulus of the bonding layer is 100 MPa or less, and when heating-generated gas mass spectrometry of the bonding layer is performed at a heating rate of 10°C / min, the rate of water generation due to the elimination of OH groups at 200 to 400°C is 1.7 wt ppm / sec or less.

3. The honeycomb structure according to claim 2, wherein the porosity of the bonding layer is 68 to 85%.

4. The honeycomb structure according to claim 2, wherein the bonding strength of the bonding layer is 400 to 1700 kPa.

5. The aforementioned bonding layer contains 45.0 to 65.0 wt% SiC and SiO 2 15.0-35.0 wt%, Al 2 O 3 A honeycomb structure according to any one of claims 1 to 3, containing 5.0 to 25.0 wt% of and 0 to 3.0 wt% of MgO.

6. The honeycomb structure according to any one of claims 1 to 3, further comprising an outer periphery coating layer disposed so as to surround the outermost periphery surface of the plurality of honeycomb segments joined via the bonding layer.

7. A honeycomb filter comprising the honeycomb structure described in any one of claims 1 to 3.

8. A catalyst carrier honeycomb filter in which a catalyst is supported on the honeycomb filter according to claim 7.

9. A step of preparing a plurality of honeycomb segments, each having an outer periphery wall and a partition wall disposed inside the outer periphery wall, which divides a plurality of cells that form fluid flow paths extending from the inlet end face to the outlet end face. A first heat treatment step involves applying a bonding material containing amorphous particles containing Si to the outer periphery walls of the plurality of honeycomb segments, and heat-treating it at 200°C or below to form a bonding layer that bonds the surfaces of the outer periphery walls of the plurality of honeycomb segments together. A second heat treatment step involves applying an outer peripheral coating material to surround the outermost surface of the plurality of honeycomb segments joined via the bonding layer, and heat-treating it at a temperature of 350°C or higher but less than 700°C. A method for manufacturing a honeycomb structure containing [a specific component].

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