Coated honeycomb structure and method of making same

Abstract

The present application provides a coated honeycomb structure to which a coating capable of contributing to suppression of peeling of a functional material-containing layer is applied. The coated honeycomb structure is provided with: an outer peripheral wall; a partition wall provided on an inner peripheral side of the outer peripheral wall and dividing a plurality of cells extending from a first end face to a second end face, the plurality of cells forming flow paths; a functional material-containing layer covering the partition wall; a first coating layer covering a partition wall portion constituting the first end face and a cell inner partition wall portion in the vicinity of the first end face in the partition wall and penetrating into the inside of these partition wall portions; and a second coating layer covering a partition wall portion constituting the second end face and a cell inner partition wall portion in the vicinity of the second end face in the partition wall and penetrating into the inside of these partition wall portions.

Description

Technical Field

[0001] This invention relates to coated honeycomb structures. Additionally, this invention relates to coated honeycomb structures. Background Technology

[0002] Previously, a honeycomb structure was known, which had an outer peripheral wall and a partition wall. The partition wall was disposed on the inner peripheral side of the outer peripheral wall and divided into multiple compartments extending from a first end face to a second end face, and the multiple compartments formed flow paths. In the honeycomb structure, various functions were imparted by forming a functional material layer containing functional materials such as a waste gas purification catalyst, a carbon dioxide (CO2) adsorbent, and a moisture-absorbing material on the surface of the partition wall.

[0003] Sometimes, a coating is further applied to the honeycomb structure having such a functional material layer. Patent Document 1 discloses a honeycomb catalyst for exhaust gas purification, which consists of a honeycomb catalyst carrier comprising porous cordierite ceramic and a catalyst layer disposed on the surface of the honeycomb catalyst carrier. The characteristic feature is that at least a portion of the inlet-side opening end face and the adjacent end face of the honeycomb catalyst carrier is composed of a surface layer (coating) smoother than the catalyst layer. Patent Document 1 discloses that the surface layer is formed by coating a vitreous material, and the length of the surface layer is within 30 mm axially measured from the opening end face of the honeycomb catalyst carrier. Furthermore, it discloses that this structure makes the area near the inlet-side opening end face smooth, thereby preventing the accumulation of recovered black smoke particles and clogging of the opening.

[0004] According to Patent Document 1, a honeycomb catalyst for exhaust gas purification can be manufactured by the following method: a material that forms a low-expansion glass after firing is coated on the open end face and the adjacent end of a honeycomb catalyst carrier containing porous cordierite ceramic, and the material is impregnated and formed into a smooth surface layer by baking. Subsequently, active alumina and catalyst metal are coated on the portion outside the surface layer to form a catalyst layer.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 4-293550 Summary of the Invention

[0008] One existing problem with honeycomb structures containing functional material layers is that these layers peel off and detach from the partition surfaces. For example, if a moisture-absorbing material layer, which is the functional material layer, is formed on the partition surface, repeated cycles of moisture absorption and release will eventually cause cracks in the moisture-absorbing material layer due to its expansion and contraction. Furthermore, if the cracks continue to propagate, the moisture-absorbing material layer will eventually peel off and detach from the partition surface.

[0009] Applying a coating to a honeycomb structure is considered an effective method to prevent the functional material layer from peeling off. Therefore, forming a surface layer of a glassy material, as described in Patent Document 1, is considered, for example. However, in Patent Document 1, to form a surface layer (coating) in the honeycomb structure, the glass is baked to impregnate it. Baking impregnation involves a process with temperatures exceeding 100°C, and some functional materials are prone to performance degradation under such high temperatures. Therefore, it is desirable to develop a technology that can form a coating without exceeding 100°C.

[0010] The present invention was made in view of the above circumstances. In one embodiment, the objective is to provide a coated honeycomb structure having a coating that helps to suppress the shedding of the functional material layer. Furthermore, in another embodiment, the objective is to provide a method for manufacturing such a coated honeycomb structure.

[0011] The inventors of this invention conducted in-depth research to solve the above-mentioned problems, and thus completed the invention as shown below.

[0012] [Option 1]

[0013] A coated honeycomb structure, comprising:

[0014] outer perimeter wall;

[0015] A partition wall is disposed on the inner circumferential side of the outer peripheral wall and divides into multiple compartments extending from the first end face to the second end face, the multiple compartments forming a flow path;

[0016] A functional material layer covers the partition wall;

[0017] A first coating covers the partition wall portion forming the first end face and the internal partition wall portion near the first end face, and penetrates into the interior of these partition wall portions; and

[0018] The second coating covers the partition wall portion forming the second end face and the internal partition wall portion near the second end face, and penetrates into the interior of these partition wall portions.

[0019] [Option 2]

[0020] According to the coated honeycomb structure described in Scheme 1, wherein...

[0021] The functional material layer covers the partition portion forming the first end face, the internal partition portion of the compartment from the first end face to the second end face, and the partition portion forming the second end face.

[0022] [Option 3]

[0023] According to the coated honeycomb structure described in scheme 1 or 2, wherein,

[0024] The first coating penetrates into the interior of the functional material layer covering the portion of the functional material layer that forms the partition wall portion of the first end face and the portion of the functional material layer that covers the internal partition wall portion near the first end face.

[0025] The second coating penetrates into the interior of the functional material layer covering the portion of the functional material layer that forms the partition wall portion of the second end face, and the portion of the functional material layer covering the internal partition wall portion of the compartment near the second end face.

[0026] [Option 4]

[0027] According to any one of Schemes 1 to 3, the coated honeycomb structure wherein...

[0028] The first coating covering the inner wall portion of the compartment near the first end face extends from the first end face along the length of the compartment with an average coverage length of 300 μm or more and is 0.2% to 2.5% of the length of the honeycomb structure.

[0029] The second coating covering the inner wall portion of the compartment near the second end face extends from the second end face along the length of the compartment with an average coverage length of more than 300 μm and is 0.2% to 2.5% of the length of the honeycomb structure.

[0030] [Option 5]

[0031] According to Scheme 3 or Scheme 4, which is subordinate to Scheme 3, the coated honeycomb structure wherein,

[0032] The average thickness of the first coating, which penetrates into the interior of the functional material layer covering the partition wall near the first end face, is 0–80 μm based on the surface of the functional material layer.

[0033] The average thickness of the second coating, which penetrates into the interior of the functional material layer in the partition wall portion near the second end face, is 0–80 μm based on the surface of the functional material layer.

[0034] [Option 6]

[0035] According to any one of schemes 1 to 5, the coated honeycomb structure wherein...

[0036] At least one of the first coating and the second coating contains an adhesive resin.

[0037] [Option 7]

[0038] According to the coated honeycomb structure described in Scheme 6, wherein...

[0039] At least one of the first coating and the second coating contains epoxy resin.

[0040] [Option 8]

[0041] According to any one of schemes 1 to 7, the coated honeycomb structure wherein...

[0042] The average penetration depth of the first coating into the interior of the partition portion constituting the first end face is 100 μm to 200 μm.

[0043] The average penetration depth of the second coating, which penetrates into the interior of the partition portion constituting the second end face, is 100 μm to 200 μm.

[0044] [Option 9]

[0045] A method for manufacturing a coated honeycomb structure, comprising:

[0046] Step A: Prepare a honeycomb structure, which has an outer peripheral wall, a partition wall disposed on the inner peripheral side of the outer peripheral wall and dividing it into multiple compartments extending from a first end face to a second end face, and a functional material layer covering the partition wall, wherein the multiple compartments form a flow path.

[0047] Step B involves allowing a first coating liquid containing adhesive resin to penetrate into the partition wall portion forming the first end face and the interior of the partition wall portion within the partition wall near the first end face.

[0048] Step C involves allowing a second coating liquid containing an adhesive resin to penetrate into the interior of the partition wall portion forming the second end face and the interior of the partition wall portion within the compartment near the second end face; and

[0049] Step D, following steps B and C, involves heating the first and second coating liquids.

[0050] [Option 10]

[0051] According to the manufacturing method of the coated honeycomb structure described in Scheme 9, wherein...

[0052] Process D is carried out in an atmosphere below 100°C.

[0053] [Option 11]

[0054] According to the manufacturing method of the coated honeycomb structure described in Scheme 9 or 10, wherein...

[0055] The adhesive resin is a curable resin.

[0056] [Option 12]

[0057] The manufacturing method of the coated honeycomb structure according to any one of Schemes 9 to 11, wherein...

[0058] The viscosities of the first and second coating liquids at 25°C, measured using a single cylindrical rotary viscometer according to JIS Z8803:2011, are 500 mP·s to 20000 mP·s.

[0059] Invention Effects

[0060] One embodiment of the present invention relates to a coated honeycomb structure that can help suppress the shedding of the functional material layer, and thus helps to extend the service life of the honeycomb structure having the functional material layer. Attached Figure Description

[0061] Figure 1 This is a schematic perspective view of a coated honeycomb structure according to one embodiment of the present invention.

[0062] Figure 2-1 This is a schematic diagram of a cross-section of a coated honeycomb structure according to an embodiment of the present invention, parallel to the direction in which the compartments extend.

[0063] Figure 2-2 yes Figure 2-1 A magnified view of the area enclosed by the thick frame.

[0064] Figure 3 This is a cross-section of a coated honeycomb structure according to one embodiment of the present invention, orthogonal to the direction of compartment extension. Figure 2-1 A schematic diagram of the XX-line cross section.

[0065] Figure 4 This is a schematic diagram of a cross-section of a coated honeycomb structure parallel to the direction of compartment extension according to another embodiment of the present invention.

[0066] Figure 5 This is a schematic diagram illustrating the mechanism by which a coating inhibits the shedding of a functional material layer covering a partition.

[0067] Figure 6 It is a graph showing the results of simulations to determine the relationship between the coating thickness and the rate of pressure drop increase. Detailed Implementation

[0068] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. The present invention is not limited to the following embodiments. It should be understood that solutions obtained by appropriately modifying or improving the following embodiments based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also included within the scope of the present invention.

[0069] (1. Coated honeycomb structure)

[0070] The coated honeycomb structure according to embodiments of the present invention can be embedded in cabin air purification systems of various vehicles, such as automobiles. The vehicle is not particularly limited, and examples include automobiles and electric vehicles. The automobile is not particularly limited, and examples include gasoline vehicles, diesel vehicles, gas-fueled vehicles using CNG (compressed natural gas), LNG (liquefied natural gas), fuel cell vehicles, electric vehicles, and plug-in hybrid electric vehicles. Furthermore, it can also be applied to systems for absorbing carbon dioxide from the atmosphere.

[0071] like Figures 1-4 As shown, the coated honeycomb structure 100 according to the embodiment of the present invention includes an outer peripheral wall 11 and a partition wall 14. The partition wall 14 is disposed on the inner peripheral side of the outer peripheral wall 11 and divides into a plurality of compartments 13 extending parallel from a first end face 12a to a second end face 12b, the plurality of compartments 13 forming flow paths. In addition, the coated honeycomb structure 100 also includes a functional material layer 20 covering the partition wall 14. Additionally, the coated honeycomb structure 100 may have a first coating 15 and a second coating 16. The first coating 15 covers the partition portion 140a constituting the first end face 12a and the inner partition portion 141a near the first end face in the partition 14, and penetrates into the interior of these partition portions 140a and 141a. The second coating 16 covers the partition portion 140b constituting the second end face 12b and the inner partition portion 141b near the second end face in the partition 14, and penetrates into the interior of these partition portions 140b and 141b.

[0072] The following is a detailed description of each component of the coated honeycomb structure 100.

[0073] (1-1. Honeycomb structure)

[0074] Here, the portion of the coated honeycomb structure 100 excluding the functional material layer 20, the first coating 15, and the second coating 16 (and including the third and fourth coatings described later) is referred to as the "honeycomb structure". The shape of the honeycomb structure is not particularly limited. For example, the shape of the cross-section orthogonal to the direction extending from the compartment 13 can be polygonal (quadrilateral (rectangle, square), pentagonal, hexagonal, heptagonal, octagonal, etc.) or has rounded shapes (circular, elliptical, oval, elliptical, oblong, rounded rectangle, etc.). Figure 3 The embodiment shown is square. It should be noted that the shapes of the end faces (first end face 12a and second end face 12b) are the same as the cross-section. Furthermore, if the cross-section and end faces are polygonal, the corners can be chamfered.

[0075] The shape of compartment 13 is not particularly limited. A cross-section orthogonal to the direction in which compartment 13 extends can be polygonal (quadrilateral (rectangle, square), pentagonal, hexagonal, heptagonal, octagonal, etc.) or with rounded curves (circular, elliptical, oval, elliptical, oblong, rounded rectangle, etc.). These shapes can be singular or a combination of two or more. Furthermore, quadrilaterals or hexagons are preferred among these shapes. Figure 3 The embodiment shown is square. By providing a compartment 13 of the above shape, pressure loss during airflow can be reduced.

[0076] The honeycomb structure can be provided in the form of a honeycomb joint, which is obtained by preparing multiple honeycomb cells, each having a honeycomb structure, and joining the outer peripheral surfaces of the multiple honeycomb cells together with the aid of a bonding layer. By using a honeycomb joint, the total cross-sectional area of ​​the compartment 13, which is crucial for ensuring airflow, can be increased while suppressing crack formation.

[0077] It should be noted that the bonding layer can be formed using a bonding material. There are no particular limitations on the bonding material; a paste made by adding a solvent such as water to ceramic raw materials can be used. The bonding material may contain a material with PTC (Positive Temperature Coefficient) properties, or it may contain the same material as the outer peripheral wall 11 and the partition wall 14. In addition to its function of bonding the cell units to each other, the bonding material can also be used as a coating material for the outer periphery after the cell units are bonded.

[0078] In this specification, the thickness of partition 14 refers to the length of a line segment passing through partition 14 when the centroids of adjacent compartments 13 are connected by a line segment in a cross section orthogonal to the direction in which the compartments 13 extend. The thickness of partition 14 is the average of the thicknesses of all partitions 14.

[0079] In this specification, the cell density refers to the value obtained by dividing the number of cells on one end face of the honeycomb structure by the area of ​​that end face (the total area of ​​the partition wall 14 and the cell 13 excluding the outer peripheral wall 11).

[0080] In this specification, the compartment opening ratio refers to the value obtained by dividing the total area of ​​the compartments 13 formed by the partition walls 14 in a cross section orthogonal to the direction in which the compartments 13 extend by the area of ​​one end face (the total area of ​​the partition walls 14 and the compartments 13 excluding the outer peripheral wall 11). It should be noted that the compartment opening ratio is calculated for a honeycomb structure and does not consider the functional material layer 20, the first coating layer 15, and the second coating layer 16 (third coating layer, fourth coating layer).

[0081] From the viewpoint of ensuring the load-bearing capacity of functional materials, the upper limit of the thickness of the partition is preferably 0.500 mm or less, more preferably 0.200 mm or less, and even more preferably 0.150 mm or less. Furthermore, from the viewpoint of ensuring the strength of the honeycomb structure, the lower limit of the thickness of the partition is preferably 0.010 mm or more, more preferably 0.020 mm or more, and even more preferably 0.030 mm or more. Therefore, the thickness of the partition is preferably, for example, 0.010 to 0.500 mm, more preferably 0.020 to 0.200 mm, and even more preferably 0.030 to 0.150 mm.

[0082] From the perspectives of suppressing increased pressure loss and ensuring the load-bearing capacity of functional materials, the upper limit of compartment density is preferably 100 compartments / cm³. 2 The following is more preferably 70 compartments / cm 2 The following is a further preferred value: 65 compartments / cm 2 From the perspective of ensuring the strength of the substrate, the lower limit of the compartment density is preferably 10 compartments / cm². 2 Therefore, the compartment density is preferably, for example, 10 to 100 compartments / cm². 2 More preferably, it is 10 to 70 compartments / cm². 2 More preferably, it is 10–65 compartments / cm². 2 .

[0083] From the viewpoint of ensuring the strength of the substrate, the upper limit of the compartment opening ratio is preferably 0.94 or less, more preferably 0.92 or less, and even more preferably 0.90 or less. Furthermore, from the viewpoint of suppressing pressure loss to a low level, the lower limit of the compartment opening ratio is preferably 0.80 or more, more preferably 0.83 or more, and even more preferably 0.85 or more. Therefore, the compartment opening ratio is preferably, for example, 0.80 to 0.94, more preferably 0.83 to 0.92, and even more preferably 0.85 to 0.90.

[0084] From the viewpoints of ensuring the strength of the honeycomb structure, reducing pressure loss when gas passes through the compartments, ensuring the load-bearing capacity of functional materials, and ensuring the contact area with the gas flowing in the compartments, it is preferable to appropriately combine the thickness of the partition wall 14, the compartment density, and the compartment opening ratio. Therefore, in a preferred embodiment, for example, the thickness of the partition wall is 0.010 to 0.500 mm, and the compartment density is 10 to 100 compartments / cm³. 2 The opening ratio of the compartments is 0.80 to 0.94.

[0085] The thickness of the outer peripheral wall 11 is not particularly limited, but it is preferably determined based on the following viewpoints. First, from the viewpoint of strengthening the honeycomb structure, the thickness of the outer peripheral wall 11 is preferably 0.05 mm or more, more preferably 0.06 mm or more, and even more preferably 0.08 mm or more.

[0086] In this specification, the thickness of the outer peripheral wall 11 refers to the length along the normal direction of the side surface of the honeycomb structure from the boundary between the outer peripheral wall 11 and the outermost peripheral compartment 13 or partition wall 14 in a cross section orthogonal to the direction in which the compartment 13 extends.

[0087] The length of the honeycomb structure in the direction of extension of compartment 13 and the cross-sectional area orthogonal to the direction of extension of compartment 13 can be adjusted according to the required dimensions of the coated honeycomb structure 100, and there are no particular limitations. For example, in the honeycomb structure, the length in the direction of extension of compartment 13 can be set to 20-350 mm, and the cross-sectional area orthogonal to the flow path direction can be set to 12.25-625 cm². 2 There are no particular restrictions on the relationship between the length of the honeycomb structure in the direction of cell extension and the maximum diameter of each end face (which refers to the maximum length of the diameter passing through the centroid of each end face of the honeycomb structure). Therefore, the length of the honeycomb structure in the direction of cell extension can be greater than the maximum diameter of each end face, or the length of the honeycomb structure in the direction of cell extension can be less than the maximum diameter of each end face.

[0088] The materials used for the partitions 14 and the outer peripheral walls 11 constituting the honeycomb structure are not particularly limited; for example, ceramics can be used. In one embodiment, the partitions 14 and the outer peripheral walls 11 contain one or more of the following materials: cordierite, silicon carbide, silicon-silicon carbide composite material, silicon nitride, mullite, alumina, aluminum titanate, and barium titanate (BaTiO3).

[0089] (1-2. Including functional material layers)

[0090] The functional material layer 20 is configured to cover the partition 14 of the honeycomb structure. For example, the functional material layer 20 may be configured to cover the partition portion (internal partition portion) 141 inside the compartment 13, or it may be configured to cover the partition portion 140a constituting the first end face 12a, or it may be configured to cover the partition portion 140b constituting the second end face 12b. In a preferred embodiment, the functional material layer 20 covers the partition portion 140a constituting the first end face 12a, the partition portion (internal partition portion) 141 inside the compartment 13 from the first end face 12a to the second end face 12b, and the partition portion 140b constituting the second end face 12b.

[0091] Additionally, the functional material layer 20 can be configured to cover the outer peripheral wall portion 111 inside the compartment 13, or it can be configured to cover the outer peripheral wall portion 110a constituting the first end face 12a, or it can be configured to cover the outer peripheral wall portion 110b constituting the second end face 12b. In a preferred embodiment, the functional material layer 20 covers the outer peripheral wall portion 111 inside the compartment 13, the outer peripheral wall portion 110a constituting the first end face 12a, and the outer peripheral wall portion 110b constituting the second end face 12b.

[0092] Therefore, in one embodiment, the functional material layer 20 covers the partition wall portion (inner partition wall portion) 141 inside the compartment 13, the partition wall portion 140a constituting the first end face 12a, the partition wall portion 140b constituting the second end face 12b, and the outer peripheral wall portion 111 inside the compartment 13, the outer peripheral wall portion 110a constituting the first end face 12a, and the outer peripheral wall portion 110b constituting the second end face 12b (see [link]). Figure 2-1 ).

[0093] In another embodiment, such as Figure 4 As shown, the functional material layer 20 covers the partition wall portion (inner partition wall portion) 141 inside the compartment 13 and the outer peripheral wall portion 111 inside the compartment 13, but does not cover the partition wall portion 140a constituting the first end face 12a, the partition wall portion 140b constituting the second end face 12b, the outer peripheral wall portion 110a constituting the first end face 12a, and the outer peripheral wall portion 110b constituting the second end face 12b.

[0094] The functional material contained in the functional material layer 20 is not particularly limited as long as it can perform the required function; for example, adsorbent materials, catalysts, etc., can be used. The adsorbent material preferably has the function of adsorbing one or more components to be removed from the air, such as water vapor, carbon dioxide, and odor components. Furthermore, it is also preferable to have the function of adsorbing harmful volatile components. In addition, the components to be removed can be purified by using a catalyst. Furthermore, for the purpose of improving the adsorbent material's ability to capture components to be removed, the adsorbent material and the catalyst can be used in combination.

[0095] The adsorbent material preferably possesses the ability to adsorb components to be removed, such as water vapor, carbon dioxide, and harmful volatile components (e.g., aldehydes, odor components, etc.), at temperatures ranging from -20 to 40°C, and to release them at temperatures above 60°C. Examples of adsorbent materials with this function include zeolite, silica gel, activated carbon, alumina, silica, low-crystallinity clay, and amorphous aluminosilicate composites. The type of adsorbent material can be appropriately selected based on the type of component to be removed. One type of adsorbent material can be used alone, or two or more can be used in combination.

[0096] As a catalyst, it is preferable to have the function of promoting redox reactions. Examples of catalysts with this function include metal catalysts such as Pt, Pd, and Ag, and oxide catalysts such as CeO2 and ZrO2. A single catalyst can be used, or two or more catalysts can be used in combination.

[0097] Harmful volatile components in the air, such as those found in train carriages, include volatile organic compounds (VOCs) and odor components. Specific examples of harmful volatile components include: ammonia, acetic acid, isovaleric acid, nonenal, formaldehyde, toluene, xylene, p-dichlorobenzene, ethylbenzene, styrene, chlorpyrifos, di-n-butyl phthalate, tetradecane, di(2-ethylhexyl) phthalate, diazinon, acetaldehyde, and N-methylcarbamate-2-(1-methylpropyl)phenyl ester.

[0098] The average thickness of the functional material layer 20 can be determined based on the size of the compartment 13 and is not particularly limited. For example, from the viewpoint of ensuring sufficient contact with the gas, the average thickness of the functional material layer 20 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of suppressing the peeling of the functional material layer 20 from the partition wall 14 or the outer peripheral wall 11, the average thickness of the functional material layer 20 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less. Therefore, the average thickness of the functional material layer 20 is preferably, for example, 20 to 400 μm, more preferably 25 to 380 μm, and even more preferably 30 to 350 μm.

[0099] The average thickness of the functional material layer 20 was measured according to the following steps. Cutting Figure 2-1 The image shown is an arbitrary cross-section of the honeycomb structure, extending along the direction of compartment 13, with the central axis O passing through it and parallel to the direction of compartment 13. A cross-sectional image at approximately 50x magnification was obtained using a scanning electron microscope or similar instrument. The position of the central axis O is the centroid of the cross-section of the honeycomb structure orthogonal to the direction of compartment 13 (see [reference]). Figure 3 For each functional material layer 20 visible in the cross-sectional image, the average thickness is calculated by dividing the cross-sectional area of ​​the functional material layer 20 present in the region sandwiched between the two ends of the coverage length (the length in the direction extending from the compartment 13, or the length in the direction perpendicular to the direction extending from the compartment 13, depending on the position of the functional material layer) by the coverage length. This calculation is performed comprehensively on all functional material layers 20 visible in the cross-section, and the overall average value is taken as the average thickness of the functional material layers 20 in the entire coated honeycomb structure.

[0100] When the functional material layer 20 is disposed in each of the following portions: the partition wall portion 141 within the compartment, the partition wall portion 140a constituting the first end face 12a, the partition wall portion 140b constituting the second end face 12b, the outer peripheral wall portion 111 inside the compartment 13, the outer peripheral wall portion 110a constituting the first end face 12a, and the outer peripheral wall portion 110b constituting the second end face 12b, the preferred range of the average thickness of the functional material layer 20 in each portion is the same as the average thickness of the functional material layer 20 in the entire coated honeycomb structure described above. Furthermore, the average thickness of the functional material layer 20 in these portions can also be measured using the same steps described above.

[0101] From the viewpoint that the functional material performs its required function, the amount of the functional material layer 20 is preferably 50 to 500 g / L relative to the volume of the coated honeycomb structure 100, more preferably 100 to 400 g / L, and even more preferably 150 to 350 g / L. It should be noted that the volume of the honeycomb structure is a value determined by the external dimensions of the honeycomb structure.

[0102] (1-3. Coating)

[0103] In one embodiment, the coated honeycomb structure 100 includes a first coating 15 and a second coating 16. The first coating 15 covers the partition portion 140a constituting the first end face 12a and the inner partition portion 141a near the first end face of the partition 14 and penetrates into the interior of these partition portions 140a and 141a. The second coating 16 covers the partition portion 140b constituting the second end face 12b and the inner partition portion 141b near the second end face of the partition 14 and penetrates into the interior of these partition portions 140b and 141b.

[0104] By having a first coating 15 and a second coating 16, the shedding of the functional material layer 20 covering the partition wall 14 can be suppressed. This invention is not intended to be theoretically limited; however, the mechanism by which the shedding of the functional material layer 20 covering the partition wall 14 can be hypothesized as follows: With the first coating 15 and the second coating 16 provided, even if the functional material layer 20 peels off from the partition wall 14, it is not easily detached from the compartment 13 because the first coating 15 and the second coating 16 act as a stop (see...). Figure 5(1)). Even if the first coating 15 and the second coating 16 do not penetrate into the interior of the functional material layer 20, the above-mentioned effect can still be obtained, but the effect is better when the first coating 15 and the second coating 16 penetrate into the interior of the functional material layer 20, so it is preferred. When the first coating 15 and the second coating 16 penetrate into the interior of the functional material layer 20, in the first stage, the coating inhibits the peeling of the functional material layer 20, and further, in the second stage, even if the functional material layer 20 has peeled off, since the first coating 15 and the second coating 16 can act as a stop, the effect of inhibiting peeling is also greater (see Figure 5 (2)).

[0105] Furthermore, the same applies when the functional material layer 20 is configured to cover the partition portion 140a constituting the first end face 12a. In the first stage, the coating inhibits the peeling of the functional material layer 20. In the second stage, even if the functional material layer 20 has peeled off, the first coating 15 and the second coating 16 act as a stop, thus preventing further peeling (see...). Figure 5 (2)).

[0106] Therefore, in a preferred embodiment, the first coating 15 penetrates into the interior of the functional material layer 20, covering the portion of the functional material layer 20 that constitutes the partition wall portion 140a of the first end face 12a and the portion of the functional material layer 20 that covers the interior partition wall portion 141a near the first end face. In addition to penetration, the first coating 15 may also cover the portion of the functional material layer 20 that covers the portion of the functional material layer 20 that constitutes the partition wall portion 140a of the first end face 12a and the portion of the functional material layer 20 that covers the interior partition wall portion 141a near the first end face. Furthermore, in a preferred embodiment, the second coating 16 penetrates into the interior of the functional material layer 20, covering the portion of the functional material layer 20 that constitutes the partition wall portion 140b of the second end face 12b and the portion of the functional material layer 20 that covers the interior partition wall portion 141b near the second end face. In addition to penetration, the second coating 16 can also cover the portion of the functional material layer 20 that covers the partition wall portion 140b constituting the second end face 12b, as well as the portion of the functional material layer 20 that covers the partition wall portion 141b in the compartment near the second end face.

[0107] In another embodiment, the coated honeycomb structure 100 includes a third coating 17 and a fourth coating 18. The third coating 17 covers the outer peripheral wall portion 110a constituting the first end face 12a and the outer peripheral wall portion (inner and outer peripheral wall portions of the compartment) 111a inside the compartment 13 near the first end face in the outer peripheral wall 11 and penetrates into the interior of these outer peripheral wall portions 110a and 111a. The fourth coating 18 covers the outer peripheral wall portion 110b constituting the second end face 12b and the outer peripheral wall portion (inner and outer peripheral wall portions of the compartment) 111b inside the compartment 13 near the second end face in the outer peripheral wall 11 and penetrates into the interior of these outer peripheral wall portions 110b and 111b.

[0108] The presence of the third coating 17 and the fourth coating 18 can suppress the shedding of the functional material layer 20 covering the outer peripheral wall 11. The mechanism for suppressing shedding is the same as the mechanism for suppressing the shedding of the functional material layer 20 covering the partition wall 14 described above.

[0109] Here, "near the first end face" refers to a range of coordinate values ​​from 0 to 0.05 × L when a coordinate axis is established with the length L of the compartment 13 extending from the first end face 12a to the second end face 12b of the honeycomb structure, and the coordinate values ​​of the first end face 12a and the second end face 12b are set to L. "Near the second end face" refers to a range of coordinate values ​​from 0.95 × L to L.

[0110] In this specification, the term "A covering B" includes both cases where A partially covers B and cases where A completely covers B. Therefore, for example, the first coating 15 covering the inner partition wall portion 141a near the first end face includes both cases where the first coating 15 partially covers the inner partition wall portion 141a near the first end face and cases where it completely covers the inner partition wall portion 141a near the first end face. Similarly, the concept of the second coating 16 covering the inner partition wall portion 141b near the second end face also includes both cases where the second coating 16 partially covers the inner partition wall portion 141b near the second end face and cases where it completely covers the inner partition wall portion 141b near the second end face.

[0111] [Average coverage length of the coating]

[0112] From the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20 covering the partition wall 14 and ensuring the function of the functional material layer, the average coverage length M1 of the first coating 15 (second coating 16) covering the partition wall portion 141a near the first end face (partition wall portion 141b near the second end face) extending from the first end face 12a (second end face 12b) along the length direction of the partition 13 is preferably 300 μm or more and is 0.2% to 2.5% of the length of the honeycomb structure (the length from the first end face 12a to the second end face 12b). The average coverage length M1 of the first coating 15 (second coating 16) extending from the first end face 12a (second end face 12b) along the length direction of the partition 13 is more preferably 750 to 3000 μm and is 0.5% to 2% of the length of the honeycomb structure. The average coverage length M1 of the first coating 15 (second coating 16) extending from the first end face 12a (second end face 12b) along the length direction of the compartment 13 is further preferably 1000 to 2000 μm and is 1% to 1.5% of the length of the honeycomb structure.

[0113] Similarly, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20 covering the outer peripheral wall 11, the average coverage length M2 of the third coating 17 (fourth coating 18) covering the inner and outer peripheral wall portions 111a (inner and outer peripheral wall portions 111b near the second end face) of the compartment 13 extending from the first end face 12a (second end face 12b) along the length direction of the compartment 13 is preferably 300 μm or more and is 0.2% to 2.5% of the length of the honeycomb structure. The average coverage length M2 of the third coating 17 (fourth coating 18) extending from the first end face 12a (second end face 12b) along the length direction of the compartment 13 is more preferably 750 to 3000 μm and is 0.5% to 2% of the length of the honeycomb structure. The average coverage length M2 of the third coating 17 (fourth coating 18) extending from the first end face 12a (second end face 12b) along the length direction of the compartment 13 is preferably 1000 to 2000 μm and is 1% to 1.5% of the length of the honeycomb structure.

[0114] The average coverage length of each of the first coating 15, second coating 16, third coating 17, and fourth coating 18 is measured according to the following steps. Cut... Figure 2-1 The central axis O, extending from the honeycomb structure along the direction of the cell extension, passes through an arbitrary cross-section parallel to the direction of cell 13 extension. Cross-sectional images at approximately 50x magnification were obtained using scanning electron microscopy or similar methods for the first coating 15, second coating 16, third coating 17, and fourth coating 18. The position of the central axis O is the centroid of the cross-section of the honeycomb structure orthogonal to the direction of cell 13 extension (see [reference]). Figure 3The coverage lengths of the first coating 15, the second coating 16, the third coating 17, and the fourth coating 18 visible in the cross section in the direction of extension of the compartment 13 were fully measured, and their respective average values ​​were calculated.

[0115] Average coating thickness

[0116] The first coating 15 (second coating 16) can penetrate into and cover the portion of the functional material layer 20 that constitutes the partition portion 140a of the first end face 12a (and the partition portion 140b of the second end face 12b). In this case, from the viewpoints of improving the effect of suppressing the shedding of the functional material layer 20 and suppressing the increase of pressure loss, the average thickness T1 of the first coating 15 (second coating 16) covering this portion is preferably 0 to 80 μm, more preferably 0 to 50 μm, and even more preferably 0 to 30 μm, based on the surface of the functional material layer 20 (in the direction of extension of the compartment 13). Here, the average thickness T1 of the first coating 15 (second coating 16) being 0 means that the first coating 15 (second coating 16) has only penetrated and has not yet covered the surface of the functional material layer 20.

[0117] The first coating 15 (second coating 16) can penetrate into and cover the portion of the functional material layer 20 that covers the partition wall portion 141a (partition wall portion 141b near the second end face) of the compartment near the first end face. In this case, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20 and suppressing the increase of pressure loss when gas flows through the compartment 13, the average thickness T2 of the first coating 15 (second coating 16) covering this portion is preferably 0 to 80 μm, more preferably 0 to 50 μm, and even more preferably 0 to 30 μm, based on the surface of the functional material layer 20 (in the direction perpendicular to the direction of extension of the compartment 13). Here, the average thickness T2 of the first coating 15 (second coating 16) being 0 means that the first coating 15 (second coating 16) has only penetrated and has not yet covered the surface of the functional material layer 20.

[0118] The third coating 17 (fourth coating 18) can penetrate into and cover the portion of the functional material layer 20 that constitutes the outer peripheral wall portion 110a of the first end face 12a (and the outer peripheral wall portion 110b of the second end face 12b). In this case, from the viewpoints of improving the effect of suppressing the shedding of the functional material layer 20 and suppressing the increase of pressure loss, the average thickness T3 of the third coating 17 (fourth coating 18) covering this portion is preferably 0 to 80 μm, more preferably 0 to 50 μm, and even more preferably 0 to 30 μm, based on the surface of the functional material layer 20 (in the direction of extension of the compartment 13). Here, the average thickness T3 of the third coating 17 (fourth coating 18) being 0 means that the third coating 17 (fourth coating 18) has only penetrated and has not yet covered the surface of the functional material layer 20.

[0119] The third coating 17 (fourth coating 18) can penetrate into the interior of the portion of the functional material layer 20 covering the inner and outer peripheral wall portion 111a (inner and outer peripheral wall portion 111b near the second end face) of the compartment, and can also cover that portion. In this case, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20 and suppressing the increase of pressure loss when gas flows through the compartment 13, the average thickness T4 of the third coating 17 (fourth coating 18) covering this portion is preferably 0 to 80 μm, more preferably 0 to 50 μm, and even more preferably 0 to 30 μm, based on the surface of the functional material layer 20 (in the direction perpendicular to the direction of extension of the compartment 13). Here, the average thickness T4 of the third coating 17 (fourth coating 18) being 0 means that the third coating 17 (fourth coating 18) has only penetrated and has not yet covered the surface of the functional material layer 20.

[0120] The average thicknesses (T1, T2, T3, T4) of the first coating 15, second coating 16, third coating 17, and fourth coating 18 are measured according to the following steps. Cut... Figure 2-1 The central axis O extending along the flow path of the honeycomb structure is shown as an arbitrary cross-section that passes through and is parallel to the direction in which compartment 13 extends. Cross-sectional images at approximately 50x magnification were obtained using scanning electron microscopy or similar methods for the first coating 15, second coating 16, third coating 17, and fourth coating 18. The position of the central axis O is the centroid of the cross-section of the honeycomb structure orthogonal to the direction in which compartment 13 extends (see [reference]). Figure 3 ).

[0121] When measuring the average thickness T1, for the first coating 15 (second coating 16) visible in this cross-section, the average thickness is calculated by dividing the cross-sectional area of ​​the first coating 15 (second coating 16) present in the region sandwiched between the two ends of the coverage length (the length in the direction perpendicular to the direction of extension of the compartment 13) of the functional material layer 20 that partially covers the partition portion 140a constituting the first end face 12a (the partition portion 140b constituting the second end face 12b). The above calculation is performed comprehensively on all the first coatings 15 (second coatings 16) visible in this cross-section, and the overall average value is taken as the average thickness T1.

[0122] When measuring the average thickness T2, for the first coating 15 (second coating 16) visible in this cross-section, the average thickness is calculated by dividing the cross-sectional area of ​​the first coating 15 (second coating 16) present in the area sandwiched between the two ends of the coverage length (length in the direction of extension of the compartment 13) of the functional material layer 20 covering the portion of the compartment wall portion 141a (partial wall portion 141b near the second end face) near the first end face by the coverage length. The above calculation is performed comprehensively on all the first coatings 15 (second coatings 16) visible in this cross-section, and the overall average value is taken as the average thickness T2.

[0123] The average thicknesses T3 and T4 can also be measured using the same steps described above.

[0124] [Average penetration depth of the coating]

[0125] From the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20, the average value D1 of the penetration depth of the first coating 15 (second coating 16) (in the direction of extension of the compartment 13) into the interior of the partition portion 140a (partition portion 140b) constituting the first end face 12a (second end face 12b) is preferably 100 μm to 200 μm, more preferably 150 μm to 200 μm, and even more preferably 190 μm to 200 μm.

[0126] Similarly, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20, the average value D2 of the penetration depth of the first coating 15 (second coating 16) (in the direction perpendicular to the direction of extension of the compartment 13) into the interior of the compartment wall portion 141a (companies near the second end face) near the first end face is preferably 100 μm to 200 μm, more preferably 150 μm to 200 μm, and even more preferably 190 μm to 200 μm.

[0127] Furthermore, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20, the average value D3 of the penetration depth (in the direction of the extension of the compartment 13) of the third coating 17 (fourth coating 18) that penetrates into the interior of the outer peripheral wall portion 110a constituting the first end face 12a (the outer peripheral wall portion 110b constituting the second end face 12b) is preferably 100 μm to 200 μm, more preferably 150 μm to 200 μm, and even more preferably 190 μm to 200 μm.

[0128] Similarly, from the viewpoint of improving the effect of suppressing the shedding of the functional material layer 20, the average value D4 of the penetration depth of the third coating 17 (fourth coating 18) (in the direction perpendicular to the direction of extension of the compartment 13) into the interior of the inner and outer peripheral wall portion 111a (inner and outer peripheral wall portion 111b near the second end face) is preferably 100 μm to 200 μm, more preferably 150 μm to 200 μm, and even more preferably 190 μm to 200 μm.

[0129] The average penetration depths (D1, D2, D3, D4) of the first coating 15, second coating 16, third coating 17, and fourth coating 18 are measured according to the following steps. Cut... Figure 2-1 The central axis O extending along the flow path of the honeycomb structure is shown as an arbitrary cross-section that passes through and is parallel to the direction in which compartment 13 extends. Cross-sectional images at approximately 50x magnification were obtained using scanning electron microscopy or similar methods for the first coating 15, second coating 16, third coating 17, and fourth coating 18. The position of the central axis O is the centroid of the cross-section of the honeycomb structure orthogonal to the direction in which compartment 13 extends (see [reference]). Figure 3 ).

[0130] When measuring the average penetration depth D1, for the first coating 15 (second coating 16) visible in this cross-section, the average thickness is calculated by dividing the cross-sectional area of ​​the first coating 15 (second coating 16) that penetrates into the interior of the partition wall portion 140a (partition wall portion 140b constituting the second end face 12b) by the coverage length (length in the direction perpendicular to the direction of extension of the compartment 13) of the partition wall portion 140a (partition wall portion 140b). This calculation is performed comprehensively on all the first coatings 15 (second coatings 16) visible in this cross-section, and the overall average value is taken as the average penetration depth D1.

[0131] When measuring the average penetration depth D2, for the first coating 15 (second coating 16) visible in this cross-section, the average thickness is calculated by dividing the cross-sectional area of ​​the first coating 15 (second coating 16) existing in the compartment partition wall portion 141a (second coating wall portion 141b) near the first end face by the coverage length (length in the direction of extension of the compartment 13) between the two ends of the coverage length. This calculation is performed uniformly on the plurality of first coatings 15 (second coatings 16) visible in this cross-section, and the overall average value is taken as the average penetration depth D2.

[0132] The average penetration depths D3 and D4 can also be measured using the same steps described above.

[0133] [Coating Materials]

[0134] From the viewpoint of improving the effect of inhibiting the peeling of the functional material layer 20, at least one, preferably both, of the first coating 15 and the second coating 16 preferably contains an adhesive resin, and more preferably contains a cured resin. Similarly, at least one, preferably both, of the third coating 17 and the fourth coating 18 preferably contains an adhesive resin, and more preferably contains a cured resin.

[0135] In a preferred embodiment, the adhesive resin content of at least one, preferably both, of the first coating 15 and the second coating 16 is preferably 5% by mass or more, more preferably 50% by mass or more. Similarly, the adhesive resin content of at least one, preferably both, of the third coating 17 and the fourth coating 18 is preferably 5% by mass or more, more preferably 50% by mass or more.

[0136] There are no particular limitations on the adhesive resin used; examples include epoxy resin, acrylic resin, phenolic resin, silicone resin, polyvinyl alcohol, and polyvinyl acetal (e.g., polyvinyl butyral). These resins can be used alone or in combination of two or more. From the viewpoint of crack resistance and adhesive strength of the coating, curable resins such as epoxy resin and phenolic resin are preferred as adhesive resins. Curable resins typically exist in the coating in a cured state, i.e., in the form of a cured resin product.

[0137] (2. Coated honeycomb structure)

[0138] The following describes, by way of example, a method for manufacturing a coated honeycomb structure according to an embodiment of the present invention.

[0139] In one embodiment, the method for manufacturing a coated honeycomb structure according to the present invention includes:

[0140] Step A: Prepare a honeycomb structure, which has an outer peripheral wall 11, a partition wall 14 disposed on the inner peripheral side of the outer peripheral wall 11 and dividing it into a plurality of compartments 13 extending from the first end face 12a to the second end face 12b, and a functional material layer 20 covering the partition wall 14, wherein the plurality of compartments 13 form a flow path.

[0141] Step B involves penetrating a first coating liquid containing adhesive resin into the interior of the partition wall portion 140a constituting the first end face 12a and the interior partition wall portion 141a near the first end face in the partition wall 14.

[0142] Step C involves allowing a second coating liquid containing adhesive resin to penetrate into the interior of the partition wall portion 140b constituting the second end face 12b and the interior partition wall portion 141b near the second end face; and

[0143] Step D, following steps B and C, involves heating the first and second coating liquids.

[0144] (2-1. Process A)

[0145] In process A, a honeycomb structure is prepared, which includes an outer peripheral wall 11, partition walls 14 disposed on the inner peripheral side of the outer peripheral wall 11 and dividing it into multiple compartments 13 extending from a first end face 12a to a second end face 12b, and a functional material layer 20 covering the partition walls 14, wherein the multiple compartments 13 form flow paths. Therefore, firstly, a raw material composition containing a pore-forming material, a binder, and a dispersing medium is mixed into a ceramic raw material and kneaded to form a blank, which is then extruded to obtain a honeycomb molded body. If necessary, additives such as dispersants can also be added to the raw material composition. During extrusion molding, a die having the desired overall shape, compartment shape, partition wall thickness, compartment density, etc., can be used.

[0146] Ceramic raw materials are those that remain after firing and serve as the framework for the honeycomb structure of ceramics. Ceramic raw materials can be provided, for example, in powder form. For instance, in the case of cordierite ceramics, cordierite-modified raw materials are used. In this case, cordierite-modified raw materials refer to raw materials that form cordierite after firing. Cordierite-modified raw materials preferably have the following chemical composition: 30-45% by mass of alumina (Al₂O₃) (including the aluminum hydroxide portion converted to alumina), 11-17% by mass of magnesium oxide (MgO), and 42-57% by mass of silicon dioxide (SiO₂).

[0147] As a pore-forming material, any material that forms pores after firing is acceptable and is not particularly limited. Examples include: wheat flour, starch, foaming resin, water-absorbing resin, silica gel, carbon (e.g., graphite), ceramic hollow spheres, polyethylene, polystyrene, polypropylene, nylon, polyester, acrylic resin, phenolic resin, etc. A single pore-forming material can be used, or two or more can be used in combination. From the viewpoint of improving the porosity of the fired honeycomb structure, the content of the pore-forming material relative to 100 parts by mass of ceramic raw material is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. From the viewpoint of ensuring the strength of the fired honeycomb structure, the content of the pore-forming material relative to 100 parts by mass of ceramic raw material is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 4 parts by mass or less.

[0148] Examples of adhesives include organic adhesives such as methylcellulose, hydroxypropoxymethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, and polyvinyl alcohol. Furthermore, from the viewpoint of improving the strength of the honeycomb molded body, the adhesive content is preferably 4 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 6 parts by mass or more, relative to 100 parts by mass of ceramic raw material. From the viewpoint of suppressing cracks caused by abnormal heating during the firing process, the adhesive content is preferably 9 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, relative to 100 parts by mass of ceramic raw material. One type of adhesive can be used alone, or two or more can be used in combination.

[0149] Examples of dispersion media include water, or a mixture of water and organic solvents such as alcohols, with water being particularly preferred.

[0150] Dispersants can be ethylene glycol, dextrin, fatty acid soaps, polyether polyols, etc. A single dispersant can be used, or two or more can be used in combination. The preferred content of the dispersant is 0 to 2 parts by mass relative to 100 parts by mass of ceramic raw material.

[0151] Next, the resulting honeycomb molded body is dried. The drying process can employ existing and known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying. From the viewpoint of being able to dry the entire molded body quickly and uniformly, a drying method combining hot air drying with microwave drying or dielectric drying is preferred.

[0152] Subsequently, a honeycomb structure can be obtained by firing the dried honeycomb molded body. A degreasing process to remove the binder can also be performed before firing. The combustion temperature of the binder is approximately 200°C, and the combustion temperature of the pore-forming material is approximately 300–1000°C. Therefore, the degreasing process can be carried out by heating the honeycomb molded body to a range of approximately 200–1000°C. The heating time is not particularly limited, but is typically approximately 10–100 hours. The firing conditions can be appropriately determined according to the material of the honeycomb molded body. For example, if the honeycomb molded body is mainly composed of cordierite, it can be fired at 1300–1450°C and held for 3–24 hours.

[0153] There are no particular restrictions on the type of furnace used; electric furnaces, gas furnaces, etc., can be used.

[0154] Next, a functional material layer 20 covering the partition 14 of the honeycomb structure obtained above is formed. Furthermore, a functional material layer 20 covering the outer peripheral wall 11 can also be formed. The method for forming the functional material layer 20 is not particularly limited; for example, it can be formed using the following method: The honeycomb structure is immersed in a slurry containing functional material, organic binder, and water for a specified time, and then excess slurry is removed by blowing and wiping. Then, the slurry is dried, thereby forming the functional material layer 20 on the partition 14 and the outer peripheral wall 11. For example, the honeycomb structure can be dried at a temperature of approximately 120–600°C. This series of steps—immersion, removal of excess slurry, and drying—can be performed only once or repeatedly to provide a functional material layer 20 of the desired thickness on the partition 14 and the outer peripheral wall 11. For areas where the functional material layer 20 does not need to be formed, masking tape or the like can be used for masking. Additionally, before forming the functional material layer 20, the first end face 12a and the second end face 12b can be pre-ground.

[0155] (2-2. Process B and Process C)

[0156] Next, a first coating 15 and a second coating 16 are formed on the partition wall 14 of the honeycomb structure having the functional material layer 20 obtained above. In addition, a third coating 17 and a fourth coating 18 may be formed on the outer peripheral wall 11. Specifically, firstly, the following steps are performed: Step B, in which a first coating liquid containing an adhesive resin is allowed to penetrate into the interior of the partition wall portion 140a constituting the first end face 12a and the interior partition wall portion 141a of the compartment near the first end face in the partition wall 14; Step C, in which a second coating liquid containing an adhesive resin is allowed to penetrate into the interior of the partition wall portion 140b constituting the second end face 12b and the interior partition wall portion 141b of the compartment near the second end face in the partition wall 14.

[0157] During step B, the first coating liquid containing adhesive resin can also be simultaneously allowed to penetrate into the outer peripheral wall portion 110a constituting the first end face 12a and the interior of the inner and outer peripheral wall portions 111a of the compartment near the first end face. Furthermore, during step C, the second coating liquid containing adhesive resin can also be simultaneously allowed to penetrate into the outer peripheral wall portion 110b constituting the second end face 12b and the interior of the inner and outer peripheral wall portions 111b of the compartment near the second end face.

[0158] In addition to the adhesive resin, curing agents, solvents, and organic binders can be appropriately added to the first and second coating liquids. Examples of curing agents include addition-polymerization curing agents such as amines, acid anhydrides, and phenols; polymerization catalysts that promote curing through ionic polymerization; and latent curing agents such as dicyandiamide. Curing agents are particularly advantageous when the adhesive resin is a curable resin.

[0159] There are no particular limitations on the method for allowing the coating liquid to penetrate into the interior of the partition wall 14 and the outer peripheral wall 11. For example, one could immerse the area near the first or second end face of the honeycomb structure having the functional material layer 20 in the coating liquid at 20–30°C for a specified time. After lifting the honeycomb structure out of the coating liquid, excess coating liquid can be removed by blowing and wiping. Furthermore, the immersion and lifting cycle can be performed multiple times.

[0160] The penetration depth can be controlled by adjusting the viscosity of the first and second coating solutions, as well as the immersion time in both solutions. To facilitate control of the penetration depth within an appropriate range, the viscosity of the first and second coating solutions at 25°C, measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, is preferably 500 mP·s to 20000 mP·s. More preferably, this viscosity is 500 mP·s to 10000 mP·s. The immersion time can be appropriately set according to the required penetration depth of the coating, for example, 5 to 10 seconds.

[0161] (2-3. Process D)

[0162] Following steps B and C, step D involves heating the first and second coating liquids. The heating atmosphere temperature can be appropriately set according to the type of adhesive resin contained in the first and second coating liquids. However, to suppress the performance degradation of the functional materials in the honeycomb structure, step D is preferably performed in an atmosphere below 100°C, more preferably in an atmosphere of 70–90°C. The heating time can be appropriately set according to the type of adhesive resin, for example, 15 to 30 minutes.

[0163] The penetration of the coating liquid (process B or process C) and the heating of the coating liquid (process D) can be repeated multiple times.

[0164] Example

[0165] (1. Fabrication of honeycomb structures with functional material layers)

[0166] [Honeycomb structure]

[0167] First, fabricate a honeycomb structure with the following design specifications.

[0168] • The shape of the cross-section and end face of the honeycomb structure orthogonal to the direction of the compartment extension: quadrilateral

[0169] • The shape of the compartment orthogonal to the direction in which it extends: square

[0170] • Thickness of outer wall: 1mm

[0171] • The thickness of the partition wall: 0.127mm

[0172] • Compartment density: 36 compartments / cm² 2

[0173] • Compartment opening ratio: 0.86

[0174] • The dimensions of the cross-section of the honeycomb structure orthogonal to the direction of the cell extension: 40mm × 40mm

[0175] • Length of the honeycomb structure in the direction of compartment extension: 40mm

[0176] • Materials constituting the outer perimeter and partitions: cordierite

[0177] [Including functional material layer]

[0178] Next, for the aforementioned honeycomb structure, a slurry containing an amino-containing solid organic compound (functional material), an organic binder, and water is applied to the compartments of the honeycomb structure and dried at a temperature of approximately 70°C, thereby forming a functional material layer covering the compartment walls and outer perimeter walls. The design specifications related to the functional material layer are as follows.

[0179] • Average thickness of the functional material layer: 0.13 mm

[0180] • Amount of functional material layer relative to the volume of the honeycomb structure: 250 g / L

[0181] • The areas containing the functional material layer are: the inner partition wall portion, the partition wall portion constituting the first end face, the partition wall portion constituting the second end face, the outer peripheral wall portion inside the partition, the outer peripheral wall portion constituting the first end face, and the outer peripheral wall portion constituting the second end face.

[0182] (2. Fabrication of coated honeycomb structures)

[0183] Regarding the aforementioned honeycomb structure with a functional material layer, coated honeycomb structures as described in the following embodiments and comparative examples were fabricated by changing the coating conditions.

[0184] [Example 1]

[0185] A room-temperature curing two-component epoxy resin adhesive was prepared as the coating liquid. The viscosity of this coating liquid at 25°C was measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, and the result was 1000 mP·s. The coating liquid was poured into a container with a flat bottom, and the honeycomb structure containing the functional material layer was immersed in the coating liquid at approximately 25°C for 5 seconds from the first end face side to a depth of approximately 0.3 mm. Subsequently, the honeycomb structure containing the functional material layer was lifted out of the coating liquid, and then immersed again from the second end face side of the honeycomb structure containing the functional material layer to the coating liquid at approximately 25°C for 5 seconds.

[0186] Next, the honeycomb structure containing the functional material layer, after being immersed in the coating liquid, is placed in a dryer heated to 70°C and kept for 20 minutes to promote the curing of the adhesive resin in the coating liquid. Then, it is placed in the atmosphere to cure.

[0187] [Example 2]

[0188] A coating liquid was prepared by mixing 5% by mass of polyvinyl butyral as an organic binder and 95% by mass of organic solvent-based colloidal silica (50% by mass of solids). The viscosity of this coating liquid at 25°C was measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, and the result was 1500 mP·s. The coating liquid was poured into a container with a flat bottom, and the honeycomb structure containing the functional material layer was immersed in the coating liquid at approximately 25°C for 5 seconds from the first end face side to a depth of approximately 0.3 mm. Subsequently, the honeycomb structure containing the functional material layer was lifted out of the coating liquid, and then immersed again from the second end face side of the honeycomb structure containing the functional material layer to the coating liquid at approximately 25°C for 5 seconds.

[0189] Next, the honeycomb structure containing the functional material layer, after being immersed in the coating liquid, is placed in a dryer heated to 70°C and kept for 20 minutes to dry the coating liquid, thus obtaining a coated honeycomb structure.

[0190] [Comparative Example 1]

[0191] A coating liquid was prepared by mixing 45% by mass of organic solvent-based colloidal silica (50% by mass of solids), 17.5% by mass of titanium dioxide powder, and 37.5% by mass of molten silica powder. The viscosity of this coating liquid at 25°C was measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, and the result was 300 mP·s. The coating liquid was poured into a container with a flat bottom, and the honeycomb structure containing the functional material layer was immersed in the coating liquid at approximately 25°C for 5 seconds from the first end face side to a depth of approximately 0.3 mm. Subsequently, the honeycomb structure containing the functional material layer was lifted out of the coating liquid, and then immersed again from the second end face side of the honeycomb structure containing the functional material layer to the coating liquid at approximately 25°C for 5 seconds.

[0192] Next, the honeycomb structure containing the functional material layer, after being immersed in the coating liquid, is placed in a dryer heated to 70°C and kept for 20 minutes to dry the coating liquid, thus obtaining a coated honeycomb structure.

[0193] [Comparative Example 2]

[0194] A coating solution was prepared by mixing 12.5% ​​by mass aqueous colloidal silica (43% by mass solids), 2.5% by mass silicon carbide powder, 10% by mass titanium dioxide powder, 25% by mass fused silica powder, and 50% by mass water. The viscosity of this coating solution at 25°C was measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, and the result was 100 mP·s. The coating solution was poured into a container with a flat bottom, and the honeycomb structure containing the functional material layer was immersed in the coating solution at approximately 25°C for 5 seconds from the first end face side to a depth of approximately 0.3 mm. Subsequently, the honeycomb structure containing the functional material layer was lifted out of the coating solution, and then immersed again from the second end face side of the honeycomb structure containing the functional material layer to the coating solution at approximately 25°C for 5 seconds.

[0195] Next, the honeycomb structure containing the functional material layer, after being immersed in the coating liquid, is placed in a dryer heated to 70°C and kept for 20 minutes to dry the coating liquid, thus obtaining a coated honeycomb structure.

[0196] [Comparative Example 3]

[0197] Prepare silicone (90% by mass solids) as the coating solution. The viscosity of this coating solution at 25°C was measured using a single-cylinder rotary viscometer according to JIS Z8803:2011, and the result was 100,000 mP·s. The coating solution was poured into a container with a flat bottom, and the honeycomb structure containing the functional material layer was immersed in the coating solution at approximately 25°C for 3 seconds from the first end face side to a depth of approximately 0.3 mm. Subsequently, the honeycomb structure containing the functional material layer was lifted out of the coating solution, and then immersed again from the second end face side of the honeycomb structure containing the functional material layer to the coating solution at approximately 25°C for 3 seconds.

[0198] Next, the honeycomb structure containing the functional material layer, after being immersed in the coating liquid, is placed in a dryer heated to 70°C and kept for 20 minutes to dry the coating liquid, thus obtaining a coated honeycomb structure.

[0199] (3. Measurement of coating length, thickness and penetration depth)

[0200] For the coated honeycomb structures involved in the above-described embodiments and comparative examples, the following measurements were performed according to the aforementioned steps. The results are shown in Table 1.

[0201] [Average coverage length of the coating]

[0202] • The average coverage length M1 of the first coating 15 covering the inner partition wall portion 141a near the first end face, extending from the first end face 12a along the length direction of the compartment 13.

[0203] • The average coverage length M1 of the second coating 16 covering the inner partition wall portion 141b near the second end face, extending from the second end face 12b along the length direction of the compartment 13.

[0204] Average coating thickness

[0205] • The average thickness T1 of the first coating 15 covering the portion of the functional material layer 20 that constitutes the partition portion 140a of the first end face 12a is 15.

[0206] • The average thickness T1 of the second coating 16 covering the portion of the functional material layer 20 that constitutes the partition portion 140b of the second end face 12b is 16.

[0207] • The average thickness T2 of the first coating 15 covering the portion of the functional material layer 20 covering the inner partition wall portion 141a near the first end face.

[0208] • The average thickness T2 of the second coating 16 covering the portion of the functional material layer 20 covering the inner partition wall portion 141b near the second end face.

[0209] [Average penetration depth of the coating]

[0210] • The average penetration depth D1 of the first coating 15 that penetrates into the interior of the partition portion 140a constituting the first end face 12a

[0211] • The average penetration depth D1 of the second coating 16 that penetrates into the interior of the partition portion 140b constituting the second end face 12b

[0212] • The average penetration depth D2 of the first coating 15 penetrating into the interior of the partition wall portion 141a near the first end face.

[0213] • The average penetration depth D2 of the second coating 16 that penetrates into the interior of the partition wall portion 141b near the second end face

[0214] [Table 1]

[0215]

[0216] (4. Evaluation of the coating adhesion of coated honeycomb structures)

[0217] [Reference Example]

[0218] First, the following cyclic tests were conducted on the uncoated honeycomb structure with a functional material layer.

[0219] 1. Place the flask containing 300-500 mm of distilled water into a water bath set to 90°C and let it stand for 20 minutes to heat the water in the flask.

[0220] 2. Connect the flask to the vacuum dryer and the vacuum dryer to the vacuum pump, and set up a 15mm square honeycomb structure sample with a functional material layer in the flow path between the flask and the dryer.

[0221] 3. Start the vacuum pump and adjust it to the pressure shown on the dryer, which should be -0.08 to -0.09 MPa.

[0222] 4. Under this condition, introduce water vapor into the adjacent sample for 20 minutes.

[0223] 5. Restore pressure and remove the sample from the flow path.

[0224] 6. Pass the extracted partition sample into the atmosphere at a speed of 8.0–10.0 m / s for 5–10 minutes to dry it.

[0225] 7. After drying, observe the end face of the partition sample using a microscope at approximately 30x magnification.

[0226] The above steps 1-7 are performed as a cycle and repeated. At the end of each cycle, the presence or absence of peeling of the functional material layer is visually confirmed. As a result, at the end of the third cycle, peeling of the functional material layer was observed in some compartments.

[0227] [Example 1]

[0228] In addition to collecting partition samples with coatings penetrating into the functional material layer from the coated honeycomb structure described in Example 1 above, the same cyclic test as in the reference example was performed. In this case, the presence or absence of coating peeling was checked at the end of each cycle. As a result, no cracks or peeling of the coating were observed during visual inspection at the end of the 7th cycle.

[0229] [Example 2]

[0230] The coated honeycomb structure described in Example 2 was subjected to the same cyclic test as in Example 1. As a result, at the end of the 7th cycle, no coating peeling was observed visually, but localized cracks were found in the coating.

[0231] [Comparative Example 1]

[0232] The coated honeycomb structure involved in Comparative Example 1 was subjected to the same cyclic test as in Example 1. As a result, at the end of the third cycle, visual observation revealed localized peeling and cracks in the coating.

[0233] [Comparative Example 2]

[0234] The coated honeycomb structure described in Comparative Example 2 was subjected to the same cyclic test as in Example 1. As a result, at the end of the third cycle, visual inspection revealed localized cracks in the coating. Furthermore, at the end of the fifth cycle, coating peeling was observed.

[0235] [Comparative Example 3]

[0236] The coated honeycomb structure involved in Comparative Example 3 was subjected to the same cyclic test as in Example 1. As a result, at the end of the third cycle, visual observation revealed localized peeling and cracks in the coating.

[0237] (5. Pressure loss assessment)

[0238] For the honeycomb structure (a honeycomb structure with a functional material layer but without coating) mentioned in the above reference example, when gas flows through the compartment from the first end face to the second end face at a flow rate of 10 m / s, the pressure loss was calculated using the Fanning formula in an Excel simulation conducted by Microsoft. Furthermore, based on this result, the rate of increase in pressure loss was calculated when the average thicknesses T1 and T2 of the glass coating were changed. The results are shown in […]. Figure 6 .Depend on Figure 6 It can be seen that if the average thicknesses T1 and T2 of the glass coating are within 0.08 mm, the pressure loss rise rate can be controlled within 5%.

[0239] Explanation of reference numerals in the attached figures

[0240] 11: Peripheral wall

[0241] 12a: First end face

[0242] 12b: Second end face

[0243] 13: Compartment

[0244] 14: Next door

[0245] 15: First coating

[0246] 16: Second coating

[0247] 17: Third coating

[0248] 18: Fourth Coating

[0249] 20: Contains functional material layer

[0250] 100: Coated honeycomb structure

[0251] 110a: The outer peripheral wall portion constituting the first end face

[0252] 110b: The portion of the outer peripheral wall constituting the second end face

[0253] 111: Peripheral wall portion

[0254] 111a: The inner and outer peripheral walls of the compartment near the first end face

[0255] 111b: The inner and outer peripheral walls of the compartment near the second end face

[0256] 140a: Part of the partition wall constituting the first end face

[0257] 140b: Part of the partition wall constituting the second end face

[0258] 141: Partition wall section inside the compartment

[0259] 141a: Part of the inner partition wall near the first end face

[0260] 141b: Part of the inner partition wall near the second end face Claims (as amended under Article 19 of the Treaty) 1. (Modified) A coated honeycomb structure, comprising: outer perimeter wall; A partition wall is disposed on the inner circumferential side of the outer peripheral wall and divides into multiple compartments extending from the first end face to the second end face, the multiple compartments forming a flow path; A functional material layer covers the partition wall, and the functional material layer contains an adsorbent material that has the function of adsorbing one or more of water vapor, carbon dioxide and odor components. A first coating covers the partition wall portion forming the first end face and the internal partition wall portion near the first end face, and penetrates into the interior of these partition wall portions; and A second coating covers the portion of the partition wall forming the second end face and the portion of the partition wall inside the partition wall near the second end face, and penetrates into the interior of these partition wall portions. The functional material layer covers the partition portion forming the first end face, the internal partition portion of the compartment from the first end face to the second end face, and the partition portion forming the second end face. 2. (Delete) 3. The coated honeycomb structure according to claim 1, wherein, The first coating penetrates into the interior of the functional material layer covering the portion of the functional material layer that forms the partition wall portion of the first end face, and the portion of the functional material layer covering the internal partition wall portion near the first end face. The second coating penetrates into the interior of the functional material layer covering the portion of the partition wall that forms the second end face and the portion of the functional material layer covering the portion of the partition wall near the second end face. 4. The coated honeycomb structure according to claim 1, wherein, The average coverage length of the first coating covering the inner wall portion of the compartment near the first end face, extending from the first end face along the length of the compartment, is 300 μm or more, and is 0.2% to 2.5% of the length of the honeycomb structure. The average coverage length of the second coating covering the partition wall portion of the compartment near the second end face extends from the second end face along the length direction of the compartment to more than 300 μm, and is 0.2% to 2.5% of the length of the honeycomb structure. 5. The coated honeycomb structure according to claim 3, wherein, The average thickness of the first coating, which penetrates into the interior of the functional material layer covering the partition wall near the first end face, is 0–80 μm based on the surface of the functional material layer. The average thickness of the second coating, which penetrates into the interior of the functional material layer in the partition wall portion near the second end face, is 0–80 μm based on the surface of the functional material layer. 6. The coated honeycomb structure according to claim 1, wherein, At least one of the first coating and the second coating contains an adhesive resin. 7. The coated honeycomb structure according to claim 6, wherein, At least one of the first coating and the second coating contains epoxy resin. 8. The coated honeycomb structure according to claim 1, wherein, The average penetration depth of the first coating into the interior of the partition portion constituting the first end face is 100 μm to 200 μm. The average penetration depth of the second coating, which penetrates into the interior of the partition portion constituting the second end face, is 100 μm to 200 μm. 9. A method for manufacturing a coated honeycomb structure, comprising: Step A: Prepare a honeycomb structure, which has an outer peripheral wall, a partition wall disposed on the inner peripheral side of the outer peripheral wall and dividing it into multiple compartments extending from a first end face to a second end face, and a functional material layer covering the partition wall, wherein the multiple compartments form a flow path. Step B involves allowing a first coating liquid containing adhesive resin to penetrate into the partition wall portion forming the first end face and the interior of the partition wall portion within the partition wall near the first end face. Step C involves allowing a second coating liquid containing an adhesive resin to penetrate into the interior of the partition wall portion forming the second end face and the interior of the partition wall portion within the compartment near the second end face; and Step D, following steps B and C, involves heating the first and second coating liquids. 10. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, Process D is carried out in an atmosphere below 100°C. 11. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, The adhesive resin is a curable resin. 12. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, The viscosities of the first and second coating liquids at 25°C, measured using a single cylindrical rotary viscometer according to JIS Z8803:2011, are 500 mP·s to 20000 mP·s.

Claims

1. A coated honeycomb structure, comprising: outer perimeter wall; A partition wall is disposed on the inner circumferential side of the outer peripheral wall and divides into multiple compartments extending from the first end face to the second end face, the multiple compartments forming a flow path; A functional material layer covers the partition wall; A first coating covers the partition wall portion forming the first end face and the internal partition wall portion near the first end face, and penetrates into the interior of these partition wall portions; as well as The second coating covers the partition wall portion forming the second end face and the internal partition wall portion near the second end face, and penetrates into the interior of these partition wall portions.

2. The coated honeycomb structure according to claim 1, wherein, The functional material layer covers the partition portion forming the first end face, the internal partition portion of the compartment from the first end face to the second end face, and the partition portion forming the second end face.

3. The coated honeycomb structure according to claim 1, wherein, The first coating penetrates into the interior of the functional material layer covering the portion of the functional material layer that forms the partition wall portion of the first end face, and the portion of the functional material layer covering the internal partition wall portion near the first end face. The second coating penetrates into the interior of the functional material layer covering the portion of the partition wall that forms the second end face and the portion of the functional material layer covering the portion of the partition wall near the second end face.

4. The coated honeycomb structure according to claim 1, wherein, The average coverage length of the first coating covering the inner wall portion of the compartment near the first end face, extending from the first end face along the length of the compartment, is 300 μm or more, and is 0.2% to 2.5% of the length of the honeycomb structure. The average coverage length of the second coating covering the partition wall portion of the compartment near the second end face extends from the second end face along the length direction of the compartment to more than 300 μm, and is 0.2% to 2.5% of the length of the honeycomb structure.

5. The coated honeycomb structure according to claim 3, wherein, The average thickness of the first coating, which penetrates into the interior of the functional material layer covering the partition wall near the first end face, is 0–80 μm based on the surface of the functional material layer. The average thickness of the second coating, which penetrates into the interior of the functional material layer in the partition wall portion near the second end face, is 0–80 μm based on the surface of the functional material layer.

6. The coated honeycomb structure according to claim 1, wherein, At least one of the first coating and the second coating contains an adhesive resin.

7. The coated honeycomb structure according to claim 6, wherein, At least one of the first coating and the second coating contains epoxy resin.

8. The coated honeycomb structure according to claim 1, wherein, The average penetration depth of the first coating into the interior of the partition portion constituting the first end face is 100 μm to 200 μm. The average penetration depth of the second coating, which penetrates into the interior of the partition portion constituting the second end face, is 100 μm to 200 μm.

9. A method for manufacturing a coated honeycomb structure, comprising: Step A: Prepare a honeycomb structure, which has an outer peripheral wall, a partition wall disposed on the inner peripheral side of the outer peripheral wall and dividing it into multiple compartments extending from a first end face to a second end face, and a functional material layer covering the partition wall, wherein the multiple compartments form a flow path. Step B involves allowing a first coating liquid containing adhesive resin to penetrate into the partition wall portion forming the first end face and the interior of the partition wall portion within the partition wall near the first end face. Step C involves allowing a second coating liquid containing an adhesive resin to penetrate into the interior of the partition wall portion forming the second end face and the interior of the partition wall portion within the compartment near the second end face; and Step D, following steps B and C, involves heating the first and second coating liquids.

10. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, Process D is carried out in an atmosphere below 100°C.

11. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, The adhesive resin is a curable resin.

12. The method for manufacturing a coated honeycomb structure according to claim 9, wherein, The viscosities of the first and second coating liquids at 25°C, measured using a single cylindrical rotary viscometer according to JIS Z8803:2011, are 500 mP·s to 20000 mP·s.

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