KR100781928B1 - Honeycomb structure - Google Patents

Abstract

In the present invention, a honeycomb unit in which a plurality of through holes are arranged in a longitudinal direction with a through hole wall surface interposed therebetween is a honeycomb structure in which a plurality of honeycomb units are bound through a seal layer, wherein the honeycomb unit includes at least ceramic particles, inorganic fibers and And / or a whisker, wherein a cross-sectional area in a cross section perpendicular to the longitudinal direction of the honeycomb unit is 5 cm 2 or more and 50 cm 2 or less, and each portion of the honeycomb unit has a shape of an R plane and / or a C plane. A honeycomb structure is provided.

Honeycomb, catalyst, exhaust

Description

Honeycomb Structures {HONEYCOMB STRUCTURE}

The present invention relates to a honeycomb structure.

Conventionally, the honeycomb catalyst generally used for automobile exhaust gas purification is produced by supporting a high specific surface area material such as activated alumina and a catalyst metal such as platinum on the surface of the cordierite-like honeycomb structure having low thermal expansion in an integral structure. . In addition, alkaline earth metals such as Ba are supported as the NOx sorbent for the treatment of NOx in an excess oxygen atmosphere such as a lean burn engine and a diesel engine. However, in order to further improve the purification performance, it is necessary to increase the probability of contact between the exhaust gas and the catalyst noble metal and the NOx sorbent. For this purpose, it is necessary to make a carrier a higher specific surface area, and to make small and high dispersion | distribution of the particle size of a noble metal. However, simply increasing the supporting amount of a high specific surface area material such as activated alumina leads to an increase in the thickness of the alumina layer and does not lead to an increase in the probability of contact or a problem that the pressure loss is too large. The density, the wall thickness, and the like are devised (see, for example, Japanese Patent Laid-Open No. 10-263416). On the other hand, as a honeycomb structure made of a high specific surface area material, a honeycomb structure extruded together with an inorganic fiber and an inorganic binder is known (see, for example, JP-A-5-213681). Moreover, in order to enlarge such a honeycomb structure, what joined the honeycomb unit through the contact bonding layer is known (for example, refer to DE4341159).

Patent Document 1: Japanese Patent Application Laid-Open No. 10-263416

Patent Document 2: DE4341159

Disclosure of the Invention

Problems to be Solved by the Invention

However, the above-described prior art had the following problems. In high specific surface area materials, such as alumina, sintering advances by heat aging and a specific surface area falls. Moreover, the supported catalyst metals, such as platinum, aggregate with them, have a large particle diameter, and a small specific surface area. In short, after heat aging (used as a catalyst carrier), it is necessary to increase the specific surface area at an early stage in order to have a higher specific surface area. In addition, as described above, in order to further improve the purification performance, it is necessary to increase the probability of contact between the exhaust gas and the catalyst noble metal and the NOx sorbent. In other words, although it is important to make the carrier a higher specific surface area and to make the particles of the catalyst metal smaller and more highly dispersed, activated alumina or the like is formed on the surface of the cordierite-like honeycomb structure such as Japanese Patent Application Laid-Open No. 10-263416. In the case of supporting a high specific surface area material and a catalyst metal such as platinum, in order to increase the probability of contact with the exhaust gas, the cell shape, the cell density, and the wall thickness were studied to make the catalyst carrier high specific surface area. It was not large, and therefore, the catalyst metal was not sufficiently dispersed, and the purification performance of the exhaust gas after thermal aging was insufficient. Therefore, in order to make up for this deficiency, it has been solved by carrying a large amount of catalyst metal and increasing the size of the catalyst carrier itself. However, precious metals such as platinum are very expensive and are a limited precious resource. In addition, when installing in an automobile, since the installation space is very limited, all were not suitable means.

In addition, the honeycomb structure of JP-A-5-213681, which extrudes a high specific surface material together with an inorganic fiber and an inorganic binder, is made of a high specific surface area material, so that the substrate has a high specific surface area, and thus a catalyst metal is sufficiently used. Although highly dispersed, alumina or the like could not be sufficiently sintered to maintain a specific surface area, and the strength of the substrate was very weak. In addition, when used for automobiles as described above, the space for installation is very limited. Therefore, in order to increase the specific surface area of the carrier per unit volume, a means such as thinning the partition wall is used. By doing so, the strength of the substrate becomes weaker. In addition, alumina or the like may have a large thermal expansion rate, and cracks are easily generated by thermal stress during firing (preliminary firing) and during use. In consideration of these, when used for automobiles, external stresses such as thermal stress or large vibration due to rapid temperature change are applied at the time of use, so that they are easily broken, and the shape as a honeycomb structure cannot be maintained, thus serving as a catalyst carrier. There was a problem that could not.

In addition, the catalyst support for automobiles in DE4341159 is intended to increase the size of the honeycomb structure. Therefore, the cross-sectional area of the honeycomb unit is disclosed to be 200 cm 2 or more. When used in the applied situation, as described above, there is a problem that it is easily broken, the shape cannot be maintained, and the function as the catalyst carrier cannot be fulfilled.

In general, since the honeycomb unit has an angular shape as a whole, stress tends to be concentrated on the corners of the outer circumferential surface, and defects (chipping) may occur in the corners. In addition, cracks were generated on the seal layer side starting from the respective parts, which caused the honeycomb structure to be destroyed. Moreover, even if it did not reach destruction, there existed a problem that exhaust gas leaked and processing efficiency will fall.

This invention is made | formed in view of such a subject, Comprising: It aims at providing the honeycomb structure which can disperse | distribute a catalyst component and can raise the intensity | strength to thermal shock and a vibration.

Task To solve  Way

The honeycomb structure of the present invention is a honeycomb structure in which a plurality of honeycomb units in which a plurality of through holes are arranged in a longitudinal direction with a through hole wall surface interposed therebetween are bonded through a sealing material layer, wherein the honeycomb unit is formed of at least ceramic particles. Containing inorganic fibers and / or whiskers, and having a cross-sectional area of 5 cm 2 or more and 50 cm 2 or less in a cross section perpendicular to the longitudinal direction of the honeycomb unit, wherein each portion of the honeycomb unit has an R plane and / or a C plane. It is characterized by the shape. As a result, a honeycomb structure can be provided that has a high strength against thermal shock and vibration, can highly disperse a catalyst component, and can increase the strength against thermal shock and vibration.

It is preferable that the radius of curvature R of each R surface of the honeycomb unit of the honeycomb structure is 0.3 to 2.5 mm. As a result, stress concentration at the end of the honeycomb structure is relaxed, and the strength of the honeycomb structure is improved.

Moreover, it is preferable that C surface of each part of the honeycomb unit of the said honeycomb structure is C surface shape of 0.3-2.5 mm. As a result, stress concentration at the end of the honeycomb structure is relaxed, and the strength of the honeycomb structure is improved.

The honeycomb structure preferably has a ratio of the sum of the cross-sectional areas in the cross section perpendicular to the longitudinal direction of the honeycomb unit to the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb structure. Do. As a result, the surface area capable of supporting the catalyst can be made relatively large, and the pressure loss can be made relatively small.

In addition, the honeycomb structure preferably has a coating material layer on the outer circumferential surface of which the through hole is not opened. Thus, the outer circumferential surface can be protected to increase the strength.

In addition, the ceramic particles of the honeycomb structure is preferably one or more selected from the group consisting of alumina, silica, zirconia, titania, ceria, mullite and zeolite. Thereby, the specific surface area of a honeycomb unit can be improved.

The inorganic fiber and / or whisker is preferably at least one member selected from the group consisting of alumina, silica, silicon carbide, silica-alumina, glass, potassium titanate and aluminum borate. Thereby, the intensity | strength of a honeycomb unit can be improved.

In addition, the honeycomb unit is manufactured using a mixture containing the inorganic particles, the inorganic fibers and / or whiskers, and an inorganic binder, wherein the inorganic binder is an alumina sol, silica sol, titania sol, water glass, sepi It is preferable that it is at least 1 sort (s) chosen from the group which consists of an olite and an atapalzite. Thereby, sufficient strength can be obtained even if the temperature which bakes a honeycomb unit is made low.

In addition, it is preferable that the honeycomb structure is supported with a catalyst component. Thereby, the honeycomb catalyst with which the catalyst component is highly dispersed can be obtained.

In addition, the catalyst component preferably contains at least one component selected from precious metals, alkali metals, alkaline earth metals and oxides.

In addition, the honeycomb structure is preferably used for exhaust gas purification of a vehicle. As a result, the purification performance can be improved.

Effects of the Invention

According to the present invention, it is possible to provide a honeycomb structure having high strength against thermal shock and vibration.

1 is a conceptual diagram of a honeycomb unit 11 of the present invention.

2 is a conceptual diagram of the honeycomb structure 10 of the present invention.

3 is an SEM photograph of the wall surface of the honeycomb unit 11 of the present invention.

4A is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

4B is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

4C is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

4D is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

5: A is explanatory drawing of the experiment example which bonded the honeycomb unit 11 in multiple numbers.

5B is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

5C is an explanatory diagram of an experimental example in which a plurality of honeycomb units 11 are joined.

6A is a front view of the vibration device 20.

6B is a side view of the vibration device 20.

7 is an explanatory diagram of the pressure loss measuring apparatus 40.

8 is a diagram showing the relationship between the cross-sectional area, weight loss rate and pressure loss of a honeycomb unit.

9 is a diagram illustrating a relationship between a unit area ratio, a weight loss rate, and a pressure loss.

FIG. 10 is a diagram showing a relationship between an aspect ratio and a weight reduction rate of silica-alumina fibers. FIG.

Explanation of the sign

10: honeycomb structure

11: Honeycomb Unit

12: through hole

13: exterior

14: seal floor

16: coating material layer

18: parts

19: circumferential end

20: vibration device

21: metal casing

22: pedestal

23: fixture

24: screw

40: pressure loss measuring device

Implement the invention  Best form for

Next, the best mode for implementing this invention is demonstrated with drawing.

As shown in FIG. 2, the honeycomb structure 10 of the present invention is a honeycomb structure in which a plurality of honeycomb units in which a plurality of through holes are arranged in the longitudinal direction with a through hole wall surface interposed therebetween are sealed through a sealing material layer. The honeycomb unit contains at least ceramic particles, inorganic fibers and / or whiskers, and has a cross-sectional area in a cross section perpendicular to the longitudinal direction of the honeycomb unit of 5 cm 2 or more and 50 cm 2 or less. Each part of is characterized in that the shape of the R surface and / or C surface.

In this honeycomb structure, since a plurality of honeycomb units have a structure in which a plurality of honeycomb units are joined through a seal material layer, strength against thermal shock and vibration can be increased. This reason is assumed to be because the temperature difference generated in each honeycomb unit can be suppressed small, even when a temperature distribution occurs in the honeycomb structure due to a sudden temperature change or the like. Or it is inferred that it is because heat shock and a vibration can be alleviated by a sealing material layer. In addition, this seal material layer prevents cracks from spreading to the entire honeycomb structure even when a crack occurs in the honeycomb unit due to thermal stress or the like, and also serves as a frame of the honeycomb structure, and maintains the shape as a honeycomb structure. It is thought that such a function will not be lost as a catalyst carrier. The size of the honeycomb unit is the area of the cross section orthogonal to the through-hole (simply referred to as cross-sectional area. The same below). When the specific surface area becomes relatively small and the pressure loss becomes relatively large, and when the cross-sectional area exceeds 50 cm 2, the size of the unit is too large and the thermal stress generated in each honeycomb unit cannot be sufficiently suppressed. In other words, when the cross-sectional area of the unit is in the range of 5 to 50 cm 2, while maintaining a large specific surface area, the pressure loss is suppressed to be small, sufficient strength to thermal stress is obtained, high durability is obtained, and the level becomes practical. Therefore, according to this honeycomb structure, the catalyst component can be highly dispersed and the strength against thermal shock and vibration can be increased. Here, when a honeycomb structure contains several honeycomb units from which a cross-sectional area differs, the cross-sectional area means the cross-sectional area of the honeycomb unit used as the basic unit which comprises a honeycomb structure, and usually, the cross-sectional area of a honeycomb unit is the largest. Say that it is.

Moreover, it is preferable that the curvature radius R of the R surface of each part of the said honeycomb unit is 0.3-2.5 mm.

In the honeycomb structured body of the present invention, since each portion on the outer circumferential surface of the honeycomb unit has a shape of an R surface and / or a C surface, it is possible to avoid stress concentration on the location. Therefore, chipping occurs in the honeycomb unit, or cracks can be prevented from occurring and propagating in the sealing material layer starting from each part. Moreover, it is preferable that the radius of curvature of the shape of this R surface is R = 0.3-2.5mm. If the radius of curvature R is less than 0.3 mm, stress concentration on each part cannot be sufficiently avoided, leading to chipping or cracking. Further, when the radius of curvature R exceeds 2.5 mm, the cross-sectional area of the honeycomb unit is reduced, and the processing capacity of the honeycomb structure is lowered.

Moreover, it is preferable that the shape of this C surface is C surface shape of 0.3 mm-2.5 mm. This is because stress concentration on the end of the honeycomb structure is relaxed, and the strength of the honeycomb structure is improved. If the shape of the C surface is less than 0.3 mm, stress concentration on each part cannot be sufficiently avoided, leading to chipping or cracking. Moreover, when the shape of C surface exceeds 2.5 mm, the difference of the thickness of a sealing material will become large and it will become easy to be destroyed by thermal stress. In addition, the cross-sectional area of the honeycomb unit is reduced, and the processing capacity of the honeycomb structure is lowered.

Moreover, it is preferable that the ratio of the sum total of the cross-sectional area in the cross section perpendicular | vertical to the longitudinal direction of the said honeycomb unit to the cross section in the cross section perpendicular | vertical to the longitudinal direction of a honeycomb structure is 85% or more, and is 90% or more. It is more preferable. This is because if the ratio is less than 85%, the cross-sectional area of the seal material layer is increased, and the total cross-sectional area of the honeycomb unit is reduced, so that the specific surface area carrying the catalyst is relatively small and the pressure loss is relatively large. Moreover, when this ratio is 90% or more, pressure loss can be made smaller.

In the honeycomb structure according to the present invention, a honeycomb unit bonded to the sealing material layer may include a coating material layer covering an outer circumferential surface of which the through hole is not opened. Thus, the outer circumferential surface of the honeycomb structure can be protected to increase the strength.

The shape of the honeycomb structure in which the honeycomb unit is joined is not particularly limited, and may be, for example, a prismatic square.

In the honeycomb structure of the present invention, the aspect ratio of the inorganic fibers and / or whiskers contained in the honeycomb unit is preferably 2 to 1000, more preferably 5 to 800, more preferably 10 to 500 Most preferred. If the aspect ratio of the inorganic fiber and / or whisker is less than 2, the contribution to the improvement of the strength of the honeycomb structure may become small. If the ratio exceeds 1000, the molding die may be easily clogged in forming, resulting in poor moldability. In addition, the inorganic fibers and / or whiskers may be folded at the time of molding such as extrusion molding to cause variation in the length, thereby reducing the contribution to the improvement of the strength of the honeycomb structure. Here, when there is distribution in the aspect ratio of the inorganic fiber and / or whisker, the average value may be used.

In the honeycomb structure of the present invention, the ceramic particles contained in the honeycomb unit are not particularly limited, and for example, 1 selected from silicon carbide, silicon nitride, alumina, silica, zirconia, titania, ceria, mullite and zeolite. Species or more are mentioned, Among these, alumina is preferable.

In the honeycomb structure of the present invention, the inorganic fibers and / or whiskers contained in the honeycomb unit are not particularly limited, and at least one selected from alumina, silica, silicon carbide, silica alumina, aluminum borate, glass and potassium titanate Can be mentioned.

30-97 weight% is preferable, as for the quantity of the ceramic particle contained in a honeycomb structure, 30-90 weight% is more preferable, 40-80 weight% is more preferable, 50-75 weight% is the most preferable. If the content of the ceramic particles is less than 30% by weight, the amount of ceramic particles contributing to the improvement of the specific surface area is relatively small, so that the specific surface area of the honeycomb structure is small, and the catalyst component cannot be highly dispersed when supporting the catalyst component. When the content exceeds 90% by weight, the amount of the inorganic fibers and / or whiskers that contribute to the strength improvement is relatively low, so that the strength of the honeycomb structure is lowered.

The amount of the inorganic fibers and / or whiskers contained in the honeycomb unit of the honeycomb structure is preferably 3 to 70% by weight, more preferably 3 to 50% by weight, still more preferably 5 to 40% by weight, 8 to 30 % By weight is most preferred. When the content of the inorganic fibers and / or whiskers is less than 3% by weight, the strength of the honeycomb structure is lowered. When the content of the inorganic fibers and / or whisker is more than 50% by weight, the amount of ceramic particles that contribute to the improvement of the specific surface area is relatively small. The specific surface area is small so that the catalyst component cannot be highly dispersed when supporting the catalyst component.

In the honeycomb structured body of the present invention, the honeycomb unit may further be produced by containing an inorganic binder. In this way, sufficient strength can be obtained even if the temperature which bakes a honeycomb unit is made low. It does not specifically limit as an inorganic binder contained in a honeycomb structure, For example, an inorganic sol, a clay binder, etc. are mentioned. Among these, as an inorganic sol, 1 or more types chosen from an alumina sol, a silica sol, a titania sol, water glass, etc. are mentioned, for example. As the clay binder, for example, one or more kinds of clay binders selected from clay, kaolin, montmorillonite, double-chain clay (sepiolite, attapalzite) and the like can be given. The amount of the inorganic binder contained in the production of the honeycomb unit is preferably 50% by weight or less, more preferably 5 to 50% by weight, still more preferably 10 to 40% by weight, as the solid content contained in the honeycomb structure. Most preferably 15 to 35% by weight. When content of an inorganic binder exceeds 50 weight%, moldability will worsen.

Although the shape of a honeycomb unit is not specifically limited, It is preferable that it is a shape which is easy to connect honeycomb units, and even if the cross section (simplistic cross-section. It is the same hereafter) of the surface orthogonal to a through-hole is square or rectangular. do. As an example of a honeycomb unit, the conceptual diagram of the honeycomb unit 11 which is a rectangular parallelepiped of cross section is shown in FIG. The honeycomb unit 11 has a plurality of through holes 12 from front to inward, and has an outer surface 13 having no through holes 12. Although the wall thickness between the through-holes 12 is not specifically limited, The range of 0.05-0.35 mm is preferable, 0.10-0.30 mm is more preferable, 0.15-0.25 mm is the most preferable. If the wall thickness is less than 0.05 mm, the strength of the honeycomb unit is lowered. If the wall thickness is more than 0.35 mm, the contact area with the exhaust gas becomes smaller, and since the gas does not penetrate deep enough, the catalyst supported in the wall This is because the catalytic performance deteriorates because the gas becomes difficult to contact with the gas. The number of through holes per unit cross-sectional area is preferably 15.5 to 186 / cm 2 (100 to 1200 cpsi), more preferably 46.5 to 170.5 / cm 2 (300 to 1100 cpsi), and 62.0 to 155 / cm 2 (400 to 1000 cpsi) is most preferred. If the number of through holes is less than 15.5 / cm 2, the area of the wall in contact with the exhaust gas inside the honeycomb unit becomes small, and if it exceeds 186 / cm 2, the pressure loss becomes high, which makes it difficult to manufacture the honeycomb unit. to be.

The honeycomb unit constituting the honeycomb structure preferably has a cross-sectional area of 5 to 50 cm 2, more preferably 6 to 40 cm 2, and most preferably 8 to 30 cm 2. If the cross-sectional area is in the range of 5 to 50 cm 2, the proportion of the sealing material layer to the honeycomb structure can be adjusted. As a result, the specific surface area per unit volume of the honeycomb structure can be largely maintained, the catalyst component can be highly dispersed, and the shape as a honeycomb structure can be maintained even when external force such as thermal shock or vibration is applied. In addition, the specific surface area per unit volume can be calculated | required by Formula (1) mentioned later.

Next, an example of the manufacturing method of the honeycomb structured body of this invention mentioned above is demonstrated. First, extrusion molding etc. are performed using the raw material paste whose main component is a ceramic particle, an inorganic fiber, and / or a whisker, and an inorganic binder mentioned above, and a honeycomb unit molded object is produced. In addition to these, you may add an organic binder, a dispersion medium, and a shaping | molding adjuvant suitably to a raw material paste according to moldability. It does not specifically limit as an organic binder, For example, 1 or more types chosen from methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, a phenol resin, and an epoxy resin is mentioned. As for the compounding quantity of an organic binder, 1-10 weight part is preferable with respect to a total of 100 weight part of ceramic particle, an inorganic fiber and / or whisker, and an inorganic binder. It does not specifically limit as a dispersion medium, For example, water, an organic solvent (benzene etc.), alcohol (methanol etc.), etc. are mentioned. It does not specifically limit as a shaping | molding adjuvant, For example, ethylene glycol, dextrin, fatty acid, fatty acid soap, and polyalcohol are mentioned.

Although a raw material paste is not specifically limited, It is preferable to mix and knead | mix, For example, you may mix using a mixer, an attritor, etc., or you may fully knead with a kneader etc. The method of molding the raw material paste is not particularly limited, and for example, molding of the raw material paste into a shape having a through hole is preferable.

By making the outer peripheral surface of the metal mold | die used for extrusion molding into the shape of R surface and / or C surface, each part of a honeycomb unit can be made into R surface and / or C surface.

Each corner portion 18 of the honeycomb unit may be chamfered, such as polishing or cutting, to form a shape of the R surface and / or the C surface of the radius of curvature R of a predetermined size. In addition, the step of a chamfering process is not limited at this time, For example, it can carry out after baking. In this case, it is preferable to thicken the film thickness of each unit part beforehand so that each unit part may not become thin.

Next, it is preferable to dry the obtained molded object. The dryer used for drying is not specifically limited, A microwave dryer, a hot air dryer, an oilfield dryer, a vacuum dryer, a vacuum dryer, and a freeze dryer are mentioned. Moreover, it is preferable to degrease the obtained molded object. The conditions for degreasing are not specifically limited, What is necessary is just to select suitably according to the kind and quantity of the organic substance contained in a molded object, but about 400 degreeC and 2hr are preferable.

Moreover, it is preferable to bake the obtained molded object. Although it does not specifically limit as baking conditions, 600-1200 degreeC is preferable and 600-1000 degreeC is more preferable. The reason for this is that when the firing temperature is less than 600 ° C, sintering of ceramic particles and the like does not proceed, and the strength as a honeycomb structure is lowered. When it exceeds 1200 ° C, sintering of ceramic particles and the like proceeds excessively and the specific surface area per unit volume becomes small. This is because the catalyst component to be supported cannot be sufficiently dispersed. Through these steps, a honeycomb unit having a plurality of through holes can be obtained.

Next, you may apply | coat the sealing material paste which becomes a sealing material layer to the obtained honeycomb unit, joining a honeycomb unit one by one, drying and immobilizing after that, and manufacturing the honeycomb unit bonding body of a predetermined | prescribed magnitude | size. It does not specifically limit as a sealing material, For example, the thing which mixed the inorganic binder and ceramic particle, the thing which mixed the inorganic binder and inorganic fiber, the thing which mixed the inorganic binder, ceramic particle, and inorganic fiber can be used. In addition, it is good also as what added the organic binder to these sealing materials. It does not specifically limit as an organic binder, For example, 1 or more types chosen from polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, etc. are mentioned.

As for the thickness of the sealing material layer which joins a honeycomb unit, 0.5-2 mm is preferable. It is because there exists a possibility that sufficient bonding strength may not be obtained when the thickness of a sealing material layer is less than 0.5 mm. In addition, since the sealing material layer does not function as a catalyst carrier, if it exceeds 2 mm, the specific surface area per unit volume of the honeycomb structure decreases, so that it cannot be sufficiently high dispersed when the catalyst component is supported. Moreover, when the thickness of a sealing material layer exceeds 2 mm, a pressure loss may become large. The number of honeycomb units to be bonded may be appropriately determined in accordance with the size of the honeycomb structure used as the honeycomb catalyst. In addition, the joined body which joined the honeycomb unit with the sealing material may be appropriately cut and polished according to the shape and size of the honeycomb structure.

You may apply | coat a coating material to the outer peripheral surface (side surface) in which the through hole of a honeycomb structure is not opened, dry it, fix it, and form a coating material layer. In this way, the outer circumferential surface can be protected to increase the strength.

The coating material is not particularly limited and may be made of the same material as the sealing material or may be made of a different material. In addition, a coating material may be made into the same compounding ratio as a sealing material, and may be made into a different compounding ratio. Although the thickness of a coating material layer is not specifically limited, It is preferable that it is 0.1-2 mm. If the thickness is less than 0.1 mm, the outer circumferential surface may not be fully protected and the strength may not be increased. If the thickness is more than 2 mm, the specific surface area per unit volume as the honeycomb structure is lowered, so that it may not be sufficiently dispersed when the catalyst component is supported. do.

It is preferable to pre-fire after joining a some honeycomb unit with a sealing material (however, after forming a coating material layer in the case of forming a coating material layer). This is because degreasing can be performed when the sealing material or the coating material contains an organic binder. Although conditions for preliminary baking may be suitably determined according to the kind and quantity of organic substance to contain, 2hr is preferable at about 700 degreeC. When the honeycomb structure obtained by preliminary firing is used, the organic binder left in the honeycomb structure is not burned, and contaminated exhaust gas is not released. Here, as an example of a honeycomb structure, the conceptual diagram of the honeycomb structure 10 in which the honeycomb unit 11 of the rectangular parallelepiped of cross section was bonded together is made into the circumferential shape is shown in FIG. The honeycomb structure 10 is formed by joining the honeycomb unit 11 by the seal material layer 14 and cutting it into a columnar shape, and then the through hole 12 of the honeycomb structure 10 is formed by the coating material layer 16. It covers the outer peripheral surface which is not opened. For example, the honeycomb unit 11 is shaped into a fan-shaped cross section or a square cross-section and bonded to each other so as to form a predetermined honeycomb structure (cylindrical in FIG. 2), thus cutting and polishing. The step may be omitted.

Although the use of the obtained honeycomb structural body is not specifically limited, It is preferable to use as a catalyst carrier for exhaust gas purification of a vehicle. Moreover, when used as a catalyst carrier for exhaust gas purification of a diesel engine, the particulate filter (DPF) which has a ceramic honeycomb structure, such as a silicon carbide, and has the function to filter and purify particulate matter (PM) in exhaust gas. Although it may be used together, the positional relationship between the honeycomb structure of the present invention and the DPF may be the front side or the rear side of the honeycomb structure of the present invention. When provided in the front side, when the honeycomb structure of the present invention exhibits a reaction involving heat generation, the honeycomb structure of the present invention can be transferred to the rear DPF to promote a temperature increase during regeneration of the DPF. In addition, when installed in the rear side, since the PM in the exhaust gas is filtered by the DPF and passes through the through hole of the honeycomb structure of the present invention, clogging is not caused well, and incomplete combustion when burning PM in the DPF is performed. This is because the honeycomb structured body of the present invention can also be treated with respect to the gas component generated by the present invention. In addition, the honeycomb structure can be used not only for the use described in the technical background described above, but also for use without using a catalyst component (for example, an adsorbent for adsorbing a gas component or a liquid component). It is not limited and can use.

Moreover, it is good also as a honeycomb catalyst by carrying a catalyst component in the obtained honeycomb structure. The catalyst component is not particularly limited and may be a noble metal, an alkali metal, an alkaline earth metal, an oxide, or the like. Examples of the noble metal include one or more selected from platinum, palladium and rhodium, and examples of the alkali metal include one or more selected from potassium, sodium, and the like, and examples of the alkaline earth metal include, for example, there may be mentioned barium, there may be an oxide of the perovskite _{(La 0 .75 K 0 .25 MnO} 3 , and so on), and CeO ₂ or the like. The obtained honeycomb catalyst is not particularly limited, and can be used, for example, as a so-called three-way catalyst or NO _x storage catalyst for exhaust gas purification of automobiles. Moreover, the support of a catalyst component is not specifically limited, You may carry out after carrying out manufacture of a honeycomb structure, and you may carry out at the stage of the ceramic particle of a raw material. The method of supporting the catalyst component is not particularly limited and may be performed by, for example, an impregnation method.

Hereinafter, although the example which manufactured the honeycomb structure specifically in various conditions is demonstrated as an experiment example, this invention is not limited to these experiment examples at all.

Experimental Example 1

First, 40 wt% of γ-alumina particles (average particle size 2 μm), 10 wt% silica-alumina fiber (average fiber diameter 10 μm, average fiber length 100 μm, aspect ratio 10), and 50 wt% silica sol (solid concentration 30 wt%) 6 parts by weight of methyl cellulose, a plasticizer and a lubricant were added in small amounts as an organic binder with respect to 100 parts by weight of the obtained mixture, followed by mixing and kneading to obtain a mixed composition. Next, this mixed composition was extrusion-molded by the extrusion molding machine, and the green mold was obtained.

Extrusion was performed using the metal mold | die so that the shape of the R surface of curvature radius R = 1.5 mm was formed in each part 18 of the honeycomb unit.

Next, the green mold was sufficiently dried using a microwave dryer and a hot air dryer, and maintained at 400 ° C. for 2 hours to be degreased.

Thereafter, firing was carried out at 800 ° C. for 2 hours, and the resultant was a prismatic mold (34.3 mm × 34.3 mm × 150 mm), a cell density of 93 cells / cm 2 (600 cpsi), a wall thickness of 0.2 mm, and a cell shape of a square (square). Honeycomb unit 11 was obtained. The electron microscope (SEM) photograph of the wall surface of this honeycomb unit 11 is shown in FIG. This honeycomb unit 11 can be seen that the silica-alumina fibers are oriented along the extrusion direction of the raw material paste.

Next, 29 wt% of γ-alumina particles (average particle diameter 2 μm), 7 wt% silica-alumina fiber (average fiber diameter 10 μm, average fiber length 100 μm), 34 wt% silica sol (solid weight 30 wt%), carboxymethylcellulose 5 wt% and 25 wt% of water were mixed to form a heat resistant sealing material paste. The honeycomb unit 11 was bonded together using this sealing material paste. 4A shows a joined body obtained by joining a plurality of honeycomb units 11 as viewed from a surface having a through hole (referred to as the front face below). This bonded body is obtained by applying a sealing material paste to the outer surface 13 of the honeycomb unit 11 described above so that the thickness of the sealing material layer 14 is 1 mm, and fixing the honeycomb unit 11 in a plurality of joints. In this way, the bonded body was fabricated, and the bonded body was cut using a diamond cutter in a columnar shape such that the front face of the bonded body was approximately point-symmetrical, and the above-mentioned sealing material paste was 0.5 mm thick on a circular outer surface having no through hole. The outer surface was coated by coating as possible. Then, it dried at 120 degreeC, hold | maintained at 700 degreeC for 2 hours, and degreased the sealing material layer and the coating material layer, and obtained the honeycomb structural body 10 of columnar shape (diameter 143.8mm (phi) x length 150mm).

The ceramic particle component, unit shape, unit cross-sectional area, and unit area ratio of the honeycomb structure 10 (the ratio of the total cross-sectional area of the honeycomb unit to the cross-sectional area of the honeycomb structure. (The ratio which occupies the total cross-sectional area of a sealing material layer and a coating material layer with respect to the cross-sectional area of a honeycomb structure is the same. The following is summarized.

1) inorganic fiber = silica-alumina fiber (diameter 10μm, length 100μm, aspect ratio 10)

2) Including the area of coating layer

Table 1 also summarizes the contents of Experimental Examples 2 to 29 described later. All samples shown in Table 1 have inorganic fibers of silica-alumina fibers (average fiber diameter of 10 μm, average fiber length of 100 μm, aspect ratio 10) and inorganic binder of silica sol (solid concentration of 30% by weight). In addition, Table 2 summarizes each numerical value such as inorganic fibers (type, diameter, length, aspect ratio), unit shape, and unit cross-sectional area of Experimental Examples 30 to 34 described later.

1) Ceramic Particle = γ-Alumina Particle

2) Unit Area Ratio = 93.5%

   Area ratio of seal layer + coating layer = 6.5%

All samples shown in Table 2 were ceramic particles of gamma alumina particles, inorganic binders of silica sol (solid concentration of 30% by weight), unit area ratio of 93.5%, and sealing material layer area ratio of 6.5%. In addition, the types of the inorganic binder of the honeycomb structural body 10 of Experimental Examples 44 to 51 which will be described later, the unit cross-sectional area, the thickness of the sealing material layer, the unit area ratio, the sealing material layer area ratio, and the firing temperature of the honeycomb unit 11 are described. Table 3 summarizes numerical values and the like.

1) Ceramic Particle = γ-Alumina Particle

  Inorganic Fiber = Silica-Alumina Fiber (Diameter 10μm, Length 100μm, Aspect Ratio 10)

2) Including the area of coating layer

In all the samples shown in Table 3, the ceramic particles were γ-alumina particles (average particle diameter 2 μm), and the inorganic fibers were silica-alumina fibers (average fiber diameter 10 μm, average fiber length 100 μm, aspect ratio 10).

In addition, in the experiment example of Tables 1-3, the curvature radius R of each part 18 of the honeycomb unit was 1.5 mm.

Experimental Examples A-T

In Experimental Examples A-T, extrusion molding is performed by changing a metal mold so that the shape of the R surface of each portion of the honeycomb unit becomes a predetermined radius of curvature R, and the radius of curvature R of each portion 18 of the honeycomb unit is zero. The honeycomb structured body was produced in the same manner as in Experimental Example 1 except that the sample was changed to ˜3.0 mm. In Experimental Examples K-T, extrusion is performed by changing molds so that the shape of the C surface of each portion of the honeycomb unit becomes a predetermined C surface shape, and the shape of the C surface of each portion 18 of the honeycomb unit is 0 to 3.0 mm. The honeycomb structured body was produced in the same manner as in Experimental Example 1 except that the C-face shape was changed. In addition, in Experimental Example J and Experimental Example T, the coating material layer 16 was not formed in the outer peripheral portion. The curvature radius R and C surface shape of each part 18 of the honeycomb unit of each experiment example were shown in Table 4 with other items, such as a unit cross-sectional area.

Experimental Examples 2-7

A honeycomb structural body 10 was produced in the same manner as Experimental Example 1 except that the honeycomb unit was manufactured so as to have the shape shown in Table 1. The shapes of the conjugates of Experimental Examples 2, 3 and 4 are shown in Figs. 4A, b, c and d, respectively, and the shapes of the conjugates of Experimental Examples 5, 6 and 7 are shown in Figs. 5A, b and c, respectively. Since Experimental Example 7 integrally formed the honeycomb structure 10, the joining step and the cutting step were not performed.

Experimental Examples 8-14

The honeycomb unit 11 was produced in the same manner as Experimental Example 1 except that the honeycomb unit was manufactured so that the ceramic particles were titania particles (average particle diameter 2 μm), and the shapes shown in the table in Table 1 were produced. A honeycomb structural body 10 was produced in the same manner as Experimental Example 1 except that the ceramic particles of the ash layer and the coating material layer were titania particles (average particle diameter 2 μm). Moreover, the shape of the joined body of Experimental Examples 8-11 is the same as that of FIGS. 4A-D, respectively, and the shape of the joined body of Experimental Examples 12-14 is the same as that of FIGS. 5A-C, respectively. In addition, Experimental Example 14 is a one-piece molded honeycomb structure (10).

Experimental Examples 15-21

The honeycomb unit 11 was produced similarly to Experimental Example 1 except having produced the honeycomb unit so that the ceramic particle of a ceramic particle may be a silica particle (average particle diameter 2 micrometer), and it becomes a shape shown in the table of Table 1, Then, the honeycomb structural body 10 was produced like Example 1 except having made the ceramic particle of the sealing material layer and the coating material layer into the silica particle (average particle diameter of 2 micrometers). In addition, the shape of the joined body of Experimental Examples 15-18 is the same as that of FIGS. 4A-D, respectively, and the shape of the joined body of Experimental Examples 19-21 is the same as that of FIGS. 5A-C, respectively. In addition, Experimental Example 21 is integrally molded of the honeycomb structure 10.

Experimental Examples 22-28

The honeycomb unit 11 was produced in the same manner as in Experiment 1 except that the honeycomb unit was manufactured so that the ceramic grain of the ceramic particle was a zirconia particle (average particle diameter 2 μm), and the shape shown in the table of Table 1 was obtained. Then, the honeycomb structural body 10 was produced like Example 1 except having made the ceramic particle of the sealing material layer and the coating material layer into zirconia particle (average particle diameter 2 micrometer). Moreover, the shape of the joined body of Experimental Examples 22-25 is the same as that of FIGS. 4A-D, respectively, and the shape of the joined body of Experimental Examples 26-28 is the same as that of FIGS. 5A-C, respectively. In addition, Experimental Example 28 is the honeycomb structural body 10 integrally formed.

Experimental Example 29

A commercially available cordierite honeycomb structure 10 having a cylindrical shape (diameter 143.8 mm φ x length 150 mm) in which alumina as a catalyst supporting layer was formed in the through hole was set as Experimental Example 29. The cell shape was hexagon, the cell density was 62 cells / cm 2 (400 cpsi), and the wall thickness was 0.18 mm. Moreover, the shape of the honeycomb structure seen from the front is the same as that of FIG. 5C.

Experimental Examples 30-34

Except having designed the honeycomb unit using the silica-alumina fiber of the shape shown in Table 2 as an inorganic fiber, the honeycomb unit 11 was produced like Example 1, and the silica of a sealing material layer and a coating material layer was then continued. -The honeycomb structural body 10 was produced similarly to Experimental Example 1 except having made the alumina fiber into the silica-alumina fiber like a honeycomb unit. In addition, the shape of the joined body of Experimental example 30-34 is the same as that of FIG. 4A.

Experimental Examples 44-47

As shown in Table 3, the honeycomb structural body 10 was produced like Example 1 except having changed the cross-sectional area of a honeycomb unit, and the thickness of the sealing material layer which joins a honeycomb unit. Moreover, the shape of the joined body of Experimental Examples 44-45 is the same as that of FIG. 4A, and the shape of the joined body of Experimental Examples 46-47 is the same as that of FIG. 4C.

Experimental Example 48

As shown in Table 3, the honeycomb structure 10 was produced in the same manner as in Experiment 1 except that a honeycomb unit was prepared using an inorganic binder as an alumina sol (solid concentration of 30% by weight).

Experimental Examples 49-50

As shown in Table 3, the honeycomb structure 10 was produced in the same manner as in Experimental Example 1 except that the honeycomb unit was prepared using the inorganic binder as sepiolite and attapalzite. Specifically, 40 wt% of γ-alumina particles (average particle size 2 μm), 10 wt% silica-alumina fiber (average fiber diameter 10 μm, average fiber length 100 μm, aspect ratio 10), 15 wt% inorganic binder, and 35 wt% water In the same manner as in Experiment 1, an organic binder, a plasticizer and a lubricant were added to perform molding and baking to obtain a honeycomb unit 11. Next, a plurality of these honeycomb units 11 are bonded together using the same sealing material paste as in Experimental Example 1, the bonded body is cut in the same manner as in Experimental Example 1 to form a coating material layer 16, and has a cylindrical shape (diameter 143.8). The honeycomb structural body 10 of mmφ x length 150mm) was obtained.

Experimental Example 51

As shown in Table 3, the honeycomb structural body 10 was produced in the same manner as in Experiment 1 except that a honeycomb unit was produced without mixing the inorganic binder. Specifically, 50 wt% of gamma alumina particles (average particle diameter 2 mu m), 15 wt% silica-alumina fiber (average fiber diameter 10 mu m, average fiber length 100 mu m, aspect ratio 10) and 35 wt% water were mixed, and Experimental Example 1 An organic binder, a plasticizer and a lubricant were added and molded in the same manner as in the above, and the molded product was baked at 1000 ° C to obtain a honeycomb unit 11. Next, a plurality of these honeycomb units 11 are bonded together using the same sealing material paste as in Experimental Example 1, the bonded body is cut in the same manner as in Experimental Example 1 to form a coating material layer 16, and has a cylindrical shape (diameter 143.8). The honeycomb structural body 10 of mmφ x length 150mm) was obtained.

[Specific surface area measurement]

The specific surface area of the honeycomb unit 11 of Experimental Examples 1-51 and Experimental Examples A-T was measured. First, the volume of the honeycomb unit 11 and the sealing material was measured, and the ratio A (vol%) of the material of the unit to the volume of the honeycomb structure was calculated. Next, the BET specific surface area B (m <2> / g) per unit weight of the honeycomb unit 11 was measured. The BET specific surface area was measured by the one-point method according to IS-R-1626 (1996) determined by Japanese Industrial Standards, using a BET measuring device (Micromeritics Probes II-2300 manufactured by Shimadzu Corporation). The sample cut out into the cylindrical small piece (diameter 15mm (phi) x length 15mm) was used for the measurement. And the external density C (g / L) of the honeycomb unit 11 is computed from the weight of the honeycomb unit 11, and the volume of an external shape, and the specific surface area S (m <2> / L) of a honeycomb structure 11 is obtained by the following formula. Obtained from (1). In addition, the specific surface area of a honeycomb structure here means a specific surface area per external volume of a honeycomb structure.

S (m 2 / L) = (A / 100) × B × C; Formula (1)

[Thermal shock and vibration repeat test]

The thermal shock and vibration repeated tests of the honeycomb structures of Experimental Examples 1 to 51 and Experimental Examples A to T were performed. The thermal shock test was carried out in a firing furnace set at 600 ° C. with an alumina mat (Mitsubishi Chemical Maftech, 46.5 cm × 15 cm, 6 mm thick) made of alumina fibers wound around the outer circumferential surface of the honeycomb structure and placed in a metal casing 21. The mixture was heated for 10 minutes, taken out of the kiln, and quenched to room temperature. Next, the vibration test was done, putting the honeycomb structure into this metal casing. The front view of the vibration apparatus 20 used for the vibration test in FIG. 6A is shown, and the side view of the vibration apparatus 20 is shown in FIG. 6B. The metal casing 21 into which the honeycomb structure was put was placed on the pedestal 22, and the metal casing 21 was fixed by tightening the substantially U-shaped fastener 23 with the screw 24. By doing so, the metal casing 21 can be vibrated in a state where the pedestal 22 and the fixture 23 are integrated. The vibration test was performed on Experimental Examples 1-51 on the conditions of frequency 160Hz, acceleration 30G, amplitude 0.58mm, holding time 10hr, room temperature, and a vibration direction Z-axis direction (up and down). On the other hand, the retention time was set to 20 Hr in Experimental Examples 1-1 to 1-9. The thermal shock test and the vibration test were repeated 10 times each in turn, and the weight T0 of the honeycomb structure before the test and the weight Ti after the test were measured, and the weight reduction rate G was calculated using the following equation (2). Obtained.

G (% by weight) = 100 x (T0-Ti) / T0; Formula (2)

[Pressure loss measurement]

The pressure loss of the honeycomb structures of Experimental Examples 1 to 51 and Experimental Examples A to T was measured. The pressure loss measuring apparatus 40 is shown in FIG. The measuring method arrange | positioned the honeycomb structure which wrapped the alumina mat in the exhaust pipe of the 2L common rail diesel engine in the metal casing, and attached the pressure gauge before and after the honeycomb structure. In addition, the measurement conditions set the engine speed to 1500 rpm and torque 50Nm, and measured the differential pressure 5 minutes after the start of operation.

[Experiment result]

Ceramic particle component, unit cross-sectional area, unit area ratio, specific surface area of honeycomb unit, specific surface area S of honeycomb structure, test weight reduction rate (G) of repeated thermal shock and vibration tests of Experimental Examples 1 to 29 and Experimental Examples 44 to 47, and Table 5 shows the sum of the numerical values of the pressure loss and the like, and FIG. 8 shows a plot of the weight loss rate (G) and the pressure loss of the thermal shock / vibration repeated test using the cross-sectional area of the honeycomb unit as the horizontal axis. Fig. 9 is a plot showing the unit area ratio as the horizontal axis and the weight loss rate (G) and the pressure loss in the thermal shock / vibration repeated test as the vertical axis.

※ Inorganic fiber = silica-alumina fiber (diameter 10 ㎛, length 100 ㎛, aspect ratio 10)

As is clear from the measurement results of Experimental Examples 1 to 29 and Experimental Examples 44 to 47 shown in Table 5 and FIG. 8, the cross-sectional area of the honeycomb unit 11 is 5 to 5 based on ceramic particles, inorganic fibers and an inorganic binder. When it set to the range of 50 cm <2>, it turned out that the specific surface area per unit volume of a honeycomb structure becomes large, and sufficient intensity | strength with respect to thermal shock and vibration is obtained. In addition, as shown in FIG. 9, when ceramic particle, an inorganic fiber, and an inorganic binder are main components, the cross-sectional area of the honeycomb unit 11 shall be 50 cm <2> or less, and a unit area ratio shall be 85% or more. It was found that the specific surface area per unit volume of the comb structure could be increased, sufficient strength against thermal shock and vibration was obtained, and the pressure loss decreased. In particular, the pressure loss was remarkable when the unit area ratio was 90% or more.

Next, the thermal shocks of Experimental Examples A to J in which the radius of curvature R of the corner portions 18 of the honeycomb unit were changed, and Experimental Examples K to T in which the C surface shape of the corner portions 18 of the honeycomb unit were changed. Table 4 summarizes the weight loss rate (G) of the vibration repeat test, the results of the pressure loss, and the like. From this result, when the curvature radius R of each part 18 of the honeycomb unit exists in the range of 0.3-2.5 mm, it turned out that favorable strength is obtained for a honeycomb structure. Moreover, when the C surface shape was 0.3-2.5 mm, it turned out that favorable strength is obtained in a honeycomb structure. Moreover, even when each part of one honeycomb unit contains both the shape of the R surface and the shape of the C surface of the said range, it is easily inferred that the same effect is acquired.

Next, with respect to Experimental Examples 1 and 30 to 34 in which the aspect ratio of the inorganic fiber was changed, the diameter, length, aspect ratio of the silica-alumina fiber, the specific surface area of the honeycomb unit 11, and the specific surface area of the honeycomb structure ( S), the weight reduction rate (G) of the thermal shock and vibration repetition test, and the numerical values of the pressure loss are shown in Table 6, and the weight reduction rate of the thermal shock and vibration repetition test with the aspect ratio of the silica-alumina fiber as the horizontal axis ( 10 is plotted with G) as the vertical axis.

※ ceramic particle = γ-alumina

From this result, it turned out that sufficient strength with respect to thermal shock and vibration is obtained when the aspect ratio of an inorganic fiber is the range of 2-1000.

Next, about the experimental examples 48-50 which produced the honeycomb unit 11 by changing the kind of inorganic binder, and Experimental example 51 produced without mixing an inorganic binder, the kind of the inorganic binder and the honeycomb unit 11 Table 7 summarizes the firing temperature, unit area ratio, specific surface area of the honeycomb unit, specific surface area (S) of the honeycomb structure, weight loss rate (G) of the thermal shock and vibration test, and numerical values of the pressure loss. .

※) Ceramic particle = γ-alumina

   Inorganic Fiber = Silica-Alumina Fiber (Diameter 10μm, Length 100μm, Aspect Ratio 10)

   Unit shape = 3.43 cm

From this result, it turned out that when an inorganic binder is not mixed, it bakes at comparatively high temperature, and sufficient strength is obtained. Moreover, when mixing an inorganic binder, even if it baked at comparatively low temperature, it turned out that sufficient strength is obtained. In addition, even when the inorganic binder was an alumina sol or a clay-based binder, it was found that the specific surface area per unit volume of the honeycomb structure 10 could be increased, and sufficient strength against thermal shock and vibration was obtained.

Honeycomb Catalyst

The honeycomb structures 10 of Experimental Examples 1 to 43 were impregnated into a platinum nitrate solution, and the catalyst components were supported by adjusting the platinum weight per unit volume of the honeycomb structure 10 to be 2 g / L, and the catalyst component was carried out at 600 ° C for 1 hr. To obtain a honeycomb catalyst.

INDUSTRIAL APPLICABILITY The present invention can be used as a catalyst carrier for purifying exhaust gas of a vehicle, or as an adsorbent for adsorbing gas components and liquid components.

Claims (11)

As a honeycomb structure in which a plurality of through-holes are arranged in a longitudinal direction with a through-hole wall surface interposed therebetween, a plurality of honeycomb structures bound together through a sealing material layer, The honeycomb unit contains at least ceramic particles, inorganic fibers, whiskers, or inorganic fibers and whiskers, and has a cross-sectional area of 5 cm 2 or more and 50 cm 2 or less in a cross section perpendicular to the longitudinal direction of the honeycomb unit, Each part of the honeycomb unit is a honeycomb structure, characterized in that the shape of the R surface, C surface, or R surface and C surface. The method of claim 1, A honeycomb structure, characterized in that the radius of curvature (R) of the R surface of each portion of the honeycomb unit is 0.3 to 2.5 mm. The method of claim 1, C surface of each portion of the honeycomb unit is a honeycomb structure, characterized in that the C-plane shape of 0.3 to 2.5mm. The method according to any one of claims 1 to 3, The honeycomb structure according to the present invention, wherein the proportion of the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb structure is 85% or more. The method according to any one of claims 1 to 3, Honeycomb structure, characterized in that it has a coating layer on the outer peripheral surface. The method according to any one of claims 1 to 3, The ceramic particle is at least one member selected from the group consisting of alumina, silica, zirconia, titania, ceria, mullite and zeolite. The method according to any one of claims 1 to 3, The inorganic fiber, whisker, or inorganic fiber and whisker is at least one member selected from the group consisting of alumina, silica, silicon carbide, silica-alumina, glass, potassium titanate and aluminum borate. The method according to any one of claims 1 to 3, The honeycomb unit is manufactured using a mixture containing the inorganic particles, the inorganic fibers, whiskers, or inorganic fibers and whiskers, and an inorganic binder, The inorganic binder is a honeycomb structure, characterized in that at least one selected from the group consisting of alumina sol, silica sol, titania sol, water glass, sepiolite and attapalzite. The method according to any one of claims 1 to 3, A honeycomb structure in which a catalyst component is supported. The method of claim 9, The catalyst component is a honeycomb structure containing one or two or more components selected from precious metals, alkali metals, alkaline earth metals and oxides. The method according to any one of claims 1 to 3, A honeycomb structure, which is used for purifying exhaust gas of a vehicle.

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