JP2008126192A - Honeycomb carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb carrier the temperature of which is raised easily up to the predetermined temperature so that a catalyst can be reached to an activation temperature in early stages and the temperature of which is hardly raised when exceeding the predetermined temperature so that the catalyst can be prevented from being exposed to unnecessary high temperature. <P>SOLUTION: The honeycomb carrier 1 is obtained by depositing a substance, which generates heat to adsorb CO<SB>2</SB>below the predetermined temperature and adsorbs heat to release the adsorbed CO<SB>2</SB>when the temperature of the substance exceeds the predetermined one, on at least a part of the honeycomb carrier to be used for depositing the catalyst. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a honeycomb carrier for supporting a catalyst. More specifically, a honeycomb that can be easily heated at a low temperature, has excellent light-off characteristics, is difficult to be heated at a high temperature, can suppress the maximum temperature low, and can suppress deterioration of the supported catalyst due to heat. Relates to the carrier.

  In order to purify exhaust gas discharged from various engines, honeycomb-structured catalytic converters are widely used. In this catalytic converter, a catalyst such as a precious metal is alumina on the partition wall surface of a honeycomb structure carrier (honeycomb carrier) having porous partition walls arranged so as to form a plurality of cells communicating between two end faces. A catalyst layer formed by dispersing and supporting a heat-resistant inorganic oxide having a high specific surface area such as the above is coated (for example, see Patent Document 1).

  Further, as a diesel particulate filter (DPF) for collecting carbon fine particles contained in the exhaust gas of a diesel engine, a plugging portion is formed at one end of each cell of the honeycomb carrier as described above. A wall flow type filter in which exhaust gas flowing in from one end surface side passes through a porous partition wall serving as a filtration layer and flows out from the other end surface side is widely used (for example, Patent Document 2). In such a filter, the carbon fine particles deposited on the partition walls are periodically burned and removed to regenerate the filter performance, but the combustion removal is promoted or combined with the collection of the carbon fine particles. In order to purify CO or HC in the exhaust gas, a catalyst layer may be coated on the surface of the partition wall.

  By the way, in the catalytic converter, it is important in terms of catalyst performance that the honeycomb catalyst body itself is likely to rise in temperature so that the catalyst can quickly reach its activation temperature. When exposed to an excessively high temperature, the noble metal, alumina and the like in the catalyst layer are aggregated and the catalytic activity is lost. Therefore, it is necessary to prevent exposure to an excessively high temperature.

  In addition, in a DPF coated with a catalyst layer, it is preferable that regeneration treatment and CO and HC purification can be performed even under the lowest possible gas temperature conditions from the viewpoint of preventing an increase in pressure loss and improving purification performance. It is important that the DPF itself easily rises in temperature so that the catalyst can reach its activation temperature quickly. On the other hand, in the regeneration process in which the carbon fine particles are burned, the vicinity of the end face on the outlet side is important. Since the part tends to become excessively high temperature, it is necessary to suppress it.

  Conventionally, as a means for causing the catalyst to reach the activation temperature quickly, the heat capacity of the honeycomb carrier is reduced or the cell density is increased to improve the heat transfer. There is a limit, and it is the fact that sufficient results are not obtained. In addition, attempts have been made to heat the gas by an electric heating means, but there is a disadvantage that a complicated device and electric energy are required.

As an alternative to these, alkaline earth metal oxides that generate heat by reacting with water (H ₂ O) are included in the catalyst, and heat is generated by reaction with water when the engine is started to warm the catalyst. Although a method is disclosed (see, for example, Patent Document 3), it easily reacts with H ₂ O in the atmosphere or exhaust gas to reach a saturated state, and therefore after an engine stop period of about one day or night Even if the engine is started again, there is a problem that no further reaction with H ₂ O occurs and the engine cannot be used for warming up at the time of starting. In addition, if it reacts with CO ₂ in the atmosphere or exhaust gas to become carbonate, the decomposition temperature is as high as about 900 ° C., and thus there is a problem that regeneration during engine operation is difficult.

On the other hand, as a means for preventing the catalyst from being exposed to an excessively high temperature, increasing the heat capacity of the honeycomb carrier is a means generally adopted in both the catalytic converter and the DPF. There is a problem that the warm-up property at the start of the engine deteriorates.
JP 2003-33664 A JP 2001-269585 A JP 59-208118 A

  The present invention has been made in view of such conventional circumstances, and the object of the present invention is to easily increase the temperature up to a predetermined temperature, to allow the catalyst to reach the activation temperature early, An object of the present invention is to provide a honeycomb carrier that is difficult to increase in temperature when the temperature is exceeded and that prevents the catalyst from being exposed to an excessively high temperature.

  In order to achieve the above object, according to the present invention, the following honeycomb carrier is provided.

[1] A honeycomb carrier used to support the catalyst, at a predetermined temperature or lower to generate heat by adsorbing CO _2, the material that absorbs heat by releasing the CO ₂ adsorbed exceeds a predetermined temperature A honeycomb carrier supported on at least a part of the honeycomb carrier.

[2] The honeycomb carrier according to [1], wherein the substance is Li ₄ SiO ₄ or Li ₂ ZrO ₃ .

[3] The honeycomb carrier according to [1] or [2], wherein the substance is supported on at least a part of the honeycomb carrier in a state where the substance is mixed in a catalyst layer containing an inorganic oxide and a catalyst.

[4] The honeycomb carrier according to any one of [1] to [3], wherein the substance is supported only in a region from one end face of the honeycomb carrier to a length of 20% or less of the total length of the honeycomb carrier.

[5] The honeycomb carrier according to any one of [1] to [3], wherein the substance is supported only in a region from each end face of the honeycomb carrier to a length of 20% or less of the total length of the honeycomb carrier.

[6] The honeycomb carrier according to any one of [1] to [5], which is used for manufacturing a catalytic converter.

[7] The honeycomb carrier according to any one of [1] to [5], which is used for producing a diesel particulate filter.

  The honeycomb carrier of the present invention has a characteristic that the temperature easily rises up to a predetermined temperature and hardly rises when the temperature exceeds the predetermined temperature. Therefore, if a catalyst is supported on the honeycomb carrier to produce a catalytic converter or a DPF. The catalyst can reach the activation temperature at an early stage, and the catalyst can be prevented from being exposed to an excessively high temperature, so that a product having a high performance and a long life can be obtained.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

The honeycomb carrier of the present invention is used for supporting a catalyst when producing a catalytic converter, a DPF with a catalyst, etc., and at least a part of the honeycomb carrier adsorbs CO ₂ at a predetermined temperature or less. The main feature is that a substance that generates heat and absorbs heat by releasing the adsorbed CO ₂ when the temperature exceeds the predetermined temperature (hereinafter referred to as “exothermic / endothermic substance”) is supported. In the present specification, the “honeycomb carrier” refers to a honeycomb structure carrier having porous partition walls arranged so that a plurality of cells (through holes) communicating between two end faces are formed.

  If a catalytic converter or a DPF with a catalyst is produced using a honeycomb carrier carrying an exothermic / endothermic substance as described above, the temperature easily rises to a predetermined temperature, and the catalyst can reach the activation temperature early. At the same time, when the temperature exceeds a predetermined temperature, it is difficult to increase the temperature, and the catalyst can be prevented from being exposed to an excessively high temperature.

Usually, the active temperature of a catalyst used for a catalytic converter or a DPF with a catalyst is about 200 to 600 ° C., and the temperature at which the catalytic activity is lost is about 800 to 1000 ° C., so it is used in the present invention. The exothermic / endothermic substance is preferably one that absorbs CO ₂ from room temperature to about 600 to 700 ° C. to generate heat, and releases the absorbed CO ₂ to absorb heat when the temperature is exceeded.

Specific examples of such exothermic / endothermic substances include Li ₄ SiO ₄ and Li ₂ ZrO ₃ , but any other substance may be used as long as it has the above properties. May be used. The following formula (1) shows the adsorption / release reaction of CO ₂ by Li ₄ SiO ₄ , and the following formula (2) shows the adsorption / release reaction of CO ₂ by Li ₂ ZrO ₃ .
Li ₄ SiO ₄ + CO ₂ ← → Li ₂ SiO ₃ + Li ₂ CO ₃ (1)
Li ₂ ZrO ₃ + CO ₂ ← → ZrO ₂ + Li ₂ CO ₃ (2)

In Li ₄ SiO ₄ and Li ₂ ZrO ₃ , the reaction (CO ₂ adsorption) in the right direction of the above formulas (1) and (2) occurs up to about 700 ° C. This reaction is an exothermic reaction. In the case of Li ₄ SiO ₄ , the reaction generates heat of about 80 kJ / mol in a temperature environment of 100 ° C., for example. In the initial stage of operation, the support temperature rises due to the heat of reaction, and the catalyst reaches the activation temperature early. On the other hand, when the temperature is exceeded, a leftward reaction (CO ₂ release) of the above formulas (1) and (2) occurs. Since this reaction is an endothermic reaction, an effect of suppressing an increase in the support temperature is generated, and deactivation and deterioration due to an excessive temperature increase of the catalyst can be suppressed.

The exothermic / endothermic substance used in the present invention preferably has a time of 100 hours or more until the CO ₂ absorption reaction at room temperature in air with a CO ₂ concentration of 1% reaches saturation. Li ₄ SiO ₄ and Li ₂ ZrO ₃ are also suitable in this respect. In the case of reaching saturation in a short time, when the engine stop period extends for a long time (for example, all day and night), CO ₂ in the atmosphere is absorbed and saturated during that period, and further after the engine is started. This is because there is a possibility that CO ₂ cannot be adsorbed. If it takes more than 100 hours to reach the saturation state, the CO ₂ absorption in the engine stop period of about a day and night can be almost ignored. Since the CO ₂ concentration contained in the exhaust gas is several percent or more, after the engine is started, it absorbs CO ₂ and generates heat in a shorter time.

  The amount of exothermic / endothermic substance supported is not particularly limited, but from the viewpoint of obtaining a sufficient exothermic / endothermic effect, the amount supported per unit volume of the honeycomb carrier is preferably 60 g / L or more, and 120 g / L or more. More preferred. The exothermic / endothermic substance may be supported on the entire honeycomb carrier or may be partially supported. In the case of being partially supported, the exothermic / endothermic substance is supported only in a region from one end face of the honeycomb carrier to a length of 20% or less of the total length of the honeycomb carrier, or from both end faces of the honeycomb carrier. It is preferably supported only in a region up to 20% or less of the total length of the carrier.

For example, in the case of a honeycomb carrier used for the production of a catalytic converter, the length from one end face of the honeycomb carrier (the end face on the exhaust gas inlet side when used as a catalytic converter) to a length of 20% or less of the total length of the honeycomb carrier. When an exothermic / endothermic substance is intensively supported in the region, the supporting region generates heat locally during CO ₂ adsorption and the catalyst is activated early, and the temperature rise is further accelerated by reaction heat generated in the catalytic reaction.

  Also, in the case of a honeycomb carrier used for the production of a DPF with a catalyst, from the viewpoint of improving warm-up properties, the honeycomb carrier starts from one end surface of the honeycomb carrier (the end surface on the exhaust gas inlet side when used as a DPF). It is preferable to intensively support the exothermic / endothermic substance in a region up to 20% of the total length, and in addition to this, the other end face of the honeycomb carrier (the one on the exhaust gas outlet side when used as a DPF) It is more preferable that the exothermic / endothermic substance is intensively supported in a region from the end face of the substrate) to a length of 20% or less of the total length of the honeycomb carrier. By doing so, it is possible to suppress an increase in temperature in the vicinity of the outlet side end face that tends to become excessively high during the regeneration process in which the carbon fine particles deposited in the DPF are burned.

  The form of the exothermic / endothermic substance supported on the honeycomb carrier is not particularly limited as long as the exothermic / endothermic substance can be supported so that it is not easily detached from the honeycomb carrier. However, the honeycomb carrier is coated when the catalytic converter or the DPF is manufactured. The catalyst layer containing the inorganic oxide and the catalyst is supported on at least a part of the honeycomb carrier in a state where exothermic / endothermic substances are mixed, so that the catalyst can reach the activation temperature early. From the viewpoint of preventing exposure to an excessively high temperature.

  In this case, preferred examples of the inorganic oxide contained in the catalyst layer include alumina and ceria. Moreover, as a catalyst contained in a catalyst layer, noble metals, such as Pt, Pd, and Rh, are mentioned as a suitable thing. A catalyst such as a noble metal is preferably coated on the honeycomb carrier in a state of being dispersed and supported on inorganic oxide particles. One kind of each of these inorganic oxides and catalysts may be used, or a plurality of kinds may be mixed in the catalyst layer.

  As a method for coating such a catalyst layer on the honeycomb carrier, a coating slurry containing these inorganic oxide, catalyst, exothermic / endothermic substance, etc. is prepared, and the honeycomb carrier is dipped into the slurry, and the surface of the partition wall And a method of drying the slurry at room temperature or under heating conditions after coating the slurry in the pores.

  In the present invention, as a material constituting the main body portion of the honeycomb carrier (a portion excluding a carrier such as an exothermic / endothermic substance), a material mainly composed of ceramic, a sintered metal, or the like can be cited as a preferred example. it can. Specifically, when it is made of a material whose main component is ceramic, ceramics include silicon carbide, cordierite, alumina titanate, sialon, mullite, silicon nitride, zirconium phosphate, zirconia, titania, alumina, Alternatively, silica or a combination thereof can be cited as a preferred example. In particular, ceramics such as silicon carbide, cordierite, mullite, silicon nitride, and alumina are preferable in terms of alkali resistance. Among these, oxide ceramics are preferable from the viewpoint of cost.

  The thickness of the partition walls of the honeycomb carrier is preferably 30 to 180 μm, more preferably 50 to 120 μm, and still more preferably 50 to 90 μm. If each partition is too thin, the strength may be insufficient and thermal shock resistance may be reduced. On the other hand, if the partition wall is too thick, the pressure loss may increase too much.

  The average pore diameter of the partition walls is preferably 1 to 20 μm, more preferably 1 to 15 μm, and still more preferably 1 to 13 μm. By setting the average pore diameter of the partition walls in such a range, when the honeycomb carrier of the present invention is used for a DPF, it is possible to increase the collection efficiency of carbon fine particles while suppressing pressure loss. When the average pore diameter of the partition walls is less than 1 μm, the pressure loss may increase excessively, and when it exceeds 20 μm, the collection efficiency decreases. Here, the “average pore diameter” is a value measured by a mercury intrusion method.

  The porosity of the partition walls is preferably 25 to 65%, more preferably 25 to 60%, and still more preferably 25 to 55%. When the porosity of the partition walls is less than 25%, the flow rate of exhaust gas passing through the partition walls increases and the purification performance tends to deteriorate. On the other hand, when the porosity exceeds 65%, the strength tends to be insufficient. The “porosity” referred to here is a value measured by a mercury intrusion method.

Cell density of the honeycomb carrier is preferably 7.8 to 186 cells ^/ cm 2 ^{(50~1200cpsi),} more preferably from 15.5 to 140 cells ^{/ cm 2 (100~900cpsi), 15} . More preferably, it is 5-93 cells / cm < ² > (100-600 cpsi). When the cell density is less than 7.8 cells / cm ² , the contact efficiency with the exhaust gas tends to be insufficient. On the other hand, when the cell density exceeds 186 cells / cm ² , the pressure loss tends to increase. “Cpsi” is an abbreviation for “cells per square inch”, and is a unit representing the number of cells per square inch.

  The overall shape of the honeycomb carrier is not particularly limited, but the cross-sectional shape perpendicular to the central axis is preferably a shape suitable for the inner shape of the exhaust system to be installed. Specifically, shapes such as a circle, an ellipse, an ellipse, a trapezoid, a triangle, a quadrangle, and a hexagon can be given. The cell shape (cell shape in a cross section perpendicular to the central axis of the honeycomb carrier) is not particularly limited, and may be any shape such as a triangle, a quadrangle, a hexagon, and the like.

  The main body portion of the honeycomb carrier can be obtained by a manufacturing method similar to a conventionally known method for manufacturing a honeycomb carrier. Specifically, first, the material for the honeycomb carrier as described above is mixed and kneaded to obtain a forming clay. For example, when cordierite is used as a honeycomb carrier material, a cordierite-forming material is kneaded with a dispersion medium such as water, a binder, a pore former, a dispersant, etc. To do. Here, the “cordierite raw material” is a ceramic raw material blended so as to be cordierite by firing. Specific examples include those containing a plurality of raw materials selected from talc, kaolin, alumina, silica, and the like at a ratio that provides a chemical composition of cordierite.

  Next, the obtained clay is formed into a honeycomb shape by extrusion molding or the like to obtain a honeycomb formed body, which is dried and then fired to obtain a honeycomb carrier. For example, in the case of a cordierite forming raw material, it is preferable that the firing conditions be fired at 1400 ° C. or higher for about 3 to 10 hours.

  The honeycomb carrier of the present invention is for carrying a catalyst, and can be suitably used for production of a catalytic converter or a DPF.

  FIG. 1 is an explanatory view schematically showing an example of an embodiment of a catalytic converter manufactured using a honeycomb carrier of the present invention, where (a) is a front view and (b) is a cross-sectional view. When purifying exhaust gas using this catalytic converter 60, exhaust gas is allowed to flow into the cell 3 from one end face 2a side, and the exhaust gas is brought into contact with a catalyst layer (not shown) on the surface of the partition wall 4 to cause harmful components in the exhaust gas. And the exhaust gas after purification is discharged from the other end face 2b side to the outside.

  FIG. 2 is an explanatory view schematically showing an example of an embodiment of a DPF manufactured using the honeycomb carrier of the present invention, in which (a) is a front view and (b) is a cross-sectional view. When the honeycomb carrier of the present invention is used for a DPF, one end of each cell 3 of the honeycomb carrier 1 is plugged with a plugging portion 10. Usually, this plugging is performed so that adjacent cells are plugged at opposite ends, and as a result, the end face of the honeycomb carrier 1 has a checkered pattern. In the DPF 50 having such a structure, the exhaust gas flows into the cell 3 from the one end surface 2a side, passes through the porous partition wall 4 serving as a filtration layer, and flows out from the other end surface 2b side to the outside. When passing through the partition walls 4, carbon fine particles in the exhaust gas are captured by the partition walls 4. Further, exhaust gas comes into contact with a catalyst layer (not shown) coated on the surfaces of the partition walls 4 and in the pores of the partition walls 4, and harmful components such as CO and HC contained in the exhaust gas are purified.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Example 1)
Pt and Rh are added in a ratio (mass ratio) of Pt: Rh = 5: 1 with respect to 1300 g of powder composed of 1000 parts by mass of Al ₂ O ₃ powder and 300 parts by mass of CeO ₂ powder, and 2000 g of water is further added. In addition, slurry A for coating was obtained by wet pulverization. Further, 1200 g of Li ₄ SiO ₄ crushed particles (average particle size 3 μm) and 1850 g of water were added to the coating slurry A, and dispersed uniformly in the slurry, thereby obtaining a coating slurry B. One end face of a cordierite honeycomb carrier (cell shape: square, cell density: 900 cpsi, partition wall thickness: 50 μm) having a diameter of 100 mm and a length of 110 mm (on the exhaust gas inlet side when mounted on an engine described later) The region from the other end surface) to 20 mm was dipped in the coating slurry B, and the coating slurry B was coated on the region. This coating operation was repeated until the amount of Li ₄ SiO ₄ supported was 120 g / L. Further, a region from the other end surface of the honeycomb carrier (the end surface on the exhaust gas outlet side when mounted on the engine described later) to 90 mm is dipped in the coating slurry A, and the coating slurry A is coated on the region. did. Thus, the honeycomb carrier coated with the coating slurries A and B was dried by heating to obtain a catalytic converter.

(Example 2)
A catalytic converter was obtained in the same manner as in Example 1 except that the coating operation of the coating slurry B was repeated until the supported amount of Li ₄ SiO ₄ reached 60 g / L.

(Example 3)
The same honeycomb carrier as that used in Example 1 was dipped in the coating slurry B, and the entire area of the honeycomb carrier was coated with the coating slurry B. This coating operation was repeated until the amount of Li ₄ SiO ₄ supported was 120 g / L. Thus, the honeycomb carrier coated with the coating slurry B was heat-dried to obtain a catalytic converter.

(Comparative example)
The same honeycomb carrier as that used in Example 1 was dipped in the coating slurry A, and the entire area of the honeycomb carrier was coated with the coating slurry A. Thus, the honeycomb carrier coated with the coating slurry A was dried by heating to obtain a catalytic converter.

[Evaluation]
The catalytic converters obtained in Examples 1 to 3 and the comparative example were each held in a metal tubular tube via an alumina fiber-based mat and mounted directly under the exhaust manifold of a 2 L gasoline engine. . The gasoline engine was first operated in the US regulated operation mode (LA-4), exhaust emission (HC emission) was measured, and the temperature of the catalytic converter 20 seconds after the start of operation was measured. The measurement results are shown in Table 1. Note that a K-type sheath thermocouple having a thickness of 0.2 mm was used for temperature measurement, and the measurement position was 10 mm from the inlet side end face of the honeycomb carrier.

  Next, the operation mode in which the idling operation and the operation at the maximum rotational speed (throttle fully opened) were alternately performed for 10 minutes was repeated, and the maximum temperature reached by the catalytic converter was measured. The results are shown in Table 2.

  Further, after the operation mode was repeated 50 cycles, the operation was stopped and left for a whole day and night, and the operation was performed again in the US regulated operation mode to measure the exhaust emission. The results are shown in Table 3.

As shown in Table 1, the catalytic converters of Examples 1 to 3 in which Li ₄ SiO ₄ was supported on the honeycomb carrier rapidly increased in temperature compared to the catalytic converter of the comparative example in which Li ₄ SiO ₄ was not supported. As a result, the initial warm-up characteristics were improved and the HC emission was kept low. Further, from the results of Example 1 and Example 3, it was found that the temperature rise is faster and the HC emission is lower when Li ₄ SiO ₄ is intensively supported near the inlet side end face of the exhaust gas. . Furthermore, from the results of Example 1 and Example 2, it was found that the higher the amount of Li ₄ SiO ₄ supported, the faster the temperature rise and the lower the HC emission.

Further, as shown in Table 2, the catalytic converters of Examples 1 to 3 in which Li ₄ SiO ₄ was supported on the honeycomb carrier reached the highest level compared with the catalytic converter of the comparative example in which Li ₄ SiO ₄ was not supported. The temperature was kept low. Furthermore, as a result of the maximum temperature reached being kept low in this way, catalyst deterioration due to heat was suppressed, and as shown in Table 3, the rate of deterioration of HC emissions was kept small.

  The present invention can be suitably used as a honeycomb carrier for producing a catalytic converter or a DPF with a catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows typically an example of embodiment of the catalytic converter produced using the honeycomb support | carrier of this invention, (a) is a front view, (b) is sectional drawing. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows typically an example of embodiment of DPF produced using the honeycomb support | carrier of this invention, (a) is a front view, (b) is sectional drawing.

Explanation of symbols

1: honeycomb carrier, 2a: end face, 2b: end face, 3: cell, 4: partition wall, 10: plugged portion, 50: DPF, 60: catalytic converter.

Claims (7)

A honeycomb carrier used to support the catalyst, at a predetermined temperature or lower to generate heat by adsorbing CO _2, the material that absorbs heat by releasing the CO ₂ adsorbed exceeds a predetermined temperature, said honeycomb A honeycomb carrier supported on at least a part of the carrier. The honeycomb carrier according to claim 1, wherein the substance is Li ₄ SiO ₄ or Li ₂ ZrO ₃ .   The honeycomb carrier according to claim 1 or 2, wherein the substance is supported on at least a part of the honeycomb carrier in a state of being mixed in a catalyst layer containing an inorganic oxide and a catalyst.   The honeycomb carrier according to any one of claims 1 to 3, wherein the substance is supported only in a region from one end face of the honeycomb carrier to a length of 20% or less of the total length of the honeycomb carrier.   The honeycomb carrier according to any one of claims 1 to 3, wherein the substance is supported only in a region from each end face of the honeycomb carrier to a length of 20% or less of the total length of the honeycomb carrier.   The honeycomb carrier according to any one of claims 1 to 5, which is used for production of a catalytic converter.   The honeycomb carrier according to any one of claims 1 to 5, which is used for producing a diesel particulate filter.

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