JP4771195B2 - Ceramic honeycomb filter and manufacturing method thereof, plugging material for ceramic honeycomb filter - Google Patents

Description

  The present invention relates to a ceramic honeycomb filter for removing fine particles contained in exhaust gas of a diesel engine and a method for manufacturing the same.

In order to remove particulates discharged from the diesel engine, the ceramic honeycomb structure has a porous partition wall and a particulate honeycomb ceramic honeycomb filter having a structure in which exhaust gas containing particulates is allowed to pass through the partition wall. Studies are underway to adopt a curate filter. In the ceramic honeycomb filter, both end faces of a flow path surrounded by an outer peripheral wall and a partition wall having a porous structure on the inner peripheral side are alternately plugged. When exhaust gas containing fine particles flows into such a ceramic honeycomb filter, the fine particles in the exhaust gas are collected in the pores formed in the partition walls. If the collected fine particles are excessively accumulated in the ceramic honeycomb filter, the pressure loss of the filter may increase, leading to a decrease in engine output. For this reason, the particulates collected periodically are burned using an external ignition means such as an electric heater or a burner to regenerate the ceramic honeycomb filter. Usually, a ceramic honeycomb filter is mounted in a single set of two, and an alternate regeneration method is employed in which one is used while the other is being regenerated.
Regarding the characteristics of the honeycomb filter with the above structure, it is important to keep the pressure loss of the filter low in order not to deteriorate the engine performance, but at the same time, it is abrupt when the filter is regenerated or the engine is stopped. It is required to have a thermal shock resistance that can withstand a thermal shock due to a temperature change, and as described below, a technique that has been improved by focusing on the plugged portion of the ceramic honeycomb filter has been disclosed. Yes.

  As a technique for plugging at a predetermined position on the end face of the ceramic honeycomb structure, in the invention described in Patent Document 1, the fired honeycomb structure is plugged with a cordierite raw material batch, and then 1300 ° C. A method for sealing the open end face of a ceramic honeycomb structure is disclosed, in which the cordierite raw material batch is fired at the above temperature to be converted into cordierite. According to the present invention, the open end face flow path of the ceramic honeycomb structure can be tightly and completely sealed, and a highly reliable cordierite honeycomb filter having excellent thermal shock resistance is obtained.

  In the invention described in Patent Document 2, a ceramic honeycomb structure that has been fired or unfired is composed of a powder that is pulverized after firing of the same material as the ceramic honeycomb structure and a powder that is crushed without firing. A ceramic honeycomb filter in which plugging portions are formed by plugging with a sealing material and heating at a high temperature of 1400 ° C. is disclosed. According to the present invention, since the pulverized powder of the same material as the ceramic honeycomb structure is used as the plugging material, the ceramic honeycomb structure and the plugging portion are used in a high temperature condition. It is assumed that cracks do not occur in the plugged portions and the honeycomb structure due to the difference in thermal expansion, and that the plugged portions are not peeled off and no problems occur.

  In addition, in the invention described in Patent Document 3, a film is attached to the opening end face of the ceramic honeycomb structure, a hole is formed in a predetermined portion of the film, and then a plugging material is introduced into the flow path from the hole. According to Example 3, the water is added to the raw material composed of the alumina cement and the mullite pulverized product, and vibration is applied to the plugging material in the form of clay. A technique is disclosed in which a honeycomb structure and a plugged portion are integrated by introducing into a predetermined flow path, and then curing by holding for 2 hours at a temperature of 55 ° C. and a humidity of 90%.

Japanese Patent Publication No. 63-28875 JP 2002-136817 A Japanese Patent Publication No. 63-24731

  However, when the ceramic honeycomb filter according to the inventions described in Patent Documents 1 to 3 as the prior art is used as a filter for collecting fine particles, due to thermal shock caused by exhaust gas, the following plugging portion is formed. A related problem occurred.

In the prior art described in Patent Document 1, since the ceramic honeycomb filter is often exposed to a high temperature during use, cordierite ceramic having heat resistance and a small thermal expansion coefficient is used for the honeycomb structure. Also for the sealing material, cordierite ceramic of the same material as the honeycomb structure is used in order to reduce the difference in thermal expansion from the ceramic honeycomb structure. For this purpose, the plugging material is fixed to the ceramic honeycomb structure by heating the cordierite raw material to a cordierite-forming temperature (for example, 1300 ° C.) or higher so as to be cordierite. By the way, the cordierite-type ceramic honeycomb structure is formed by orienting the raw plate-like kaolin particles in the wall surface when passing through a narrow slit of the mold by an extrusion molding method, and thereafter, the cordierite crystals produced by firing are aligned. Orientation is performed so that the thermal expansion coefficient in the flow path direction and the radial direction of the honeycomb structure becomes small. However, since the plugging material forming the plugging portion does not pass through the narrow slit of the mold, the orientation of the cordierite crystal becomes random, and it is difficult to make the thermal expansion coefficients of the two completely coincide. . Therefore, by integrating the plugging material with the honeycomb structure at a high temperature of 1300 ° C. or higher and then returning to room temperature, due to the difference in thermal expansion coefficient between the plugging portion of the honeycomb structure and the cell wall, A large residual stress acts on the interface. Since the magnitude of this residual stress is determined by the difference in thermal expansion coefficient between them and the temperature at which they are fixed and integrated, a large residual stress acts when integrated at 1300 ° C. or higher. For this reason, by having this residual stress, the plugged portion or the plugged portion and the honeycomb are affected by a thermal shock caused by exhaust gas when actually mounted on an automobile or a mechanical shock from engine vibration or road surface vibration. There may be a problem that a crack occurs at the interface of the structure or the plugged portion easily falls off.
In the case of plugging into a fired ceramic honeycomb fired body, a step of firing the ceramic honeycomb formed body and a cordierite forming temperature (for example, 1300 ° C.) for fixing the plugging material to the ceramic honeycomb fired body There is also a problem in that an excessive manufacturing cost is generated because the two baking steps of heating and baking are necessary.

  In the prior art described in Patent Document 2, a fired or unfired ceramic honeycomb structure is composed of a powder pulverized after firing of the same material as the ceramic honeycomb structure and an unfired pulverized powder. Plugged with a sealing material and heated at a high temperature of 1400 ° C. to form a plugged portion. For this reason, when, for example, cordierite ceramic is used for the ceramic honeycomb structure, it is difficult to make the thermal expansion coefficients of the honeycomb structure and the plugged portions completely coincide with each other as in Patent Document 1. In addition, since the temperature for fixing and integration is as high as 1400 ° C., a large residual stress acts. For this reason, by having this residual stress, the plugged portion or the plugged portion and the honeycomb are affected by a thermal shock caused by exhaust gas when actually mounted on an automobile or a mechanical shock from engine vibration or road surface vibration. There may be a problem that a crack occurs at the interface of the structure or the plugged portion easily falls off.

  Moreover, in Example 3 of the invention described in Patent Document 3, since the plugging material is not fired and the plugging material may be cured at 55 ° C., the temperature is 1300 ° C. or more as in the above-described conventional technique. The residual stress generated is smaller than in the case of integration, and there is no problem of excessive manufacturing costs due to the two firing steps. However, in order to fix the cordierite honeycomb structure with a small thermal expansion coefficient and the plugging portion at low temperature, the plugging portion is formed of mullite having a large thermal expansion coefficient and alumina cement having a larger thermal expansion coefficient. Therefore, due to the thermal expansion difference between the partition walls and the plugging portions of the cordierite honeycomb structure, cracks may occur between the two due to the thermal shock caused by the exhaust gas when actually attached to the automobile. In some cases, the sealing part peels off and falls off, leading to a problem that unpurified exhaust gas is discharged.

  An object of the present invention is to solve the problem that occurs between the partition walls and the plugging portions of the ceramic honeycomb structure, and to firmly fix the partition walls and the plugging portions and to have excellent thermal shock resistance. An object of the present invention is to provide a manufacturing method capable of obtaining a filter and reducing the manufacturing cost of the ceramic honeycomb filter.

  The present inventors have selected the plugging material of the ceramic honeycomb filter and optimized the manufacturing method for fixing the plugging material, thereby comparing with a ceramic honeycomb filter manufactured by a conventional manufacturing method. The inventors have come up with the invention of a ceramic honeycomb filter that can greatly improve the adhesion and thermal shock resistance between the partition walls and the plugging portions, and further reduce the manufacturing cost.

That is, the ceramic honeycomb filter of the present invention forms a plugged portion in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and exhausts it to a porous partition wall that partitions the flow path. A ceramic honeycomb filter for removing fine particles contained in exhaust gas by allowing gas to pass therethrough, wherein at least the plugging portions are formed of at least ceramic particles and a colloidal oxide existing therebetween. An amorphous oxide matrix formed from a colloidal oxide present between the ceramic particles in the plugging portion is formed with respect to 100 parts by mass of the ceramic particles. It is -35 mass parts.

In the ceramic honeycomb filter of the present invention, the ceramic particles are preferably cordierite particles and / or amorphous silica particles. The ceramic particles are preferably composed of pulverized powder of the same material as the ceramic honeycomb fired body.
In the ceramic honeycomb filter of the present invention, the colloidal oxide is preferably colloidal silica and / or colloidal alumina.

In the method for manufacturing a ceramic honeycomb filter of the present invention, a plugging portion is formed with a plugging material in a predetermined channel of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and the channel is partitioned. A method of manufacturing a ceramic honeycomb filter that removes fine particles contained in exhaust gas by allowing exhaust gas to pass through a porous partition wall, wherein the plugging portion is composed of at least ceramic particles and a colloidal oxide. The plugging material is fixed to the ceramic honeycomb fired body at a temperature of 1000 ° C. or less, and the plugging portion is present between the ceramic particles of the plugging portion with respect to 100 parts by mass of the ceramic particles. amorphous oxide matrix formed from the colloidal oxide is characterized by 2 to 35 parts by der Rukoto.

In the method for manufacturing a ceramic honeycomb filter of the present invention, the temperature at which the plugging portion fixes the plugging material composed of at least ceramic particles and colloidal oxide to the ceramic honeycomb fired body is 500 ° C. or less. It is preferable, More preferably, it is 150 degrees C or less.

In the method for manufacturing a ceramic honeycomb filter of the present invention, it is preferable that the ceramic particles are composed of pulverized powder of the same material as the ceramic honeycomb fired body.

The plugging material for a ceramic honeycomb filter according to the present invention is a porous material that forms plugging portions in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and partitions the flow path. A plugging material for a ceramic honeycomb filter that removes fine particles contained in the exhaust gas by allowing the exhaust gas to pass through a quality partition wall, the plugging material comprising at least ceramic particles and a colloidal oxide consists, with respect to the ceramic particles 100 parts by weight, it characterized that you blend the colloidal oxide in an amount of 2 to 35 parts by weight in terms of solid content.

The operation of the present invention will be described below.
First, the ceramic honeycomb filter of the present invention will be described in detail with reference to FIGS. FIG. 1 is a perspective view of a ceramic honeycomb filter 11 of the present invention, and FIG. 2 is a schematic cross-sectional view when the ceramic honeycomb filter 11 of FIG. 1 is used as an exhaust gas purification filter. As shown in FIGS. 1 and 2, the ceramic honeycomb filter 11 of the present invention has an outer peripheral wall 11a and a flow path 11c surrounded by a partition wall 11b on the inner peripheral side of the outer peripheral wall 11a. Both end surfaces of the inflow side 11d and the outflow side 11e are alternately plugged with plugging portions 12a and 12b. The ceramic honeycomb filter 11 is held in the metal storage container 14 with the outer peripheral wall 11a held by the holding members 13a and 13b, and the exhaust gas containing fine particles is opened on the inflow side 11d. After flowing in the channel 11c (indicated by 10a) and passing through the partition wall 11b made of porous ceramic, it is discharged from the outflow side 11e (indicated by 10b) through the adjacent channel. At this time, fine particles contained in the exhaust gas are collected in pores (not shown) formed in the partition walls 11b, and the ceramic honeycomb filter 11 can be used as an exhaust gas purification filter.
In the ceramic honeycomb filter of the present invention, a plugged portion is formed in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and exhaust gas is supplied to a porous partition wall that divides the flow path. A ceramic honeycomb filter that removes particulates contained in exhaust gas by allowing it to pass through, wherein the plugged portion is an amorphous formed from at least ceramic particles and a colloidal oxide existing therebetween It is composed of an oxide matrix. Thus, in order to fix the ceramic honeycomb structure and the plugging portion, it is not necessary to perform high-temperature firing at 1300 ° C. or higher, for example, as in the prior art, and the honeycomb structure and plugging at a temperature of 1000 ° C. or lower. Since the stop portion can be fixed, the residual stress accompanying the fixation of both can be reduced. By suppressing this residual stress to a small level, the plugged portion or the plugged portion and the honeycomb structure are affected by thermal shock caused by exhaust gas when mounted on an automobile or mechanical shock from engine vibration or road surface vibration. It is possible to avoid the problem that cracks are generated at the interface and the plugged portions are dropped. Here, the reason for fixing the partition wall and the plugging portion to 1000 ° C. or less is as follows.
The plugging material is composed of at least a ceramic particle and an amorphous oxide matrix formed from a colloidal oxide existing between them, and the colloidal oxide contains a water content to form a colloidal state. Since the solid is irreversibly solid, that is, an amorphous oxide matrix is obtained by dehydrating the moisture, the ceramic particles are firmly bonded at a temperature of 1000 ° C. or lower, This is because the ceramic honeycomb structure can be firmly fixed to the partition walls, and the partition walls and the plugging portions can be fixed and integrated. Thus, since the partition wall and the plugging portion can be fixed and integrated, the temperature for fixing the partition wall and the plugging material may be higher than the temperature at which dehydration of the colloidal oxide is performed, or 500 ° C. or lower, A temperature of 150 ° C. or lower is also possible. Moreover, since the plugging portion is composed of at least ceramic particles and an amorphous oxide matrix formed from a colloidal oxide existing between them, the thermal expansion coefficient of the plugging portion is reduced. In addition, since the difference in thermal expansion coefficient with the cordierite ceramic honeycomb structure having low thermal expansion can be reduced, the generated residual stress can be reduced.

  In the ceramic honeycomb filter of the present invention, the ceramic particles constituting the plugged portion are preferably cordierite particles and / or amorphous silica particles. That is, as the ceramic particles, only cordierite particles or amorphous silica particles may be used, or cordierite particles and amorphous silica particles may be mixed. This is because the thermal expansion coefficient of the cordierite particles and amorphous silica particles is small, so the thermal expansion coefficient of the plugged portion can be reduced, and the thermal expansion of the plugged portion and the cordierite ceramic honeycomb structure can be reduced. This is because the coefficient difference can be further reduced. For this reason, since the residual stress accompanying the adhesion between the plugging portion and the partition walls of the honeycomb structure can be reduced, the thermal shock caused by the exhaust gas when actually mounted on the automobile, the engine vibration and the road surface vibration This is because it is possible to more easily avoid the problem that cracks occur at the plugged portion or the interface between the plugged portion and the honeycomb structure or the plugged portion falls off due to mechanical impact.

  In the ceramic honeycomb filter of the present invention, it is preferable that the ceramic particles constituting the plugging portion are made of pulverized powder of the same material as the ceramic honeycomb fired body, as described above. Since the difference in thermal expansion coefficient of the light-quality ceramic honeycomb structure can be further reduced, there is a problem that a crack occurs at the plugged portion or the interface between the plugged portion and the honeycomb structure, or the plugged portion falls off. This is because it can be more easily avoided. Here, it is said that the ceramic particles are preferably composed of pulverized powder of the same material as the ceramic honeycomb fired body, but it is not necessary that all of the ceramic particles are pulverized powder of the same material as the ceramic honeycomb fired body. One kind or two or more kinds of ceramic particles such as cordierite particles and amorphous silica particles may be contained.

  In the ceramic honeycomb filter of the present invention, it is preferable that the colloidal oxide forming the amorphous oxide matrix existing between the ceramic particles in the plugged portion is mainly composed of colloidal silica or colloidal alumina. . Or it is good also considering the mixture of colloidal silica and colloidal alumina as a main component. This is due to the following reason. In the step of forming the plugging portion, when the plugging material is inserted into the flow path, the viscosity of the plugging material is appropriately adjusted by using colloidal oxide of colloidal silica and / or colloidal alumina. Therefore, the plugging material can be filled up to the corners of the flow path, the adhesion between the partition walls and the plugging portions can be maintained, and the bonding property with the ceramic particles is excellent. This is because a strong plugged portion can be formed.

  The plugging portion constituting the ceramic honeycomb filter of the present invention is composed of ceramic particles and an amorphous oxide matrix formed from a colloidal oxide existing between them. It is not necessary to limit to the material which comprises these, In addition to these, a ceramic fiber, cement, an unbaked ceramic powder, etc. can be included as needed. Furthermore, organic substances such as a binder may be included.

  In the plugged portion constituting the ceramic honeycomb filter of the present invention, an amorphous oxide matrix formed from a colloidal oxide existing between the ceramic particles in the plugged portion is formed with respect to 100 parts by mass of the ceramic particles. It is preferable that it is 2-35 mass parts. If the amount is less than 2 parts by mass, the bonding force between the ceramic particles and the amorphous oxide matrix may be insufficient, and the plugged portion may fall off. On the other hand, when the amount exceeds 35 parts by mass, the thermal expansion coefficient of the plugged portion is increased, so that the thermal shock resistance may be deteriorated. A more preferable ratio is when the ratio of the amorphous oxide matrix formed from the colloidal oxide to 5 parts by mass is 100 parts by mass of the ceramic particles.

In the method for manufacturing a ceramic honeycomb filter of the present invention, a plugged portion is formed in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and a porous partition wall that partitions the flow path is formed. A method for manufacturing a ceramic honeycomb filter in which fine particles contained in exhaust gas are removed by allowing exhaust gas to pass through, wherein the plugging portion includes a plugging material composed of ceramic particles and a colloidal oxide. Since the ceramic honeycomb fired body is fixed, the ceramic honeycomb structure and the plugging portion need not be fired at a high temperature of, for example, 1300 ° C. or higher as in the prior art, and 1000 ° C. or lower. Since the honeycomb structure and the plugging material can be fixed at the above temperature, the residual stress accompanying the fixation of both can be reduced. By suppressing this residual stress to a small level, the plugged portion or the plugged portion and the honeycomb structure are affected by thermal shock caused by exhaust gas when mounted on an automobile or mechanical shock from engine vibration or road surface vibration. It is possible to avoid the problem that cracks are generated at the interface and the plugged portions are dropped.
Here, the temperature at which the partition wall and the plugging portion are fixed can be set to 1000 ° C. or less because the plugging portion is an amorphous material formed from ceramic particles and a colloidal oxide existing therebetween. This colloidal oxide exhibits a colloidal state by containing water, and is irreversibly solid solids when the water is sufficiently dehydrated at 1000 ° C. or less, that is, This is because an amorphous oxide matrix is obtained. This is because the ceramic particles can be firmly bonded at a temperature of 1000 ° C. or lower, and can be firmly bonded to the partition walls of the ceramic honeycomb structure, so that the partition walls and the plugging portions can be fixedly integrated. Thus, since the partition wall and the plugging portion can be fixed and integrated, the temperature for fixing the partition wall and the plugging portion may be higher than the temperature at which the colloidal oxide is dehydrated, and preferably 500 ° C. or lower. More preferably, a temperature of 150 ° C. or lower is also possible. Moreover, since the plugging portion is composed of ceramic particles and an amorphous oxide matrix formed from a colloidal oxide existing between them, the thermal expansion coefficient of the plugging portion is reduced. Since the difference in thermal expansion coefficient with the cordierite ceramic honeycomb structure having low thermal expansion can be reduced, the generated residual stress can be reduced.

  In the case of forming a plugged portion in a fired ceramic honeycomb structure, the temperature required for fixing the plugged portion is set to a cordierite-forming temperature, for example, 1300 ° C. or higher as in the prior art. Since the temperature can be reduced to 1000 ° C. or lower, there is an effect that the energy cost for fixing can be reduced.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, the plugging portion is preferably fixed to the ceramic honeycomb structure at a temperature of 500 ° C. or lower, as described above, the fixing temperature is lowered. As a result, the residual stress caused by the difference in thermal expansion coefficient between the honeycomb structure and the plugged portion can be further reduced, and the energy cost associated with fixing can be reduced.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, it is preferable that the ceramic particles are composed of pulverized powder of the same material as the ceramic honeycomb fired body, as described above. This is because the difference in thermal expansion coefficient can be reduced.

  The ceramic honeycomb filter of the present invention can be applied to an alternating regeneration system as shown in the prior art, and is also a continuous regeneration type ceramic honeycomb filter in which fine particles are continuously burned in combination with a noble metal catalyst. Needless to say, it can be applied.

  The ceramic honeycomb filter of the present invention is made of a material having cordierite as a main crystal, and the material having cordierite as a main crystal is a material containing at least 30% by mass of cordierite crystal. In addition, crystals such as mullite, spinel, corundum, and silicon carbide may be included. Here, in order to effectively utilize the low thermal expansion characteristics of cordierite, it is preferable to contain 50% or more of cordierite crystals, and more preferably 80% or more.

  The plugging material for a ceramic honeycomb filter of the present invention is composed of at least ceramic particles and a colloidal oxide, but the colloidal oxide is 2 to 35 parts by mass in terms of solid content with respect to 100 parts by mass of the ceramic particles. It is preferable to mix | blend in the ratio. If the colloidal oxide is less than 2 parts by mass in terms of solid content, the bonding strength between the amorphous oxide matrix formed from the ceramic particles and the colloidal oxide at the plugged portion after fixing to the honeycomb structure. This is because the plugging portion may fall off. On the other hand, when the colloidal oxide exceeds 35 parts by mass in terms of solid content, the thermal expansion coefficient of the plugged portion after being fixed to the honeycomb structure is increased, so that the thermal shock resistance may be deteriorated. Because. In addition, the blending ratio in terms of solid content of colloidal oxide with respect to 100 parts by mass of ceramic particles is more preferably 5 to 20 parts by mass. In addition, the sealing material for a ceramic honeycomb filter of the present invention is not limited to ceramic particles and colloidal oxides. In addition to these, ceramic fiber, cement and the like can be included as necessary. . Moreover, organic substances, such as a binder, and solvents, such as water, can also be included in order to adjust the viscosity of a sealing material and to make workability | operativity favorable.

  The plugging material for the ceramic honeycomb filter of the present invention is used to fill the plugging material at the end of the predetermined flow path of the first ceramic honeycomb fired body. After filling the end of a predetermined flow path with a plugging material, the plugging materials of the first ceramic honeycomb fired body and the second ceramic honeycomb fired body are brought into contact with each other, and then heated to a temperature of 1000 ° C. or lower. Then, by fixing the plugging material, it is possible to obtain a ceramic honeycomb filter in which the contacted plugging portions are fixedly integrated and connected in the flow path direction. In this case, by forming the plugged portion of the first ceramic honeycomb fired body on the upstream side of the flow channel only on the downstream side of the flow channel, a space is formed on the upstream side of the inflow side plugged portion. A ceramic honeycomb filter can be obtained. In such a ceramic honeycomb filter in which a space is formed on the upstream side of the inflow side plugged portion, fine particles contained in the exhaust gas are collected in this space. Even when the fine particles are burned by the external ignition means provided on the filter inflow side and the filter is regenerated, the fixed plugging portions and the partition walls of the first and second ceramic honeycomb fired bodies are Since it is firmly fixed and integrated, it has a thermal shock resistance that can withstand a thermal shock caused by a rapid temperature change.

  The ceramic honeycomb filter of the present invention is formed of a colloidal oxide and can reduce the difference in thermal expansion coefficient between the ceramic honeycomb structure and the plugged portion by making the plugged portions at least ceramic particles. Since a residual stress hardly remains in the ceramic honeycomb structure obtained by lowering the fixing temperature using an amorphous oxide matrix, a ceramic honeycomb filter having excellent thermal shock resistance can be obtained. In addition, the manufacturing cost can be greatly reduced by lowering the fixing temperature.

Hereinafter, although an embodiment of the present invention is described based on an example, the present invention is not limited to these.
Example 1
A cordierite forming raw material was mixed and kneaded, and a honeycomb structure formed body was obtained by extrusion molding. The obtained formed body was fired at a temperature of 1425 ° C. to obtain a cordierite ceramic honeycomb structure having an outer diameter of 266.7 mm and a total length of 304.8 mm.
And the plugging material slurry was prepared as shown next.
First, as plugging materials in the present invention examples, ceramic particles and colloidal oxides shown in Table 1 are used as main raw materials, mixed at a mixing ratio shown in Test Examples 1 to 27 in Table 2, and further, as an organic binder. 1.2 parts by mass of methylcellulose and water were added and kneaded to adjust the ceramic honeycomb structure so that it could be plugged into a slurry to obtain a plugging material slurry. As ceramic particles constituting the plugged portions, fused silica A was used in Test Examples 1 to 9, fused silica B was used in Test Examples 10 to 12, and cordierite was used in Test Examples 13 to 27. Here, among the ceramic particles, cordierite is produced by pulverizing a cordierite honeycomb structure having a porosity of 65%. As colloidal oxides, colloidal silica was used in Test Examples 1 to 25, and colloidal alumina was used in Test Examples 26 to 27.
Next, as the plugging material of the comparative example, the plugging material raw materials as shown in Table 3 were mixed at the blending ratios shown in Test Examples 28 to 30 in Table 3, and methylcellulose as the organic binder was further mixed. 1.2 parts by mass of water was added and kneaded to adjust the ceramic honeycomb structure so that it could be plugged into a slurry to obtain a plugging material slurry. In Test Examples 28 and 29, cordierite particles shown in Table 1 (produced by pulverizing a cordierite honeycomb structure having a porosity of 65%) and cordierite-based unfired raw material powder were used. Light quality unfired raw material powder was used. Here, the cordierite unfired raw material powder is a raw material powder containing 15% talc, 24% calcined talc, 20% kaolin, 26.5% calcined kaolin, and 14.5% alumina.
Furthermore, as a plugging material of the conventional example (Test Example 31), the raw material batch No. 1 of the example described in Patent Document 1 (calcined talc 38.2%, kaolin 20.0%, calcined kaolin 21.8) %, Alumina 19.5%, aluminum hydroxide 9.5%) to 100 parts by mass of cordierite green raw material powder, 1 part by mass of methylcellulose, 9.25 parts by mass of glycerin and 30 parts by mass of water are added and kneaded. Then, a plugging material slurry was obtained by adjusting the ceramic honeycomb structure so that it could be plugged into a slurry.
Next, a method for plugging a predetermined flow path will be described with reference to FIG. In order to plug a predetermined flow path, a resin mask 21 having an opening formed in a resin material was prepared. here,
In order to form the opening, the resin plate material can be machined, heated, etc., or a resin mask can be formed by an injection molding method or the like.
Next, the plugging material slurry 12c prepared above is prepared in the plugging material container 20, and a predetermined opening end on one end side in the flow path of the honeycomb structure is preliminarily formed as shown in FIG. The plugging material slurry 12c was immersed so as to obtain a predetermined depth on one end side of the honeycomb structure by closing with the prepared resin mask 21. After the water in the slurry that has entered from the flow path at the opening end of the honeycomb structure is absorbed from the partition walls, the plugged portion is formed, and then the honeycomb structure is pulled up from the slurry and the plugged portion is dried. It was. Further, the same operation was performed on the opening end on the other end side to obtain a honeycomb structure in which the opening ends of the flow path were alternately plugged.
And in order to fix this plugging part, it heated at the heating temperature shown in Table 2, and produced the ceramic honeycomb filter by which the opening edge part of the flow path was plugged alternately. In view of the influence of the plugging depth on the thermal shock, the plugging depth was 10 mm.
The ceramic honeycomb filters thus obtained were evaluated for thermal shock resistance and compared with the strength of the plugged portions.

  In the examples of the present invention, fused silica and cordierite honeycomb filter pulverized pulverized powder are used as the ceramic particles. However, mullite ceramic materials and other ceramic powders can be used as the ceramic particles. At this time, the ceramic particles preferably have a maximum particle size of 100 μm or less and an average particle size of 5 to 15 μm. In the examples of the present invention, colloidal oxide and colloidal alumina were used as colloidal oxides. However, other than organic binders and dispersants other than methylcellulose, colloidal oxides other than colloidal silica and colloidal alumina, ceramic fibers Etc. can be used.

  Regarding thermal shock resistance, the ceramic honeycomb filter was heated from room temperature to a set temperature in an electric furnace, held at the set temperature for 2 hours or more, then taken out of the furnace, and cracking at that time was confirmed. As a result, the case where cracks did not occur at 500 ° C. or higher was accepted, the case where cracks did not occur at 600 ° C. or higher was excellent (A), and the case where cracks did not occur at 550 ° C. or higher and lower than 600 ° C. The case where no crack was generated at a temperature of 500 ° C. or higher and lower than 550 ° C. was evaluated as acceptable (Δ), and the case where a crack was generated at a temperature lower than 500 ° C. was evaluated as a defective product (×).

As for the strength of the plugged portion, the strength when the plugged portion was pushed out with a round bar-shaped indenter having a tip of φ1.0 was measured, and the strength of Test Example 22 which is a conventional example was 1. The relative value in the case of 0 was used as the intensity comparison result.
Table 2 shows the test results.

As shown in Table 2, the ceramic honeycomb filters of Test Examples 1 to 3, 5 to 8 , 10 to 13 , 15 to 24 , 26 , and 27 according to the present invention are test examples 28 to 30 that are comparative examples and conventional ones. It can be seen that the thermal shock resistance and strength are very good as compared with Test Example 31 as an example. From the thermal shock resistance evaluation results, Test Example 29, which is a comparative example heated at 1400 ° C., and Test Example 31, which is a conventional example, became NG because cracks occurred at less than 500 ° C. On the other hand, Test Examples 1 and 13 having a heating temperature of 1000 ° C. were acceptable because the thermal shock temperature was 500 ° C. or higher. Further, in Test Examples 2-3 , 5-8, 10-12, 15-24 , 26, and 27 in which the heating temperature was 150 ° C to 850 ° C, the thermal shock temperature was 500 ° C or higher. In particular, Test Examples 18, 19, and 22 using a heating temperature of 500 ° C. or less, using honeycomb filter fired pulverized powder as an aggregate, and using 5 to 20 parts by mass of colloidal silica as a binder in a preferable range in terms of solid content. , 23 gave a very good result that the thermal shock temperature was 600 ° C.

(Example 2)
A cordierite forming raw material was mixed and kneaded, and a honeycomb structure formed body was obtained by extrusion molding. The obtained molded body was fired at a temperature of 1425 ° C., and a cordierite ceramic honeycomb structure 10 having an outer diameter of 266.7 mm and a total length of 204 mm, and a cordierite ceramic honeycomb structure having an outer diameter of 266.7 mm and a total length of 100 mm A structure 30 was obtained.
And the plugging material slurry was prepared as follows.
In Example 2, cordierite produced by pulverizing a cordierite honeycomb structure having a porosity of 65%, which is a ceramic particle shown in Table 1, as a plugging material in the present invention, and a colloidal oxide Colloidal silica is used as a main raw material and mixed at a blending ratio shown in Test Examples 32-34 in Table 4. Further, 1.2 parts by mass of methylcellulose as an organic binder and water are added and kneaded to obtain a ceramic honeycomb structure. The plugging material slurry was obtained by adjusting the slurry so as to form a slurry.
Further, as the plugging material of the comparative example, cordierite particles (produced by pulverizing a cordierite honeycomb structure having a porosity of 65%) shown in Table 1 and cordierite-based unfired raw material powder are used. The mixture is mixed at a blending ratio shown in Test Example 35 of Table 4, and 1.2 parts by mass of methyl cellulose as an organic binder and water are kneaded to form a slurry that can be plugged into a ceramic honeycomb structure. Thus, a plugging material slurry was obtained.
Furthermore, as test example 36, the raw material batch No. 1 of the example described in Patent Document 1 (calcined talc 38.2%, kaolin 20.0%, calcined kaolin 21.8%, alumina 10.5%, water 1 part by weight of methylcellulose, 9.25 parts by weight of glycerin, and 30 parts by weight of water are added to 100 parts by weight of cordierite green raw material powder of aluminum oxide (9.5%) and plugged into the ceramic honeycomb structure. The plugging material slurry was obtained by adjusting the slurry so as to be a slurry.
Next, a method for plugging a predetermined flow path will be described with reference to FIG. In order to plug a predetermined flow path, a resin mask 21 having an opening formed in a resin material was prepared. here,
In order to form the opening, the resin plate material can be machined, heated, etc., or a resin mask can be formed by an injection molding method or the like.
Next, the plugging material slurry 12c prepared above is prepared in the plugging material container 20, and as shown in FIG. 3 (a), a predetermined opening end portion on one end side 11d in the flow path of the honeycomb structure 10 Was closed with a resin mask 21 prepared in advance, and plugging material slurry 12c was immersed in one end side 11d of the honeycomb structure 10 so as to obtain a predetermined depth. After the water in the slurry that had entered from the flow path of the opening end portion 11d of the honeycomb structure 10 was absorbed by the partition walls to form a plugged portion, the honeycomb structure 10 was pulled up from the slurry. Further, the same operation was performed on the open end portion of the other end side 11e to obtain the honeycomb structure 10 in which the open end portions of the flow paths were alternately plugged. Further, the same operation was performed at a predetermined opening end portion on one end side 31e in the flow path of the honeycomb structure 30 to obtain a honeycomb structure 30 in which a plugging portion was formed only on the one end side 31e.
Next, the end face 11d of the honeycomb structure 10 and the end face 31e of the honeycomb structure 30 are brought into contact with each other, and wooden alignment pins are provided at several locations in the flow path where the plugged portions are not formed in the honeycomb structure 30. The honeycomb structures 10 and 30 are positioned so that the flow paths of the honeycomb structure 30 and the honeycomb structure 10 coincide with each other, and the plugged portions 12a of the honeycomb structure 10 and the plugged portions of the honeycomb structure 30 are positioned. The plugging portions 12a and 31 were integrated by abutting and crimping 32b.
Then, after the plugged portion is dried, in order to fix the plugged portion, heating is performed at the heating temperature shown in Table 4, and the contacted plugged portions 12a and 32b are fixed and integrated in the flow path direction. A connected ceramic honeycomb filter 41 was produced. In view of the influence of the plugging depth on the thermal shock, the plugging depth was 10 mm.
The ceramic honeycomb filter thus obtained was evaluated for thermal shock resistance in the same manner as in Example 1, and the strength of the plugged portion 12b formed on the end face 11e side was compared. Note that the strength of the plugged portion was a relative value when the strength of Test Example 36 using the raw material batch described in Patent Document 1 was 1.0. The results are shown in Table 4.
It can be seen that the ceramic honeycomb filters of Test Examples 32-34, which are examples of the present invention, have better thermal shock resistance and plugging portion strength than Test Examples 35, 36 which are comparative examples. In particular, in Test Examples 33 and 34 having heating temperatures of 500 ° C. and 150 ° C., the thermal shock temperature was 600 ° C. or higher. On the other hand, Test Examples 35 and 36, which are comparative examples heated at 1400 ° C., became NG because cracks occurred at less than 500 ° C.

The perspective view of the ceramic honeycomb filter of the present invention Schematic sectional view of the ceramic honeycomb filter of the present invention The figure which showed formation of the plugging material of the ceramic honeycomb filter of this invention Schematic sectional view of a ceramic honeycomb filter according to Example 2 of the present invention

Explanation of symbols

10, 30: Ceramic honeycomb structure 10a: Inflow 10b: Discharge 11, 41: Ceramic honeycomb filter 11a, 31a: Outer peripheral wall 11b, 31b: Partition wall 11c, 31c: Channel 11d, 31d: Inflow side 11e, 31e: Outflow side 12a, 12b, 32b: plugging portion 12c: slurry 13a, 13b: gripping member 14: storage container 20: plugging material container 21: resin mask

Claims (8)

A plugged portion is formed in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and exhaust gas is allowed to pass through a porous partition wall that partitions the flow path. A ceramic honeycomb filter for removing fine particles contained in a ceramic honeycomb filter, wherein at least the plugging portion is composed of at least ceramic particles and an amorphous oxide matrix formed from a colloidal oxide existing therebetween. The amorphous oxide matrix formed from the colloidal oxide existing between the ceramic particles of the plugged portion is 2 to 35 parts by mass with respect to 100 parts by mass of the ceramic particles. Ceramic honeycomb filter. The ceramic honeycomb filter according to claim 1, wherein the ceramic particles are cordierite particles and / or amorphous silica particles. The ceramic honeycomb filter according to claim 1 or 2, wherein the ceramic particles are made of pulverized powder made of the same material as the ceramic honeycomb fired body. The ceramic honeycomb filter according to any one of claims 1 to 3, wherein the colloidal oxide is colloidal silica and / or colloidal alumina. Forming a plugging portion with a plugging material in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and allowing an exhaust gas to pass through a porous partition wall defining the flow path; A method for manufacturing a ceramic honeycomb filter that removes particulates contained in exhaust gas, wherein the plugging portion has a plugging material composed of at least ceramic particles and a colloidal oxide at a temperature of 1000 ° C. or lower. The plugged portion is fixed to the ceramic honeycomb fired body, and the plugging portion is formed of the colloidal oxide that is present between the ceramic particles of the plugged portion with respect to 100 parts by mass of the ceramic particles. method for producing a ceramic honeycomb filter amorphous oxide matrix, characterized in 2-35 parts by der Rukoto. Forming a plugging portion with a plugging material in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and allowing an exhaust gas to pass through a porous partition wall defining the flow path; The method for producing a ceramic honeycomb filter for removing particulates contained in exhaust gas, wherein the plugging portion is a plugging material composed of at least ceramic particles and a colloidal oxide at a temperature of 500 ° C. or lower. The plugged portion is fixed to the ceramic honeycomb fired body, and the plugging portion is formed of the colloidal oxide that is present between the ceramic particles of the plugged portion with respect to 100 parts by mass of the ceramic particles. method for producing a ceramic honeycomb filter amorphous oxide matrix, characterized in 2-35 parts by der Rukoto. The method for manufacturing a ceramic honeycomb filter according to claim 5 or 6, wherein the ceramic particles are made of pulverized powder of the same material as the ceramic honeycomb fired body. A plugged portion is formed in a predetermined flow path of a ceramic honeycomb fired body made of a material having cordierite as a main crystal, and exhaust gas is allowed to pass through a porous partition wall that partitions the flow path. A plugging material for a ceramic honeycomb filter that removes fine particles contained in the ceramic honeycomb filter, wherein the plugging material is composed of at least ceramic particles and a colloidal oxide, and the colloid is contained in 100 parts by mass of the ceramic particles. A plugging material for a ceramic honeycomb filter, wherein the oxide in a solid form is blended at a ratio of 2 to 35 parts by mass in terms of solid content.

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