JP2011057539A - Sealant for honeycomb structure, the honeycomb structure, and method of manufacturing the honeycomb structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealant for a honeycomb structure, in which biosolubility of an inorganic fiber is excellent, which exhibits excellent coating property to a ceramic block or the like even when long time is elapsed after sealant paste is prepared and which can prevent the deterioration of strength after solidification. <P>SOLUTION: The sealant for a honeycomb structure contains the inorganic fiber comprising a biosoluble inorganic compound, oxide sol, an inorganic particle and a metal-containing material containing at least one selected from a group comprising Mg, Ca and Sr and shows acidity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a sealing material for a honeycomb structure, a honeycomb structure, and a method for manufacturing the honeycomb structure.

Used as a filter to remove particulates etc. in exhaust gas discharged from internal combustion engines such as diesel engines, or as a catalyst carrier to remove harmful components such as HC (hydrocarbon) and CO (carbon monoxide) in exhaust gas In the honeycomb structure and the exhaust gas purification apparatus using the honeycomb structure, inorganic fibers are used as materials for various components.
Specifically, for example, a sealing material (adhesive) for bundling a plurality of honeycomb fired bodies into a ceramic block, or a sealing material (outer sealing material or outer coating material) applied to the outer periphery of the ceramic block. ), A sealing material containing inorganic fibers is used.

If such inorganic fibers invade the body, particularly the lungs, and remain as they are for a long time, the human body may be adversely affected. Therefore, it is desirable that the inorganic fiber used for the sealing material is a material excellent in safety to the human body.

Patent Document 1 describes a sealing material containing at least one compound selected from the group consisting of alkali metal compounds, alkaline earth metal compounds, and boron compounds as inorganic fibers.

The inorganic fiber containing the compound described in Patent Document 1 is a so-called biosoluble fiber. Biosoluble fibers have the property of dissolving in physiological saline, so even if they are taken into the body, they are dissolved and discharged outside the body. ing.

WO05 / 110578 pamphlet

The sealing material described in Patent Document 1 is prepared as a paste-like mixture by mixing inorganic binder, organic binder, inorganic particles, water and the like in addition to the inorganic fibers. And a predetermined sealing material layer (an outer periphery sealing material layer or an adhesive material layer) can be formed by applying the sealing material to a ceramic block or a honeycomb fired body.

However, if the biosoluble fiber is used as the inorganic fiber and the sealing material is prepared and stored using the oxide sol as the inorganic binder, the pasty sealing material may aggregate or gel as time passes. As a result, the viscosity of the sealing material increases and the fluidity may decrease.
When a phenomenon such as aggregation or gelation of the sealing material occurs, it becomes difficult to apply the sealing material to a ceramic block or the like, and there is a problem that a disadvantage in work increases.
In addition, when the sealing material is gelled, it becomes difficult to uniformly apply to the ceramic block, etc., so the thickness of the applied sealing material tends to vary, and the final strength of the outer peripheral sealing material layer, etc. There was also a problem that variations occurred.

As a result of repeated studies on the cause of aggregation or gelation of the sealing material, the present inventor has found that the inorganic particles and / or oxide sol contained in the sealing material when the pH value of the sealing material paste increases. It has been found that gelation of the sealing material is likely to occur due to gelation.

Although the details of the gelation mechanism of the sealing material are unclear, it is considered as follows.
Usually, an electric double layer is formed on the surfaces of the inorganic particles and the oxide sol (oxide in the oxide sol) contained in the sealing material, whereby the inorganic particles and the oxide sol (in the oxide sol) It is considered that the oxide is present stably in a dispersed state.
However, when the pH value of the sealing material paste increases, for example, when the pH of the sealing material paste exceeds 6, such as Ca ²⁺ (calcium ion) and Mg ²⁺ (magnesium ion) contained in the biosoluble fiber. The polyvalent metal ions are eluted, and these polyvalent metal ions interfere with the surface charge of the inorganic particles and / or oxide sol. It is estimated that due to this interference phenomenon, the balance of charges on the surface of the inorganic particles and / or oxide sol is lost, and the inorganic particles and / or oxide sol are aggregated, so that the sealing material is gelled.

In this specification, gelation means that the solid component dispersed in the sol causes aggregation, association, or phase change due to change in pH, presence of polyvalent metal ions, etc. This is a phenomenon in which the viscosity increases.

As a result of investigation based on the above findings, the present inventor has found that gelling of the sealing material can be prevented by using an acidified sealing material paste when preparing the sealing material.
The mechanism is not completely clear, but by making the sealing material paste acidic, it is possible to prevent polyvalent metal ions from eluting from the biosoluble fiber, thus preventing the sealing material from gelling. I think it can be done.
Examples of the method for acidifying the sealing material paste include a method using an acidic oxide sol, a method of mixing an alkaline oxide sol and an acidic solution, and the like.

However, when the sealing material paste is acidic, it is possible to prevent the sealing material from gelling, but the strength after solidifying the acidic sealing material is less than the sealing material before acidifying the sealing material paste. There was a problem that it became weaker than the strength after solidification. For example, when the sealing material is used as an outer peripheral sealing material, the strength of the outer peripheral sealing material layer is weakened, so that damage such as chipping is likely to occur in the outer peripheral sealing material layer during the manufacturing process or use of the honeycomb structure. As a result, there may occur a problem that a solution containing the catalyst leaks in the catalyst application step when manufacturing the honeycomb structure, and the exhaust gas leaks in the exhaust gas purification apparatus using the honeycomb structure. In addition, when the sealing material is used as an adhesive for a collective honeycomb structure, the strength of the adhesive layer is weakened. Therefore, in the exhaust gas purification apparatus using the honeycomb structure, the honeycomb fired body may be displaced or extreme. In some cases, the problem of missing may occur.

The present invention has been made in order to solve such problems, the inorganic fiber has good biosolubility, and can be applied to a ceramic block or the like even if a long time has elapsed after the preparation of the sealing material paste. An object of the present invention is to provide a sealing material for a honeycomb structure that has good coating properties and can prevent a decrease in strength after solidification.
Another object of the present invention is to provide a honeycomb structure manufactured using the sealing material for a honeycomb structure and a method for manufacturing the honeycomb structure.

Then, this inventor examined the cause of the strength fall after solidification in an acidic sealing material in order to solve the subject mentioned above. The present inventor thought that the polyvalent metal ions eluted in the sealing material, which is considered to be the cause of gelation of the sealing material, had some influence on the strength maintenance (improvement) after solidification. . And as a result of repeated examination based on this idea, when the sealing material is acidic, elution of polyvalent metal ions is suppressed as described above, or the content of the polyvalent metal ions in the sealing material is small, Or since the polyvalent metal ion does not exist in the sealing material, it was concluded that the strength after solidification of the sealing material may be reduced.

Based on such examination results, the present inventor further adds a predetermined polyvalent metal ion to the sealing material while making the sealing material acidic to prevent gelation of the sealing material. Thus, it was found that strength reduction after solidification can be prevented, and the present invention was completed.

Note that the above-described mechanism for preventing gelation of the sealing material and the mechanism for preventing the decrease in strength when the acidic sealing material is solidified may be other mechanisms as long as the effect can be obtained by the configuration of the present invention. Well, it is not to be interpreted in a limited way.

The sealing material for a honeycomb structure according to claim 1 includes an inorganic fiber made of a biosoluble inorganic compound, an oxide sol, inorganic particles, Mg (magnesium), Ca (calcium), and Sr (strontium). And a metal-containing material containing at least one selected from the group consisting of:

Since the inorganic fiber contained in the sealing material for honeycomb structure according to claim 1 is made of a biologically soluble inorganic compound, it has solubility under physiological conditions even if it is taken into the human body. And the safety | security with respect to the human body of the sealing material for honeycomb structures containing an inorganic fiber is securable.

Hereinafter, in this specification, an inorganic fiber made of a biosoluble inorganic compound is also referred to as a “biosoluble fiber”.

In addition, since the sealing material for honeycomb structure according to claim 1 shows acidity, it is possible to suppress elution of polyvalent metal ions from the biosoluble fiber, thereby preventing gelation of the sealing material. be able to.
Therefore, even if a long time elapses after the preparation of the sealing material paste, it is possible to prevent the viscosity of the sealing material paste from increasing and the fluidity of the sealing material paste from decreasing.

Further, the honeycomb structure sealing material according to claim 1 includes a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr.
Therefore, even if elution of polyvalent metal ions is suppressed due to the acidity of the sealing material, the polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material can be supplied into the sealing material. The strength of the sealing material after solidification can be prevented from being lowered.

In the sealing material for a honeycomb structure according to claim 2, the inorganic compound is at least one of an alkali metal compound and an alkaline earth metal compound. By containing these inorganic compounds, the biological solubility of inorganic fibers can be improved.

In the sealing material for a honeycomb structure according to claim 3, the metal-containing material is at least one selected from the group consisting of calcium carbonate, calcium acetate, magnesium carbonate, magnesium nitrate, magnesium sulfate, and magnesium acetate. . Since these metal-containing materials are easily ionized in the seal material paste, it is desirable because they can easily supply polyvalent metal ions necessary for maintaining (improving) the strength of the seal material and are easily available. .

As in the sealing material for a honeycomb structure according to claim 4, the metal-containing material may be calcium carbonate or calcium acetate. Since these calcium-containing materials are more easily ionized in the sealing material paste, the polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material can be easily supplied. It is possible to prevent a reduction in strength after solidification.

When the Ca content in the honeycomb structure sealing material is 0.01 to 1.0% by weight as in the honeycomb structure sealing material according to claim 5, the honeycomb structure sealing material is A decrease in strength after solidification can be suitably prevented.
When the Ca content in the sealing material for honeycomb structure is less than 0.01% by weight, the effect of maintaining or improving the strength of the sealing material after solidification may not be sufficiently obtained. Further, when the Ca content in the honeycomb structure sealing material exceeds 1.0% by weight, the content of inorganic fibers, oxide sol, and inorganic particles, which are other components in the honeycomb structure sealing material, Since the amount is relatively small, the strength after solidification as the whole honeycomb structure sealing material may be weakened.

The honeycomb structure according to claim 6, wherein a ceramic block comprising a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween,
A honeycomb structure comprising an outer peripheral sealing material layer formed on the outer peripheral surface of the ceramic block,
The said outer periphery sealing material layer is formed by solidifying the sealing material for honeycomb structures in any one of Claims 1-5.

Since the honeycomb structure according to claim 6 uses biosoluble fibers as the material constituting the outer peripheral sealing material layer, the honeycomb structure has high safety to the human body, such as workers and consumers. Can be handled with confidence. Moreover, in the manufacturing process of the honeycomb structure according to claim 6, since the gelation of the sealing material for the honeycomb structure does not occur, the sealing material can be uniformly applied in the process of forming the outer peripheral sealing material layer. This makes it difficult to prevent the outer peripheral sealing material layer from becoming uneven in thickness. Thereby, the dispersion | variation or fall of the intensity | strength resulting from the nonuniformity of the thickness of an outer periphery sealing material layer can be prevented.

Further, in the honeycomb structure according to claim 6, since the outer peripheral sealing material layer is formed by solidifying the honeycomb structure sealing material according to any one of claims 1 to 5, Multivalent metal ions necessary for strength maintenance (improvement) can be supplied into the sealing material, and the strength of the outer peripheral sealing material layer can be prevented from being lowered. As a result, it is possible to prevent breakage such as chipping in the outer peripheral sealing material layer during the manufacturing process of the honeycomb structure or during use, for example, leakage of a solution containing the catalyst in the catalyst application step when manufacturing the honeycomb structure. In addition, it is possible to prevent the occurrence of a problem that exhaust gas leaks in an exhaust gas purification apparatus using a honeycomb structure.

In the honeycomb structure according to claim 7, the ceramic block includes a plurality of honeycomb fired bodies and an adhesive layer formed between side surfaces of the plurality of honeycomb fired bodies.
As described above, the honeycomb structure of the present invention may be an integrated honeycomb structure in which the ceramic block is formed of one honeycomb fired body, or may be an aggregated honeycomb structure in which the ceramic block is formed of a plurality of honeycomb fired bodies.

As in the honeycomb structured body according to claim 8, the adhesive layer may be formed by solidifying the adhesive.

In the honeycomb structured body according to claim 9, the adhesive is the honeycomb structure sealing material according to any one of claims 1 to 5.
In a honeycomb structure in which a plurality of honeycomb fired bodies are gathered, an adhesive layer between the honeycomb fired bodies is necessary, and thus the total amount of inorganic fibers contained in the honeycomb structure is inevitably increased. In the case of a conventional honeycomb structure, the possibility of incorporating inorganic fibers into the human body has increased with an increase in the adhesive layer, but the honeycomb structure according to claim 9 is claimed as an adhesive. Since the honeycomb structure sealing material according to any one of 1 to 5 is used, safety to the human body can be ensured even if the total amount of inorganic fibers contained in the entire honeycomb structure is increased.

Further, in the honeycomb structure according to claim 9, since the sealing material for honeycomb structure according to any one of claims 1 to 5 is used as an adhesive, the strength (improvement) of the adhesive (sealing material) is maintained. ) Multivalent metal ions necessary for the action can be supplied into the adhesive (sealant), and the strength of the adhesive layer can be prevented from being lowered. As a result, for example, in an exhaust gas purification apparatus using a honeycomb structure, it is possible to prevent the occurrence of a problem that the honeycomb fired body is displaced or, in an extreme case, detached.

A method for manufacturing a honeycomb structured body according to claim 10, wherein a ceramic block comprising a honeycomb fired body in which a large number of cells are arranged in parallel in a longitudinal direction with a cell wall therebetween,
A method for manufacturing a honeycomb structure comprising an outer peripheral sealing material layer formed on an outer peripheral surface of the ceramic block,
It includes an inorganic fiber made of a biologically soluble inorganic compound, an oxide sol, inorganic particles, and a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr, and exhibits acidity A honeycomb structure sealing material preparation step for preparing a honeycomb structure sealing material;
An outer periphery sealing material layer forming step of forming an outer periphery sealing material paste layer made of the honeycomb structure sealing material on the outer peripheral surface of the ceramic block, and forming the outer periphery sealing material layer by solidifying the outer periphery sealing material paste layer It is characterized by including.

In the method for manufacturing a honeycomb structure according to claim 10, since the honeycomb structure sealing material prepared in the honeycomb structure sealing material preparation step shows acidity, polyvalent metal ions are eluted from the biosoluble fiber. And the gelation of the sealing material can be prevented. Therefore, even if a long time elapses after the preparation of the sealing material paste, it is possible to prevent the viscosity of the sealing material paste from increasing and the fluidity from decreasing. In addition, since the fluidity of the sealing material for the honeycomb structure can be maintained high, the use management of the sealing material is facilitated, and the outer peripheral sealing material paste is applied to the outer periphery of the ceramic block in the outer peripheral sealing material layer forming step. It can prevent that workability | operativity at the time of forming in a surface falls.

In addition, in the method for manufacturing a honeycomb structure according to claim 10, since the outer peripheral sealing material layer containing inorganic fibers made of a biosoluble inorganic compound can be formed, the honeycomb structure having excellent safety to the human body Can be manufactured. Furthermore, since the biosoluble fiber is used, the worker can work safely in the honeycomb structure sealing material preparation step and the outer peripheral sealing material layer forming step.

Furthermore, the honeycomb structure sealing material prepared in the honeycomb structure sealing material preparation step includes a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr.
Therefore, even if elution of polyvalent metal ions is suppressed due to the acidity of the sealing material, the polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material can be supplied into the sealing material. The strength of the sealing material after solidification can be prevented from being lowered. Therefore, breakage such as chipping in the outer peripheral sealing material layer can be prevented.

The method for manufacturing a honeycomb structured body according to claim 11, wherein a honeycomb aggregate formed by binding a plurality of honeycomb fired bodies via an adhesive layer paste is produced, and the adhesive layer paste of the honeycomb aggregate is obtained. It further includes a bundling step of producing a ceramic block in which a plurality of honeycomb fired bodies are bundled via the adhesive layer by passing through a step of solidifying and forming an adhesive layer.
By including this bundling step, an aggregated honeycomb structure formed by aggregating a plurality of honeycomb fired bodies can be manufactured.

In a method for manufacturing a honeycomb structure according to a twelfth aspect, the honeycomb structure sealing material is used as the adhesive layer paste.
The above adhesive layer paste (honeycomb structure sealing material) is acidic, so it is possible to suppress the elution of polyvalent metal ions from the biosoluble fiber and prevent gelation of the adhesive material (sealing material). can do. Therefore, even if a long time elapses after the preparation of the adhesive layer paste (sealing material paste), the viscosity of the adhesive layer paste (sealing material paste) increases and the fluidity is prevented from decreasing. Can do. In addition, since the fluidity of the adhesive layer paste (honeycomb structure sealing material) can be maintained at a high level, the use management of the adhesive layer paste (sealing material) becomes easy, and a plurality of It is possible to prevent the workability when the honeycomb fired body is bundled through the adhesive layer paste (honeycomb structure sealing material) from being lowered.

Further, in the method for manufacturing a honeycomb structure according to claim 12, since an adhesive layer containing inorganic fibers made of a biosoluble inorganic compound can be formed, a honeycomb structure excellent in safety to the human body is obtained. Can be manufactured. Furthermore, since the biosoluble fiber is used, the worker can work safely in the binding process of the plurality of honeycomb fired bodies.

Further, the honeycomb structure sealing material includes a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr.
Therefore, even if elution of polyvalent metal ions is suppressed due to the acidity of the sealing material, the polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material can be supplied into the sealing material. The strength of the sealing material after solidification can be prevented from being lowered. Therefore, the honeycomb fired body can be firmly fixed, and a honeycomb structure that can be used stably for a long time can be manufactured.

In the method for manufacturing a honeycomb structured body according to claim 13, the inorganic compound is at least one of an alkali metal compound and an alkaline earth metal compound. By using such a compound, the inorganic fiber can specifically function as a biosoluble fiber, and the safety of the sealing material for a honeycomb structure and thus the honeycomb structure using the same can be improved.

In the method for manufacturing a honeycomb structured body according to claim 14, the metal-containing material is at least one selected from the group consisting of calcium carbonate, calcium acetate, magnesium carbonate, magnesium nitrate, magnesium sulfate, and magnesium acetate. .
Since these metal-containing materials are excellent in availability and handling, it is possible to improve the ease of manufacturing preparation and the workability in the manufacturing process of the honeycomb structure. In addition, since these metal-containing materials are easily ionized in the sealing material paste, it is possible to easily supply polyvalent metal ions necessary for maintaining the strength of (enhancing) the sealing material for the honeycomb structure. The strength reduction after solidifying the body sealing material can be prevented.

In the method for manufacturing a honeycomb structured body according to claim 15, the metal-containing material is calcium carbonate or calcium acetate.
Since these calcium-containing materials are more easily ionized in the sealing material paste, it is possible to easily supply polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material for the honeycomb structure. It is possible to prevent a decrease in strength after the sealing material for solidification is solidified.

When the Ca content in the honeycomb structure sealing material is 0.01 to 1.0% by weight as in the method for manufacturing a honeycomb structure according to claim 16, the honeycomb structure sealing material is solidified. It is possible to suitably prevent a decrease in strength after the treatment.
If the Ca content in the honeycomb structure sealing material is less than 0.01% by weight, the effect of maintaining or improving the strength of the solidified sealing material cannot be obtained. The strength of the material layer may be weakened. Further, when the Ca content in the honeycomb structure sealing material exceeds 1.0% by weight, the content of inorganic fibers, oxide sol, and inorganic particles, which are other components in the honeycomb structure sealing material, Since the amount is relatively small, the strength after solidification of the entire honeycomb structure sealing material is weakened, and the strength of the outer peripheral sealing material layer and the adhesive material layer may be weakened.

It is a perspective view showing typically an example of the honeycomb structure of the present invention. Fig. 2 (a) is a perspective view schematically showing an example of a honeycomb fired body constituting the honeycomb structure of the present invention, and Fig. 2 (b) is a diagram of the honeycomb fired body shown in Fig. 2 (a). It is AA sectional view. It is a perspective view which shows typically the method of producing the sample for evaluation in an Example and a comparative example. It is a side view which shows typically the measuring method of the fracture strength of the outer periphery sealing material layer for evaluation in an Example and a comparative example. It is a graph which shows the relationship between Ca content in a sealing material for honeycomb structures, and fracture strength about the sealing material for honeycomb structures prepared in Examples 1-10 and Comparative Example 1. FIG. It is a perspective view which shows typically another example of the honeycomb structure of this invention.

(First embodiment)
Hereinafter, embodiments of a sealing material for a honeycomb structure, a honeycomb structure, and a method for manufacturing the honeycomb structure of the present invention will be described with reference to the drawings.

First, the sealing material for honeycomb structures according to the embodiment of the present invention will be described.
The sealing material for honeycomb structure of the present embodiment is at least one selected from the group consisting of inorganic fibers made of a biosoluble inorganic compound, oxide sol, inorganic particles, Mg, Ca, and Sr. It contains the metal containing material containing, and is characterized by showing acidity.

In order to evaluate the biological solubility of inorganic fibers made of inorganic compounds, the solubility of inorganic compounds in inorganic fibers in physiological saline is measured by the following method. In an extraction solution in which 0.5 g of inorganic fiber is added to 25 ml of physiological saline, shaken at 37 ° C. for 5 hours and then filtered to remove the solid inorganic fiber and a part of the inorganic fiber is dissolved. The elements in inorganic fibers such as silicon, sodium, calcium and magnesium are measured by atomic absorption analysis. In addition, normal saline may be used. If the target compound is dissolved in the extracted solution by 100 ppm (0.01% by weight) or more in total, it can be said that the inorganic fiber is composed of a biologically soluble inorganic compound. Further, from this measurement result, the ratio of the eluate eluted from the inorganic fiber can also be calculated. When the physiological saline contains the element to be measured in advance, the amount of the element in the physiological saline is confirmed, and the amount may be subtracted from the amount of the element in the measured sample.

The inorganic fibers contained in the honeycomb structure sealing material of the present embodiment desirably have a solubility in physiological saline at 37 ° C. of 300 ppm (0.03% by weight) or more. Since the inorganic fiber having a solubility of 300 ppm (0.03% by weight) or more dissolves rapidly under physiological conditions, the risk of the inorganic fiber being taken into the human body can be further reduced.

The inorganic compound in the inorganic fibers contained in the honeycomb structure sealing material of the present embodiment is at least one of an alkali metal compound and / or an alkaline earth metal compound.
Examples of the alkali metal compound include sodium and potassium oxides and salts, and examples of the alkaline earth metal compound include magnesium, calcium, and barium oxides and salts. Biosoluble fibers can be produced by including oxides or salts of sodium, potassium, magnesium, calcium, barium, boron in silica, alumina, silica alumina, glass or the like used as a material for inorganic fibers. .

The inorganic fiber contained in the honeycomb structure sealing material of the present embodiment desirably contains 60 to 85% by weight of silica in addition to the inorganic compound, and more desirably 70 to 80% by weight. The silica is SiO or SiO ₂ . When the content of silica is less than 60% by weight, the strength of the inorganic fibers may be weakened. On the other hand, when the content of silica exceeds 85% by weight, the content of the inorganic compound in the inorganic fibers decreases, and thus the biosolubility may be lowered.

The inorganic fiber contained in the honeycomb structure sealing material of the present embodiment contains at least one of an alkali metal compound or an alkaline earth metal compound having biosolubility, and the SiO ₂ content contained in the inorganic fiber is low. It is desirable that it is 70 weight% or more. In general, many alkali metal and alkaline earth metal silicates have biological solubility. However, when the SiO ₂ content exceeds 85% by weight, the content of the alkali metal compound or alkaline earth metal compound having biosolubility becomes too small, which is not preferable.

Moreover, as for the inorganic fiber contained in the sealing material for honeycomb structures of this embodiment, it is desirable that the content of Al ₂ O ₃ contained in the inorganic fiber is 2% by weight or less. The Al ₂ O ₃ content may be 0% by weight as long as it is 2% by weight or less. In general, alkali metal or alkaline earth metal aluminates or aluminosilicates are often not biosoluble or small.

The inorganic fiber is an inorganic material having a large aspect ratio (major axis / minor axis), and is generally particularly effective for improving the elasticity of the sealing material.
The aspect ratio of the inorganic fibers contained in the honeycomb structure sealing material of the present embodiment is preferably 2 to 1000, more preferably 5 to 800, and particularly preferably 10 to 500. If the aspect ratio of the inorganic fiber is less than 2, the contribution of improving the elasticity of the sealing material is small, and if the aspect ratio of the inorganic fiber exceeds 1000, the adhesive strength with the honeycomb fired body may be lowered. Here, when there is a distribution in the aspect ratio of the inorganic fiber, it is expressed as an average value thereof.

In addition, the lower limit of the content of inorganic fibers contained in the honeycomb structure sealing material of the present embodiment is preferably 10% by weight and more preferably 20% by weight in terms of solid content. On the other hand, the upper limit of the content of the inorganic fiber is preferably 70% by weight, more preferably 40% by weight, and further preferably 30% by weight in terms of solid content. If the content of the inorganic fiber is less than 10% by weight in terms of solid content, the proportion of the inorganic fiber contributing to elasticity decreases, and the elasticity of the sealing material may be reduced. On the other hand, if the content of the inorganic fiber exceeds 70% by weight in solid content, the proportion of inorganic particles contributing to thermal conductivity decreases, leading to a decrease in the thermal conductivity of the sealing material and a decrease in adhesive strength. There are things to do.

Further, the lower limit of the average fiber length of the inorganic fibers contained in the sealing material for honeycomb structure of the present embodiment is desirably 0.1 μm. On the other hand, the upper limit of the average fiber length of the inorganic fibers is desirably 1000 μm, more desirably 100 μm, and further desirably 50 μm.
If the average fiber length is less than 0.1 μm, the elasticity of the sealing material may decrease. On the other hand, when the average fiber length exceeds 1000 μm, the inorganic fibers are likely to take a form like a pill, so that it is difficult to reduce the thickness of the adhesive layer or the outer peripheral sealing material layer, The dispersibility of the inorganic particles may deteriorate.

The oxide sol contained in the honeycomb structure sealing material mainly serves as a binder for adhering particles to each other after the sealing material is solidified, and examples thereof include silica sol, alumina sol, and zirconia sol. These may be used alone or in combination of two or more. Among these, silica sol or alumina sol is desirable.

In addition, the lower limit of the content of the oxide sol contained in the honeycomb structure sealing material is preferably 1% by weight and more preferably 5% by weight in terms of solid content. On the other hand, the upper limit of the content of the oxide sol is desirably 30% by weight, more desirably 15% by weight, and further desirably 9% by weight in terms of solid content. If the content of the solid content of the oxide sol is less than 1% by weight in terms of solid content, the ratio of the oxide sol acting as a binder is reduced, which may lead to a decrease in adhesive strength. If the solid content exceeds 30% by weight in solid content, the proportion of inorganic particles contributing to thermal conductivity decreases, which may cause a decrease in the thermal conductivity of the sealing material.

Moreover, the average particle diameter of the oxide contained in the oxide sol contained in the sealing material for honeycomb structure is desirably 5 to 30 nm.
The smaller the average particle size of the oxide contained in the oxide sol, the more the adhesion strength with the honeycomb fired body tends to be improved. The dispersibility of the oxide tends to decrease. Moreover, when the average particle diameter of the oxide is less than 5 nm, it is difficult to produce the oxide and it is difficult to obtain it. On the other hand, when the average particle diameter of the oxide exceeds 30 nm, the adhesion site between the particles decreases, and the adhesion strength with the honeycomb fired body tends to decrease.

In the present specification, the average particle diameter of the oxide contained in the oxide sol is measured by the following method.
When the oxide sol is a silica sol, the silica sol is first dried, and its BET specific surface area is measured.
Then, assuming that the silica particles in the silica sol are dense spherical particles, the particle diameter is calculated from the following formula (1).
BET specific surface area = (6000 / ρ) / particle diameter (1)
(In the formula, ρ is the true density of silica (2.2 g / cm ³ ).)

Examples of the inorganic particles contained in the honeycomb structure sealing material include carbide particles, nitride particles, and the like, specifically, inorganic powder or whisker made of silicon carbide, silicon nitride, boron nitride, or the like. Can be mentioned. These may be used alone or in combination of two or more. Among the inorganic particles, silicon carbide particles are desirable because of excellent thermal conductivity.
Whisker can be classified as inorganic fiber, but in this specification, whisker is included in inorganic particles.

Moreover, the lower limit of the content of the inorganic particles contained in the honeycomb structure sealing material is desirably 3% by weight, more desirably 10% by weight, and further desirably 20% by weight. On the other hand, the upper limit of the content of the inorganic particles is desirably 80% by weight, more desirably 60% by weight, and further desirably 40% by weight. When the content of the inorganic particles is less than 3% by weight, the proportion of the inorganic particles decreases, and the thermal conductivity of the sealing material may be lowered. On the other hand, when the content of the inorganic particles exceeds 80% by weight, when the adhesive layer or the outer peripheral sealing material layer is exposed to a high temperature and the inorganic particles having a high coefficient of thermal expansion expand, a minute amount near the expanded position. Cracks may occur, which may cause a decrease in the adhesive strength of the entire sealing material.

The lower limit of the average particle size of the inorganic particles contained in the honeycomb structure sealing material is preferably 0.01 μm, and more preferably 0.1 μm. On the other hand, the upper limit of the average particle size of the inorganic particles is desirably 100 μm, more desirably 15 μm, and further desirably 10 μm. If the average particle diameter of the inorganic particles is less than 0.01 μm, the dispersibility of the inorganic particles in the sealing material may be reduced, and the cost may be increased. On the other hand, when the average particle diameter of the inorganic particles exceeds 100 μm, the adhesive strength or thermal conductivity of the sealing material may be lowered.

Examples of the metal-containing material contained in the honeycomb structure sealing material of the present embodiment include salts and complexes containing Mg, Ca, or Sr that are easily ionized under acidic conditions. These may be used alone or in combination of two or more. Examples of the salt containing Mg, Ca, or Sr include carbonates, nitrates, sulfates, phosphates, acetates, citrates, or oxalates of Mg, Ca, or Sr. Moreover, as a complex containing Mg, Ca, or Sr, an inorganic complex formed by using carbonate ions, sulfate ions, phosphate ions, or the like as inorganic ligands, or dicarboxylic acids, diamines, or those And organic complexes formed using the above derivatives as organic ligands.
Among the metal-containing materials, calcium carbonate, calcium acetate, magnesium carbonate, magnesium nitrate, magnesium sulfate, or magnesium acetate is desirable, and calcium carbonate or calcium acetate is more desirable. Since these metal-containing materials are easily ionized in the sealing material paste, it is possible to easily supply polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material for the honeycomb structure, and for the honeycomb structure. It is possible to prevent a decrease in strength after the sealing material is solidified. These metal-containing materials are also desirable because they are easily available.

When the above-mentioned metal-containing material is contained in the honeycomb structure sealing material of the present embodiment, polyvalent metal ions necessary for the strength maintenance (improvement) action of the honeycomb structure sealing material are supplied into the sealing material. Therefore, the strength reduction of the sealing material after solidification can be prevented.

When the metal-containing material contained in the honeycomb structure sealing material of the present embodiment is calcium carbonate or calcium acetate, the lower limit of the Ca content contained in the honeycomb structure sealing material is desirably 0.01% by weight. 0.1% by weight is more desirable. On the other hand, the upper limit of the Ca content is desirably 1.0% by weight, and more desirably 0.5% by weight.
If the Ca content is less than 0.01% by weight, the effect of maintaining or improving the strength of the solidified sealing material may not be sufficiently obtained. Further, if the Ca content exceeds 1.0% by weight, the content of inorganic fibers, oxide sol, and inorganic particles, which are other components in the honeycomb structure sealing material, is relatively small. In some cases, the strength of the sealing material for the honeycomb structure as a whole becomes weak after solidification.

Moreover, it is desirable that the sealing material for honeycomb structure of the present embodiment includes an organic binder. Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose and the like. These may be used alone or in combination of two or more. Among the organic binders, carboxymethylcellulose is desirable because it is excellent in adjusting the viscosity of the sealing material.

The lower limit of the content of the organic binder contained in the honeycomb structure sealing material of the present embodiment is preferably 0.1% by weight, more preferably 0.2% by weight, and still more preferably 0.4% by weight in terms of solid content. . On the other hand, the upper limit of the content of the organic binder contained in the honeycomb structure sealing material is preferably 5.0% by weight, more preferably 1.0% by weight, and still more preferably 0.6% by weight in terms of solid content. If the solid content of the organic binder is less than 0.1% by weight, the viscosity of the sealing material is low, so that it is difficult to form a paste and it may be difficult to apply the sealing material. On the other hand, if the solid content of the organic binder exceeds 5.0% by weight, it may be difficult to apply the sealing material because the viscosity of the sealing material becomes too high. Further, when the adhesive layer or the outer peripheral sealing material layer is exposed to a high temperature, the organic component in the sealing material disappears, and as a result, the portion in which the organic component in the sealing material disappears may become a cavity. If the content of the solid content of the organic binder exceeds 5.0% by weight, the ratio of the organic component contained in the sealing material for honeycomb structure is excessively increased, and thus the organic component in the sealing material is lost. The ratio occupied by the cavities may increase, and the strength of the adhesive layer or the outer peripheral sealing material layer may decrease.

Suitable components and their content in the honeycomb structure sealing material of the present embodiment, inorganic fibers 30-40% by weight and a SiO ₂ and MgO and CaO and _Al 2 _{O 3,} silica sol is 15 to 20 weight %, Silicon carbide particles are 30 to 40% by weight, calcium carbonate is 0.01 to 1% by weight, and carboxymethylcellulose is 0.4 to 0.6% by weight.

In addition, the honeycomb structure sealing material (sealing material paste) of the present embodiment exhibits acidity.
The pH of the honeycomb structure sealing material is not particularly limited as long as it is acidic, but it is preferably 4 to 6. When the pH of the sealing material is less than 4, the inorganic particles tend to aggregate after the sealing material paste is prepared. On the other hand, when the pH of the sealing material exceeds 6, gelation of the sealing material paste tends to occur after the preparation of the sealing material paste.

Examples of the method for preparing the honeycomb structure sealing material by adjusting the pH of the sealing material to 4 to 6 include a method using an acidic oxide sol.
Although pH of acidic oxide sol is not specifically limited, It is desirable that pH is 3-6. When the pH of the oxide sol is less than 3, the pH after preparing the sealing material paste is low, and aggregation of inorganic particles is likely to occur. On the other hand, when the pH of the oxide sol exceeds 6, the pH after the preparation of the sealing material paste becomes high, and the sealing material is likely to be gelled.
As the acidic oxide sol, an acidic silica sol or alumina sol can be preferably used.

Next, a method for preparing the honeycomb structure sealing material of the present embodiment will be described.
Inorganic fiber, inorganic particles, metal-containing material, and organic binder are mixed at the above-mentioned ratio to prepare a mixture, and further, an acidic oxide sol and an appropriate amount of water are added, mixed, and kneaded. Thus, an acidic honeycomb structure sealing material is prepared.

As described above, the bio-solubility of the inorganic fiber is good, and the coating property to the ceramic block is good even after a long time has elapsed after the preparation of the sealing material paste, and further the strength reduction after solidification is prevented. A sealing material for a honeycomb structure that can be prepared can be prepared.

Subsequently, a honeycomb structure according to an embodiment of the present invention will be described.
The honeycomb structure of the present embodiment is manufactured by using the honeycomb structure sealing material of the present embodiment described above.
FIG. 1 is a perspective view schematically showing an example of the honeycomb structure of the present invention, and FIG. 2A is a perspective view schematically showing an example of the honeycomb fired body constituting the honeycomb structure of the present invention. Fig. 2 (b) is a cross-sectional view taken along line AA of the honeycomb fired body shown in Fig. 2 (a).

In the honeycomb structure 100 shown in FIG. 1, a plurality of honeycomb fired bodies 110 made of porous silicon carbide are bound together via an adhesive layer 101 to form a ceramic block 103, and the outer peripheral surface of the ceramic block 103 An outer peripheral sealing material layer 102 is formed on the surface. The honeycomb fired body 110 has a shape shown in FIGS. 2 (a) and 2 (b).

In the honeycomb fired body 110 shown in FIGS. 2 (a) and 2 (b), a large number of cells 111 are arranged in parallel in the longitudinal direction (direction a in FIG. 2 (a)) with a cell wall 113 therebetween. Any one end of the cell 111 is sealed with a sealing material 112. Therefore, the exhaust gas G that has flowed into the cell 111 with one end face opened always flows out from the other cell 111 with the other end face open after passing through the cell wall 113 separating the cells 111.
Therefore, the cell wall 113 functions as a filter for collecting PM and the like.

In the honeycomb structure 100 of the present embodiment, the adhesive layer 101 and the outer peripheral sealing material layer 102 are formed using the above-described honeycomb structure sealing material of the present embodiment.
Hereinafter, an embodiment of a method for manufacturing a honeycomb structure of the present invention will be described.

First, a forming step for producing a honeycomb formed body by extruding a wet mixture containing a ceramic powder and a binder is performed.
Specifically, a wet mixture for manufacturing a honeycomb formed body is prepared by mixing silicon carbide powder having different average particle diameters as ceramic powder, an organic binder, a liquid plasticizer, a lubricant, and water.
Subsequently, the wet mixture is put into an extruder and extruded to produce a honeycomb formed body of a predetermined shape.

Next, the honeycomb formed body is cut into a predetermined length, dried using a microwave dryer, hot air dryer, dielectric dryer, vacuum dryer, vacuum dryer, freeze dryer, etc. A sealing step of filling the cell with a sealing material paste as a sealing material and sealing the cell is performed.

Next, a degreasing process is performed in which the organic matter in the honeycomb formed body is removed by heating in a degreasing furnace, and the honeycomb fired body is transported to the firing furnace and the firing process is performed to produce a honeycomb fired body.
In addition, the conditions currently used when manufacturing a honeycomb fired body can be applied to the conditions of a cutting process, a drying process, a sealing process, a degreasing process, and a firing process.

Next, a bundling step is performed in which an adhesive layer is formed between the plurality of honeycomb fired bodies by the following method, and the plurality of honeycomb fired bodies are bonded via the adhesive layer.
A paste adhesive made of the sealing material for honeycomb structure of the present embodiment is applied to each predetermined side surface of the honeycomb fired body in which predetermined ends of each cell are sealed to form an adhesive paste layer Then, the process of sequentially laminating other honeycomb fired bodies on this adhesive paste layer is repeated to produce a honeycomb aggregate in which a plurality of honeycomb fired bodies are bundled through the adhesive paste layer.
Subsequently, the honeycomb aggregate is heated to solidify the adhesive paste layer, thereby producing a ceramic block in which the adhesive layer is formed.

Subsequently, a peripheral processing step is performed in which the side surface of the ceramic block is processed into a cylindrical shape by using a diamond cutter or the like.

Furthermore, the outer periphery sealing material layer formation process which forms an outer periphery sealing material layer in the outer peripheral surface of a ceramic block is performed with the following method.
The honeycomb structure sealing material of the present embodiment is applied to the outer peripheral surface of the ceramic block using a squeegee to form an outer peripheral sealing material paste layer, and the outer peripheral sealing material paste layer is solidified to form the outer peripheral sealing material layer. Form.

Through the above steps, a honeycomb structure in which an adhesive layer and an outer peripheral sealing material layer are formed using the honeycomb structure sealing material of the present embodiment can be manufactured.

Hereinafter, the effects of the sealing material for honeycomb structure, the honeycomb structure, and the manufacturing method of the honeycomb structure of the present embodiment will be listed.
(1) The inorganic fibers contained in the honeycomb structure sealing material of the present embodiment are biosoluble fibers. Therefore, even if the inorganic fiber is taken into the human body, it has solubility under physiological conditions, and thus the safety of the sealing material for honeycomb structure including the inorganic fiber to the human body can be ensured.
In addition, the honeycomb structure manufactured using the honeycomb structure sealing material of the present embodiment has high safety to the human body, and can be handled with peace of mind by workers and consumers.
Furthermore, when manufacturing a honeycomb structure using the honeycomb structure sealing material of the present embodiment, an operator can work safely.

(2) Since the sealing material for honeycomb structure of the present embodiment shows acidity, it can suppress elution of polyvalent metal ions from the biosoluble fiber. Therefore, gelation of the sealing material can be prevented.
Therefore, even if a long time elapses after the preparation of the sealing material paste, it is possible to prevent the viscosity of the sealing material paste from increasing and the fluidity of the sealing material paste from decreasing.
Further, in the process of forming the outer peripheral sealing material layer of the honeycomb structure using the honeycomb structure sealing material of the present embodiment, gelation of the honeycomb structure sealing material does not occur. Since it becomes difficult to apply, it is possible to prevent the thickness of the outer peripheral sealing material layer from becoming uneven. Thereby, the dispersion | variation or fall of the intensity | strength of an outer periphery sealing material layer resulting from the nonuniformity of the thickness of an outer periphery sealing material layer can be prevented.

(3) The honeycomb structure sealing material of the present embodiment includes a metal-containing material including at least one selected from the group consisting of Mg, Ca, and Sr. Therefore, even if elution of polyvalent metal ions is suppressed due to the acidity of the sealing material, the polyvalent metal ions necessary for maintaining (improving) the strength of the sealing material can be supplied into the sealing material. The strength of the sealing material after solidification can be prevented from being lowered.

(4) The honeycomb structure of the present embodiment is a collective honeycomb structure including a plurality of honeycomb fired bodies.
In a honeycomb structure in which a plurality of honeycomb fired bodies are gathered, an adhesive layer between the honeycomb fired bodies is necessary, and thus the total amount of inorganic fibers contained in the honeycomb structure is inevitably increased. Even in such a case, in the honeycomb structure of the present embodiment, the honeycomb structure sealing material of the present embodiment is used as the adhesive, so that safety to the human body can be ensured.

(5) In the honeycomb structure of the present embodiment, the outer peripheral sealing material layer is formed by solidifying the honeycomb structure sealing material of the present embodiment. Since the sealing material for a honeycomb structure of the present embodiment does not decrease the strength of the sealing material after solidification, damage such as chipping in the outer peripheral sealing material layer can be prevented.

(6) In the honeycomb structure of the present embodiment, the adhesive layer is formed by solidifying the honeycomb structure sealing material of the present embodiment. Since the sealing material for the honeycomb structure of the present embodiment does not decrease the strength of the sealing material after solidification, the honeycomb fired body bundled through the adhesive layer can be prevented from being displaced or detached. The honeycomb structure can be used stably for a long time.

(7) In the method for manufacturing a honeycomb structure of the present embodiment, the honeycomb structure sealing material of the present embodiment is applied to the outer peripheral surface of the ceramic block in the outer peripheral sealing material layer forming step. Further, when the adhesive layer is formed, the honeycomb structure sealing material of the present embodiment is applied to the side surface of the honeycomb fired body. The sealing material for honeycomb structure of the present embodiment, even if a long time passes after the preparation of the sealing material paste, the viscosity of the sealing material paste increases, and the fluidity of the sealing material paste does not decrease, It can prevent that workability | operativity at the time of outer periphery sealing material layer formation or adhesive material layer formation falls.

Examples that more specifically disclose the first embodiment of the present invention will be described below. In addition, this invention is not limited only to these Examples.

(1) Preparation of sealing material for honeycomb structure In each example and comparative example, a sealing material for honeycomb structure was prepared using the following oxide sol and inorganic fibers.
The oxide sol used in each example and comparative example is an acidic silica sol, and the composition of the oxide sol is as follows: SiO ₂ , 20.4 wt%; Na ₂ O, 0.11 wt %; Al ₂ O ₃ , 0.17% by weight; and H ₂ O, 79.3% by weight.
Moreover, the inorganic fiber used in each Example and Comparative Example is a biosoluble fiber, and the composition of the biosoluble fiber is as follows: SiO ₂ , 70.8 wt%; MgO, 0.6 wt%; CaO, 25.9 _{wt%; Al} 2 O 3, 0.8 wt%; and other components, 1.9% by weight.

Example 1
(Preparation of sealing material for honeycomb structure)
37.4% by weight of the above-mentioned biosoluble fiber as inorganic fiber, 31.4% by weight of SiC powder as inorganic particles, 0.03% by weight of calcium carbonate as metal-containing material, carboxymethylcellulose as organic binder ( CMC) is 0.4 wt%, the average particle size is 12 nm, pH is 6.7, 17.4 wt% of the above acidic silica sol and 13.4 wt% of water are added and mixed, and the pH is lowered by kneading. A sealing material for a honeycomb structure of 6.7 was prepared.

(Examples 2 to 10)
A sealing material for honeycomb structure was prepared in the same manner as in Example 1 except that the Ca content in the sealing material for honeycomb structure was changed as shown in Table 1 by changing the amount of calcium carbonate.

(Examples 11 and 12)
A sealing material for a honeycomb structure was prepared in the same manner as in Example 1 except that magnesium carbonate and calcium sulfate were used instead of calcium carbonate.

(Comparative Example 1)
A honeycomb structure sealing material was prepared in the same manner as in Example 1 except that calcium carbonate was not added.

(Comparative Examples 2-6)
A sealing material for a honeycomb structure was prepared in the same manner as in Example 1 except that lithium carbonate, sodium carbonate, potassium carbonate, copper sulfate, and aluminum sulfate were used instead of calcium carbonate.

(2) Evaluation of sealing material for honeycomb structure The sealing material for honeycomb structure prepared in each Example and Comparative Example was evaluated by the following method.
In order to evaluate the honeycomb structure sealing material, first, a honeycomb fired body was prepared, and an evaluation sample using the obtained two honeycomb fired bodies and the honeycomb structure sealing material was prepared. Using this evaluation sample, evaluation was made based on the breaking strength.
Next, 16 honeycomb fired bodies were bonded using a honeycomb structure sealing material to produce a ceramic block, and an outer peripheral sealing material layer was formed on the outer peripheral portion of the obtained ceramic block to manufacture the honeycomb structure. Then, using this honeycomb structure, the perforation occurrence rate of the outer peripheral sealing material layer was evaluated.

(2-1) Preparation of evaluation sample and evaluation of mechanical properties of solidified sealing material for honeycomb structure by fracture strength using the evaluation sample (preparation of honeycomb fired body)
Silicon carbide coarse powder 52.8% by weight having an average particle diameter of 22 μm and silicon carbide fine powder 22.6% by weight having an average particle diameter of 0.5 μm were mixed. 2.1% by weight of resin, 4.6% by weight of organic binder (methyl cellulose), 2.8% by weight of lubricant (Unilube manufactured by NOF Corporation), 1.3% by weight of glycerin, and 13.8% by weight of water were added. After forming a wet mixture by kneading, an extrusion molding step of extrusion molding is performed, and a raw honeycomb molding in which the shape is substantially the same as the shape shown in FIG. 2A and the cells are not sealed The body was made.

Next, after drying the raw honeycomb molded body using a microwave dryer to obtain a dried honeycomb molded body, a predetermined cell is filled with a sealing material paste having the same composition as the wet mixture, The dried body of the honeycomb formed body filled with the plug material paste was dried again using a dryer.

Next, a degreasing process of degreasing the dried honeycomb molded body at 400 ° C. is performed, and a firing process is performed at 2200 ° C. for 3 hours under an atmospheric pressure of argon atmosphere. A honeycomb fired body made of a silicon carbide sintered body having a size of 34.3 mm × 34.3 mm × 150 mm, a cell number (cell density) of 300 / inch ² , and a cell wall thickness of 0.25 mm (10 mil). The body was made.

(Preparation of sample for evaluation)
Then, the sample for evaluation was produced with the following method.
FIG. 3 is a perspective view schematically showing a method for producing an evaluation sample.
First, a total of four cardboard spacers (thickness 2.0 mm, Young's modulus 0.01 GPa) 710 were pasted, one by one, near the four corners of the side surface of one honeycomb fired body 110. The attachment position of the spacer 710 is a position where the shortest distance between the outer peripheral portion of the spacer 710 and the two sides formed by the corners of the side surface of the honeycomb fired body 110 is 4.5 mm. Next, the honeycomb structure sealing material prepared in each of Examples and Comparative Examples was applied to the side surface of the honeycomb fired body 110 to which the spacer 710 was attached, and another honeycomb was interposed through the spacer 710 and the honeycomb structure sealing material. The fired body 110 was adhered. Further, the two honeycomb fired bodies 110 coated with the honeycomb structure sealing material 110 are heated to 120 ° C. to solidify the honeycomb structure sealing material, thereby forming an adhesive layer 101 having a thickness of 2.0 mm. did.
As described above, an adhesive body 300 including the two honeycomb fired bodies 110 and the adhesive layer 101 was manufactured (see FIG. 3).

Next, an outer peripheral sealing material layer for evaluation was formed on the upper surface of the adhesive body 300.
A rectangular jig 700 having a width of 70.6 mm, a length of 150 mm, and a thickness of 0.2 mm and having a rectangular opening therein was placed on the upper surface of the adhesive body 300. Next, the honeycomb structure sealing material 10 prepared in each of the examples and the comparative examples is filled into the opening, and the filled honeycomb structure sealing material 10 is matched to the thickness of the jig 700 using a squeegee. Leveled.
After leveling the honeycomb structure sealing material 10, the jig 700 is removed, and the adhesive body 300 is heated to 120 ° C. in a dryer to solidify the honeycomb structure sealing material 10. Formed.
By the above method, an evaluation sample including an adhesive body 300 as shown in FIG. 3 and an evaluation outer peripheral sealing material layer (thickness 0.2 mm) 320 (see FIG. 4) was produced. FIG. 3 shows the jig 700 used for producing the outer peripheral sealing material layer 320 for evaluation, but the jig 700 is removed when measuring the breaking strength.

(Evaluation of breaking strength)
For each sample for evaluation of Examples and Comparative Examples, the breaking strength of the outer peripheral sealing material layer for evaluation was measured by the following method, and this was used as an index of the adhesive strength of the sealing material for honeycomb structure.
FIG. 4 is a side view schematically showing a method for measuring the breaking strength of the evaluation outer peripheral sealing material layer.
A compressive load was applied to the portion (hereinafter referred to as the center portion) 321 of the outer peripheral sealing material layer 320 for evaluation extending between the two honeycomb fired bodies 110, and the load when the center portion 321 was broken was defined as the breaking strength. For the measurement of the breaking strength, a texture analyzer 800 was used, and a probe having a cylinder length of 1.5 mm and a total length of 10 mm was used as the probe 810 for applying a compressive load.
First, as shown in FIG. 4, the evaluation sample 310 was placed so that the tip of the probe 810 came to the center 321 when the probe 810 was lowered. Next, the probe 810 was lowered to the central portion 321 at a speed of 10 mm / s, and the compressive load (MPa) when the central portion 321 was broken was measured, and this compressive load was defined as the breaking strength (MPa). Table 1 shows the measurement results of the breaking strength of the samples for evaluation.

(2-2) Preparation of honeycomb structure and evaluation of coverage of sealing material for honeycomb structure based on perforation occurrence rate of outer peripheral sealing material layer using the honeycomb structure (production of honeycomb structure)
A honeycomb fired body is placed along the V-shape of the above-mentioned base on a base having a V-shaped cross section, and the honeycomb prepared in each of the examples and comparative examples is on the side facing the upper side of the honeycomb fired body. The structure sealing material was applied with a squeegee to form an adhesive paste layer.
Four spacers (thickness: 1.0 mm) were placed on the adhesive paste layer, one in the vicinity of the four corners of the side surface.
The four spacers were placed at positions where the shortest distance between the outer periphery of the spacer and the two sides formed by the side corners of the honeycomb fired body was 4.5 mm.

Then, another honeycomb fired body was placed on the adhesive paste layer and the spacer. Further, the above honeycomb fired body is coated with the above-mentioned sealing material for the honeycomb structure, another spacer is placed, and another honeycomb fired body is placed repeatedly. A honeycomb aggregate composed of four honeycomb fired bodies was produced.
At this time, the thickness of the adhesive paste layer (interval between the honeycomb fired bodies) was set to 1.0 mm.
Further, this honeycomb aggregate was heated at 120 ° C. to solidify the adhesive paste layer, and a ceramic block was produced as an adhesive layer.

Next, the outer periphery of the ceramic block was ground into a cylindrical shape using a diamond cutter.
Subsequently, an outer peripheral sealing material paste layer having a thickness of 0.2 mm was formed on the outer peripheral portion of the ceramic block by using the outer peripheral sealing material paste made of the same material as the sealing material for the honeycomb structure. And this outer periphery sealing material paste layer was dried at 120 degreeC, and the cylindrical honeycomb structure of diameter 132.5mm x length 150mm in which the outer periphery sealing material layer was formed in the outer peripheral part of the ceramic block was produced.

(Catalyst loading)
Next, γ-alumina powder was mixed with a sufficient amount of water and stirred to prepare an alumina slurry. The honeycomb structure was immersed in this alumina slurry with one end face down and held for 1 minute. Then, the drying process which heats this honeycomb structure at 110 degreeC for 1 hour was performed, and also the baking process calcined at 700 degreeC for 1 hour was performed, and the catalyst support layer was formed.
At this time, the immersion in the alumina slurry, the drying step, and the firing step are performed so that the formation amount of the catalyst supporting layer is 40 g per 1 liter of the apparent volume of the honeycomb structure where the catalyst supporting layer is formed. Repeatedly.

A honeycomb having a catalyst support layer formed in a dinitrodiammine platinum nitrate solution ([Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] HNO ₃ , platinum concentration 4 wt%) after forming the catalyst support layer on the honeycomb structure The structure was immersed with the end face on the gas inflow side down and held for 1 minute. Subsequently, the honeycomb structure was dried at 110 ° C. for 2 hours and fired at 500 ° C. for 1 hour in a nitrogen atmosphere, thereby supporting the platinum catalyst on the catalyst support layer of the honeycomb structure. The amount of catalyst supported was such that 3 g of platinum was supported on 20 g of alumina as the catalyst supporting layer.

(Evaluation of perforation occurrence rate of outer peripheral sealing material layer)
Using 100 honeycomb structures manufactured as described above, evaluation was performed based on the occurrence rate of holes in the outer peripheral sealing material layer of the honeycomb structure before the canning process.
With respect to the honeycomb structure before the canning step was performed, it was visually determined whether holes or chips were generated in the outer peripheral sealing material layer. Then, the perforation occurrence rate (%) of the outer peripheral sealing material layer was determined from the ratio of the number of honeycomb structures in which holes or chips were generated in the outer peripheral sealing material layer with respect to 100 honeycomb structures. Table 1 shows the evaluation results of the perforation occurrence rate of the outer peripheral sealing material layer.

About the sealing material for honeycomb structure of Examples 1-12 and Comparative Examples 1-6, the kind and metal content of the metal-containing material used for the preparation of the sealing material for honeycomb structure, and the fracture strength and the outer periphery seal Table 1 summarizes the results of the perforation occurrence rate of the material layer.
Further, from the measurement results of the breaking strength in Examples 1 to 10 and Comparative Example 1, the relationship between the Ca content in the sealing material for honeycomb structure and the breaking strength is shown in the graph of FIG.

As a result of measuring the breaking strength of the outer peripheral sealing material layer for evaluation, when the Ca content in the sealing material for honeycomb structure is 0.01 wt% to 1.0 wt%, the breaking strength is 6.1. It was a high value of ˜8.3 MPa. When the Ca content in the honeycomb structure sealing material is 2.0% by weight, the fracture strength is 7.8 MPa, and the Ca content in the honeycomb structure sealing material is saturated (saturation). ).
If the fracture strength of the outer peripheral sealing material layer for evaluation is 6.0 MPa or more, it is considered that the honeycomb structural sealing material can be practically used as the outer peripheral sealing material.

Further, from the graph of FIG. 5, the fracture strength increases as the Ca content increases until the Ca content in the honeycomb structure sealing material becomes saturated. It can be seen that the fracture strength of depends on the Ca content in the honeycomb structure sealing material.

Furthermore, in the case of a honeycomb structure sealing material prepared using magnesium carbonate or calcium sulfate instead of calcium carbonate, the fracture strength is 6.1 MPa, and the honeycomb structure sealing material prepared using calcium carbonate is used. As with the case of the material, it was 6.0 MPa or more.

On the other hand, when the Ca content in the honeycomb structure sealing material was 0% by weight, the fracture strength was a low value of 4.3 MPa.

In addition, in the case of a honeycomb structure sealing material prepared using lithium carbonate, sodium carbonate, or potassium carbonate instead of calcium carbonate, the fracture strengths are 4.2 MPa, 4.0 MPa, and 4.3 MPa, respectively. It was the same value as the result of the comparative example 1 which has not added content. That is, when these metal-containing materials were used, there was no effect of improving the breaking strength of the sealing material.
In addition, when copper sulfate or aluminum sulfate was used, the sealing material paste gelled when the honeycomb structure sealing material was produced, and the honeycomb structure sealing material could not be produced.

Next, when the Ca content in the sealing material for the honeycomb structure is 0.01 wt% to 1.0 wt% as a result of evaluating the occurrence rate of the outer perforation in the outer peripheral sealing material layer, The perforation occurrence rate was 0%, and no holes or chips were generated in the outer peripheral sealing material layer. Further, even when the Ca content in the honeycomb structure sealing material was 2.0% by weight, no holes or chips were generated in the outer peripheral sealing material layer.

Further, in the case of the honeycomb structure sealing material prepared using magnesium carbonate or calcium sulfate instead of calcium carbonate, the perforation occurrence rate of the outer peripheral sealing material layer was 0%.

In contrast, when the Ca content in the sealing material for honeycomb structure is 0% by weight, or the sealing material for honeycomb structure prepared using lithium carbonate, sodium carbonate, or potassium carbonate instead of calcium carbonate. In the case, the perforation occurrence rate of the outer peripheral sealing material layer was a high value of 7 to 9%.

From the above, it has been found that by adding a metal-containing material containing Ca or Mg to the honeycomb structure sealing material, an evaluation outer peripheral sealing material layer having excellent fracture strength can be formed. For this reason, this honeycomb structure sealing material is considered to have excellent adhesive strength, and when this honeycomb structure sealing material is used as the outer peripheral sealing material of the honeycomb structure, the outer peripheral sealing material layer is not chipped. It is thought that damage can be prevented.

In addition to the use of the metal-containing material, it is assumed that the same effect as in the present embodiment is produced when calcium acetate, magnesium nitrate, magnesium sulfate, magnesium acetate, or strontium carbonate is used.

(Second embodiment)
Hereinafter, a second embodiment which is an embodiment of the present invention will be described.
In this embodiment, the structure of the sealing material for the honeycomb structure and the honeycomb structure is the same as that of the first embodiment, but the method for forming the adhesive layer in the method for manufacturing the honeycomb structure is different from that of the first embodiment. Different.

First, a plurality of honeycomb fired bodies are juxtaposed vertically and horizontally through a spacer designed to have a thickness equivalent to the thickness of the adhesive layer formed between the honeycomb fired bodies. Therefore, a gap corresponding to the thickness of the spacer is formed between the honeycomb fired bodies.
Then, 16 honeycomb fired bodies are juxtaposed in four rows in the vertical and horizontal directions to produce a parallel body of honeycomb fired bodies.

Subsequently, the gaps between the honeycomb fired bodies arranged in parallel are filled with the sealing material for the honeycomb structure described in the first embodiment by using a filling device.
When filling the gap between the honeycomb fired bodies with the sealing material for the honeycomb structure described in the first embodiment, the parallel body of the honeycomb fired bodies is installed in the internal space of the cylindrical body, and the sealing material paste feeder Is attached to the end face of the cylindrical body. Then, the honeycomb structure sealing material described in the first embodiment is pushed out from the sealing material paste chamber of the sealing material paste supply device using the extrusion mechanism, and the gap between the honeycomb fired bodies is filled with the honeycomb structure sealing material. To do.
In this way, a laminate of honeycomb fired bodies in which 16 honeycomb fired bodies are filled with the honeycomb structure sealing material as an adhesive is manufactured.

Subsequently, the honeycomb fired body laminate is heated using a dryer or the like to dry and solidify the adhesive, thereby forming an adhesive layer.
By such a process, a ceramic block on a prism made of 16 honeycomb fired bodies can be manufactured.

In the outer periphery sealing material forming step, the method for applying the honeycomb structure sealing material described in the first embodiment to the outer peripheral surface of the ceramic block using the squeegee after the outer periphery processing step, as in the first embodiment. Use.

In the present embodiment, the effects (1) to (6) described in the first embodiment can be exhibited, and the following effects can be exhibited.
(8) In the method for manufacturing a honeycomb structure of the present embodiment, when forming the adhesive layer, the honeycomb structure sealing material described in the first embodiment is filled between the honeycomb fired bodies. The honeycomb structure sealing material does not increase the viscosity of the sealing material paste and the fluidity of the sealing material paste does not decrease even if a long time has elapsed after the preparation of the sealing material paste. The honeycomb structure sealing material can be easily filled.

(9) In the honeycomb structure manufacturing method of the present embodiment, the honeycomb structure sealing material described in the first embodiment is applied to the outer peripheral surface of the ceramic block in the outer peripheral sealing material layer forming step. Since the sealing material for honeycomb structure does not increase the viscosity of the sealing material paste and decrease the fluidity of the sealing material paste even if a long time elapses after the preparation of the sealing material paste, the outer peripheral sealing material It can prevent that workability | operativity at the time of layer formation falls.

(Third embodiment)
Hereinafter, a third embodiment which is an embodiment of the present invention will be described.
In the present embodiment, the structure of the sealing material for honeycomb structure and the honeycomb structure is the same as that of the first embodiment, and the shape of the honeycomb structure is substantially the same as that of the first embodiment. The shape of the honeycomb fired body used in the manufacturing method and the method of forming the adhesive layer and the outer peripheral sealing material layer are different from those in the first embodiment.

In the method for manufacturing a honeycomb structure of the present embodiment, three types of honeycomb fired bodies having different cross-sectional shapes perpendicular to the longitudinal direction are manufactured. One of the honeycomb fired bodies has a cross section surrounded by two straight lines and one curve, and one of the honeycomb fired bodies has a cross section surrounded by three straight lines and one curve. One of the honeycomb fired bodies has a cross-sectional shape surrounded by four straight lines.
These three types of honeycomb fired bodies having different cross-sectional shapes can be produced by changing the shape of a die used in extrusion forming. These honeycomb fired bodies correspond to, for example, the honeycomb fired bodies of three types that form the honeycomb structure shown in FIG.

Then, a plurality of these three kinds of honeycomb fired bodies are juxtaposed in the vertical and horizontal directions through spacers, thereby producing a parallel body of honeycomb fired bodies having a substantially circular cross-sectional shape perpendicular to the longitudinal direction.
At this time, a gap corresponding to the thickness of the spacer is formed between the honeycomb fired bodies.

Subsequently, a parallel body of honeycomb fired bodies is installed in a filling apparatus having a cylindrical tubular body, and gaps formed between the honeycomb fired bodies and formed between the honeycomb fired body and the cylindrical body. The voids are filled with the honeycomb structure sealing material described in the first embodiment.

The filling device used in the present embodiment includes a cylindrical tubular body and a sealing material paste feeder. The inner diameter of the cylindrical body is slightly larger than the diameter of the parallel body of the honeycomb fired bodies to be installed, and when the parallel body of honeycomb fired bodies is installed in the internal space of the cylindrical body, It is comprised so that a space | gap may be formed between parallel bodies.

The sealing material paste supply device includes the honeycomb structure sealing material described in the first embodiment accommodated in the sealing material paste chamber, the gap between the honeycomb fired bodies, and the parallel body of the tubular body and the honeycomb fired body. It is comprised so that a space | gap can be filled simultaneously.

In the method for manufacturing a honeycomb structured body of the present embodiment, using the parallel body of honeycomb fired bodies and the filling device as described above, the gaps between the honeycomb fired bodies, and the honeycomb fired bodies and the tubular bodies The gap formed therebetween is filled with the honeycomb structure sealing material described in the first embodiment. Subsequently, the honeycomb structure sealing material is dried and solidified to simultaneously form an adhesive layer and a peripheral sealing material layer between the honeycomb fired bodies.

In the present embodiment, the effects (1) to (6) described in the first embodiment can be exhibited, and the following effects can be exhibited.
(10) In the method for manufacturing a honeycomb structured body of the present embodiment, when forming the adhesive layer and the outer peripheral sealing material layer, the honeycomb structure sealing material described in the first embodiment is used as a gap between the honeycomb fired bodies, And it fills the space | gap formed between the honeycomb fired body and the cylindrical body. The honeycomb structure sealing material does not increase the viscosity of the sealing material paste and decrease the fluidity of the sealing material paste even if a long time elapses after the preparation of the sealing material paste. It is possible to easily fill the honeycomb structure sealing material as the outer peripheral sealing material. As a result, the adhesive material layer and the outer peripheral sealing material layer between the honeycomb fired bodies can be simultaneously and easily formed.

(11) In the method for manufacturing a honeycomb structure according to the present embodiment, a plurality of three types of honeycomb fired bodies having different cross-sectional shapes perpendicular to the longitudinal direction are juxtaposed in the vertical and horizontal directions, thereby obtaining a cross-section perpendicular to the longitudinal direction. A parallel body of honeycomb fired bodies having a substantially circular shape is produced. Therefore, a honeycomb structure having a predetermined outer peripheral shape can be manufactured without performing the outer peripheral processing step.

(Fourth embodiment)
Hereinafter, a fourth embodiment which is an embodiment of the present invention will be described.
In the present embodiment, the configuration of the sealing material for the honeycomb structure is the same as that of the first embodiment, but the shape of the honeycomb structure and the method for manufacturing the honeycomb structure are different from those of the first embodiment.

FIG. 6 is a perspective view schematically showing another example of the honeycomb structure of the present invention.
A honeycomb structure 150 shown in FIG. 6 has a ceramic block 155 made of a single pillar-shaped honeycomb fired body in which a large number of cells 151 are arranged in parallel in the longitudinal direction with a cell wall 152 therebetween, and around the ceramic block 155. A peripheral sealing material layer 154 is formed.

In the method for manufacturing a honeycomb structure of the present embodiment, a honeycomb fired body is manufactured in the same manner as in the first embodiment except that a substantially cylindrical honeycomb formed body is manufactured by changing the shape of a die used for extrusion molding. To do.
This honeycomb fired body becomes a ceramic block without performing a binding process of the plurality of honeycomb fired bodies.
And the outer periphery sealing material layer formation process which forms an outer periphery sealing material layer on the outer peripheral surface of a ceramic block using the sealing material for honeycomb structures of 1st embodiment is performed.

In the outer peripheral sealing material layer forming step, a method of applying the honeycomb structure sealing material to the outer peripheral surface of the ceramic block using a squeegee as in the first embodiment may be used, and as in the third embodiment. A method of filling the gap formed between the outer peripheral surface of the ceramic block and the cylindrical body with the sealing material for the honeycomb structure using a filling device may be used.

Also in this embodiment, the effects (1) to (4) described in the first embodiment and the effect (9) described in the second embodiment can be exhibited.

(Other embodiments)
In the honeycomb structure of the present invention, the honeycomb structure sealing material used for forming the adhesive layer and the honeycomb structure sealing material used for forming the outer peripheral sealing material layer may be the same material. However, different materials may be used.
Further, as the adhesive, in addition to the honeycomb structure sealing material of the present invention, an adhesive paste conventionally used for manufacturing a honeycomb structure can also be used.

The method for preparing the honeycomb structure sealing material of the present invention may employ an alkaline oxide sol in addition to the method using an acidic oxide sol.
The pH of the alkaline oxide sol is not particularly limited, but is preferably 8.5 to 10.5.
As the alkaline oxide sol, an alkaline silica sol can be preferably used.

And acidic solution is mixed with alkaline oxide sol, and pH of the sealing material paste obtained is adjusted to 4-6.
Although the pH of an acidic solution is not specifically limited, It is desirable that the pH of an acidic solution is 1-3.
Moreover, the kind of acidic solution is not specifically limited, For example, hydrochloric acid, a sulfuric acid, nitric acid, phosphoric acid, lactic acid, an acetic acid, or the aqueous solution of formic acid etc. are mentioned. Among the acidic solutions, a lactic acid aqueous solution is particularly desirable.

The shape of the honeycomb fired body is not particularly limited, but is preferably a shape that is easily bundled when the honeycomb fired bodies are bundled together to produce a honeycomb structure. A rectangle, a hexagon, a fan shape, etc. are mentioned.

In addition, the shape of the honeycomb structure of the present invention is not limited to a columnar shape, and may be an arbitrary shape such as an elliptical column shape, a long columnar shape, or a prismatic shape.

The porosity of the honeycomb fired body is not particularly limited, but is preferably 35 to 60%.
When the honeycomb structure manufactured using the honeycomb fired body is used as a filter, if the porosity is less than 35%, the filter may be clogged immediately, while the porosity exceeds 60%. This is because the strength of the honeycomb fired body is reduced, and the filter may be easily broken.

The average pore diameter of the honeycomb fired body is desirably 5 to 30 μm.
When the honeycomb structure manufactured using the above honeycomb fired body is used as a filter, if the average pore diameter is less than 5 μm, the filter may easily clog, while the average pore diameter exceeds 30 μm. This is because the particulates pass through the pores, and the honeycomb fired body cannot collect the particulates and cannot function as a filter.

The porosity and pore diameter can be measured by a conventionally known method such as a mercury intrusion method, an Archimedes method, or a measurement using a scanning electron microscope (SEM).

The cell density in the cross section perpendicular to the longitudinal direction of the honeycomb fired body is not particularly limited, but a desirable lower limit is 31.0 cells / cm ² (200 cells / inch ² ), and a desirable upper limit is 93.0 cells / cm ^2. (600 pieces / inch ² ), the more desirable lower limit is 38.8 pieces / cm ² (250 pieces / inch ² ), and the more desirable upper limit is 77.5 pieces / cm ² (500 pieces / inch ² ).
Further, the thickness of the cell wall of the honeycomb fired body is not particularly limited, but is desirably 0.1 to 0.4 mm.

The main component of the constituent material of the honeycomb fired body is not limited to silicon carbide. Other ceramic raw materials include, for example, nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, and titanium nitride, zirconium carbide, and carbonized Examples thereof include ceramic powders such as carbide ceramics such as titanium, tantalum carbide, and tungsten carbide, and oxide ceramics such as alumina, zirconia, cordierite, mullite, and aluminum titanate.
Of these, non-oxide ceramics are preferred, and silicon carbide is particularly preferred. It is because it is excellent in heat resistance, mechanical strength, thermal conductivity and the like. In addition, ceramic raw materials such as silicon-containing ceramics in which metallic silicon is mixed with the above-mentioned ceramics, and ceramics in which the above-described ceramics are bonded with silicon or a silicate compound can be cited as constituent materials. Those containing silicon (silicon-containing silicon carbide) are desirable.
In particular, a silicon-containing silicon carbide ceramic containing 60% by weight or more of silicon carbide is desirable.

It does not specifically limit as an organic binder used when preparing a wet mixture, For example, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyethyleneglycol etc. are mentioned. Of these, methylcellulose is desirable. In general, the blending amount of the organic binder is desirably 1 to 10 parts by weight with respect to 100 parts by weight of the ceramic powder.

The plasticizer used when preparing the wet mixture is not particularly limited, and examples thereof include glycerin. The lubricant is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether. Specific examples of the lubricant include polyoxyethylene monobutyl ether and polyoxypropylene monobutyl ether.
In some cases, the plasticizer and the lubricant may not be contained in the wet mixture.

In preparing the wet mixture, a dispersion medium liquid may be used. Examples of the dispersion medium liquid include water, an organic solvent such as benzene, and an alcohol such as methanol.

Furthermore, a molding aid may be added to the wet mixture.
The molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol and the like.

Furthermore, a pore-forming agent such as balloons that are fine hollow spheres containing oxide ceramics, spherical acrylic particles, and graphite may be added to the wet mixture as necessary.
The balloon is not particularly limited, and examples thereof include an alumina balloon, a glass micro balloon, a shirasu balloon, a fly ash balloon (FA balloon), and a mullite balloon. Of these, alumina balloons are desirable.

Although it does not specifically limit as a sealing material paste which seals a cell, What has the porosity of 30-75% of the sealing material manufactured through a post process is desirable, for example, the wet mixture of the raw material of a honeycomb fired body The same can be used.

The honeycomb structure may be loaded with a catalyst for purifying exhaust gas. As the catalyst to be loaded, for example, a noble metal such as platinum, palladium, rhodium or the like is desirable, and among these, platinum is more desirable. Further, as other catalysts, for example, alkali metals such as sodium and potassium, and alkaline earth metals such as barium can be used. These catalysts may be used independently and may use 2 or more types together.

So far, as the honeycomb structure, the honeycomb structure (honeycomb filter) in which either one end of the cell is sealed has been described. However, the honeycomb structure of the present invention has the end of the cell. It does not need to be sealed. Such a honeycomb structure can be suitably used as a catalyst carrier.

10 Honeycomb structure sealing material 100, 150 Honeycomb structure 101 Adhesive layer 102, 154 Outer peripheral sealing material layer 103, 155 Ceramic block 110 Honeycomb fired body 111, 151 Cell 113, 152 Cell wall G Exhaust gas

Claims (16)

It includes an inorganic fiber made of a biologically soluble inorganic compound, an oxide sol, inorganic particles, and a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr, and exhibits acidity A sealing material for a honeycomb structure characterized by the above. The sealing material for a honeycomb structure according to claim 1, wherein the inorganic compound is at least one of an alkali metal compound and an alkaline earth metal compound. The honeycomb structure seal according to claim 1 or 2, wherein the metal-containing material is at least one selected from the group consisting of calcium carbonate, calcium acetate, magnesium carbonate, magnesium nitrate, magnesium sulfate, and magnesium acetate. Wood. The sealing material for a honeycomb structure according to claim 3, wherein the metal-containing material is calcium carbonate or calcium acetate. The sealing material for a honeycomb structure according to claim 4, wherein the Ca content in the sealing material for a honeycomb structure is 0.01 to 1.0% by weight. A ceramic block composed of a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction across the cell wall;
A honeycomb structure comprising an outer peripheral sealing material layer formed on the outer peripheral surface of the ceramic block,
The honeycomb structure according to claim 1, wherein the outer peripheral sealing material layer is formed by solidifying the sealing material for a honeycomb structure according to any one of claims 1 to 5. The honeycomb structure according to claim 6, wherein the ceramic block includes a plurality of the honeycomb fired bodies and an adhesive layer formed between side surfaces of the plurality of honeycomb fired bodies. The honeycomb structure according to claim 7, wherein the adhesive layer is formed by solidifying the adhesive. The honeycomb structure according to claim 8, wherein the adhesive is the honeycomb structure sealing material according to any one of claims 1 to 5. A ceramic block composed of a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction across the cell wall;
A method for manufacturing a honeycomb structure comprising an outer peripheral sealing material layer formed on an outer peripheral surface of the ceramic block,
It includes an inorganic fiber made of a biologically soluble inorganic compound, an oxide sol, inorganic particles, and a metal-containing material containing at least one selected from the group consisting of Mg, Ca, and Sr, and exhibits acidity A honeycomb structure sealing material preparation step for preparing a honeycomb structure sealing material;
An outer peripheral sealing material layer forming step of forming an outer peripheral sealing material paste layer made of the honeycomb structure sealing material on the outer peripheral surface of the ceramic block, and forming the outer peripheral sealing material layer by solidifying the outer peripheral sealing material paste layer A method for manufacturing a honeycomb structure, comprising: A step of producing a honeycomb aggregate formed by binding a plurality of the honeycomb fired bodies through an adhesive layer paste, and solidifying the adhesive layer paste of the honeycomb aggregate to form an adhesive layer The manufacturing method of the honeycomb structure according to claim 10, further comprising a bundling step for producing a ceramic block in which a plurality of the honeycomb fired bodies are bundled through the adhesive layer. The method for manufacturing a honeycomb structure according to claim 11, wherein the sealing material for a honeycomb structure is used as the adhesive layer paste. The method for manufacturing a honeycomb structured body according to any one of claims 10 to 12, wherein the inorganic compound is at least one of an alkali metal compound and an alkaline earth metal compound. The honeycomb structure according to any one of claims 10 to 13, wherein the metal-containing material is at least one selected from the group consisting of calcium carbonate, calcium acetate, magnesium carbonate, magnesium nitrate, magnesium sulfate, and magnesium acetate. Body manufacturing method. The method for manufacturing a honeycomb structured body according to claim 14, wherein the metal-containing material is calcium carbonate or calcium acetate. The method for manufacturing a honeycomb structure according to claim 15, wherein a Ca content in the sealing material for a honeycomb structure is 0.01 to 1.0% by weight.

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