Plugged honeycomb structure

0001The present invention relates to an eye-sealing honeycomb structure. More specifically, the present invention relates to an eye-sealing honeycomb structure which can suppress a temperature rise when used at a high temperature and has excellent thermal shock resistance.

0002Exhaust gas emitted from internal combustion engines such as diesel engines and various combustion devices contains a large amount of particulate matter mainly composed of soot (hereinafter, also referred to as "particulate matter" or "PM"). There is. If this PM is released into the atmosphere as it is, it causes environmental pollution. Therefore, the exhaust gas exhaust system is equipped with a particulate filter for collecting PM. For example, examples of the particulate filter include a diesel particulate filter (DPF) used for purifying exhaust gas emitted from a diesel engine.

0003For such a DPF, for example, a honeycomb structure having a porous partition wall that partitions a plurality of cells serving as an exhaust gas flow path is used. This honeycomb structure is a mesh sealing portion for sealing the opening of a predetermined cell on the end face on the outflow side of the fluid and the opening of the remaining cell on the end face on the inflow side of the fluid. Is arranged and used as a sealing honeycomb structure. Hereinafter, particulate filters such as DPFs using a sealable honeycomb structure may be collectively referred to as a "honeycomb filter".

0004As the honeycomb structure used for DPF and the like, for example, the partition wall is MgO and SiO.₂A ceramic honeycomb structure composed of a main crystal of aluminum titanate obtained by solid-solving the above has been proposed (see, for example, Patent Document 1). The honeycomb structure includes, for example, a specific heat c (kJ / kg · K) and a specific gravity ρ (kg / m).³The heat capacity C represented by the product of) is 400.0 to 2000.0 (kJ / m).³A honeycomb structure having K) and a thermal conductivity κ of 1.0 to 30.0 (W / m · K) has also been proposed (see, for example, Patent Document 2).

0005In a honeycomb filter such as a DPF, the pressure loss gradually increases due to the PM accumulated inside the filter over time, so the PM accumulated inside the honeycomb filter is burned and removed at regular intervals. Sometimes. For example, as a method for regenerating the DPF, a regeneration method is known in which the temperature of the exhaust gas discharged from the engine is raised and the DPF is heated by using the high temperature exhaust gas. As a method of raising the temperature of the exhaust gas, for example, a method of burning the excess fuel by post-injection in which the fuel is temporarily excessively injected in the latter half of the explosion stroke or in the exhaust stroke to raise the temperature of the exhaust gas can be mentioned. ..

<p num="0006"><patcit num="1"><text>International Publication No. 2009/63997</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2008-136981</text></patcit></p>

<p num="0007"> In recent years, improvement of fuel efficiency of automobiles has been required from the viewpoint of global environmental protection and resource saving. Since the regeneration of the DPF by the post injection described above consumes fuel that is not related to the engine output at the time of regeneration, the higher the frequency of regeneration, the worse the fuel efficiency of the automobile. Therefore, for the purpose of improving the fuel efficiency of diesel engines for automobiles, reduction of the number of times of regeneration of the above-mentioned DPF (in other words, a sealing honeycomb structure) has been studied. That is, as the number of times the DPF is regenerated is reduced, the consumption of fuel required for regeneration is suppressed, and the fuel efficiency of the engine can be improved.</p><p num="0008"> However, when the number of regenerations of the DPF is reduced, the interval until regeneration (in other words, the regeneration cycle) becomes longer, so that a larger amount of soot is deposited on the surface of the partition wall during regeneration. It becomes a state. When the amount of soot deposited on the surface of the partition wall increases, the temperature rise due to the combustion of the soot increases, and the thermal shock generated in the DPF also increases accordingly. Therefore, reducing the number of times the DPF is regenerated increases the possibility of damage to the DPF due to thermal shock.</p><p num="0009"> In order to prevent damage due to the above-mentioned thermal shock due to a decrease in the number of regenerations of the DPF, a method of increasing the heat capacity of the partition wall of the sealing honeycomb structure used for the DPF can be considered. For example, in order to increase the heat capacity of the partition wall, there is a method of reducing the porosity of the partition wall. However, reducing the porosity of the bulkhead creates another problem of increased DPF pressure loss.</p><p num="0010"> As another method for increasing the heat capacity of the partition wall, a method of using a material having a higher heat capacity than the material used for the partition wall of the conventional sealing honeycomb structure can be considered as the material constituting the partition wall. However, all of the conventionally known materials disclosed as the material of the partition wall of the sealing honeycomb structure have a sufficiently high heat capacity so as to suppress damage due to thermal shock due to a decrease in the number of regenerations of the DPF. I don't have it. Therefore, the sealant is made of a new material having a high heat capacity, which can be used as a partition wall of the sealant honeycomb structure and can effectively suppress damage due to thermal shock due to a decrease in the number of regenerations of the DPF. The development of a honeycomb structure is desired.</p><p num="0011"> The present invention has been made in view of the above-mentioned problems. The present invention provides an eye-sealing honeycomb structure which can suppress a temperature rise when used at a high temperature and has excellent thermal shock resistance.</p>

<p num="0012"> In order to solve the above-mentioned problems, the present invention provides the following eye-sealing honeycomb structure.</p><p num="0013">[1] A columnar honeycomb structure having a porous partition wall forming a plurality of cells extending from a first end surface to a second end surface, which is a flow path of a fluid, and an opening of a predetermined cell on the first end surface. And a sealant portion disposed in the opening of the residual cell on the second end surface, and the partition wall serves as the main phase.<u style="single">40% by mass or more</u>α-Al₂O₃From a porous body containing aluminum titanate and glass.<u style="single">The α-Al of the porous body</u>_{<u style="single">2</u>}<u style="single">O</u>_{<u style="single">3</u>}<u style="single">The mass ratio of to the aluminum titanate is 60/40 to 90/10, and the porous body is the α-Al.</u>_{<u style="single">2</u>}<u style="single">O</u>_{<u style="single">3</u>}<u style="single">And 5 to 15% by mass of the glass with respect to 100% by mass of the total of the aluminum titanate and the glass.</u>, Eye-sealing honeycomb structure.</p><p num="0015"> [<u style="single">2</u>] The porous body is a solid solution of at least one component selected from the first group consisting of Fe, Mg, and Si in the aluminum titanate.<u style="single">] To</u>The eye-sealing honeycomb structure according to the description.</p><p num="0016"> [<u style="single">3</u>] Al obtained by converting Al and Ti contained in the aluminum titanate into oxides₂O₃And TiO₂Fe, Mg, and Si of the solid-dissolved components contained in the aluminum titanate are converted into oxides with respect to the total mass of the mass of₂O₃, MgO, and SiO₂The ratio of each mass of is 0.1 to 10.0 mass%.<u style="single">2</u>] The eye-sealing honeycomb structure according to.</p><p num="0018"> [<u style="single">4</u>] The glass is SiO₂, And Al₂O₃Including the above [1] to [<u style="single">3</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0019"> [<u style="single">5</u>] The glass further comprises an oxide consisting of at least one component selected from the group consisting of alkali metals, alkaline earth metals, Ti, and Fe.<u style="single">4</u>] The eye-sealing honeycomb structure according to.</p><p num="0020"> [<u style="single">6</u>] The true density of the materials that make up the porous body is 3.65 to 3.85 g / cm.³The above [1] to [<u style="single">5</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0021"> [<u style="single">7</u>] The heat capacity of the material constituting the porous body at 600 ° C is 4.25 to 4.50 J / K / cm.³The above [1] to [<u style="single">6</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0022"> [<u style="single">8</u>] The average coefficient of thermal expansion of the porous body at 40 to 800 ° C is 2.5 to 6.0 ppm / K, as described above [1] to [<u style="single">7</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0023"> [<u style="single">9</u>] The porous body satisfies the relationship of the following formula (1), and the above [1] to [<u style="single">8</u>] The eye-sealing honeycomb structure according to any one of. C-0.007 × α² 4.20 (1) (However, in the above formula (1), C is the heat capacity (J / K / cm) of the material constituting the porous body at 600 ° C.³), Α indicates the average coefficient of thermal expansion (ppm / K) of the porous body at 40 to 800 ° C. )</p><p num="0024"> [<u style="single">10</u>] The porosity of the porous body is 20 to 50%, the above [1] to [<u style="single">9</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0025"> [<u style="single">11</u>] The average pore diameter of the porous body is 5 to 20 μm, as described above [1] to [<u style="single">10</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0026"> [<u style="single">12</u>] A segment in which the honeycomb structure portion has a plurality of columnar honeycomb segments having the partition wall and is joined in a state of being arranged adjacent to each other so that the side surfaces of the plurality of honeycomb segments face each other. The structure, [1] ~ [<u style="single">11</u>] The eye-sealing honeycomb structure according to any one of.</p><p num="0027"> [<u style="single">13</u>] A catalyst for purifying exhaust gas is supported on at least one of the surface of the partition wall and the pores of the partition wall of the honeycomb structure portion.<u style="single">12</u>] The eye-sealing honeycomb structure according to any one of.</p>

<p num="0028"> The sealant honeycomb structure of the present invention has α-Al as the main phase.₂O₃It has a partition wall made of a porous body containing aluminum titanate and glass. The porous body constituting the partition wall has a higher heat capacity per unit volume of the material constituting the porous body than the material of the partition wall used for the conventionally known sealing honeycomb structure. In the sealing honeycomb structure of the present invention, since the heat capacity per unit volume of the material constituting the porous body is high, it is possible to suppress the temperature rise when used at a high temperature, and it is remarkable that the heat impact resistance is excellent. It works. Therefore, when the sealing honeycomb structure of the present invention is used as a DPF, the temperature rise during regeneration of the DPF can be suppressed, and for example, even if the number of regenerations of the DPF is reduced, thermal shock is obtained. Damage is less likely to occur.</p>

0029<figref num="1">It is a schematic perspective view which looked at one Embodiment of the eye-sealing honeycomb structure of this invention from the inflow end face side.</figref><figref num="2">It is a schematic perspective view of the eye-sealing honeycomb structure shown in FIG. 1 as seen from the outflow end face side.</figref><figref num="3">It is a schematic plan view of the sealing honeycomb structure shown in FIG. 1 as seen from the inflow end face side.</figref><figref num="4">It is a schematic plan view of the sealing honeycomb structure shown in FIG. 1 as seen from the outflow end face side.</figref><figref num="5">FIG. 5 is a schematic cross-sectional view showing a cross section of the sealing honeycomb structure shown in FIG. 1 parallel to the extending direction of the cell.</figref><figref num="6">It is a schematic perspective view which looked at the other embodiment of the eye-sealing honeycomb structure of this invention from the inflow end face side.</figref><figref num="7">It is a schematic diagram which shows an example of the SEM photograph of the porous body in one Embodiment of the eye-sealing honeycomb structure of this invention.</figref>

0030Next, a mode for carrying out the present invention will be described in detail with reference to the drawings. It is understood that the present invention is not limited to the following embodiments, and design changes, improvements, etc. may be appropriately made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

0031One embodiment of the eye-sealing honeycomb structure of the present invention includes a columnar honeycomb structure 4 as shown in FIGS. 1 to 5 and an eye-sealing portion 5 arranged in the opening of the cell 2. The eye-sealing honeycomb structure 100 comprising. The honeycomb structure portion 4 is a columnar structure having a porous partition wall 1 for partitioning a plurality of cells 2 extending from a first end surface 11 to a second end surface 12 which is a flow path of a fluid. The mesh sealing portion 5 is arranged in the opening of any one of the plurality of cells 2 and seals the opening of the cell 2. In FIGS. 1 to 5, the sealing portion 5 is an opening of a predetermined cell 2b (hereinafter, also simply referred to as "cell 2b") on the first end surface 11 and a residual cell 2a (hereinafter, also simply referred to as "cell 2b") on the second end surface 12. Hereinafter, it is simply arranged in the opening of the "cell 2a"). The eye-sealing honeycomb structure 100 configured in this way can be used as a particulate filter that purifies the exhaust gas discharged from the internal combustion engine or various combustion devices. The eye-sealing honeycomb structure 100 shown in FIGS. 1 to 5 further has an outer peripheral wall 3 located at the outermost periphery of the honeycomb structure portion 4.

0032Here, FIG. 1 is a schematic perspective view of an embodiment of the eye-sealing honeycomb structure of the present invention as viewed from the inflow end face side. FIG. 2 is a schematic perspective view of the sealing honeycomb structure shown in FIG. 1 as viewed from the outflow end face side. FIG. 3 is a schematic plan view of the sealing honeycomb structure shown in FIG. 1 as viewed from the inflow end face side. FIG. 4 is a schematic plan view of the sealing honeycomb structure shown in FIG. 1 as viewed from the outflow end face side. FIG. 5 is a schematic cross-sectional view showing a cross section of the sealing honeycomb structure shown in FIG. 1 parallel to the extending direction of the cell. In FIG. 5, reference numeral G indicates a fluid (for example, exhaust gas) passing through the cell, and the fluid moves in the direction of the arrow indicated by reference numeral G.

0033In the sealing honeycomb structure 100, the partition wall 1 is α-Al as the main phase.₂O₃It is composed of a porous body containing aluminum titanate and glass. Such a porous body has a higher heat capacity per unit volume of the material constituting the porous body than the material of the partition wall used for the conventionally known sealing honeycomb structure. In the sealing honeycomb structure 100, since the heat capacity per unit volume of the material constituting the porous body is high, it is possible to suppress the temperature rise when used at a high temperature, and it has a remarkable effect of being excellent in heat impact resistance. Play. Therefore, when the sealing honeycomb structure 100 of the present embodiment is used as the DPF, the temperature rise during regeneration of the DPF can be suppressed, and for example, even if the number of regenerations of the DPF is reduced, heat is generated. Damage due to impact is less likely to occur.

0034Here, the "heat capacity per unit volume of the material" means the heat capacity measured in a solid material in which pores or the like are not formed. For example, in the case of a porous body, the heat capacity of the material itself constituting the porous body is obtained without considering the pores formed in the porous body. Hereinafter, in the present specification, the heat capacity in consideration of the pores formed in the porous body is described as "heat capacity per unit volume of the porous body" and is distinguished from the above-mentioned "heat capacity per unit volume of the material". And. The "heat capacity per unit volume of a material" is sometimes simply referred to as the "heat capacity of a material". The "heat capacity per unit volume of the porous body" may be simply referred to as the "heat capacity of the porous body". In the present specification, unless otherwise specified, the "heat capacity" means the heat capacity at 600 ° C. In this specification, unless otherwise specified, the values of "heat capacity" and "heat capacity per unit volume" are 1 cm.³Heat capacity per unit (J / K / cm³).

0035The "main phase" in the porous body constituting the partition wall 1 means a substance having a mass ratio of 40% by mass or more. On the other hand, a substance having a mass ratio of less than 20% by mass, which does not correspond to the above-mentioned main phase and is identified by the X-ray diffraction method, may be referred to as a "secondary phase". In the mesh-sealed honeycomb structure of the present embodiment, glass or the like contained in the porous body corresponds to the sub-phase. The "main phase" in the porous body is not limited to one type, and when there are two types of substances satisfying the above conditions, both of the two types of substances become the "main phase". As used herein, the term "substance" means a substance (substance) that has a chemical composition and cannot be separated into two or more kinds of substances by physical manipulation.

0036Further, in the present specification, "aluminum titanate" is referred to as "Al".₂TiO₅May be written as. In addition, in this specification, "Al₂TiO₅And "α-Al₂O₃In addition to the components described in the chemical formula, the case where other components are dissolved in solid solution is also included. For example, examples of other components that are in solid solution include Fe, Mg, Si, and the like.

0037Porous α-Al₂O₃Mass ratio of aluminum titanate to aluminum titanate (α-Al)₂O₃/ Al₂TiO₅)<u style="single">Is</u>, 60/40 ~ 90/10<u style="single">Ri</u>, 70/30 ~ 90/10<u style="single">Is good</u>Furthermore, it is particularly preferable that it is 80/20 to 90/10. For example, the proportion of aluminum titanate contained in the porous body is relatively too high (in other words, α-Al).₂O₃If the ratio is too small), the heat capacity per unit volume of the material constituting the porous body may not be sufficiently improved. On the other hand, the ratio of aluminum titanate contained in the porous body is relatively too small (in other words, α-Al).₂O₃If the ratio is too large), the average coefficient of thermal expansion of the porous body at 40 to 800 ° C will increase. In the mesh-sealed honeycomb structure of the present embodiment, the value of "F" shown in the following formula (2) is preferably 4.20 or more, and when the heat capacity is low or the average coefficient of thermal expansion is large, this "F" The value of "F" may be less than 4.20.

0038F = C-0.007 × α² (2) (However, in the above formula (2), C is the heat capacity (J / K / cm) of the material constituting the porous body at 600 ° C.³), Α indicates the average coefficient of thermal expansion (ppm / K) of the porous body at 40 to 800 ° C. )

0039Porous α-Al₂O₃The mass ratio of to aluminum titanate can be determined by the following method. First, a test piece for determining the mass ratio is prepared using the porous body constituting the partition wall of the sealing honeycomb structure. The test piece can be produced by cutting out a test piece having a predetermined size from the porous body. Next, the obtained test piece is crushed into a powder. After the test piece is powdered, its mass is measured. The obtained powder is put into a liquid containing hydrofluoric acid. The liquid containing hydrofluoric acid is a mixture of hydrofluoric acid (content 46%), sulfuric acid (content 97%), hydrochloric acid (content 36%) and distilled water in a volume ratio of 10: 2: 3: 25. It is a thing. After adding the powder to the liquid containing hydrofluoric acid, hold the liquid at 0 ° C for 30 minutes to dissolve the glass in the powder. Then, the amount of each solute component in the liquid is measured, each solute component is converted into an oxide, and the total is taken as the amount of glass. For example, Al is Al₂O₃Converted as oxide. In this way, the mass ratio of the glass contained in the test piece can be obtained. Then α-Al in the residue₂O₃The quantity is quantified by the internal standard method of X-ray diffraction (XRD). And the rest in the residue is Al₂TiO₅And. Α-Al measured in this way₂O₃And Al₂TiO₅The mass ratio can be obtained from the mass of. Here, the "residue" means the powder after melting the glass in the powder. In addition, "remaining in the residue" means α-Al from the residue.₂O₃It means the amount minus the amount. In addition, the "internal standard method of X-ray diffraction (XRD)" utilizes the fact that the internal standard substance and the sample are mixed at a constant ratio and a linear relationship can be obtained between the substance concentration and the diffraction line intensity ratio. Then, a calibration curve is prepared and analyzed with a standard sample having a known concentration.

0040The porous body is preferably a solid solution of at least one component selected from the first group consisting of Fe, Mg, and Si in aluminum titanate. When at least one component selected from the first group is dissolved in aluminum titanate contained in the porous body, the heat-resistant decomposition property of the partition wall composed of the porous body is improved.

0041The components dissolved in aluminum titanate can be analyzed by the following method. First, the partition wall of the sealing honeycomb structure is cut, and the cut surface of the porous body constituting the partition wall is embedded in the resin. Then, the cut surface of the porous body is polished, and the cut surface is observed with a scanning electron microscope (hereinafter, also referred to as "SEM"). In the observed SEM image (5000x), Al₂TiO₅(Aluminum titanate), α-Al₂O₃, The chemical composition of each part of the glass is analyzed by energy dispersive X-ray analysis (hereinafter, also referred to as "EDS"). By such a method, aluminum titanate, α-Al₂O₃, The chemical composition of each part of the glass can be analyzed.

0042An SEM image (SEM photograph) of observing the porous body constituting the partition wall is as shown in FIG. 7, for example. FIG. 7 is a schematic view showing an example of an SEM photograph of a porous body in one embodiment of the eye-sealing honeycomb structure of the present invention. A SEM photograph is a photograph taken by a scanning electron microscope. As shown in FIG. 7, the porous body is represented by "α-Al" indicated by reference numeral 6.₂O₃, The "aluminum titanate" indicated by reference numeral 7, and the "glass" indicated by reference numeral 8. A plurality of "pores (also referred to as pores)" indicated by reference numeral 9 are formed in the porous body.

0043The solid solution amount of the components contained in the first group dissolved in aluminum titanate is preferably 0.1 to 10.0% by mass, more preferably 0.1 to 5.0% by mass, and 0.5 to 3.0% by mass. It is particularly preferable to have. The "solid solution amount (mass%) of the components contained in the first group" means the following mass ratio (mass%). First, the denominator of the mass ratio (mass%) indicated by the amount of solid solution is Al obtained by converting Al and Ti contained in aluminum titanate into oxides.₂O₃And TiO₂It is the total mass of the mass of the above and the mass of the solid solution component contained in the aluminum titanate converted into an oxide. The "solid solution amount (mass%) of the components contained in the first group" is obtained by converting Fe, Mg, and Si of the solid solution components contained in aluminum titanate into oxides with respect to the total mass. Fe₂O₃, MgO, and SiO₂It is the ratio (mass%) of each mass of. That is, in the present specification, the "solid solution amount (mass%)" means the mass ratio (mass%) in the oxide substitution of the solid solution component. The above-mentioned solid solution components are all components solidly dissolved in aluminum titanate, and include components other than the components contained in the first group. If the solid solution amount of the component contained in the first group is less than 0.1% by mass, the suitable effect of the solid solution component may not be sufficiently exhibited. If the solid solution amount of the components contained in the first group exceeds 10.0% by mass, the average coefficient of thermal expansion may increase. For the solid solution amount of the components contained in the first group, the aluminum titanate portion is arbitrarily measured at 10 points each in the EDS for analyzing the chemical composition of aluminum titanate described above, and the average value is calculated for the component ratio. To do. The solid solution amount can be obtained from the obtained component ratio.

0044The porous body that constitutes the partition wall is α-Al.₂O₃It may contain 5 to 15% by mass of glass with respect to the total of 100% by mass of aluminum titanate and glass.<u style="single">Needed</u>, 5 ~ 12% by mass<u style="single">Is good</u>Furthermore, it is particularly preferable to contain 7 to 12% by mass. α-Al₂O₃When the content of glass is less than 5% by mass with respect to the total of 100% by mass of aluminum titanate and glass, the porosity of the partition wall (in other words, the porous body) becomes high, and the honeycomb structure is sealed. The strength of the body may decrease. α-Al₂O₃If the content of glass exceeds 15% by mass with respect to the total of 100% by mass of aluminum titanate and glass, the heat capacity per unit volume of the material constituting the porous body may not be sufficiently improved. The content of glass in the porous body is the α-Al described above.₂O₃When determining the mass ratio of and aluminum titanate, it can be determined from the mass of glass dissolved in the acid solution. In addition, in this specification, glass means an oxide which does not have a specific diffraction pattern in XRD.

0045The glass contained in the porous body is SiO₂, And Al₂O₃May include. The glass is SiO₂, And Al₂O₃When is contained, the strength of the partition wall composed of the porous body is improved. Further, the glass may further contain an oxide composed of at least one component selected from the group consisting of alkali metals, alkaline earth metals, Ti, and Fe. Further containing at least one selected from the above group is more preferable in that the strength of the partition wall is further improved. Each component contained in the glass can be analyzed by the same method as the method for analyzing the component dissolved in aluminum titanate. That is, in the SEM image when analyzing the components dissolved in aluminum titanate, the chemical composition of the glass portion can be analyzed by EDS and each component can be qualitatively analyzed.

0046The true density of the materials that make up the porous body is 3.65 to 3.85 g / cm.³It is preferable that it is 3.70 to 3.85 g / cm.³Is more preferable, 3.75 to 3.85 g / cm.³Is particularly preferable. When the true density of the material constituting the porous body is within the above numerical range, it is preferable that the amount of glass in the porous body is small. For example, the true density of the materials that make up the porous body is 3.65 g / cm.³If it is less than, the heat capacity may be too small, 3.85 g / cm.³If it is too high, the strength may be too low or the average coefficient of thermal expansion may be too large. The true density of the material constituting the porous body can be measured by the Archimedes method in accordance with JIS R 1634.

0047The heat capacity of the material constituting the porous body at 600 ° C is 4.25 to 4.50 J / K / cm.³It is preferable that it is 4.30 to 4.50 J / K / cm.³Is more preferable, 4.35 to 4.50 J / K / cm.³Is particularly preferable. The heat capacity of the material constituting the porous body at 600 ° C is 4.50 J / K / cm.³If it exceeds, the balance with the average coefficient of thermal expansion becomes poor, which is not very preferable. On the other hand, the heat capacity of the material constituting the porous body at 600 ° C is 4.25 J / K / cm.³If it is less than, the effect of suppressing the temperature rise may be reduced.

0048The heat capacity of the material constituting the porous body at 600 ° C. can be determined by the following method. First, the heat capacity (J / K / g) per unit mass of the material constituting the porous body at 600 ° C is measured using an adiabatic specific heat measuring device manufactured by ULVAC Riko. The heat capacity per unit mass (J / K / g) obtained and the true density (g / cm) of the materials constituting the porous body measured by the Archimedes method at room temperature.³By multiplying by), the heat capacity (J / K / cm) per unit volume of the material constituting the porous body³) Is calculated. The heat capacity can be measured by cutting out a test piece (sample) having a predetermined size from the porous body constituting the partition wall, preparing the test piece, and using the test piece.

0049The average coefficient of thermal expansion of the porous body at 40 to 800 ° C is preferably 2.5 to 6.0 ppm / K, more preferably 3.0 to 5.0 ppm / K, and more preferably 4.0 to 5.0 ppm / K. Especially preferable. When the average coefficient of thermal expansion of the porous body at 40 to 800 ° C is within the above numerical range, the thermal shock resistance of the sealing honeycomb structure becomes excellent. If the average coefficient of thermal expansion is less than 2.5 ppm / K, the heat capacity may become too small, which is not very preferable. If the average coefficient of thermal expansion exceeds 6.0 ppm / K, the thermal shock resistance may become too low, which is not very preferable. The average coefficient of thermal expansion can be measured with a differential detection type thermal expansion meter.

0050It is preferable that the porous body satisfies the relationship of the following formula (3). C-0.007 × α² 4.20 (3) (However, in the above formula (3), C is the heat capacity (J / K / cm) of the material constituting the porous body at 600 ° C.³), Α indicates the average coefficient of thermal expansion (ppm / K) of the porous body at 40 to 800 ° C. )

0051When the porous body satisfies the relationship of the above formula (3), in the sealing honeycomb structure of the present embodiment, the heat capacity (J / K / cm) of the material constituting the porous body at 600 ° C.³) And the average coefficient of thermal expansion (ppm / K) of the porous body at 40 to 800 ° C are suitable values. That is, the heat capacity (J / K / cm)³) Is an effective parameter for suppressing the temperature rise of the sealing honeycomb structure, and the average coefficient of thermal expansion (ppm / K) is an effective parameter for improving the thermal shock resistance of the sealing honeycomb structure. .. Then, when the porous body satisfies the relationship of the above formula (3), it is possible to balance the effect of suppressing the temperature rise and the effect of improving the thermal shock resistance.

0052The porosity of the porous body is preferably 20 to 50%, more preferably 20 to 45%, and particularly preferably 25 to 45%. If the porosity of the porous body is less than 20%, the pressure loss of the sealing honeycomb structure may increase. If the porosity of the porous body is more than 50%, the partition wall of the sealing honeycomb structure may become brittle and easily chipped. Further, if the porosity of the porous body is too high, the heat capacity of the porous body becomes small, so that the temperature of the sealing honeycomb structure may easily rise. The porosity of the porous body is the porosity of the partition wall of the sealing honeycomb structure. The porosity of the porous body can be measured by the Archimedes method in accordance with JIS R 1634.

0053The average pore diameter of the porous body is preferably 5 to 20 μm, more preferably 8 to 15 μm, and particularly preferably 8 to 12 μm. If the average pore diameter of the porous body is less than 5 μm, the pressure loss of the sealing honeycomb structure may increase. If the average pore diameter of the porous body is more than 20 μm, when the sealing honeycomb structure is used as a filter for DPF or the like, a part of PM in the exhaust gas may pass through the partition wall of the filter. The collection efficiency may be low. The average pore diameter of the porous body can be measured by the mercury press-fitting method in accordance with JIS R 1655.

0054Further, a state in which the honeycomb structure portion of the sealing honeycomb structure has a plurality of columnar honeycomb segments having partition walls and is arranged adjacent to each other so that the side surfaces of the plurality of honeycomb segments face each other. It may be a segment structure joined by. As the eye-sealing honeycomb structure provided with the honeycomb structure portion of the segment structure, for example, the eye-sealing honeycomb structure 200 as shown in FIG. 6 can be mentioned. In the eye-sealing honeycomb structure 200 shown in FIG. 6, a plurality of honeycomb segments 36 are adjacent to each other so as to face each other, and the honeycomb structure portion 34 is joined by the joining layer 37. It is equipped with. The honeycomb segment 36 is arranged so as to surround the porous partition wall 31 and the partition wall 31 that partition a plurality of cells 32 (cells 32a, 32b) that serve as a fluid flow path extending from the first end surface 41 to the second end surface 42. It has an outer wall 38 provided. The joining layer 37 is for joining the outer walls 38 of the honeycomb segments 36 arranged adjacent to each other. The bonding layer 37 may have a function as a buffer material for cushioning the thermal stress generated in the honeycomb structure portion 34. In the eye-sealing honeycomb structure 200 shown in FIG. 6, the outer peripheral wall 33 is arranged on the outermost circumference of the joined body to which the plurality of honeycomb segments 36 are joined.

0055In the honeycomb structure portion of the segment structure, the partition wall of at least one honeycomb segment among the plurality of honeycomb segments is α-Al as the main phase.₂O₃It is preferable that it is composed of a porous body containing aluminum titanate and glass. In the honeycomb structure part of the segment structure, the partition walls of all the honeycomb segments are α-Al as the main phase.₂O₃It may be composed of a porous body containing aluminum titanate and glass. As the bonding layer, a layer having the same structure as the bonding layer in the honeycomb structure portion having a conventionally known segment structure can be used.

0056The mesh-sealed honeycomb structure 200 as shown in FIG. 6 may be obtained by obtaining a bonded body obtained by joining a plurality of honeycomb segments 36 and processing the outer peripheral portion of the obtained bonded body by grinding or the like. By processing the outer peripheral portion of the joint body, the shape of the cross section orthogonal to the extending direction of the cell 32 of the joint body can be made into a desired shape such as a circle. After processing the outer peripheral portion of the joint, the outer peripheral wall 33 may be arranged by applying a ceramic material to the outermost peripheral portion. FIG. 6 is a schematic perspective view of another embodiment of the sealing honeycomb structure of the present invention as viewed from the inflow end face side. In FIG. 6, reference numeral 35 indicates a "mesh sealing portion" arranged in the opening of the cell 32. Even with such a so-called segment-structured eye-sealing honeycomb structure, it is possible to obtain the same effects as those of the so-called integrated eye-sealing honeycomb structure as shown in FIGS. 1 to 5. it can.

0057The thickness of the partition wall of the honeycomb structure is not particularly limited, but is preferably 100 to 500 μm, more preferably 150 to 400 μm, and particularly preferably 150 to 300 μm. By setting the thickness of the partition wall in such a range, it is possible to suppress an increase in pressure loss while maintaining the strength of the partition wall of the sealing honeycomb structure.

0058There is no particular limitation on the cell density of the honeycomb structure, but it is 15 to 100 cells / cm.²It is preferably 30 to 65 cells / cm.²Is more preferred, 30-50 cells / cm.²Is particularly preferable. By setting the cell density in such a range, when the sealing honeycomb structure is used for DPF or the like, the collection efficiency can be improved while suppressing the pressure loss.

0059The shape of the cells formed in the honeycomb structure is not particularly limited. Here, the "cell shape" is the shape of the cell in the cross section orthogonal to the extending direction of the cell in the honeycomb structure portion. Examples of the cell shape include a quadrangle, a hexagon, an octagon, or a combination thereof.

0060The shape of the honeycomb structure is not particularly limited, and for example, the bottom surface is a circular columnar shape (cylindrical shape), the bottom surface is an oval-shaped columnar shape, and the bottom surface is a polygonal shape (quadrangle, pentagon, hexagon, heptagon, octagon, etc.). It can be shaped like a columnar shape.

0061The length from the first end surface to the second end surface of the honeycomb structure and the size of the cross section orthogonal to the extending direction of the cells of the honeycomb structure are determined by using the sealing honeycomb structure of the present embodiment as an exhaust gas purification filter. When used, it may be appropriately selected so as to obtain the optimum purification performance. For example, the length from the first end surface to the second end surface of the honeycomb structure portion is preferably 100 to 500 mm, more preferably 100 to 300 mm. The area of the cross section orthogonal to the extending direction of the cells of the honeycomb structure is 7,000 to 70,000 mm.²Is preferable, and it is 7,000 to 30,000 mm.²Is more preferable.

0062A catalyst for purifying exhaust gas may be supported on at least one of the surface of the partition wall of the honeycomb structure and the pores of the partition wall. As a catalyst, for example, porous γ-Al₂O₃Can be mentioned as a support of a platinum group metal. Since the catalyst supported on the partition wall of the honeycomb structure is a component different from the partition wall (in other words, the porous body), the "material constituting the porous body" described above is described above. The catalyst shall not be included.

0063Next, a method for manufacturing the eye-sealing honeycomb structure of the present embodiment will be described. When manufacturing a sealable honeycomb structure, first, aluminum titanate and α-Al₂O₃, And a molding raw material for producing a porous body containing glass. The molding raw material is not particularly limited as long as the above three substances can be contained in the fired body (porous body) obtained by firing the molding raw material. For example, as a molding raw material, a desired amount of Al₂O₃, TiO₂, Talc, mica, clay and the like can be blended and prepared. Also, as a molding raw material, Al (OH)₃, Forsterite, feldspar, kaolin, Na₂OK₂O, MgO, CaO, SrO, Fe₂O₃, Y₂O₃, La₂O₃, Ga₂O₃, ZrO₂, CeO₂, SiO₂, CuO, NiO, these carbon oxides, hydroxides, chlorides, and glass adjusted to a desired composition can also be used. By adjusting the blending amount of the above-mentioned raw materials, the substances contained in the obtained porous body and the ratio thereof can be adjusted. Regarding the blending amount of the molding raw material, at least α-Al in the obtained fired body.₂O₃The blending amount is adjusted so that is the main phase (that is, 40% by mass or more in terms of mass ratio). Further, in addition to the above-mentioned raw materials, a dispersion medium or an additive may be further added to the molding raw material.

0064Examples of the additive include a binder, a pore-forming material, and the like. Examples of the dispersion medium include water and the like.

0065Examples of the binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol and the like. The pore-forming material is not particularly limited as long as it becomes pores after firing, and examples thereof include starch, foamed resin, water-absorbent resin, and silica gel.

0066By adjusting the particle size and blending amount of the raw material powder described above, and the particle size and blending amount of the pore-forming material powder to be added, a porous body having a desired porosity and average pore diameter can be obtained.

0067Next, the obtained molding raw material is kneaded to form a clay. The method for forming the clay is not particularly limited, and examples thereof include a method using a kneader, a vacuum clay kneader, and the like.

0068Next, the obtained clay is extruded to produce a honeycomb molded body. Extrusion molding can be performed using a base having a desired cell shape, partition wall thickness, and cell density. Next, the obtained honeycomb molded product may be dried to obtain a dried honeycomb product obtained by drying the honeycomb molded product. The drying method is not particularly limited, and examples thereof include hot air drying, microwave drying, dielectric drying, vacuum drying, vacuum drying, freeze drying, and the like. Among these, dielectric drying and microwave drying can be mentioned. Alternatively, it is preferable to perform hot air drying alone or in combination. The drying conditions are preferably a drying temperature of 30 to 150 ° C. and a drying time of 1 minute to 2 hours.

0069Next, the opening of the cell of the obtained honeycomb molded body or the dried honeycomb molded body is sealed with a sealing material. As a method of sealing the opening of the cell, a method of filling the opening of the cell with a sealing material can be mentioned. As a method of filling the sealing material, it can be carried out according to a conventionally known method for producing a sealing honeycomb structure. As the ceramic raw material for forming the sealing material, the ceramic raw material used in the conventionally known method for producing the sealing honeycomb structure can be used, but the same ceramic as the honeycomb molded body (or honeycomb dried body) is used. It is preferable to use a raw material. The particle size and blending amount of the ceramic raw material powder, and the particle size and blending amount of the pore-forming material powder to be added in order to adjust the porosity and pore size of the sealing portion formed by the sealing material. May be changed as appropriate.

0070Next, the honeycomb molded body (or honeycomb dried body) filled with the sealing material in the opening of the cell is fired. The obtained honeycomb fired body becomes the eye-sealing honeycomb structure of the present embodiment. The firing temperature is preferably 1400 to 1600 ° C, more preferably 1400 to 1500 ° C. The firing time is preferably about 1 to 10 hours. The firing can be performed in, for example, an atmosphere, a steam atmosphere, or a hydrocarbon gas combustion atmosphere.

0071Before forming the mesh sealing portion on the honeycomb molded body, the honeycomb molded body is fired to obtain a honeycomb fired body, and after forming the mesh sealing portion at the opening of the cell of the obtained honeycomb fired body, further firing is performed. By doing so, a sealing honeycomb structure can also be obtained. As described above, the mesh-sealed honeycomb structure of the present embodiment can be manufactured.

<p num="0072"> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.</p><p num="0073"> In the examples shown below, α-Al as shown in Table 1.₂O₃Powder, TiO₂Molding raw materials were prepared using powders, talc powders, mica powders, and raw material powders made from clay. Table 1 shows the types of raw material powders used as molding raw materials, the chemical composition (mass%), and the average particle size (μm). The chemical composition of the raw material powder shown in Table 1 was determined by fluorescent X-ray analysis. The average particle size of the raw material powder shown in Table 1 was determined by a laser diffraction method. In Table 1, α-Al₂O₃(1) to (4) are α-Al with different chemical composition and average particle size.₂O₃It is a raw material powder. In Table 1, talc (1) and (2) are talc raw material powders having different chemical compositions and average particle sizes. α-Al₂O₃Compared to (1) of₂O₃(2) is alumina (Al₂O₃) Is low in purity. α-Al₂O₃Compared to (1) of₂O₃In (3), the average particle size is small. α-Al₂O₃Compared to (1) of₂O₃(4) has a large average particle size. Compared to talc (1), talc (2) is iron oxide (Fe).₂O₃), And the average particle size is large.</p><p num="0074"><tables num="1"><img id="000002" he="65" wi="159" file="JP6231908B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0075">(Example 1) In Example 1, α-Al shown in Table 1₂O₃(1), TiO₂, Talc (1), and mica were used to prepare molding materials. Table 2 shows the compounding formulation (unit: g) of the molding raw material of Example 1. In addition, "Al" in Table 2₂O₃/ TiO₂In the column of ", α-Al used as the molding raw material of Example 1"₂O₃"Al" contained in the powder₂O₃", TiO₂"TiO contained in the powder of₂"Mole ratio with (Al₂O₃/ TiO₂) Is shown.</p><p num="0076"> In Example 1, in addition to the raw materials shown in the formulation shown in Table 2, 50 g of starch was added as a pore-forming material, 200 g of methyl cellulose was added as a binder, and an appropriate amount of water was added.</p><p num="0077"><tables num="2"><img id="000003" he="107" wi="159" file="JP6231908B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0078"> Next, the obtained molding raw material was kneaded with a kneader, and then soil was kneaded with a vacuum clay kneader to form a clay. Next, the obtained clay was extruded to prepare a honeycomb molded body. After firing, the honeycomb molded body has a partition wall thickness of 300 μm and a cell density of 46.5 cells / cm.²It was supposed to be. The shape of the cells of the honeycomb molded body was set to be square after firing. Next, the honeycomb molded body was dried to obtain a honeycomb dried body. For drying, first, microwave drying was performed, and then hot air drying was performed. Next, an eye-sealing portion was arranged at the opening of the cell of the obtained dried honeycomb body. Next, the obtained dried honeycomb body was degreased. Solvent degreasing was performed in the air at 450 ° C. for 5 hours. Next, the degreased dried honeycomb structure was fired to obtain a mesh-sealed honeycomb structure. Baking was carried out in the air at 1500 ° C. for 4 hours.</p><p num="0079"> The composition of the partition wall (porous body) constituting the mesh-sealed honeycomb structure of Example 1 was qualitatively and quantified by the following method. Table 3 shows the composition of the partition walls (porous bodies) constituting the sealing honeycomb structure of Example 1. In addition, "α-Al" in Table 3₂O₃/ Al₂TiO₅The column of "" is α-Al₂O₃And Al₂TiO₅Mass ratio with (α-Al₂O₃/ Al₂TiO₅) Indicates the value. In qualitatively and quantifying the composition of the partition wall (porous body), first, the amount of glass is determined by immersing the partition wall constituting the obtained eye-sealing honeycomb structure in acid to dissolve the glass in the partition wall and glass. The amount was quantified. Then α-Al in the residue₂O₃Quantify the amount with XRD and the rest with Al₂TiO₅And said. True density (g / cm)³) And porosity (%) were measured by the Archimedes method (JIS R 1634). The average pore size (μm) was measured by the mercury press-fitting method (JIS R 1655).</p><p num="0080"> Heat capacity (J / K / cm³) Was measured by the following method. First, the heat capacity (J / K / g) per unit mass of the material constituting the porous body was measured at 600 ° C. using an adiabatic specific heat measuring device manufactured by ULVAC Riko. Next, in addition to the obtained heat capacity per unit mass (J / K / g), the true density (g / cm) of the materials constituting the porous body at room temperature measured by the Archimedes method.³By multiplying by), the heat capacity (J / K / cm) per unit volume of the material constituting the porous body³) Was calculated.</p><p num="0081"> "CTE (ppm / K)" in Table 3 is the average coefficient of thermal expansion (ppm / K). The average coefficient of thermal expansion of the porous body was determined by measuring the average coefficient of thermal expansion at 40 to 800 ° C. with a differential detection type thermal expansion meter.</p><p num="0082"> "F" in Table 3 is "C-0.007 x α"²Indicates the value of. Here, C is the heat capacity (J / K / cm) of the material constituting the porous body at 600 ° C.³), Α indicates the average coefficient of thermal expansion (ppm / K) of the porous body at 40 to 800 ° C.</p><p num="0083"><tables num="3"><img id="000004" he="226" wi="102" file="JP6231908B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0084"> The partition wall (porous body) constituting the mesh-sealed honeycomb structure of Example 1 has α-Al as the main phase.₂O₃Including, and also Al₂TiO₅It consisted of a porous body containing glass and glass. Al in the porous body₂TiO₅Part, α-Al₂O₃The chemical composition (mass%) of each part was measured for the part of No. 1 and the part of glass. In Table 4,<u style="single">each</u>Implementation<u style="single">Example</u>"Α-Al" of the partition wall (porous body) that constitutes the sealing honeycomb structure₂O₃, "Al₂TiO₅, And the measurement results of the chemical composition (mass%) of each part of "glass" are shown. The chemical composition shown in Table 4 was analyzed by the following method. First, the partition wall of the sealing honeycomb structure was cut, and the cut surface of the porous body constituting the partition wall was embedded in the resin. Then, the cut surface of the porous body was polished, and the cut surface was observed with a scanning electron microscope (SEM). In the observed SEM image (5000 times), α-Al₂O₃, Al₂TiO₅The chemical composition of each part of (aluminum titanate) and glass was analyzed by energy dispersive X-ray analysis (EDS).</p><p num="0085"><tables num="4"><img id="000005" he="101" wi="155" file="JP6231908B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0086">(Example 2 ~<u style="single">12 and reference examples 1 to 3</u>) An eye-sealing honeycomb structure was prepared in the same manner as in Example 1 using the formulation as shown in Table 2. Example<u style="single">12</u>In, the amount of starch added as a pore-forming material was set to 500 g. Example 2 ~<u style="single">12 and reference examples 1 to 3</u>The composition of the partition wall (porous body) constituting the mesh-sealed honeycomb structure was qualitatively and quantified by the same method as in Example 1. Table 3 shows Examples 2 ~<u style="single">12 and reference examples 1 to 3</u>The composition of the partition wall (porous body) constituting the mesh-sealed honeycomb structure is shown. Also, true density (g / cm)³), Porosity (%), average pore size (μm), heat capacity (J / K / cm)³) And CTE (ppm / K) were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Also, "C-0.007 x α²The value of "F" was also calculated. The values of "F" are shown in Table 3.</p><p num="0087"> Example 2 ~<u style="single">12 and reference examples 1 to 3</u>The partition wall (porous body) that constitutes the sealing honeycomb structure is α-Al as the main phase.₂O₃Including, and also Al₂TiO₅It consisted of a porous body containing glass and glass. Α-Al in the porous body₂O₃Part, Al₂TiO₅The chemical composition (mass%) of each part was measured for the part of No. 1 and the part of glass. Table 4 shows Example 2,<u style="single">5</u>,<u style="single">7</u>,<u style="single">10</u>,<u style="single">11</u>"Α-Al" of the partition wall (porous body) that constitutes the sealing honeycomb structure₂O₃, "Al₂TiO₅, And the measurement results of the chemical composition (mass%) of each part of "glass" are shown.</p><p num="0088">(Comparative example 1) Α-Al in Table 1₂O₃(1), TiO₂, Talc (1), and mica were used to prepare an eye-sealing honeycomb structure in the same manner as in Example 1. The compounding formulation of the molding raw material in Comparative Example 1 is α-Al.₂O₃(1) 2550g, TiO₂Was 1950 g, talc (1) was 350 g, and mica was 150 g. The amount of the pore-forming material, the binder, and water added was the same as in Example 1.</p><p num="0089">(Comparative example 2) In Comparative Example 2, a molding raw material was prepared using α-SiC powder having an average particle size of 12 μm and α-SiC powder having an average particle size of 2 μm. The amount of each of the above powders used is 3000 g for α-SiC powder having an average particle size of 12 μm and 2000 g for α-SiC powder having an average particle size of 2 μm. Further, 300 g of methyl cellulose as a binder and an appropriate amount of water were added to the molding raw material. In Comparative Example 2, the same method as in Example 1 was used except that the molding raw material was prepared as described above and the dried honeycomb body was fired at 2200 ° C for 2 hours in an argon atmosphere. A mesh-sealed honeycomb structure was produced.</p><p num="0090">(Comparative example 3) In Comparative Example 3, a molding raw material was prepared using kaolin powder having an average particle diameter of 3 μm, talc powder having an average particle diameter of 24 μm, alumina powder having an average particle diameter of 6 μm, and silica powder having an average particle diameter of 21 μm. .. The amount of each of the above powders used is 1110 g for kaolin powder, 2135 g for talc powder, 1210 g for alumina powder, and 540 g for silica powder. The amount of the pore-forming material, the binder, and water added was the same as in Example 1. A sealing honeycomb structure was produced in the same manner as in Example 1 except that the molding raw material was prepared as described above and the dried honeycomb structure was fired at 1420 ° C. for 4 hours.</p><p num="0091"> The true density (g / cm) of the partition walls (porous bodies) constituting the mesh-sealed honeycomb structures of Comparative Examples 1 to 3 was carried out in the same manner as in Example 1.³), Porosity (%), average pore size (μm), heat capacity (J / K / cm)³), And CTE (ppm / K) were measured. The measurement results are shown in Table 5. Also, "C-0.007 x α²The value of "F" was also calculated. The values of "F" are shown in Table 5.</p><p num="0092"><tables num="5"><img id="000006" he="34" wi="160" file="JP6231908B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0093">(result) The eye-sealing honeycomb structure of Example 1 has a heat capacity (J / K / cm) as compared with the eye-sealing honeycomb structure of Comparative Examples 1 to 3.³) Was big. α-Al₂O₃And Al₂TiO₅Heat capacity (J / K / cm) by changing the mass ratio with³) Changes, and the sealing honeycomb structures of Examples 2 to 4 have a higher heat capacity (J / K / cm) than the sealing honeycomb structures of Example 1.³) Was big.<u style="single">Reference example 1</u>Is α-Al₂O₃The mass ratio of was less than 60% by mass. Therefore, the heat capacity was smaller than that of Example 1.<u style="single">Reference example 2</u>Is α-Al₂O₃The mass ratio of was over 90% by mass. Therefore, the CTE was larger than that of Example 4.<u style="single">Reference example 3</u>,<u style="single">Example 5</u>In the eye-sealing honeycomb structure of No. 3, the mass ratio of glass was smaller than that of the eye-sealing honeycomb structure of Example 3. It was confirmed that the porosity tends to increase as the mass ratio of glass decreases. If the porosity of the partition wall of the sealing honeycomb structure is increased, the strength may decrease. Example<u style="single">6</u>In the eye-sealing honeycomb structure of No. 1, the mass ratio of glass was larger than that of the eye-sealing honeycomb structure of Example 1. Example<u style="single">6</u>The heat capacity (J / K / cm) of the sealing honeycomb structure of No. 1 is higher than that of the sealing honeycomb structure of Example 1.³) Was small.</p><p num="0094"> Example<u style="single">7</u>The sealable honeycomb structure is made of relatively low-purity alumina (α-Al) as a molding raw material.₂O₃(2)) was used. Example<u style="single">7</u>The heat capacity (J / K / cm) of the sealing honeycomb structure of No. 1 is higher than that of the sealing honeycomb structure of Comparative Examples 1 to 3.³) Was big. Example<u style="single">8</u>The mesh-sealed honeycomb structure of No. 1 had an average pore diameter smaller than that of the mesh-sealed honeycomb structure of Example 1. Such an embodiment<u style="single">8</u>The heat capacity (J / K / cm) of the sealing honeycomb structure of No. 1 is also higher than that of the sealing honeycomb structure of Comparative Examples 1 to 3.³) Was big. Example<u style="single">9</u>~<u style="single">12</u>In, the partition wall is α-Al as the main phase.₂O₃The composition of the partition wall (porous body) was changed as shown in Table 3 in the range of forming a porous body containing aluminum titanate and glass. Such an embodiment<u style="single">9</u>~<u style="single">12</u>The heat capacity (J / K / cm) of the sealing honeycomb structure of No. 1 is also higher than that of the sealing honeycomb structure of Comparative Examples 1 to 3.³) Was big.</p>

0095The sealing honeycomb structure of the present invention can be used as a filter for purifying exhaust gas to purify exhaust gas.

00961,31: partition wall, 2,32: cell, 2a, 32a: cell, 2b, 32b: cell, 3,33: outer peripheral wall, 4,34: honeycomb structure part, 5,35: eye seal part, 6: α-Al₂O₃, 7: Aluminum titanate, 8: Glass, 9: Pore, 11,41: First end face (end face), 12,42: Second end face (end face), 36: Honeycomb segment, 37: Bonding layer, 38: Outer wall (Outer wall of honeycomb segment), 100,200: Sealed honeycomb structure.