JPH0470053B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a cordierite honeycomb structured catalyst carrier, particularly a high-strength, low-expansion honeycomb structured catalyst carrier used as a catalyst carrier for purifying automobile exhaust gas, and a method for producing the same. (Conventional technology) Cordierite honeycomb ceramic, which has excellent thermal shock resistance and is porous, absorbs hydrocarbons in various exhaust gases,
It is attracting particular attention as a honeycomb-shaped catalyst carrier material used in devices for purifying carbon monoxide and nitrogen oxides. Ceramic honeycomb catalyst carriers used in automobile exhaust gas purification devices, which are now widely used among various exhaust gas purification devices, are required to have several important properties. One of the required properties is so-called thermal shock resistance, which is caused by the temperature change caused by rapid heat generation due to the catalytic oxidation reaction of unburned hydrocarbons and carbon monoxide in the exhaust gas, and the temperature difference that occurs within the honeycomb. It has the property of resisting cracking or destruction due to thermal stress caused. This thermal shock resistance is expressed by the rapid heating and cooling durability temperature difference, and it has been found that the durability temperature difference is inversely proportional to the thermal expansion coefficient among the characteristics of honeycomb, and the smaller the thermal expansion coefficient, the larger the durability temperature difference. . Another property required of the ceramic honeycomb catalyst carrier is adhesion between the honeycomb catalyst carrier and the catalytically active substance and the catalytic substance. Another important property required of a ceramic honeycomb catalyst carrier is the initial activity or light-off performance of the honeycomb catalyst. It has been known that cordierite ceramic exhibits low expansion properties, for example, as described in U.S. Patent No.
As disclosed in Specification No. 3885977 (Japanese Unexamined Patent Publication No. 75611/1983), the coefficient of thermal expansion between 25°C and 1000°C is 11×10 ^-7 (1/°C) in at least one direction.
Smaller oriented cordierite ceramics are known, and the planar orientation caused by platy clays such as kaolin and laminated clays is described as the cause of this orientation. Further, JP-A-53-82822 discloses that cordierite ceramic exhibits extremely low thermal expansion by using a magnesia source material such as talc in a limited coarse grain region of 10 to 50 μm. (Problem to be solved by the invention) On the other hand, in recent years, with the significant improvement in catalyst supporting technology on honeycomb structure catalyst carriers, the requirement for porosity, which was previously strongly required for honeycomb structure catalyst carriers, has decreased, and on the contrary, the Reducing the volume of the carrier, i.e. improving catalyst performance, improving light-off performance, lowering pressure loss to improve fuel efficiency and increasing engine output, improving strength to reduce the cost of canning the casing, and increasing catalyst activity. There is a strong desire to improve thermal shock resistance and strength due to the need to install it near the engine in order to improve the thermal shock resistance. As countermeasures, thinner walls and higher cell density of the ribs of the honeycomb structure have been considered to improve catalyst performance, and thinner walls and lower cell density to lower pressure loss have been considered. There is a problem of reduced strength due to thinner walls of cordierite ceramics.
Furthermore, due to the reduction in the width of the die slit during extrusion molding, the raw materials used, especially the magnesia source material, must be made into fine particles, resulting in the problem of a significant increase in the coefficient of thermal expansion. Furthermore, it is difficult to densify cordierite ceramics, especially for cordierite substrates that exhibit low thermal expansion coefficients of 2.0×10 ^-6 /℃ or less from room temperature to 800℃.
Since it is necessary to limit the amount of impurities such as potash and soda that serve as fluxing agents to an extremely small amount, the glass phase is extremely small and the material becomes porous. In particular, cordierite honeycomb structures, which have been used as catalyst carriers for automobile exhaust gas purification in recent years, require a thermal expansion coefficient of 1.5 x 10 ^-6 /°C or less from room temperature to 800°C. , kaolin, alumina, and other raw materials are used, and even if the source of these raw materials, raw material system, raw material particle size, etc. are selected, the porosity of the fired cordierite body is at most 20 to 45.
In particular, for honeycomb structures with a porosity of 30% or less, it is necessary to increase the amount of impurities and make the raw material atomized, and the thermal expansion coefficient from room temperature to 800℃ is 1.0 × 10 ^-6 / ℃ or lower was not obtained. Furthermore, in the structure of cordierite honeycomb structures with relatively low porosity, cracks are likely to occur due to large shrinkage during drying and firing processes, making it difficult to manufacture large-sized honeycomb structures with good yield. . For the above technical reasons, there is a need for an extremely low thermal expansion cordierite honeycomb structure catalyst carrier that is thin-walled and has a low porosity level that satisfies strength properties. (Means for solving the problem) As disclosed in Japanese Patent Application Laid-open No. 53-82822, when fine talc is used as a raw material for a honeycomb structure and fired, there is a drawback that the coefficient of thermal expansion becomes significantly large. Among the fine talcs having this drawback, the present inventors purposely used talc with an average particle size of 7 μm or less, preferably 5 μm or less, which is particularly fine, and suppressed the increase in the thermal expansion rate of the particles, which also belong to the ultrafine particle size, of 2 μm or less. , preferably in combination with kaolin with a particle size of 1 μm or less, as well as alumina and/or aluminum hydroxide with a fine average particle size of 2 μm or less, or a combination of these with high-purity amorphous silica, reducing the porosity to 30% or less. It has been found that even when the walls of the honeycomb structure ribs are made thinner, a strength level that can withstand practical use can be achieved. Furthermore, the present inventors have found that it is preferable to use kaolin having an average particle size of 1/3 or less of the average particle size of talc. Furthermore, in the present invention, from the relationship between the thermal expansion coefficient in the direction perpendicular to the honeycomb structure flow channels (through holes) (referred to as the B axis) and the orientation of cordierite crystals, which has a large contribution rate to the thermal shock resistance of the honeycomb structure, The difference between the coefficient of thermal expansion in the flow path (through hole) direction (referred to as the A axis) of the honeycomb structure having the lowest thermal expansion characteristics is
It became clear that it could be made very small. In cordierite honeycomb structures that use conventional coarse-grained raw materials, talc,
The orientation of raw materials such as kaolin that are oriented during extrusion molding is disordered, and compared to the thermal expansion coefficient of the A axis, the thermal expansion coefficient of the B axis is 0.2 × 10 ^-6 /
It showed a high value exceeding ℃. It has been found that by using the ultrafine grain raw material of the present invention, the adverse effect on the thermal expansion of the honeycomb structure at the intersection point is reduced, and the B-axis thermal expansion of the honeycomb structure, which is extremely important for improving thermal shock resistance, can be significantly reduced. In the present invention, the chemical composition of the main component is based on weight.
_SiO2 42-56%, _{Al2O3 30-45} %, MgO12-16%
It has a honeycomb structure in which the main component of the crystalline phase is cordierite, and the porosity is 30% or less, more preferably 25% or less, and porosity is 40% to 40% in the flow path direction of the honeycomb structure.
Thermal expansion coefficient between 800℃ is 0.8×10 ^-6 /℃ or less, and the thermal expansion coefficient between 40 and 800℃ in the direction perpendicular to the flow path is 1.0×
This is a high-strength, low-expansion cordierite honeycomb structure catalyst carrier characterized by a temperature of 10 ^-6 /°C or less. The present invention also provides that the chemical composition of the main component is based on weight.
_SiO2 42-56%, _{Al2O3 30-45} %, MgO12-16%
Talc with an average particle size of 7 μm or less, kaolin with an average particle size of 2 μm or less and 1/3 or less of the average particle size of talc, and other cordierite forming raw materials are mixed so that By adding a binder and a plasticizer, mixing and kneading to plasticize it so that it can be extruded, extrusion molding into a honeycomb structure, drying, and baking at a temperature of 1350 to 1440 ° C.
The main component of the crystalline phase is cordierite, the porosity is 30% or less, and the porosity is 40 to 40% in the flow path direction of the honeycomb structure.
The coefficient of thermal expansion at 800℃ is 0.8×10 ^-6 /℃ or less, and the coefficient of thermal expansion from 40 to 800℃ in the direction perpendicular to the flow path is 1.0×
10 ^-6 /℃ or less and the difference in thermal expansion coefficient is 0.2×
The present invention is a method for producing a cordierite honeycomb structure catalyst carrier, which is characterized by obtaining a cordierite honeycomb structure catalyst carrier having high strength and low expansibility of 10 ^-6 /°C or less. Furthermore, the present invention has SiO ₂ 42-56%, Al ₂ O ₃ 30-45%
%, average particle size 7 μm to make MgO 12-16%
The following talc, kaolin with an average particle size of 2 μm or less and 1/3 or less of the average particle size of talc, alumina and/or aluminum hydroxide with an average particle size of 2 μm or less, and other cordierite forming raw materials are prepared. , an organic binder and a plasticizer are added to this mixture, mixed and kneaded to make it plasticized so that it can be extruded, extruded into a honeycomb structure, dried,
By firing at a temperature of ~1440℃, the main component of the crystal phase is cordierite, the porosity is 25% or less, and the A-axis CTE (coefficient of thermal expansion) of the honeycomb structure catalyst carrier is 0.8×10 ^-6 /℃ or less. Obtain elite honeycomb structure catalyst support or _SiO2 42~56
%, Al ₂ O ₃ 30-45%, MgO 12-16% Talc with an average particle size of 7 μm or less, average particle size 2 μm
Kaolin with an average particle size of 1/3 or less of the average particle size of talc, alumina and/or aluminum hydroxide with an average particle size of 2 μm or less, high purity amorphous silica of 8% or less, and other cordierite forming raw materials An organic binder and a plasticizer are added to this mixture, mixed and kneaded to plasticize it so that it can be extruded, and after extrusion molding into a honeycomb structure, it is dried.
By firing at a temperature of ~1440℃, the main component of the crystal phase is cordierite, the porosity is 30% or less, and the A-axis CTE of the honeycomb structure catalyst is 0.5×10 ^-6 /
℃ or less, B axis CTE1.0×10 ^-6 /℃ or less or porosity
25% or less, A axis CTE 0.6×10 ^-6 /℃ or less, B axis
This is a manufacturing method for obtaining a cordierite honeycomb structure catalyst carrier having a CTE of 1.0×10 ^-6 /°C or less. The chemical composition of the honeycomb structure of the present invention is based on the theoretical composition point of cordierite (2MgO.
SiO ₂ 42 on a weight basis centered on 2Al ₂ O ₃・5SiO ₂ )
~56%, preferably 47-53%, _Al2O3 30-45 _% preferably 32-38%, MgO12-16% preferably
In the region of 12.5 to 15%, the desired porosity is 30% or less by changing various manufacturing conditions, and the A-axis thermal expansion coefficient of 40 to 800℃ is 0.8×10 ^-6 /℃ or less, which is also 1×
It is possible to achieve a B-axis thermal expansion of less than 10 ^-6 /°C. Chemical components other than the main components often have a negative effect on thermal expansion properties, such as TiO ₂ , CaO, K ₂ O, Na ₂ O,
It is desirable to suppress impurities such as Fe ₂ O ₃ and P ₂ O ₅ to 2.5% or less as a whole, especially CaO, K ₂ O,
The lower the Na ₂ O alkali content, the better the thermal expansion properties. Also, it does not substantially contain P ₂ O ₅ .
Must be less than 0.1%. It is preferable that the crystal phase consists essentially of cordierite crystals, with the amount of cordierite crystals being 90% by weight or more, and mullite and spinel (including saphirin) as other crystals contained being 2.5% by weight or less, respectively. The fine talc to be used is preferably one with a low alkaline content, and the pulverization method used for fine pulverization is a pulverization method such as grinding that destroys the particle shape, for example, the use of a ball mill etc. is not preferable, and a pulverization method such as a Raymond mill is preferable. It is. Talc with a particle size exceeding 7 μm has a large difference in coefficient of thermal expansion along the A-B axis and a large porosity. Fine-grained kaolin preferably has few impurities, and preferably has little variation in crystal shape and does not contain large crystals. For example, kaolin, such as New Zealand kaolin, which has large variations in crystal shape and tends to form secondary particles, is not preferred. In addition, as a method of pulverizing kaolin medium-calcined kaolin, using a wet ball mill pulverized raw material is extremely suitable for densification. When using kaolin with a particle size exceeding 2 μm, the particle size
Thermal expansion increases when used with talc of 7μm or less,
The porosity becomes large. In addition, talc with an average particle size of 5 μm or less and/or
Alternatively, by using kaolin with an average particle size of 1 μm or less and 1/3 or less of the average particle size of talc, the porosity can be further reduced while maintaining low thermal expansion. The particle sizes of talc and kaolin were determined from the average particle size based on the blended weight ratio of raw and calcined products. In the present invention, when talc and kaolin are made into fine particles,
It also includes the use of calcined talc and calcined kaolin, which are effective in suppressing the occurrence of cracks in honeycomb structures due to shrinkage during drying and firing. Increasing the calcination temperature of talc or kaolin increases the porosity and the coefficient of thermal expansion, so when a calcined product is used, it is preferable that the calcination temperature be as low as possible. The effects of the present invention cannot be obtained unless fine particles having a particle size similar to that of the raw raw material are used. In order to achieve a porosity of 30% or less, other cordierite forming raw materials, such as alumina source raw materials such as alumina and aluminum hydroxide, and silica source raw materials such as amorphous silica and silica sand, that have been conventionally used are used. However, it is necessary to optimize the amount of impurities such as alkali in the chemical composition and to optimize the particle size such as cutting of the coarse particles depending on the rib thickness of the honeycomb structure to be manufactured. Furthermore, when using fine particles of alumina and/or fine particles of aluminum hydroxide to achieve a porosity of 25% or less, use of particles with a particle size of 2 μm or less will not reduce the porosity, which is the objective of the present invention. Contributes and also low soda alumina ( _Na2O0.12 %
By using the following), further effects can be obtained due to lower expansion and lower porosity. Furthermore, the addition of high-purity amorphous silica to achieve low expansion also contributes to lowering the porosity;
Addition exceeding this amount is not preferable because it deteriorates the properties of the catalyst carrier. As the manufacturing process in the present invention, it is possible to apply the extrusion molding process used in the conventional manufacturing of cordierite honeycomb structures. In the firing process, especially in the temperature range of 1100-1350℃, 20-300℃
It is desirable to raise the temperature at an average temperature increase rate of 30 to 200 °C/Hr, and to bake at a maximum temperature of 1350 to 1440 °C for 0.5 to 24 hours. Average heating rate 20℃/
If it is less than 300°C/Hr, the coefficient of thermal expansion will be large, and if it exceeds 300°C/Hr, the fired product will be significantly deformed. Also, 1350
Below 1440°C, the coefficient of thermal expansion becomes large, and above 1440°C, the fired product becomes significantly deformed. (Function) Regarding the cell structure and strength characteristics, the compressive strength in the A-axis direction of the honeycomb structure is determined by the rib thickness to withstand vibrations during automobile operation, holding pressure of the carrier container, etc. when used as a catalyst carrier for automobile exhaust gas purification. 152μ
Square cell structure with 62 cells per square centimeter (referred to as 152μm/62 cells/ ^cm2 ) with at least 150
~200Kg/cm2 or ^more is required, but in the present invention, it was achieved to reduce the porosity to 30% or less without increasing the thermal expansion of the cordierite material, so A-axis compression at 152μm/62 pieces/ ^cm2 was achieved. Strength 300Kg/cm ²
Higher levels are now possible. Furthermore, conventionally, it was impossible to actually use it due to its strength.
Even with a cell structure of 102μm/93 cells/ ^cm2 , which was impossible to actually use in terms of 152μm/47 cells/ ^cm2 , strength, and thermal expansion, the A-axis compressive strength is at a level of 200Kg/cm2 ^or higher, which allows it to withstand severe usage conditions. It has become possible to design various cell structures depending on the shape design and installation conditions of the catalyst carrier. In other words, when applied to honeycomb structures with thin walls and high cell density, the strength improvement achieved by the present invention exhibits superior effects in terms of thermal shock resistance, catalytic performance, etc. compared to conventional products, and also has a thin wall and low cell density. By applying it to a dense honeycomb structure, it exhibits excellent thermal shock resistance, low pressure loss, etc. compared to conventional products. Compared to the conventionally used honeycomb structure with a rib thickness of 300 μm and 47 cells per square centimeter,
The present invention has a rib thickness of 102 μm and a number of cells per square centimeter.
93 honeycomb structures were obtained, and in addition to greatly improving catalytic activity due to the high-density cell structure, it also greatly improved thermal shock resistance, making it a cordierite material suitable for installation in manifolds near the engine as a carrier for automobile exhaust gas. A honeycomb structure was realized. Also, compared to the conventional honeycomb structure of 300μm/47 pieces/ ^cm2 , the honeycomb structure of 152μm/62 pieces/ ^cm2 has significantly improved A-axis compressive strength, which simplifies the canning of the honeycomb structure into a casing. This made it possible to create a honeycomb structure that is suitable for installation in manifolds, etc. near engines that experience severe vibrations. Furthermore, a honeycomb structure of 152 μm/47 pieces/cm ² having the same level of thermal expansion and A-axis compressive strength as a honeycomb structure of 300 μm/47 pieces/cm ² was obtained,
A honeycomb structure suitable for improving engine output and reducing fuel consumption due to low pressure loss of automobile exhaust gas has been realized. This thermal expansion behavior in the B-axis direction of the honeycomb structure according to the present invention is particularly advantageous for increasing the cell density for improving the performance of the catalyst carrier. The honeycomb structure of the present invention has the advantage of being a significantly thinner-walled honeycomb structure compared to conventional honeycomb structures having rib thicknesses of 203 μm or less. That is, it is suitable for a honeycomb structure with thin walls and a high cell density, or a honeycomb structure with a thin wall and a relatively low cell density. On the other hand, by increasing the strength, it has become widely applicable to honeycomb structures with large rib thickness and low cell density. (Examples) Example 1 The present invention will be described in more detail below with reference to Examples and Comparative Examples. Using the raw materials with chemical analysis values and particle sizes shown in Table 1 below, batches No. 1 to No. 32 in Table 2 were prepared according to the proportions shown in Table 2, and 100 parts by weight of the raw materials were prepared. 3.8 parts by weight of methyl cellulose and added water were added to the mixture to form a clay that could be kneaded and extruded.
All raw materials used here passed through a 63 μm sieve. Next, the clay of each batch was molded using a known extrusion method to form a square cell structure with a rib thickness of 102 μm and 93 cells per square centimeter, and a diameter of 93 mm in height.
It was molded into a 100mm cylindrical honeycomb structure. After drying the honeycomb structures from each batch, they were fired under the firing conditions shown in Table 2, and the characteristics of the sintered bodies were the coefficient of thermal expansion (CTE) at 40 to 800°C of the A-axis and B-axis of the honeycomb structure, and the pores. Evaluations were made for the ratio, amount of cordierite crystals, compressive strength in the A-axis direction of the honeycomb structure, and thermal shock resistance. The evaluation results are also shown in Table 2.
In addition, P ₂ O ₅ is 0.1 as the chemical composition of all sintered bodies.
It was less than %. The particle size distribution and average particle diameter of the raw material were determined by the X-ray sedimentation method, and in the present invention were measured using a Sedigraph manufactured by Micromeritics.

【table】

【table】

【table】

【table】

[Table] Test Nos. 1 and 2 in Table 2 have a particle size of talc.
Since the porosity is larger than 7 μm, the porosity exceeds 30%, and test Nos. 8, 11, 14, and 24 are A because the average particle size of kaolin is larger than 2 μm and larger than 1/3 of the particle size of talc. The coefficient of thermal expansion of the shaft is 0.8×
Greater than 10 ^-6 /℃, B-axis thermal expansion coefficient is 1.0×
10 ^-6 /℃, and the porosity exceeds 30%. In addition, in Test No. 21, the porosity exceeds 30% because the particle size of talc is larger than 7 μm and the average particle size of kaolin is larger than 2 μm, and in Test No. 23, kaolin is not used, so the A-axis The coefficient of thermal expansion is
B-axis thermal expansion coefficient is greater than 0.8×10 ^-6 /°C and 1.0
×10 ^-6 /℃ and the porosity exceeds 30%. In addition, in Test Nos. 26 and 27, the average particle size of kaolin was larger than 1/3 of the particle size of talc, so A
The coefficient of thermal expansion of the shaft exceeds 0.8×10 ^-6 /°C, and the coefficient of thermal expansion of the B-axis exceeds 1.0×10 ^-6 /°C. Example 2 The batches No. 6 and No. 21 in Table 2 were extruded using dies with different cell structures in the same manner as in Example 1, and fired, resulting in a diameter having the cell structure shown in Table 3. Cylindrical honeycomb structure No. 93mm and height 100mm.
41 to No. 47 were manufactured. The coefficient of thermal expansion between 40 and 800°C on the A-axis and B-axis of each honeycomb structure, and A
The axial compressive strength was evaluated. The evaluation results are also shown in Table 3.

[Table] As is clear from Tables 2 and 3, the cordierite honeycomb structure of the present invention exhibited extremely excellent low expansion and strength characteristics as a catalyst carrier. Example 3 Using raw materials with the characteristics shown in Table 4 below,
Batch Nos. 51 to 87 were mixed according to the proportions shown in Table 5, and 3.8 parts by weight of methyl cellulose and added water were added to 100 parts by weight of the raw materials and kneaded.
It was made into a cup clay that can be extruded. All raw materials used here passed through a 63 μm sieve. Next, the clay from each batch was formed into a cylindrical honeycomb structure of 93 mm in diameter and 100 mm in height, having a rib thickness of 102 μm and a square cell structure with 93 cells per square centimeter, by a known extrusion molding method. After drying, the honeycomb structures of each batch were fired under the firing conditions shown in Table 5, and the characteristics of the sintered bodies were the coefficient of thermal expansion (CTE) at 40 to 800°C of the A-axis and B-axis of the honeycomb structure, and the pores. Evaluations were made for the ratio, amount of cordierite crystals, compressive strength in the A-axis direction of the honeycomb structure, and thermal shock resistance. The evaluation results are also shown in Table 5. The chemical composition of all the sintered bodies contained less than 0.1% P ₂ O ₅ . The particle size distribution and average particle diameter of the raw material are data obtained by an X-ray sedimentation method, and in the present invention, they were measured using a Sedigraph manufactured by Micromeritics.

【table】

【table】

【table】

[Table] In Table 5, test Nos. 51 to 62, 64, 65, in which alumina and/or aluminum hydroxide with an average particle size of 2 μm or less were added to fine talc and kaolin,
67, and test Nos. 71 and 73 to 87 in which 8% or less of high-purity amorphous silica was added, compared to Example 1 in which relatively coarse alumina with an average particle diameter of 4 μm was added.
It has been found that lower porosity can be achieved. In addition, in Test Nos. 63, 66 and 71, the particle size of the added aluminum hydroxide was 3.6 μm, which is larger than 2.0 μm, and in Test No. 72, crystalline silica was used as the added silica, so the porosity was low. increased compared to other test examples, but in Example 1
These data are also within the scope of the present invention. Example 4 Table 5 No. 60 (porosity 18.0%), No. 56 (porosity 20.3
%), No.53 (porosity 23.0%), No.51 (porosity 25.0%)
,
No. 78 (porosity 27.0%) and No. 73 (porosity 30.0%) batches were extruded and molded using dies with different cell structures in the same manner as in Example 3, and fired to have the cell structures shown in Table 6. A cylindrical honeycomb structure having a diameter of 93 mm and a height of 100 mm was manufactured, and the A-axis compressive strength of each honeycomb structure was measured. From this measurement, A
The points at which the axial compressive strength was 200±10 (Kg/cm ² ) were plotted, and the relationship between porosity, rib thickness, and number of cells is shown in Figure 4.

[Table] From Table 6 and Figure 4, A of the honeycomb structure
When the rib thickness is calculated from the porosity within the range of the present invention when the axial compressive strength is 200Kg/ ^cm2 , the cell density is 2.
It was found that the rib thickness could be defined as 437 μm or less within the range of ~140 cells/cm ² . (Effects of the Invention) Thus, according to the present invention, a high-strength, low-expansion, thin-walled, high-cell-density honeycomb structure and a thin-walled, low-cell-density honeycomb structure with a porosity of 30% or less can be obtained. This honeycomb structure can be used more widely as a catalyst carrier, and is particularly useful as an automobile exhaust gas purification catalyst carrier. Therefore, the present invention is extremely useful industrially.

[Brief explanation of the drawing]

Figure 1 shows the particle size distribution curves of talc (A) to (E) in Tables 1 and 4, and Figure 2 shows the particle size distribution curves of kaolin (A) to (E) in Tables 1 and 4. Diagram showing the distribution curve,
FIG. 3 is a perspective view showing an example of the honeycomb structure of the present invention, and FIG. 4 is a graph showing the relationship between the porosity rib thickness and the number of cells in the honeycomb structure of the present invention.

Claims (1)

[Claims] 1. The chemical composition of the main component is SiO ₂ 42 to 56 on a weight basis.
%, Al ₂ O ₃ 30-45%, MgO 12-16%, the main component of the crystal phase is cordierite, the porosity is 30% or less, and the temperature of 40-800℃ in the flow path direction of the honeycomb structure is A cordierite honeycomb structure catalyst characterized by having a thermal expansion coefficient of 0.8×10 ^-6 /℃ or less in the direction perpendicular to the flow path and a thermal expansion coefficient of 1.0×10 ^-6 /℃ or less in the direction perpendicular to the flow path between 40 and 800℃. carrier. 2. The cordierite honeycomb structure catalyst carrier according to claim 1, wherein the porosity is 25% or less. 3 The difference in coefficient of thermal expansion between 40 and 800°C between the flow path direction and the direction perpendicular to the flow path of the honeycomb structure is 0.2×10 ^-6 /
The cordierite honeycomb structure catalyst carrier according to claim 1, which has a temperature of .degree. C. or less. 4 The compressive strength in the flow path direction of the honeycomb structure is 200
The cordierite honeycomb structured catalyst carrier according to claim 1, wherein the catalyst carrier has a catalyst support of at least Kg/cm ² . 5. The cordierite honeycomb structure catalyst carrier according to claim 1, wherein the rib thickness of the honeycomb structure is 437 μm or less. 6 The chemical composition of the main component is SiO ₂ 42-56 on a weight basis
%, Al ₂ O ₃ 30-45%, MgO 12-16% with talc with an average particle size of 7 μm or less and an average particle size of 2 μm
It is possible to mix kaolin and other cordierite forming raw materials with an average particle size of 1/3 or less of the average particle size of talc, add an organic binder and a plasticizer to this mixture, mix and knead it, and then extrude it. plasticized into
A method for producing a cordierite honeycomb structure catalyst carrier, which comprises extrusion molding into a honeycomb structure and then firing at a temperature of 1350 to 1440°C. 7. The manufacturing method according to claim 6, using talc having an average particle diameter of 5 μm or less. 8. The manufacturing method according to claim 6, using kaolin having an average particle diameter of 1 μm or less. 9 The chemical composition of the main component is SiO ₂ 42-56 on a weight basis
%, Al ₂ O ₃ 30-45%, MgO 12-16% with talc with an average particle size of 7 μm or less and an average particle size of 2 μm
Kaolin with an average particle size of 1/3 or less of the average particle size of talc, alumina and/or aluminum hydroxide with an average particle size of 2 μm or less, and other cordierite forming raw materials are mixed, and this mixture is added with an organic binder. A method for producing a cordierite honeycomb structure catalyst carrier, which comprises adding a plasticizer and mixing and kneading to make it plasticized to enable extrusion molding, extrusion molding into a honeycomb structure, and then firing at a temperature of 1350 to 1440°C. . 10. The manufacturing method according to claim 9, using talc having an average particle diameter of 5 μm or less. 11. The manufacturing method according to claim 9, using kaolin having an average particle diameter of 1 μm or less. 12. The method for producing a cordierite honeycomb structured catalyst carrier according to claim 9, wherein Na ₂ O in alumina in the cordierite forming raw material is 0.12%. 13. The method for producing a cordierite honeycomb structure catalyst carrier according to claim 9, wherein the calcined kaolin of the kaolin is pulverized using a wet ball mill. 14 The chemical composition of the main component is SiO ₂ 42 ~ on a weight basis
Talc with an average particle size of 7 μm or less and an average particle size of 2 μm so that the amount is 56%, Al ₂ O ₃ 30-45%, and MgO 12-16%.
Kaolin with an average particle size of 2 μm or less and 1/3 of the average particle size of talc, alumina and/or aluminum hydroxide with an average particle size of 2 μm or less, high-purity amorphous silica, and other cordierite forming raw materials are mixed. , a cordier characterized in that an organic binder and a plasticizer are added to this mixture, the mixture is kneaded and plasticized to enable extrusion molding, and after extrusion molding into a honeycomb structure, it is fired at a temperature of 1350 to 1440°C. A method for producing a light honeycomb structured catalyst carrier. 15. The manufacturing method according to claim 14, using talc having an average particle diameter of 5 μm or less. 16. The manufacturing method according to claim 14, using kaolin having an average particle diameter of 1 μm or less. 17 Claim 1, wherein the Na ₂ O content of alumina among the cordierite forming raw materials is 0.12% or less.
4. The method for producing a cordierite honeycomb structure catalyst carrier according to item 4. 18. The method for producing a cordierite honeycomb structured catalyst carrier according to claim 14, wherein the calcined kaolin of the kaolin is pulverized using a wet ball mill. 19. The method for producing a cordierite honeycomb structured catalyst carrier according to claim 14, wherein the amount of the high-purity amorphous silica added is 8% or less.