WO2008059608A1

WO2008059608A1 - Process for production of honeycomb structures

Info

Publication number: WO2008059608A1
Application number: PCT/JP2006/324983
Authority: WO
Inventors: Kazushige Ohno; Takahiko Ido; Chizuru Kasai
Original assignee: Ibiden Co., Ltd.
Priority date: 2006-11-16
Filing date: 2006-12-14
Publication date: 2008-05-22
Also published as: DE602007004411D1

Abstract

The invention provides a process for the production of honeycomb structures free from deformation or cracking, that is, a process for the production of honeycomb structures which comprises the starting composition preparation step of mixing inorganic particles essentially with an inorganic fiber and/or whisker and an inorganic binder solution to prepare a starting composition, the molding step of extruding the starting composition into a columnar honeycomb wherein many cells are arranged in the lengthwise direction with each cell surrounded by a cell wall, and the burning step of burning the honeycomb to form a burned honeycomb, characterized in that the inorganic binder solution is used in an amount of 30 to 60% by weight based on the total amount of the inorganic particles, the inorganic fiber and/or whisker, and the inorganic binder solution and the concentration of the inorganic binder solution is 35 to 50% by weight.

Description

Specification

Manufacturing method of honeycomb structure

Technical field

[0001] The present invention relates to a method for manufacturing a honeycomb structured body.

Background art

[0002] Conventionally, a hard-cam catalyst in which a catalyst component is supported on a hard-cam structure used for exhaust gas purification of a vehicle is an active alumina on the surface of a cordierite-type no-cam structure having an integral structure and low thermal expansion. It is manufactured by supporting a high specific surface area material such as platinum and a catalytic metal such as platinum. In addition, such a honeycomb catalyst carries an alkaline earth metal such as Ba as a NOx storage agent for NOx treatment in an oxygen-excess atmosphere such as a lean burn engine and a diesel engine. By the way, in order to further improve the purification performance, it is necessary to increase the contact probability between the exhaust gas, the catalyst noble metal and the NOx storage agent. For this purpose, it is necessary to make the support have a higher specific surface area, to reduce the particle size of the noble metal and to disperse it with high dispersion. For this reason, for example, a hard cam structure obtained by extruding inorganic particles and inorganic fibers together with an inorganic binder is known as a hard cam structure having a high specific surface area material force (see, for example, Patent Documents 1 to 3). ).

Patent Document 1: Japanese Patent Laid-Open No. 2005-218935

Patent Document 2: JP-A-2005-349378

Patent Document 3: Japanese Patent Laid-Open No. 5-213681

Disclosure of the invention

Problems to be solved by the invention

[0003] However, as disclosed in Patent Documents 1 to 3, when a honeycomb structure is manufactured through a process of extruding inorganic particles and inorganic fibers together with an inorganic binder, heat treatment is performed on the extruded molded body. When subjected to (drying treatment, degreasing treatment, firing treatment, etc.), cracks and deformation may occur in the molded product and the fired product.

Means for solving the problem

[0004] As a result of intensive studies to solve the above-described problems, the present inventors have found that The occurrence of racks and deformation is caused by the composition of the raw material composition to be extruded, that is, when the amount of solid content is small in the inorganic binder solution used when preparing the raw material composition. The amount of the solvent such as water is relatively large, and as a result, the amount of the solvent such as water contained in the raw material composition is increased. Using such a raw material composition, It has been found that if heat treatment such as subsequent drying treatment is performed, the molded body shrinks greatly, and thus cracks and deformation as described above occur.

Furthermore, in order to prevent the occurrence of cracks and deformation as described above, it has been found that the concentration of the inorganic binder contained in the inorganic binder solution may be adjusted within a predetermined range, and the present invention is completed.

[0005] That is, the method for producing a her cam structure of the present invention comprises at least inorganic particles, inorganic fibers and

A raw material composition production process for producing a raw material composition by mixing Z or Wis power and an inorganic binder solution;

A forming step of producing a columnar honeycomb formed body in which a large number of cells are arranged in parallel in the longitudinal direction across the cell wall by extrusion molding using the raw material composition;

A firing process for producing a honeycomb fired body by subjecting the honeycomb formed body to a firing treatment,

The blending amount of the inorganic binder solution is 30 to 60% by weight with respect to the total amount of the inorganic particles and the inorganic fibers and Z or the whistle force and the inorganic binder solution. The concentration is characterized by being 35-50% by weight.

In the present invention, the concentration of the inorganic binder refers to the percentage of the weight of the inorganic binder with respect to the total weight of the inorganic binder solution.

[0006] In the manufacturing method of the her cam structure of the present invention, the inorganic binder solution is a group that also includes alumina sol, silica sol, titasol, water glass, suspension of sepiolite and suspension of attapulgite. It is desirable that the force is also at least one selected.

The invention's effect

[0007] In the manufacturing method of the her cam structure of the present invention, the inorganic binder solution having a predetermined concentration is mixed in the raw material composition in a predetermined blending amount, so that the manufacturing of the her cam structure is performed. In the process, the honeycomb molded body is not deformed or cracked in the honeycomb fired body. A two-cam structure can be manufactured.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, a method for manufacturing a honeycomb structured body of the present invention will be described in detail.

The manufacturing method of the hercome structure of the present invention comprises a raw material composition preparation step of preparing a raw material composition by mixing at least inorganic particles and inorganic fibers and z or whistle force and an inorganic binder solution;

Note that in this specification, the columnar shape includes an arbitrary shape such as a columnar shape, an elliptical columnar shape, or a polygonal columnar shape.

[0009] Hereinafter, a method for manufacturing a her cam structure of the present invention will be described in the order of steps.

(1) In the method of manufacturing a her cam structure of the present invention, first, a raw material composition preparation step for preparing a raw material composition containing at least inorganic particles, inorganic fibers, and Z or Wis power and an inorganic binder solution is performed. Do.

[0010] As the above-mentioned raw material composition, an organic binder and a molding aid appropriately arranged according to the moldability can be used as necessary.

[0011] In the method of manufacturing a her cam structure of the present invention, an inorganic binder solution having a lower concentration limit of 35 wt% and an upper limit of 50 wt% is used as the inorganic binder solution.

By manufacturing a her cam structure using such a raw material composition containing an inorganic binder solution, cracks and deformations occurred in the her cam fired body during the manufacturing process. Don't do it.

On the other hand, when the concentration of the inorganic binder solution is less than 35% by weight, the amount of the solvent such as water contained in the raw material composition increases. Although good formability can be ensured, cracks and deformation may occur in the honeycomb fired body during the manufacturing process of the her cam structure. On the other hand, if the concentration of the inorganic binder solution exceeds 50% by weight, when the raw material composition is extruded, the moldability may be inferior and a molded article having a desired shape may not be produced. The desirable upper limit of the concentration of the inorganic binder solution is 45% by weight.

[0012] As the inorganic binder solution, a suspension of an inorganic sol or clay binder can be used, and specific examples of the inorganic sol include, for example, alumina sol, silica sol, titasol, water glass, and the like. Can be mentioned. Examples of the clay-based binder include double-chain structure type clays such as white clay, ryoolin, montmorillonite, sepiolite, and attapulgite. These may be used alone or in combination of two or more.

Of these, at least one selected from the group force of alumina sol, silica sol, titasol, water glass, sepiolite suspension and attapulgite suspension is desirable.

[0013] The average particle size of the inorganic binder contained in the inorganic binder solution is desirably a lower limit of lOnm and an upper limit of 50 nm. This is because a two-cam structure having a large specific surface area and excellent strength can be manufactured through a manufacturing process described later.

When the average particle size of the inorganic binder is less than lOnm or more than 50 nm, the strength of the produced no-cam structure may be insufficient.

The reason is considered as follows.

That is, in the method for producing a hard structure of the present invention, the inorganic binder is considered to play a role of mainly bonding the inorganic particles, the inorganic fibers, and the whiskers, and between the inorganic fibers and the inorganic particles. It is considered that the adhesive function is exerted by contacting the inorganic fibers and the inorganic particles at the same time, interposing between the inorganic particles and contacting different inorganic particles at the same time.

Here, when the average particle diameter is less than lOnm, it is difficult to contact the inorganic fibers and the inorganic particles at the same time, or to contact different inorganic particles at the same time, and a sufficient adhesive force cannot be obtained. On the other hand, if the average particle diameter exceeds 50 nm, the number of adhesion points will decrease, and as a result, the strength will be insufficient. Furthermore, when the average particle size of the inorganic binder exceeds 50 nm, the specific surface area of the manufactured Hercam structure is not sufficiently large, which is disadvantageous when the honeycomb structure is used as a catalyst carrier. .

The more desirable average particle size of the inorganic binder is a lower limit of 20 nm and an upper limit force On m.

[0014] The average particle size of the inorganic binder can be measured, for example, by the following method.

Specifically, when the inorganic noinda is a silica sol, the silica sol is first dried and its BET specific surface area is measured.

Then, assuming that the silica particles in the silica sol are dense spherical particles, the following calculation formula (1) is used.

BET specific surface area = (6000 / _P ) Z particle size '· · · (1)

(Wherein p is the true density of silica (2.2 gZcm ³ ))

The average particle size of the inorganic binder can also be directly measured using, for example, a TEM (transmission electron microscope).

[0015] In addition, in the method of manufacturing the above-mentioned hard cam structure, the blending amount of the inorganic binder solution with respect to the total amount of the inorganic particles, the inorganic fibers, and Z or Wis power and the inorganic binder solution is: The lower limit is 30% by weight and the upper limit is 60% by weight.

When the blending amount of the inorganic binder solution is less than 30% by weight, the amount of the inorganic binder contained in the manufactured hard cam structure is small, and the strength of the hard cam structure may be lowered. This is because if the amount of the inorganic noinda solution exceeds 60% by weight, the moldability of the raw material composition tends to deteriorate.

The blending amount of the inorganic noinda solution with respect to the total amount of the inorganic particles, the inorganic fibers, the Z or Wis power and the inorganic noinda solution is desirably 50% by weight.

[0016] Examples of the inorganic particles include alumina, silica, zirconia, titer, ceria, mullite, and zeolite. These may be used alone or in combination of two or more. Of these, alumina particles and ceria particles are particularly desirable.

[0017] The amount of the inorganic particles is based on the inorganic particles, the inorganic fibers, and the Z or whistle force. The desired lower limit is 30% by weight, the more desirable lower limit is 40% by weight, and the more desirable lower limit is 50% by weight with respect to the total amount of the inorganic binder solution and the solid content (hereinafter referred to as the total amount of essential raw materials). It is.

On the other hand, a desirable upper limit is 85% by weight, a more desirable upper limit is 80% by weight, and a further desirable upper limit is 75% by weight.

When the blended amount of the inorganic particles is less than 30% by weight, the amount of inorganic particles contributing to the improvement of the specific surface area is relatively small, so that the specific surface area of the produced two-cam structure is small, and the catalyst component When the catalyst is supported, the catalyst component may not be highly dispersed. On the other hand, if it exceeds 85% by weight, the amount of inorganic binder, inorganic fiber, and whisker that contributes to strength improvement will be relatively small, so the strength of the manufactured two-cam structure tends to decrease.

[0018] In addition, it is desirable that the inorganic particles to be blended in the raw material composition have an average secondary particle size of 0.5 to 20 µm! / ヽ.

When the average particle diameter is less than 0.5 m, the produced no-cam structure is densified, and when used as a catalyst carrier, the gas permeability may be inferior, while exceeding And the specific surface area of the manufactured honeycomb structure tends to be small.

The average particle size of the primary particles of the inorganic particles is preferably 5 to: LOOnm. In the present specification, primary particles are particles constituting a powder aggregate, and are the smallest unit particles that exist without breaking bonds between molecules. Secondary particles are particles formed by agglomeration of primary particles.

[0019] The inorganic particles (secondary particles) preferably have a specific surface area of 50 to 300 m ² / g.

When the specific surface area is less than 50 m ² Zg, the specific surface area of the manufactured honeycomb structure tends to be small. On the other hand, when the specific surface area exceeds 300 m ² Zg, the specific surface area of the two-cam structure is increased even if the specific surface area is increased. This is because the specific surface area does not improve so much.

Moreover, in the method for producing a her cam structure of the present invention, the average aspect ratio of the inorganic particles (secondary particles) is 1 to 5.

[0020] Examples of the inorganic fiber twist force include alumina, silica, silicon carbide, silica-alumina, Examples include inorganic fiber whiskering force, which can be lath, potassium titanate or aluminum borate.

These inorganic fibers can be used alone or in combination of two or more. In the method of manufacturing a her cam structure of the present invention, the inorganic fiber whisking force has an average aspect ratio exceeding 5.

The desirable average aspect ratio of the inorganic fiber wis power is 10 to: LOOO.

[0021] The total blending amount of the inorganic fiber and Z or the whisking force is preferably 3% by weight, more preferably 5% by weight, and more preferably 8% by weight based on the total amount of the essential raw materials. %. On the other hand, the desirable upper limit is 50% by weight, the more desirable upper limit is 40% by weight, and the more desirable upper limit is 30% by weight.

If the total amount of the inorganic fiber and Z or the whisking force is less than 3% by weight, the strength of the manufactured honeycomb structure is reduced. On the other hand, if it exceeds 50% by weight, the manufactured honeycomb structure is reduced. Therefore, when the manufactured honeycomb structure is used as a catalyst carrier, when the catalyst component having a small specific surface area is supported, the honeycomb structure is used as a catalyst carrier. The catalyst component may not be highly dispersed.

[0022] The organic binder is not particularly limited, and examples thereof include methyl cellulose, canoleoxy methylenoresenorelose, hydroxyethinoresenorelose, and polyethylene glycol.

These may be used alone or in combination of two or more.

The blending amount of the organic binder is desirably 1 to 10 parts by weight with respect to a total of 100 parts by weight of the solid content of the inorganic particles, the inorganic fibers, the whiskers, and the inorganic binder solution.

[0023] The molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid sarcophagus, and polyalcohol.

In this, in order to improve a moldability more, it is good to mix | blend oleic acid further.

[0024] Preparation of the raw material composition is not particularly limited, but it is preferable to mix and knead the raw materials. For example, a kneader that can be mixed using a mixer, an attritor, etc. Thoroughly knead.

[0025] (2) Next, a forming step is performed in which a columnar honeycomb formed body in which a large number of cells are arranged side by side in the longitudinal direction with cell walls being separated is formed by extrusion using the raw material composition.

[0026] (3) Next, the honeycomb formed body is subjected to a drying treatment as necessary.

The drying treatment can be performed using, for example, a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, a freeze dryer, or the like.

(4) Next, the honeycomb formed body that has been subjected to a drying treatment as necessary is subjected to a degreasing treatment as necessary.

In this case, the degreasing conditions are not particularly limited, and are appropriately selected depending on the type and amount of the organic substance contained in the molded body, but are preferably about 400 ° C. and about 2 hours.

[0028] (5) Next, a firing process is performed to produce a honeycomb fired body by subjecting the Hercam molded body, which has been subjected to a drying process and a degreasing process, as necessary to a firing process.

The firing temperature in the firing treatment is not particularly limited, but 500-1200 ° C is desirable, and 600-1000 ° C is more desirable.

If the firing temperature is less than 500 ° C, the adhesive function due to the inorganic binder is difficult to develop, and the sintering of the inorganic particles or the like hardly progresses, so the strength of the manufactured honeycomb structure may be lowered. When the temperature exceeds 1200 ° C, the sintering of inorganic particles proceeds too much, and the specific surface area per unit volume of the manufactured Hercam structure becomes small. When the Hercam structure is used as a catalyst support, In some cases, the catalyst component to be supported cannot be sufficiently dispersed.

[0029] By passing through such a process, it is possible to manufacture a columnar hard cam fired body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween.

The no-cam fired body manufactured through such steps is itself a her cam structure, and in the method for manufacturing the her cam structure of the present invention, all the steps may be completed so far. . In addition, a seal material layer (coat layer) may be formed around the no-cam fired body manufactured by the method described so far to obtain a finished product of the her cam structure. Such a her cam structure having a single hard cam firing strength is also referred to as an integrated her cam structure hereinafter.

In addition, the method for forming the sealing material layer (coat layer) is a method of firing a plurality of Hercoms described later. This is the same as the method of forming a sealing material layer (coat layer) around the honeycomb block when the bodies are bound to produce a honeycomb structure.

[0030] Further, in the method of manufacturing a her cam structure of the present invention, after manufacturing a her cam fired body by the above-described method, a plurality of the honeycomb fired bodies are bundled to manufacture a honeycomb structure. Also good.

In this case, specifically, the following method may be used.

A her cam structure formed by binding a plurality of her cam fired bodies is hereinafter also referred to as a collective her cam structure.

[0031] That is, a sealing material paste to be a sealing material layer (adhesive layer) is applied to the obtained her cam fired body to sequentially bind the her cam fired body, and then dried and fixed. Then, an aggregate of honeycomb fired bodies having a predetermined size that is bound through a sealing material layer (adhesive layer) is produced.

Further, after assembling a predetermined number of her-cam fired bodies through a spacer, a sealing material paste is injected into the gap between the her-cam fired bodies, and then dried, fixed, and sealed. An aggregate of honeycomb fired bodies of a predetermined size that are bound through layers (adhesive layers) may be produced.

[0032] The sealing material paste for forming the adhesive layer is not particularly limited, but for example, a mixture of an inorganic binder and ceramic particles, or a mixture of an inorganic binder and inorganic fibers. Or a mixture of an inorganic binder, ceramic particles and inorganic fibers can be used.

Further, an organic binder may be added to these sealing material pastes.

[0033] The organic binder is not particularly limited, and examples thereof include polyvinyl alcohol, methenoresenorelose, ethinoresenorelose, and canoleboxymethinoresenorelose.

These can be used alone or in combination of two or more.

[0034] The thickness of the sealing material layer (adhesive layer) is preferably 0.5 to 5 mm.

If the thickness of the sealing material layer (adhesive layer) is less than 0.5 mm, sufficient bonding strength may not be obtained. If the thickness exceeds 5 mm, the sealing material layer (adhesive layer) serves as a catalyst carrier. Function Since this is not a portion, the specific surface area per unit volume of the her cam structure is lowered, and when the catalyst component is supported, it may not be possible to sufficiently disperse the catalyst component.

If the thickness of the sealing material layer (adhesive layer) exceeds 5 mm, the pressure loss may increase.

[0035] Here, the number of honeycomb fired bodies to be bundled may be appropriately determined according to the size of the honeycomb structure.

The aggregate of the honeycomb fired bodies in which the honeycomb fired bodies are bound through the sealing material layer (adhesive layer) is appropriately cut and polished as necessary to form a hard cam block.

[0036] Next, if necessary, a sealant paste for forming a coat layer is applied to the outer peripheral surface of the her cam block, dried, and fixed to form a sealant layer (coat Layer).

By forming the sealing material layer (coat layer), the outer peripheral surface of the her cam block can be protected, and as a result, the strength of the her cam structure can be increased.

[0037] The sealing material paste for forming the coating layer is not particularly limited, and may be made of the same material as the sealing material paste for forming the adhesive layer, or may be made of a different material. It may be.

Further, when the sealing material paste for forming the coating layer has the same material strength as that of the sealing material paste for forming the adhesive layer, the blending ratios of the components are the same. It may be different.

[0038] The thickness of the sealing material layer (coat layer) is not particularly limited, but is preferably 0.1-2 mm. If the thickness is less than 1 mm, the outer peripheral surface may not be protected and the strength may not be increased. If the thickness exceeds 2 mm, the specific surface area per unit volume of the her-cam structure decreases, and the catalyst component is supported. When this occurs, it may not be possible to achieve sufficiently high dispersion.

[0039] Further, in this manufacturing method, after binding a plurality of hard cam fired bodies through a sealing material layer (adhesive layer) (provided that the sealing material layer (coating layer) is provided) It is desirable to calcine after forming the coat layer.

As a result, an organic binder is contained in the sealing material layer (adhesive layer) and the sealing material layer (coat layer). This is because this organic noinda can be degreased and removed. The conditions for calcining are appropriately determined depending on the type and amount of organic substances contained, but it is desirable that the conditions are approximately 700 ° C and 2 hours.

[0040] Next, the configuration of the her cam structure manufactured by the method of manufacturing the her cam structure of the present invention will be described with reference to the drawings.

FIG. 1 (a) is a perspective view schematically showing an example of a hard cam fired body manufactured by the method for manufacturing a hard cam structure of the present invention, and FIG. 1 (b) is a schematic view of the hard cam shown in FIG. -A perspective view schematically showing an example of a hard structure using a cam fired body.

[0041] As shown in Fig. 1 (a), the honeycomb fired body 20 has a quadrangular prism shape, and a large number of cells 21 are separated from each other by cell walls 22 in the longitudinal direction (in Fig. 1 (a), the arrow a Direction).

As shown in FIG. 1 (b), the her cam structure 10 includes a plurality of two-cam fired bodies 20 shown in FIG. 1 (a) that are bound together through a sealing material layer (adhesive layer) 14. Thus, the ceramic block 15 is formed, and a sealing material layer (coat layer) 13 is formed on the outer periphery thereof.

[0042] In the above hard cam fired body, the thickness of the cell wall is not particularly limited. Force The desirable lower limit is 0.05 mm, the more desirable lower limit is 0.10 mm, and the particularly desirable lower limit. Is 0.15mm. On the other hand, the desirable upper limit of the cell wall thickness is 0.35 mm, the more desirable upper limit is 0.30 mm, and the particularly desirable upper limit is 0.25 mm.

[0043] If the cell wall thickness is less than 0.05 mm, the strength of the Hercam fired body may be reduced. On the other hand, if the cell wall thickness exceeds 0.35 mm, the Hercam When the structure is used as a catalyst carrier for purifying exhaust gas, the contact area with the exhaust gas is reduced and the gas does not penetrate deep enough, so the catalyst supported inside the cell wall and the gas come into contact with << As a result, the gas purification performance may deteriorate.

[0044] Further, the cell density of the above-mentioned Hercam fired body has a desirable lower limit of 15.5 pieces / cm ² (100 cpsi), and a more desirable lower limit force of 6.5 pieces Zcm ² (300 cpsi), and is further desirable. The lower limit is 62 pieces Zcm ² (400cpsi). On the other hand, the desirable upper limit of the cell density is 186 Zcm ² (1200 cpsi), the more desirable upper limit is 170.5 Zcm ² (1100 cpsi), and the more desirable upper limit is 155 Zcm ² (1000 cpsi).

If the cell density force is less than 15.5 Zcm ² , the above-mentioned Hercom structure will be exhausted. When the catalyst carrier is used, the area of the cell wall that comes into contact with the exhaust gas inside the honeycomb fired body is reduced. When the cell wall exceeds 186 cells / cm ² , the pressure loss increases and the production of the Hercam fired body becomes possible. This is because it becomes difficult.

[0045] The cross-sectional area in the direction perpendicular to the longitudinal direction of the Hercam fired body preferably has a lower limit of 5 cm ² and an upper limit of 50 cm ^2. Is a range formed by binding a plurality of honeycomb fired bodies, it is desirable to be within the above range. If the cross-sectional area is less than 5 cm ² , the area occupied by a sealing material layer (adhesive layer) that joins a plurality of her-cam fired bodies in the cross-section perpendicular to the longitudinal direction of the her-cam structure However, when the honeycomb structure is used as a catalyst carrier, the area on which the catalyst can be supported becomes relatively small. On the other hand, if the cross-sectional area exceeds 50 cm ² , the honeycomb fired body is large, and thus there is a fear that the thermal stress generated in the honeycomb fired body cannot be sufficiently suppressed.

A more desirable lower limit of the cross-sectional area is 6 cm ² , a particularly desirable lower limit is 8 cm ² , and a more desirable upper limit is 40 cm ² , especially desirable! /, And an upper limit is 30 cm ² .

[0046] The shape of the cross section perpendicular to the longitudinal direction of the cells formed in the honeycomb fired body is not particularly limited, and other than the square shape such as the two-cam fired body shown in Fig. 1 (a), It may be a substantially triangular shape or a substantially hexagonal shape.

[0047] Further, when a sealing material layer (adhesive layer) or a sealing material layer (coat layer) is formed on the her cam structure, in a cross section perpendicular to the longitudinal direction of the honeycomb structure, The ratio of the total cross-sectional area of the honeycomb fired body to the cross-sectional area of the honeycomb structure is preferably 90% or more. If it is less than 90%, the specific surface area of the her cam structure will be small.

[0048] In addition, the specific surface area per unit area of the above-mentioned hard cam structure is preferably 25000 m ² ZL or more.

This is because when the specific surface area is in the above range, it becomes easy to disperse and carry the catalyst sufficiently widely over the entire honeycomb structure.

The desirable upper limit of the specific surface area is 70000 m ² ZL in consideration of the dispersion limit of the catalyst (for example, platinum). [0049] More specifically, the higher the bending strength of the honeycomb structure, the more desirable it is, for example, when the honeycomb fired body has a prismatic shape of 37 mm X 37 mm X 75 mm, it is 3. OMpa or more. It is desirable.

This is a force that reduces the possibility of destruction due to thermal stress generated during use.

[0050] Further, the hard cam structure manufactured by the method of manufacturing a hard cam structure of the present invention is shown in FIG.

It is not limited to the collective type hard cam structure as shown in (b), but may be an integral type hard cam structure as shown in FIG.

FIG. 2 is a perspective view schematically showing another example of the honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention.

A hard cam structure 30 shown in FIG. 2 has a columnar shape, and a large number of cells 31 are arranged side by side in the longitudinal direction (in the direction of arrow b in FIG. 2) with the cell walls 32 therebetween. It consists of one piece.

In such an integrated her cam structure, a seal material layer (coat layer) may be formed around the her cam fired body.

[0051] In addition, it is desirable that a catalyst is supported on the hard cam structure having such a configuration. The above-mentioned Hercam structure also has a force that can be suitably used as a catalyst carrier.

The catalyst is not particularly limited, and examples thereof include noble metals, alkali metals, alkaline earth metals, and oxides. These may be used alone or in combination of two or more.

[0052] Examples of the noble metal include platinum, noradium, and rhodium. Examples of the alkali metal include potassium and sodium. Examples of the alkaline earth metal include, for example, For example, perovskite (La

0. 75

K MnO) and CeO.

0. 25 3 2

[0053] The Hercam structure on which the catalyst as described above is supported is not particularly limited. For example, it may be used as a so-called three-way catalyst or NOx storage catalyst for automobile exhaust gas purification. Togashi.

The catalyst loading time is not particularly limited. You may carry | support after manufacturing, You may carry | support to the inorganic particle in a raw material composition. Further, the catalyst loading method is not particularly limited, and for example, it can be carried out by an impregnation method or the like.

[0054] Heretofore, the method for manufacturing a honeycomb structure of the present invention, and Z or the hard structure manufactured by this manufacturing method have been described mainly using the case as a catalyst carrier as an example. However, the honeycomb structure can be used other than the catalyst carrier, for example, as an adsorbent for adsorbing a gas component or a liquid component. Example

[0055] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1)

(1) γ-alumina particles (secondary particles with an average particle size of 2 μm) 2250 g as inorganic particles, aluminum borate whisker as inorganic fibers (fiber diameter 0.5-1 m, fiber length 10-30 μm) 680 g, silica sol (average particle size 15 nm, concentration 35 weight ⁰ / _O ) 2600 g as an inorganic noda solution, and 320 g of methyl cellulose as an organic binder and uniloop as a lubricant (manufactured by NOF Corporation) 290 g and 225 g of glycerin (manufactured by NOF Corporation) as a plasticizer were added and further mixed and kneaded to prepare a raw material composition. Next, this mixed composition was subjected to extrusion molding with an extruder to produce a honeycomb formed body.

[0056] (2) Next, the honeycomb formed body was sufficiently dried using a microwave dryer and a hot air dryer, and further degreased by being held at 400 ° C for 2 hours.

After that, it was held at 900 ° C for 2 hours and fired, prismatic (37mm x 37mm x 75mm), cell density 93 pieces Zcm ² (600cpsi), cell wall thickness 0.2mm, cell cross-sectional shape A square (square) honeycomb fired body was manufactured.

[0057] (Examples 2 and 3)

A Hercham sintered body was produced in the same manner as in Example 1 except that the silica sol (average particle size 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[Example 4] In the same manner as in Example 1 except that alumina sol (average particle size 15 nm, concentration 35% by weight) was used in place of silica sol when preparing the raw material composition, a hard cam fired body was produced.

[Example 5]

As inorganic particles, instead of γ-alumina particles, γ-alumina particles (secondary particles with an average particle size of 2 μm) 50 wt% and 13 zeolite particles (secondary particles with an average particle size of 2 μm) 50 wt% A hard cam fired body was produced in the same manner as in Example 1 except that the mixed particles were used.

[0060] (Examples 6 and 7)

A Hercam sintered body was produced in the same manner as in Example 5 except that the silica sol (average particle diameter 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[Example 8]

A hard cam fired body was produced in the same manner as in Example 5 except that alumina sol (average particle size 15 nm, concentration 35% by weight) was used instead of silica sol when preparing the raw material composition.

[0062] (Example 9)

As inorganic particles, instead of secondary particles of γ-alumina particles, 50% by weight of γ-alumina particles (secondary particles with an average particle size of 2 μm) and 50% by weight of CeO particles (secondary particles with an average particle size of 2 μm) %

2

A hard-cam fired body was produced in the same manner as in Example 1 except that the mixed particles were used.

[0063] (Examples 10 and 11)

A Hercam sintered body was produced in the same manner as in Example 9 except that the silica sol (average particle size 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used when preparing the raw material composition. .

[0064] (Example 12)

A hard cam fired body was produced in the same manner as in Example 9 except that alumina sol (average particle size 15 nm, concentration 35 wt%) was used instead of silica sol when preparing the raw material composition.

[Example 13] A Hercam sintered body was produced in the same manner as in Example 1 except that the raw material composition was prepared by the following method.

That is, 2970 g of γ-alumina particles (secondary particles with an average particle diameter of 2 μm) as inorganic particles, aluminum borate whisker as inorganic fibers (fiber diameter 0.5 to: L m, fiber length 10 to 30 / ζ m) 90 og, inorganic Noinda solution as silica sol (average particle size 15 nm, concentration 35 weight ^_0/0) 1660 g were mixed for further resulting mixture methylcellulose 320 g as an organic binder, Yunirupu (manufactured by NOF Corporation as a lubricant ) 290 g, 225 g of glycerin (manufactured by Nippon Oil & Fats Co., Ltd.) as a plasticizer was added and further mixed and kneaded to prepare a raw material composition.

[0066] (Examples 14 and 15)

A Hercam fired body was produced in the same manner as in Example 13 except that the silica sol (average particle size 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[0067] Example 16

A Hercam sintered body was produced in the same manner as in Example 1 except that the raw material composition was prepared by the following method.

That is, 1780 g of γ-alumina particles (secondary particles with an average particle diameter of 2 μm) as inorganic particles, aluminum borate whisker (fiber diameter 0.5-1 m, fiber length 10-30 / zm) 40 Og as inorganic fibers, silica sol as an inorganic Noinda solution (average particle diameter 15 nm, concentration 35 weight ^_0/0) were mixed 3300 g, further to the obtained mixture, methyl cellulose 320 g as an organic binder, Yunirupu (manufactured by NOF Corporation) as a lubricant 290g Then, 225 g of glycerin (manufactured by Nippon Oil & Fats Co., Ltd.) was added as a plasticizer and further mixed and kneaded to prepare a raw material composition.

[Examples 17 and 18]

A Hercam fired body was produced in the same manner as in Example 16 except that the silica sol (average particle diameter 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[0069] (Comparative Examples 1 and 2)

As the inorganic binder solution used for preparing the raw material composition, silica sol (average particle size 15 nm) having the concentration shown in Table 1 was used, and the Herkham calcination was performed in the same manner as in Example 1. An adult was produced.

[0070] (Comparative Example 3)

A hard-cam fired body was produced in the same manner as in Example 4 except that an alumina sol (average particle size of 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[0071] (Comparative Examples 4 and 5)

[0072] (Comparative Example 6)

A hard-cam fired body was produced in the same manner as in Example 8, except that the alumina sol (average particle size 15 nm) having the concentrations shown in Table 1 was used as the inorganic binder solution used in preparing the raw material composition. .

[0073] (Comparative Examples 7 and 8)

[0074] (Comparative Example 9)

A hard-fired fired body was produced in the same manner as in Example 12 except that the alumina sol (average particle size 15 nm) having the concentration shown in Table 1 was used as the inorganic binder solution used when preparing the raw material composition. did.

[0075] (Comparative Example 10)

A hard cam fired body was produced in the same manner as in Comparative Example 1 except that the amount of the inorganic binder solution (silica sol) used in preparing the raw material composition was 2000 g.

[0076] In Examples 1 to 18 and Comparative Examples 1 to 10, as a silica sol having a concentration of 30% by weight, Snowtech 30 manufactured by Nissan Chemical Co., Ltd. was used, and the concentration was 35% by weight, 40% by weight, 50% by weight. As the silica sol of 60% by weight and 60% by weight, a Snow Tech 30 concentrated to a predetermined concentration was used. In addition, as an alumina sol with a concentration of 30% by weight and 35% by weight, Alumina sol 520 (alumina concentration 20% by weight) concentrated to a predetermined concentration was used.

[0077] Evaluation of honeycomb fired body

In the manufacture of the honeycomb fired bodies according to the examples and the comparative examples, after the extruded non-nickel molded bodies were dried, the presence of cracks was evaluated on the dried two-cam molded bodies. In addition, we evaluated the shape (presence / absence of deformation) of the manufactured two-cam sintered body.

The results are shown in Table 1.

[0078] (Evaluation of occurrence of cracks)

Looking at the dried honeycomb molded body? Observations were made to observe the presence or absence of cracks.

[0079] (Shape evaluation of honeycomb fired body)

For the manufactured hard cam fired body, the flatness of the side surface was measured by the following method, and the hard cam fired body having a flatness of all side faces of 0.5 mm or less was “O”. Her-cam fired bodies with a flatness exceeding 0.5 mm were evaluated as “XJ”.

That is, the flatness of the Hercam fired body was evaluated by plotting the position coordinates of the side face of the Hercam fired body using a three-dimensional measuring machine (BH-V507, manufactured by Mitutoyo Corporation).

[0080] [Table 1]

Of inorganic binder

Inorganic binder concentration

Compounding amount (Note) Crack presence or absence Shape evaluation

(Wt%) (wt%)

Example 1 35 47 None 〇 Example 2 40 47 実施〇 Example 3 50 47 〇〇 Example 4 35 47 〇 Example 5 35 47 ∎ 〇 Example 6 40 47 〇 Example 7 50 47 〇 Example 8 35 47 None ○ Example 9 35 47 ○ Example 1 0 40 47 ○ Example 1 1 50 47 ○ Example 1 2 35 47 ○ Example 1 3 35 30 None ○ Example 1 4 40 30 ○ Example 1 5 50 30 ○ Example 1 6 35 60 iffi ○ Example 1 7 40 60 m ○ Example 1 8 50 60 ○ Comparative Example 1 30 47 Yes Yes Comparative Example 2 60 47 to X Comparative Example 3 30 47 Yes Yes Comparative Example 4 30 47 Yes Yes Comparative Example 5 60 47 No X Comparative Example 6 30 47 Yes Yes Comparative Example 7 30 47 Yes Yes Comparative Example 8 60 47 No X Comparative Example 9 30 47 Yes Yes Comparative Example 1 0 30 41 No X

(Note) Amount of inorganic binder:

Compounding amount of the inorganic binder solution with respect to the total amount of the inorganic particles, the weiss force and the inorganic binder As is apparent from the results shown in Table 1, an inorganic binder solution having a concentration of 35 to 50% by weight, 30 to 60% by weight By using the blended amount, no cracks are generated when the her cam formed body is dried, and a her cam fired body having a desired shape without deformation can be produced.

On the other hand, when the concentration of the inorganic binder solution was less than 35% by weight, no deformation was observed in the shape of the honeycomb fired body, but cracks were observed when the hard cam formed body was dried. It was. In addition, when the concentration of the inorganic binder solution exceeded 50% by weight, the dried hard-cam molded body had a strong force with no cracks observed, and the produced no-cam fired body was deformed.

[0082] Further, in the above-described examples and comparative examples, a single hard cam fired body was manufactured and evaluated as a hard cam structure, but a plurality of the hard cam fired bodies were used. Thus, the same result is obtained when a collective hard cam structure as shown in FIGS. 1 (a) and 1 (b) is manufactured. Brief Description of Drawings

[0083] [FIG. 1] (a) is a perspective view schematically showing an example of a hard cam fired body manufactured by the method of manufacturing a hard cam structure of the present invention. FIG. 2 is a perspective view schematically showing an example of a no-cam structure using the her cam fired body shown in a).

Explanation of symbols

[0084] 10, 30 Hercam structure

13 Sealing material layer (coat layer)

14 Sealing material layer (adhesive layer)

20 Hercam fired body

21, 31 Senore

22, 32 Senor wall

Claims

The scope of the claims

[1] A raw material composition preparation step for preparing a raw material composition by mixing at least inorganic particles, inorganic fibers, and Z or Wis power and an inorganic binder solution;

A molding step of producing a columnar honeycomb molded body in which a large number of cells are arranged in parallel in the longitudinal direction with cell walls being separated by extrusion molding using the raw material composition;

The blending amount of the inorganic binder solution is 30 to 60% by weight with respect to the total amount of the inorganic particles and the inorganic fibers and Z or the whistle force and the inorganic binder solution, and the inorganic binder solution A process for producing a Hercam structure, wherein the concentration is 35 to 50% by weight.

[2] The inorganic binder solution according to claim 1, wherein the inorganic binder solution is at least one selected from a group force consisting of alumina sol, silica sol, titasol, water glass, sepiolite suspension, and attapulgite suspension. A method for manufacturing a honeycomb structure.