JP2016132582A - Method for producing honeycomb structured body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a honeycomb structured body, which can be used when various honeycomb structured bodies are produced and in which a paste layer, that was used when a honeycomb fired body is stuck or an outer peripheral coat layer is formed, can be dried without forming macropores thereon and the honeycomb structured body excellent in mechanical characteristics can be produced efficiently.SOLUTION: The method for producing the honeycomb structured body comprises: such an adhesive material paste layer formation step that an adhesive material paste layer, which contains at least one of an inorganic particle and an inorganic fiber, and an inorganic binder consisting of sol, is formed between the adjacent outer peripheral walls of a plurality of honeycomb fired bodies, each of which has porous cell partition walls for partitioning/forming a plurality of cells being flow passages of exhaust gas and the outer peripheral wall; an adhesive material paste layer freeze treatment step of performing freeze treatment on the formed adhesive material paste layer existing between the adjacent outer peripheral walls of the plurality of honeycomb fired bodies; and an adhesive material paste layer drying step of drying the freezed adhesive material paste layer existing between the adjacent outer peripheral walls of the plurality of honeycomb fired bodies to form an adhesive material layer.SELECTED DRAWING: Figure 8

Description

The present invention relates to a method for manufacturing a honeycomb structure.

Recently, particulates such as soot (hereinafter referred to as PM) and other harmful components contained in exhaust gas discharged from internal combustion engines such as buses and trucks and construction machinery and the like are harmful to the environment and the human body. It is a problem. Accordingly, various honeycomb structures made of porous SiC have been proposed as honeycomb filters for collecting PM in exhaust gas and purifying the exhaust gas.
Various honeycomb catalysts that purify harmful gases such as NOx have also been proposed.

When manufacturing such a honeycomb structure or the like, first, ceramic particles are kneaded with an organic binder and the like, and then formed into a predetermined shape using an extrusion mold or the like, and a plurality of through holes are elongated. A honeycomb formed body arranged in the direction is manufactured. Thereafter, if necessary, one end of any of the through holes constituting the formed body is plugged, and the obtained honeycomb formed body is fired at 2000 to 2300 ° C. in a firing furnace to form a flow path for exhaust gas. A honeycomb fired body having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells is manufactured.

Thereafter, an adhesive paste containing an inorganic binder such as inorganic particles, inorganic fibers, silica sol, and an organic binder is applied to the outer peripheral wall of the honeycomb fired body to form an adhesive paste layer, and a plurality of adhesive paste layers are formed via the adhesive paste layer. The honeycomb fired bodies are bonded and dried to produce a honeycomb aggregate in which a plurality of honeycomb fired bodies are bonded via an adhesive layer. Further, if necessary, the honeycomb aggregate is cut into a predetermined shape using a diamond cutter or the like, and an outer peripheral coat layer is formed on the outer periphery to manufacture a columnar honeycomb structure.

However, in the above manufacturing process, until the drying of the adhesive paste layer formed between the plurality of honeycomb fired bodies is finished, moisture in the adhesive paste layer is absorbed by the porous honeycomb fired body, When moisture evaporates by heating, silica contained in the sol aggregates and tends to be unevenly distributed in the adhesive layer. As a result, large pores (macropores) are formed, reducing the strength of the adhesive layer. There was a problem that. Further, when the outer peripheral coat layer is formed, the same problem occurs because the same material as the adhesive paste is used.

In order to prevent such deterioration of the mechanical strength of the adhesive layer, in the method for manufacturing a honeycomb structure disclosed in Patent Document 1, first, a plurality of honeycomb fired bodies can be bonded before bonding with an adhesive. By combining a plurality of honeycomb fired bodies through the spacers, a honeycomb aggregate having a predetermined shape is formed. Thereafter, the honeycomb aggregate is housed inside a cylindrical body, which is a restraining jig, and an adhesive paste to which a foaming agent has been added is filled in the space between the honeycomb fired bodies and dried to collect the adhesive layer. It was as a body.
According to the above method, a large number of very small pores can be introduced into the adhesive paste, and the presence of the small pores can prevent macropores from being generated in the adhesive layer after drying. Have been described.

In the method for manufacturing a honeycomb structure of Patent Document 2, a plurality of honeycomb fired bodies are combined through an adhesive spacer to form a honeycomb aggregate having a predetermined shape, and then accommodated in the frame mold, A method is disclosed in which a paste used as a peripheral coating material is filled and dried between spaces in a honeycomb fired body and between a honeycomb aggregate and a frame to simultaneously form an adhesive layer and a peripheral coat layer.
Further, in Patent Document 2, in order to prevent the mechanical strength of the outer peripheral coat layer from being lowered, a ventilation portion made of paper, nonwoven fabric or the like is provided inside the frame body, and moisture is unilaterally fired during drying. It moves toward the body and prevents the composition of the outer peripheral coat layer from being biased depending on the location.

International Publication No. 2008/120390 Pamphlet International Publication No. 2011/135683 Pamphlet

However, in the method for manufacturing a honeycomb structure disclosed in Patent Document 1, an adhesive paste containing a foaming agent is used, and the shape of the honeycomb aggregate is maintained when the adhesive paste is dried. There is a problem that it cannot be diverted to another method for manufacturing a honeycomb structure without using a restraining jig. Moreover, since the internal shape of the cylindrical body is constant, there is a problem that a new cylindrical body must be manufactured in order to manufacture a honeycomb structure of another shape.

In the method for manufacturing a honeycomb structure disclosed in Patent Document 2, it takes a predetermined time to dry the adhesive paste layer, but it cannot be released from the frame mold until the drying of the adhesive paste is completed. In mass production, a large number of frame molds are required, and there is a problem that the manufacturing cost increases.

The present invention has been made in view of the above problems, and can be used in various methods for manufacturing a honeycomb structure. Macropores are present in a paste layer used for bonding a honeycomb fired body or forming an outer peripheral coat layer. An object of the present invention is to provide a method for manufacturing a honeycomb structure that can dry the paste layer without being formed, and can efficiently manufacture a honeycomb structure having excellent mechanical characteristics. .

In order to achieve the above object, a first method for manufacturing a honeycomb structure according to the present invention includes firing a plurality of honeycombs including a porous cell partition wall and an outer peripheral wall that define a plurality of cells serving as exhaust gas flow paths. An adhesive paste layer forming step for forming an adhesive paste layer containing an inorganic binder made of sol and at least one of inorganic particles and inorganic fibers between the outer peripheral walls of the body and the plurality of honeycomb fired bodies An adhesive paste layer freezing process for freezing the adhesive paste layer present in the substrate, and drying the adhesive paste layer existing between the plurality of honeycomb fired bodies to form an adhesive paste layer And a drying step.

In the above-described method for manufacturing a honeycomb structure, a freezing treatment is performed before drying the adhesive paste layer formed for bonding the honeycomb fired body. By this freezing treatment, the sol contained in the adhesive paste layer is gelled, and an inorganic substance such as silica contained in the sol forms a three-dimensional structure. The three-dimensional structure does not break. Therefore, moisture is removed and an adhesive layer having high mechanical strength is formed without forming large pore marks (macropores) in the adhesive layer in the drying step. As a result, a honeycomb structure having excellent mechanical characteristics can be manufactured.

In the method for manufacturing a honeycomb structure of the present invention, the outer periphery coating material further includes an inorganic binder composed of at least one of inorganic particles and inorganic fibers and a sol on the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer. The outer periphery coating material paste layer forming step for forming the outer periphery coating material paste layer using the paste, the outer periphery coating material paste layer freezing step for freezing the outer periphery coating material paste layer, and the outer periphery coating material paste layer are dried. It is desirable to include an outer periphery coating material paste layer drying step for forming an outer periphery coating layer.

In the above-described method for manufacturing a honeycomb structure, a freezing treatment is performed before drying the outer peripheral coating material paste layer formed on the outer periphery of the plurality of honeycomb fired bodies. By this freezing treatment, the outer peripheral coat layer having high mechanical strength is formed without forming large pore marks (macropores) in the outer peripheral coat layer as in the adhesive paste described above, and as a result, the mechanical properties are excellent. A honeycomb structure can be manufactured.

In the method for manufacturing a honeycomb structured body of the present invention, a frame mold is disposed around the periphery of the plurality of honeycomb fired bodies, and between the plurality of honeycomb fired bodies and between the honeycomb fired body and the frame mold. In addition, it is desirable that the adhesive paste layer forming step and the outer peripheral coat material paste layer forming step are simultaneously performed by filling the adhesive paste and the outer peripheral coat material paste.

As described in Patent Document 2, a plurality of honeycomb fired bodies are combined through an adhesive spacer to form a honeycomb aggregate having a predetermined shape, which is then housed in a frame mold, and adhesive paste and outer periphery coating By filling the material paste, the number of steps can be reduced. Further, in the method for manufacturing a honeycomb structure of the present invention, since the adhesive paste layer and the outer periphery coating material paste layer are then subjected to a freezing treatment, large pore marks (macropores) are formed in the adhesive material layer and the outer periphery coating material layer. Without being formed, moisture is removed, and an adhesive layer and an outer peripheral coating material layer having high mechanical strength are formed. Also, by filling the outer periphery coating material paste between the plurality of honeycomb fired bodies and the frame mold, after the freezing treatment, the honeycomb structure can be formed in a short time without breaking the shape of the outer periphery coating material paste layer. It can be released from the frame mold. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased.

In the method for manufacturing a honeycomb structured body of the present invention, in the outer peripheral coating material paste layer forming step, a frame mold is disposed around the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer, and the plurality of honeycomb fired bodies and the above-mentioned It is desirable to form the outer periphery coating material paste layer by filling the outer periphery coating material paste with the frame mold.

In the above-described method for manufacturing a honeycomb structure, when the outer peripheral coating material paste was filled between the plurality of honeycomb fired bodies having the adhesive layer and the frame mold, the outer peripheral coating material paste layer was subjected to a freezing treatment. Then, it can release in a short time, without destroying the shape of an outer periphery coating material paste layer. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased.

In the method for manufacturing a honeycomb structured body of the present invention, cutting is performed on the plurality of honeycomb fired bodies having the adhesive layer after the adhesive paste layer drying step and before the outer peripheral coating material paste layer forming step. It is desirable to perform a cutting process to give a predetermined shape.
When the above-described cutting process is added in the method for manufacturing a honeycomb structure, a honeycomb structure having various shapes can be manufactured by cutting, so that the application range in manufacturing the honeycomb structure can be expanded.

According to the second method for manufacturing a honeycomb structure of the present invention, inorganic particles are formed on the outer periphery of a single honeycomb fired body having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths. And an outer peripheral coating material paste layer forming step of forming an outer peripheral coating material paste layer using an outer peripheral coating material paste containing an inorganic binder composed of at least one of inorganic fibers and a sol;
Peripheral coating material paste layer freezing process for subjecting the formed outer peripheral coating material paste layer to a freezing process, and an outer peripheral coating material paste layer for drying the outer peripheral coating material paste layer subjected to the freezing process to form an outer peripheral coating layer And a drying step.

In the method for manufacturing a honeycomb structured body, the outer peripheral coating material paste layer is subjected to a freezing treatment before drying the outer peripheral coating material paste layer formed on the surface of the outer peripheral wall of the honeycomb fired body. By this freezing treatment, the sol contained in the outer periphery coating material paste layer is gelled, and silica or the like contained in the sol forms a three-dimensional structure. The original structure will not break. Therefore, in the outer periphery coating material paste layer drying step, moisture is removed and an outer periphery coating layer having high strength is formed without forming large pore marks (macropores) in the outer periphery coating material paste layer. As a result, a honeycomb structure having excellent mechanical characteristics can be manufactured.

In the second method for manufacturing a honeycomb structured body of the present invention, in the outer peripheral coating material paste layer forming step, a frame mold is disposed around the outer periphery of one honeycomb fired body, and the honeycomb fired body, the frame mold, It is desirable to form the outer periphery coating material paste layer by filling the outer periphery coating material paste during the period.

In the above honeycomb structure manufacturing method, when the outer peripheral coating material paste is filled between one honeycomb fired body and the frame mold, the outer peripheral coating material paste layer is subjected to a freezing treatment, and then the outer peripheral coating material is applied. The mold can be released in a short time without breaking the shape of the material paste layer. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased.

In the method for manufacturing a honeycomb structured body of the present invention, it is desirable to cool to a temperature of −30 to −196 ° C. in the freezing step.
Freezing treatment can be performed by cooling to the above temperature range, and this freezing treatment causes the sol contained in the adhesive paste layer and the outer periphery coating material paste layer to gel, and solid tertiary such as silica contained in the sol An original structure can be formed. Therefore, moisture is removed without forming large pore marks (macropores) in the adhesive paste layer and the outer periphery coating material paste layer in the subsequent drying step, and an adhesive layer and outer periphery coating layer having high strength are formed. The

In the method for manufacturing a honeycomb structured body of the present invention, it is desirable to cool so as to pass through a temperature range of -1 to -5 ° C within 30 seconds.

The temperature range of −1 to −5 ° C. is a temperature range called the maximum ice crystal formation zone, and is a temperature range where the freezing point to 80% of water becomes ice, and ice crystals grow in this temperature range. By passing through this temperature zone as soon as possible, ice crystals do not grow and remain small crystals, so that there is little movement of moisture in the adhesive paste layer and the outer coating material paste layer during freezing.
As a result, in the manufacturing method of the honeycomb structure, moisture is removed without forming large pore traces (macropores) derived from ice crystals in the adhesive layer and the outer peripheral coat layer in the subsequent drying step, and the strength is increased. A high adhesive layer and a peripheral coat layer are formed.

In the method for manufacturing a honeycomb structure of the present invention, it is desirable to perform drying at 100 to 200 ° C. in the adhesive paste layer drying step or the outer peripheral coating material paste layer drying step.
By drying under the above conditions, moisture is firmly scattered from the adhesive paste layer and the outer peripheral coat material paste layer, and an adhesive layer or outer peripheral coat layer having high mechanical strength is formed.

In the method for manufacturing a honeycomb structure of the present invention, the adhesive paste or the outer periphery coating material paste preferably contains an organic binder.
When an organic binder is contained in the adhesive paste or the outer periphery coating material paste, the viscosity of the adhesive paste or the outer periphery coating material paste is improved, and the adhesive paste layer and the outer periphery coating material paste layer can be easily formed. .

Fig.1 (a) is a perspective view which shows typically the honeycomb molded object obtained at the formation process in the manufacturing method of the honeycomb structure of this invention, FIG.1 (b) is shown to Fig.1 (a). It is an AA line sectional view of a honeycomb fabrication object. Fig. 2 (a) is a front view schematically showing an example of the adhesive paste layer forming step and the bonding step in the method for manufacturing a honeycomb structure of the present invention, and Fig. 2 (b) is the bonding step completed. It is a front view which shows the temporary adhesion body in the case typically. FIG. 3 is a front view showing another freezing treatment method in the method for manufacturing a honeycomb structure according to the first embodiment. FIG. 4A is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the ceramic block that has been subjected to the cutting process for the bonded assembly, and FIG. It is sectional drawing perpendicular | vertical to the longitudinal direction of the ceramic block which shows a process and an outer periphery coating material paste layer freezing process process typically. 5 (a), 5 (b), and 5 (c) are perspective views schematically showing an example of a honeycomb fired body manufactured in the second embodiment. Fig. 6 (a) is a perspective view schematically showing another example of the honeycomb structure manufactured in the second embodiment, and Fig. 6 (b) schematically shows the honeycomb fired body constituting the honeycomb structure. FIG. FIG. 7 is a cross-sectional view showing a state in which the honeycomb fired body is arranged inside the frame mold in the second embodiment of the present invention in a cross section perpendicular to the longitudinal direction of the cells. FIG. 8A is a cross-sectional view schematically showing a cross section perpendicular to the longitudinal direction of the frame mold in which the supply device is mounted in the second embodiment of the present invention, and FIG. In 2nd embodiment, it is sectional drawing which shows the cross section parallel to the longitudinal direction of the frame type | mold which mounted | wore with the supply apparatus. FIG. 9A is a cross-sectional view schematically showing a cross section perpendicular to the longitudinal direction of a frame mold filled with paste in the second embodiment of the present invention. FIG.9 (b) is sectional drawing which shows typically the cross section parallel to the longitudinal direction of the frame type | mold filled with the paste in 2nd embodiment of this invention. Fig. 10 (a), Fig. 10 (b), Fig. 10 (c), Fig. 10 (d), Fig. 10 (e) and Fig. 10 (f) are honeycomb structures according to the third embodiment of the present invention. FIG. 6 is a process diagram illustrating a fixing process of a honeycomb fired body in the manufacturing method of FIG. FIG. 11 is a cross-sectional view schematically showing an outer periphery coating material paste layer forming step and an outer periphery coating material paste layer freezing treatment step in the fifth embodiment of the present invention. FIG. 12 is a perspective view showing a honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention. Fig. 13 (a) is a perspective view showing a honeycomb fired body constituting the honeycomb structure shown in Fig. 12, and Fig. 13 (b) is a BB of the honeycomb fired body shown in Fig. 13 (a). It is line sectional drawing. FIG. 14 is a photograph showing the result of observing the outer peripheral coat layer with a scanning electron microscope (SEM) for the honeycomb structure obtained in Example 1. FIG. 15 is a photograph showing the result of observing the outer peripheral coat layer with an SEM of the honeycomb structure obtained in Comparative Example 1.

Hereinafter, the manufacturing method of the honeycomb structure of the present invention will be specifically described. However, the present invention is not limited to the following description, and can be appropriately modified and applied without departing from the scope of the present invention.

The first honeycomb structure manufacturing method of the present invention, between the outer peripheral walls of a plurality of honeycomb fired bodies having a porous cell partition wall and an outer peripheral wall defining a plurality of cells serving as exhaust gas flow paths, An adhesive paste layer forming step of forming an adhesive paste layer including an inorganic binder composed of at least one of inorganic particles and inorganic fibers and a sol; and an adhesive paste layer existing between the plurality of honeycomb fired bodies. It includes an adhesive paste layer freezing process for performing a freezing process, and an adhesive paste layer drying process for drying the adhesive paste layer existing between the plurality of honeycomb fired bodies to form an adhesive layer And

Further, in the second method for manufacturing a honeycomb structure of the present invention, on the outer periphery of one honeycomb fired body having a porous cell partition wall and an outer peripheral wall that partition and form a plurality of cells serving as exhaust gas flow paths, An outer periphery coating material paste layer forming step of forming an outer periphery coating material paste layer using an outer periphery coating material paste containing an inorganic binder composed of at least one of inorganic particles and inorganic fibers and a sol, and the formed outer periphery coating material paste The outer peripheral coating material paste layer freezing step for subjecting the layer to a freezing treatment, and the outer peripheral coating material paste layer drying step for drying the outer peripheral coating material paste layer subjected to the freezing treatment to form an outer peripheral coating layer. Features.

The structure of the honeycomb structure to be manufactured is different between the above-described manufacturing method of the first honeycomb structure and the manufacturing method of the second honeycomb structure. That is, in the honeycomb structure manufactured by the first method for manufacturing a honeycomb structure, a plurality of honeycomb fired bodies are bonded through the adhesive layer and the outer peripheral coat layer is formed on the outer periphery. The honeycomb structure manufactured by this method for manufacturing a honeycomb structure is different in that the outer peripheral coat layer is formed on the outer periphery of one honeycomb fired body.

In addition, since there are several different embodiments in the first honeycomb structure manufacturing method and the second honeycomb structure manufacturing method, the following description will be divided into each embodiment. And

(First embodiment)
Hereinafter, a first embodiment which is an embodiment of a method for manufacturing a first honeycomb structure of the present invention will be described.
The method for manufacturing a honeycomb structure according to the first embodiment is provided on the outer peripheral wall surface of a plurality of honeycomb fired bodies having a porous cell partition wall and an outer peripheral wall that partition and form a plurality of cells serving as exhaust gas flow paths. An adhesive paste layer forming step of forming an adhesive paste layer by applying an adhesive paste containing an inorganic binder composed of at least one of inorganic particles and inorganic fibers and a sol, and via the adhesive paste layer Adhesion process for bonding a plurality of honeycomb fired bodies, an adhesive paste layer freezing process for freezing an adhesive paste layer existing between the plurality of honeycomb fired bodies, and between the plurality of honeycomb fired bodies The adhesive paste layer drying step of drying the adhesive paste layer to form an adhesive layer.

In the first embodiment, further, an outer periphery coating material paste including an inorganic binder composed of at least one of inorganic particles and inorganic fibers and sol is used on the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer, An outer periphery coating material paste layer forming step for forming an outer periphery coating material paste layer, an outer periphery coating material paste layer freezing step for freezing the outer periphery coating material paste layer, and an outer periphery coating layer by drying the outer periphery coating material paste layer. It is desirable to include an outer periphery coating material paste layer drying step.

In the manufacturing process of the honeycomb structure described above, after manufacturing the honeycomb structure including the plurality of honeycomb fired bodies having the adhesive layer, the outer periphery coating is further performed on the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer. Since the material paste layer is often formed as the outer peripheral coat layer, the above-described steps will be described together here. However, the formation of the outer peripheral coat layer is not essential and may be performed as necessary.

In the method for manufacturing a honeycomb structure according to the first embodiment, first, a honeycomb fired body having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths is manufactured.
The honeycomb fired body is obtained through the following (1-1) molded body raw material preparation step, (1-2) molded body preparation step, (1-3) degreasing step, and (1-4) firing step. Below, the manufacturing method of the honeycomb fired body based on the said process is demonstrated.

In the following, a case where the porous ceramic constituting the honeycomb structure to be manufactured is made of silicon carbide will be described as an example. However, the material of the porous ceramic is not limited to silicon carbide. For example, nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, titanium nitride, carbide ceramics such as zirconium carbide, titanium carbide, tantalum carbide, tungsten carbide, alumina, zirconia, cordierite, mullite, aluminum titanate, etc. And oxide ceramics.

(1-1) Molded body raw material preparation step In this molded body raw material preparation step, a raw material composition containing a silicon carbide powder and an organic additive containing at least an organic binder is mixed to prepare a molded body raw material. .

The particle size and the like of the silicon carbide powder are not particularly limited, but it is preferable to use two types of silicon carbide powders having different average particle sizes.

Examples of the organic additive include an organic binder, a dispersion medium liquid, a plasticizer, and a lubricant.
Examples of the organic binder include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, phenol resin, and epoxy resin. Of these, methylcellulose is preferred.

Examples of the dispersion medium liquid include alcohols such as methanol, organic solvents such as benzene, and water. It does not specifically limit as said plasticizer, For example, glycerol etc. are mentioned.

The lubricant is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether. Specific examples of the lubricant include polyoxyethylene monobutyl ether and polyoxypropylene monobutyl ether.

When preparing the raw material for a molded body, the raw material for a molded body is prepared by mixing silicon carbide powder, an organic binder, and water as a dispersion medium liquid using a wet mixer. In that case, you may add the said plasticizer, the said lubricant, etc. as needed.

(1-2) Molded body manufacturing process In this molded body manufacturing process, a honeycomb molded body is manufactured by extruding the prepared raw material for a molded body.
In this process, the raw material for the obtained molded body is put into an extrusion molding machine, extrusion molding is performed using a mold, a prismatic continuous body is produced, and then cut into a predetermined length. A raw honeycomb formed body having a large number of cells arranged in the longitudinal direction is manufactured. The raw honeycomb formed body is dried by a dryer to obtain a dried honeycomb formed body.

Next, a predetermined amount of a plug material paste is filled in any one of the end portions of the cells constituting the dried body of the honeycomb formed body, and the through holes are plugged to obtain a honeycomb formed body. Through such a process, a honeycomb formed body in which one end of the cell is plugged is manufactured.

FIG. 1 (a) is a perspective view schematically showing a honeycomb formed body manufactured in the forming step in the method for manufacturing a honeycomb structure of the present invention, and FIG. 1 (b) is a view shown in FIG. 1 (a). It is AA sectional view taken on the line of the shown honeycomb formed body. In FIG. 1A, a direction indicated by a double arrow A is referred to as a longitudinal direction, a surface in which an opening by a cell is formed is referred to as an end surface, and a surface other than the end surface is referred to as a side surface.
As shown in FIGS. 1A and 1B, the manufactured honeycomb formed body 200 has a large number of cells 201 whose one end is plugged with a sealing portion 202 arranged in parallel in the longitudinal direction. A wall 203 is formed between the cells 201.

(1-3) Degreasing Step Next, as the degreasing step, the produced honeycomb formed body is heated to 300 to 650 ° C. in an oxygen-containing atmosphere to oxidatively decompose and completely remove the organic matter.
In this degreasing process, the produced plurality of honeycomb molded bodies are accommodated in a molded body placing jig having a predetermined shape, and the molded body placing jig in which the honeycomb molded body is accommodated is further placed on the conveying member, A degreasing process is performed by carrying in a degreasing furnace.

(1-4) Firing step In the firing step, the conveying member on which the honeycomb formed body that has been degreased is placed is directly carried into a firing furnace, where the firing treatment is performed at 2000 to 2300 ° C. To do.
The manufactured honeycomb fired body has a basic structure similar to that of the honeycomb formed body 200 shown in FIG. 1, and includes porous cell partition walls and outer peripheral walls that form a plurality of cells that serve as exhaust gas flow paths. I have.

Using the honeycomb fired body obtained as described above, a honeycomb structure is manufactured by the steps described below.

(1-5) Adhesive Paste Layer Forming Step FIG. 2A is a front view schematically showing an example of the adhesive paste layer forming step and the adhering step in the method for manufacturing a honeycomb structure of the present invention. 2 (b) is a front view schematically showing the temporary bonded body when the bonding process is completed.
In this adhesive paste layer forming step, as shown in FIG. 2A, the honeycomb fired body 20 manufactured in the above-described step is placed on a mounting table 31 having a V-shaped concave portion, and the honeycomb fired body 20 is placed. An adhesive paste containing an inorganic binder made of at least one of inorganic particles and inorganic fibers and a sol is applied to the side surface 20a of the substrate 20a to form an adhesive paste layer 11 ′.

Examples of the inorganic particles used for forming the adhesive paste layer 11 ′ include carbide, nitride, and the like. Specifically, inorganic powder or whisker made of silicon carbide, silicon nitride, boron nitride, or the like. Etc. These may be used alone or in combination of two or more. Among the inorganic particles, silicon carbide having excellent thermal conductivity is desirable.

Examples of the inorganic fibers include ceramic fibers made of silica-alumina, mullite, alumina, silica, and the like. These may be used alone or in combination of two or more. Among the inorganic fibers, silica-alumina fiber is desirable.

Examples of the inorganic binder made of sol include alumina sol, silica sol, and titania sol. These may be used alone or in combination of two or more.

The adhesive paste preferably contains an organic binder. Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and the like. These may be used alone or in combination of two or more. Among the organic binders, carboxymethyl cellulose is desirable.

The adhesive paste only needs to contain at least one of inorganic particles and inorganic fibers, but preferably contains both.
Usually, an adhesive paste having a predetermined viscosity is prepared by mixing at least one of inorganic particles and inorganic fibers, an inorganic binder, and an organic binder, which is an optional component, and the adhesive paste is fired into a plurality of honeycombs. It is desirable to form the adhesive paste layer 11 ′ by applying to the surface of the outer peripheral wall of the body.

(1-6) Bonding Step Next, a plurality of honeycomb fired bodies are bonded through the adhesive paste layer 11 ′.
In this bonding step, as shown in FIG. 2 (b), an adhesive paste is applied to the side surface 20a of the honeycomb fired body 20, and another honeycomb fired body 20 is placed thereon, whereby a plurality of honeycomb fired bodies 20 are placed. Are temporarily bonded through the adhesive paste layer 11 ′.

Although not shown, a spacer having a thickness of 0.5 to 2 mm is attached to the side surface 20a of the honeycomb fired body 20 so that the adhesive paste 11 ′ has a thickness of 0.5 to 2 mm. May be. The material of the spacer is not particularly limited, and examples thereof include those made of cardboard, fiber paper, non-woven fabric, or inorganic filled paper.

(1-7) Adhesive Paste Layer Freezing Treatment Step Next, the adhesive paste layer 11 ′ existing between the plurality of honeycomb fired bodies (temporary adhesion aggregate 17) is subjected to a freezing treatment.
This freezing treatment can be performed by bringing the mounting table 31 having the temporary adhesion aggregate 17 into a space (room) where the freezing treatment can be performed and cooling it to a temperature of −30 to −196 ° C. By disposing the wheel on the bottom of the mounting table 31, it can be carried into a space (room) where freezing can be easily performed.
When it is carried into a space (room) where freezing treatment is possible, the temperature of the adhesive paste layer 11 ′ decreases, but the temperature of the adhesive paste layer 11 ′ is in the temperature range of −1 to −5 ° C. for 30 seconds. It is desirable to cool so as to pass within.

By passing through the temperature zone as soon as possible, in the adhesive paste layer 11 ′, ice crystals do not grow and remain small crystals, so that there is little movement of moisture in the adhesive paste layer 11 ′ during freezing. . As a result, water is removed without forming large pore traces (macropores) derived from ice crystals in the adhesive layer in the subsequent drying step, and an adhesive layer having high strength is formed.

FIG. 3 is a front view showing another freezing treatment method in the method for manufacturing a honeycomb structure according to the first embodiment.
In the above-described freezing process, the temporary adhesion assembly 17 is brought into a space (room) where the freezing process can be performed, and the freezing process is performed, but as shown in FIG. In the portion, a refrigerant circulation portion 31a for circulating a liquid refrigerant is formed, and the refrigerant is allowed to flow, and also the liquid refrigerant can be caused to flow inside a side portion that does not contact the mounting table 31 of the temporary adhesive assembly 17. A cooling member 32 that can be bent in a mat shape is installed around the temporary adhesive assembly 17, and the temporary adhesive assembly 17 is made to flow by flowing a coolant through the coolant circulation part 31 a and the cooling member 32. Freezing may be performed.

(1-8) Adhesive paste layer drying step Thereafter, the temporary bonded assembly 17 is brought into a drying device and dried at a temperature of, for example, 100 ° C to 200 ° C, whereby the honeycomb fired body 20 is bonded to the adhesive layer. A bonded assembly bonded through the substrate is prepared.

(1-9) Cutting Step FIG. 4A is a cross-sectional view showing a cross section perpendicular to the longitudinal direction with respect to the ceramic block that has finished the cutting step on the bonded assembly, and FIG. These are sectional drawings perpendicular | vertical to the longitudinal direction of the ceramic block which show an outer periphery coating material paste layer formation process and an outer periphery coating material paste layer freezing process process typically.
In the cutting step, the bonded assembly is cut using a diamond cutter or the like to produce a ceramic block 15 having a cylindrical shape as shown in FIG. The ceramic block 15 is not limited to a columnar shape as long as it is columnar, and may be of an arbitrary shape such as an elliptical columnar shape or a prismatic shape.

(1-10) Outer peripheral coating material paste layer forming step In the outer peripheral coating material paste layer forming step, the outer peripheral coating material includes an inorganic binder made of at least one of inorganic particles and inorganic fibers and sol on the outer periphery of the ceramic block 15. A paste is used to form a peripheral coating material paste layer.
At that time, an outer periphery coating material paste layer may be formed by applying an outer periphery coating material paste to the outer periphery of the ceramic block 15 using an application jig and leveling it to a uniform thickness. ), A cylindrical frame 35 having a slightly larger diameter than the ceramic block 15 is placed around the ceramic block 15, and the ceramic block 15 is placed between the frame 35 and the ceramic block 15. It is desirable to form the outer peripheral coating material paste layer 12 ′ by filling the outer peripheral coating material paste. By disposing a frame mold 35 having a coolant circulation portion 37 capable of circulating a coolant between the inner frame 36 and the outer frame 38 in the outer periphery coat material paste layer 12 ′, the outer periphery coat material paste layer 12 ′. This is because the outer peripheral coating material paste layer freezing treatment step can be performed by immediately flowing the refrigerant through the refrigerant flow part 37 after the formation of the above. The inner frame 36 and the outer frame 38 are made of copper, nickel, stainless steel, or an alloy using at least one of these metals.

In order to prepare the adhesive paste, the inorganic particles, inorganic fibers and inorganic binder used for preparing the outer periphery coating material paste can be the same as those used for preparing the adhesive paste. The used organic binder can also be used. However, the blending ratio and the like may be changed according to required characteristics such as viscosity.

(1-11) Outer peripheral coating material paste layer freezing process step After forming the outer peripheral coating material paste layer 12 ', the outer peripheral coating material paste layer 12' is subjected to a freezing process by causing the refrigerant to flow through the refrigerant circulation part 37 immediately. Can do.

As a result, the sol contained in the outer peripheral coating material paste layer 12 ′ is gelled, and the silica or the like contained in the sol forms a three-dimensional structure. The original structure will not break. Therefore, in the above drying step, moisture is removed and an outer peripheral coat layer having high strength is formed without forming large pore marks (macropores) in the outer peripheral coat material paste layer 12 ′. As a result, a honeycomb structure having excellent mechanical characteristics can be manufactured.

Further, when the above freezing treatment is performed, the outer peripheral coating material paste layer 12 'is frozen, so that the inner frame 36 is removed from the frozen outer peripheral coating material paste layer 12' without breaking the shape of the outer peripheral coating material paste layer 12 '. They can be easily separated and released in a short time. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased.

(1-12) Outer peripheral coating material paste layer drying step The outer peripheral coating material paste layer 12 ′ formed on the outer periphery of the ceramic block 15 is, for example, dried at a temperature of 100 to 200 ° C. to obtain the outer peripheral coating layer 12. The manufacture of the honeycomb structure ends.

(Second embodiment)
Next, a second embodiment which is an embodiment of the method for manufacturing the first honeycomb structure of the present invention will be described.
In the method for manufacturing a honeycomb structure according to the second embodiment, a plurality of honeycomb fired bodies having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths are fixed at predetermined positions. A fixing step for arranging a frame mold around the periphery, a filling step for filling a paste functioning as an adhesive paste and a peripheral coating material paste in the frame mold, a freezing step for freezing the filled paste, and a freezing It includes a drying step of drying and solidifying the treated paste.

In the above honeycomb structure manufacturing method, the adhesive paste layer forming step and the outer periphery coating material paste layer described in the first embodiment can be performed simultaneously, and the adhesive paste layer freezing treatment step and the outer periphery coating material are performed. The paste layer freezing process can be performed simultaneously.

Also in the method for manufacturing a honeycomb structure according to the second embodiment, first, a honeycomb fired body having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths is manufactured.
The honeycomb fired body is obtained through the following (2-1) molded body raw material preparation step, (2-2) molded body preparation step, (2-3) degreasing step, and (2-4) firing step.

In the method for manufacturing a honeycomb structure according to the second embodiment, (2-1) forming body raw material preparation step, (2-3) degreasing step, and (2-4) firing step are the honeycombs according to the first embodiment. This is exactly the same as (1-1) forming body raw material preparation step, (1-3) degreasing step, and (1-4) firing step of the structure manufacturing method. Accordingly, the description of the above process is omitted, but the (2-2) molded body manufacturing step is slightly different from the (1-2) molded body manufacturing process in the honeycomb structure manufacturing method according to the first embodiment. (2-2) The forming body manufacturing process will be described.

(2-2) Formed body manufacturing process FIGS. 5A, 5B, and 5C are perspective views schematically showing an example of a honeycomb fired body manufactured in the second embodiment. It is. 5 (a), 5 (b), and 5 (c), the direction indicated by the double arrow A is referred to as the longitudinal direction, the surface in which the cells are open is referred to as the end surface, and the surface other than the end surface is the side surface. That's it.
In the second embodiment, as the honeycomb fired body, three types of honeycomb fired bodies 40, 50, and 20 having different cross-sectional shapes when the cross section perpendicular to the longitudinal direction of the honeycomb fired body is viewed are manufactured.

The side surface of the honeycomb fired body 40 shown in FIG. 5A is composed of two planes and one curved surface. The honeycomb fired body 40 has a configuration in which a large number of cells 41 are arranged in parallel in the longitudinal direction (the direction of a double-headed arrow A) with the cell partition walls 43 therebetween. In the honeycomb fired body 40, any one end portion of the cell 41 is plugged with a sealing material layer 42.
The side surface of the honeycomb fired body 50 shown in FIG. 5B is composed of three planes and one curved surface. Similarly to the honeycomb fired body 40, the honeycomb fired body 50 has a configuration in which a large number of cells 51 are arranged in parallel in the longitudinal direction (direction of a double-headed arrow A) with a cell partition wall 53 interposed therebetween. In the honeycomb fired body 50, any one end portion of the cell 53 is plugged with the sealing material layer 52.
The side surface of the honeycomb fired body 20 shown in FIG. 5 (c) has the same structure as the honeycomb fired body 20 shown in the first embodiment, and has a quadrangular prism shape constituted by four planes. The honeycomb fired body 20 also has a configuration in which a large number of cells 21 are arranged in parallel in the longitudinal direction (in the direction of the double-headed arrow A) with the cell partition walls 23 therebetween. Further, in the honeycomb fired body 20, any one end portion of the cell 21 is plugged with a sealing material layer 22.

Therefore, in the molded body manufacturing process, the molded body raw material prepared using three types of molds having different shapes so that the above-described honeycomb fired bodies 40, 50, and 20 having three different shapes can be manufactured. A honeycomb formed body is manufactured by extrusion molding.
In the second embodiment, a honeycomb formed body is produced in the same manner as in the first embodiment except that the mold used is different, and (2-3) the degreasing step and the same as in the first embodiment. (2-4) A firing process is performed to manufacture the honeycomb fired bodies 40, 50, and 20 shown in FIGS. 5 (a), 5 (b), and 5 (c). Fig. 6 (a) is a perspective view schematically showing another example of the honeycomb structure manufactured in the second embodiment, and Fig. 6 (b) schematically shows the honeycomb fired body constituting the honeycomb structure. FIG.

In the molded body creation step, two types of molds having different shapes are used so that the honeycomb fired body 20 shown in FIG. 5C and the honeycomb fired body 90 shown in FIG. 6B can be manufactured. You may produce a molded object and may perform the process after the (2-5) fixing process mentioned below similarly. In this case, the honeycomb structure 100 shown in FIG. 6A is manufactured. Reference numeral 91 is a cell, reference numeral 92 is a sealing material layer, and reference numeral 93 is a cell partition.

In the method for manufacturing a honeycomb structured body according to the second embodiment, after manufacturing the honeycomb fired bodies 40, 50, 20, (2-5) fixing step, (2-6) filling step, and (2-7) freezing treatment A honeycomb structure is manufactured through a process and (2-8) a drying process. Hereinafter, the said process is demonstrated.

(2-5) Fixing Step In this fixing step, the obtained three types of honeycomb fired bodies 40, 50, and 20 are assembled and fixed so that the outline thereof is a columnar shape, and a frame (cylindrical) is formed around the periphery. Place the jig). At this time, the bottom and top surfaces of the cylindrical jig are covered so that the sealing material paste does not leak from the frame mold even when the sealing material paste is filled. Further, a lid may be provided on the upper surface or the bottom surface of the jig composed of the cylindrical jig and the bottom or upper plate.
FIG. 7 is a cross-sectional view showing a state in which the honeycomb fired body is arranged inside the frame mold in the second embodiment of the present invention in a cross section perpendicular to the longitudinal direction of the cells.

In the frame mold 60 shown in FIG. 7, a refrigerant circulation portion 62 that can circulate refrigerant between the metal inner frame 61 and the outer frame 63 is provided. The inner frame 61 and the outer frame 63 are formed of copper, nickel, stainless steel, or an alloy using at least one of these metals.
The frame mold 60 has a cylindrical shape in which spaces for arranging the honeycomb fired bodies 40, 50, and 20 are formed. The inner surface of the frame mold 60 may be coated with a fluororesin or the like for the purpose of improving releasability.

As shown in FIG. 7, the frame mold 60 is assembled and fixed via spacers 66 so that the outlines of the plurality of honeycomb fired bodies 40, 50, and 20 have a circular shape. Such an aggregate of cylindrical honeycomb fired bodies 40, 50, and 20 is formed by bonding the honeycomb fired bodies 40, 50, and 20 via spacers 66 each having an adhesive applied thereto. be able to. As shown in FIG. 7, a frame mold 60 is arranged around the aggregate of the cylindrical honeycomb fired bodies 40, 50, 20 bonded and fixed through the spacers 66 formed as described above. . The material, thickness, and the like of the spacer 66 are the same as those of the spacer 66 used in the first embodiment.

(2-6) Filling step In the filling step, the gap 67 between the side surfaces of the honeycomb fired bodies 40, 50, 20 and the cylindrical shape formed by the combination of the frame mold 60 and the honeycomb fired bodies 40, 50, 20 The gap 68 is filled with an adhesive paste and a paste that functions as an outer periphery coating material paste. The paste filling method is not particularly limited, but in the present embodiment, an example in which a paste supply device is attached to the frame mold 60 will be described.

FIG. 8A is a cross-sectional view schematically showing a cross section perpendicular to the longitudinal direction of the frame mold in which the supply device is mounted in the second embodiment of the present invention, and FIG. In 2nd embodiment, it is sectional drawing which shows the cross section parallel to the longitudinal direction of the frame type | mold which mounted | wore with the supply apparatus.

As shown in FIGS. 8A and 8B, the frame mold 60 is provided with a supply device 70 for filling the paste. The supply device 70 includes a paste chamber 71 for containing the paste, and an extrusion mechanism 72 for extruding the paste from the paste chamber 71 into the frame mold 60.
The frame mold 60 is formed with a paste injection port 64 at a connection portion with the supply device 70, and the paste is filled through the injection port 64. In the frame mold 60, a plurality of openings 65 are formed on both end face sides of the honeycomb fired bodies 40, 50, 20.

FIG. 9A is a cross-sectional view schematically showing a cross section perpendicular to the longitudinal direction of a frame mold filled with paste in the second embodiment of the present invention. FIG.9 (b) is sectional drawing which shows typically the cross section parallel to the longitudinal direction of the frame type | mold filled with the paste in 2nd embodiment of this invention.
The paste is supplied to the paste chamber 71 of the supply device 70 shown in FIGS. 9 (a) and 9 (b), and the paste is added by the extrusion mechanism 72 as shown in FIGS. 9 (a) and 9 (b). When pressed, the paste is supplied from the paste chamber 71 into the frame 60 through the injection port 64. As a result, the paste is applied to the gap 67 between the side surfaces of the honeycomb fired bodies 40, 50, and 20 of the frame mold 60 and the gap 68 between the frame mold 60 and the column formed by the combination of the honeycomb fired bodies 40, 50, and 20. Filled to form an adhesive paste layer 45 'and an outer periphery coating material paste layer 46'. The paste supply device may be installed on the end face side of the honeycomb fired body and filled from the end face direction to form the adhesive paste layer 45 ′ and the outer peripheral coating material paste layer 46 ′.

The paste used in this embodiment is made of the same material as the adhesive paste used in the first embodiment, but has a reduced viscosity compared to the adhesive paste used in the first embodiment. Also good. It is for making the said filling process advance favorably.

(2-7) Freezing treatment step In this freezing treatment step, the refrigerant is caused to flow through the refrigerant circulation portion 62 of the frame mold 60 and cooled to a temperature of -30 to -196 ° C.
When the coolant is passed through the coolant circulation part 62 of the frame 60, the temperature of the adhesive paste layer 45 ′ and the outer coating material paste layer 46 ′ decreases, but the adhesive paste layer 45 ′ and the outer coating material paste layer 46 are decreased. It is desirable that the temperature of 'is cooled so as to pass through the temperature range of -1 to -5 ° C within 30 seconds.

By passing through the temperature zone as soon as possible, in the adhesive paste layer 45 ′ and the outer peripheral coating material paste layer 46 ′, ice crystals do not grow and remain small crystals. There is little movement of moisture in 'and the outer periphery coating material paste layer 46'. As a result, the adhesive layer and the outer peripheral coat layer have a high strength without the formation of large pore traces (macropores) derived from ice crystals in the adhesive layer and the outer peripheral coat layer in the subsequent drying step. It is formed.

Moreover, since the outer periphery coating material paste layer freezes when the freezing treatment is performed, the outer periphery coating material paste layer can be released in a short time without breaking the shape of the outer periphery coating material paste layer. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased. In this embodiment, the cutting process can be omitted.

(2-8) Drying step The honeycomb fired bodies 40, 50, and 20 having the adhesive paste layer 45 ′ and the outer periphery coating material paste layer 46 ′ are dried at, for example, a temperature of 100 ° C. to 200 ° C. Layer and outer peripheral coat layer to complete the manufacture of the honeycomb structure

(Third embodiment)
Next, a third embodiment which is an embodiment of the method for manufacturing the first honeycomb structure of the present invention will be described.
In the second embodiment described above, the honeycomb fired bodies 40, 50, and 20 having different shapes are used and combined through spacers 66 each having an adhesive layer formed on both sides to form a cylindrical shape. In the embodiment, in the (3-5) fixing step, a fixing method for fixing both ends of the honeycomb fired body 110 from above and below is used. (3-1) Molded body raw material preparation process, (3-2) Molded body preparation process, (3-3) Degreasing process, and (3-4) Firing process, which are processes prior to this fixing process, It carries out similarly to embodiment.

(3-5) Fixing process FIGS. 10 (a), 10 (b), 10 (c), 10 (d), 10 (e) and 10 (f) are the third views of the present invention. FIG. 3 is a process diagram for explaining a fixing process of a honeycomb fired body in the method for manufacturing a honeycomb structure according to the embodiment. The above process diagram is a cross-sectional view schematically showing a cross section perpendicular to the longitudinal direction of the honeycomb fired body with respect to the arrangement of the honeycomb fired body. The frame mold is configured in the same manner as the frame mold 60 used in the second embodiment.

When the honeycomb fired bodies 40, 50, and 20 are arranged, the honeycomb fired bodies 40, 50, and 20 having appropriate shapes are arranged so that the outline forms a circle.
First, in FIG. 10A, two honeycomb fired bodies 40 and two honeycomb fired bodies 50 are arranged so that the honeycomb fired bodies 50 are sandwiched between the honeycomb fired bodies 40. A certain interval is provided between the honeycomb fired body 40 and the honeycomb fired body 50 so that the sealing material paste can be filled in a subsequent process.
The honeycomb fired bodies 40 and 50 are transported and arranged using, for example, a robot arm or a transport member having a placement surface on which four honeycomb fired bodies can be placed at a time.

Next, as shown in FIG. 10B, both end faces of the honeycomb fired bodies 40 and 50 are fixed by fixing pins 75 that support and fix the honeycomb fired bodies 40 and 50 from above and below. The fixing pin 75 supports and fixes the honeycomb fired bodies 40 and 50 so that the end faces of the honeycomb fired bodies 40 and 50 are aligned on the same plane.

Next, as shown in FIG. 10C, the two honeycomb fired bodies 50 and the two honeycomb fired bodies 20 are arranged so that the honeycomb fired bodies 20 are sandwiched between the honeycomb fired bodies 50. In the same manner as described above, both end faces of the honeycomb fired bodies 50 and 20 are fixed with fixing pins 75.

Next, as shown in FIG. 10 (d), the two honeycomb fired bodies 50 and the two honeycomb fired bodies 20 are arranged in the same manner as described above and fixed by the fixing pins 75. Further, as shown in FIG. 10 (e), the two honeycomb fired bodies 40 and the two honeycomb fired bodies 50 are arranged in the same manner as described above and fixed by the fixing pins 75. Thereby, the outline of the aggregate of the honeycomb fired bodies 40, 50, and 20 becomes a cylindrical shape.

In this way, the 16 honeycomb fired bodies 40, 50, and 20 constituting the honeycomb structure can be arranged so as to be parallel to the length direction and have the same plane on both end faces.
Thereafter, as shown in FIG. 10 (f), the frame mold 60 is arranged around the aggregate of the honeycomb fired bodies 40, 50, 20.

The (3-6) filling step, the (3-7) freezing treatment step, and the (3-8) drying step after the above steps may be performed in the same manner as in the second embodiment.
In the third embodiment, the same effect as in the second embodiment can be obtained.

(Fourth embodiment)
Next, a fourth embodiment, which is an embodiment of the first method for manufacturing a honeycomb structure of the present invention, will be described.
In the second embodiment and the third embodiment, the honeycomb fired bodies 40, 50, and 20 having different shapes are combined to produce an aggregate having a cylindrical shape and disposed inside the frame shape. In the fourth embodiment, only the rectangular pillar-shaped honeycomb fired bodies 20 are used, and the honeycomb fired bodies 20 having the three types shown in the second embodiment are manufactured by cutting the honeycomb fired bodies 20. In addition, the honeycomb fired body uses the same method as that of the first embodiment, and (4-1) a molded body raw material preparation step, (4-2) a molded body manufacturing step, (4-3) a degreasing step, and (4 -4) It can manufacture by performing a baking process.

Thereafter, as in the third embodiment, (4-5) fixing step, (4-6) filling step, (4-7) freezing treatment step, and (4-8) drying step may be performed.
The obtained honeycomb structure is different from the second embodiment or the third embodiment because the plurality of honeycomb fired bodies 20 are subjected to cutting, and thus cells are cut on the cut surfaces. As a result, the outer periphery is exposed as a recess (groove), and the exposed recess is filled with paste by the filling process. Therefore, in the filling step, the portion including the concave portion becomes the outer peripheral coating material paste layer, and after drying, the portion including the concave portion becomes the outer peripheral coating layer.

In the fourth embodiment, in contrast to the effects of the invention in the second embodiment and the third embodiment, it is necessary to perform a cutting process, but conversely, a plurality of molds are used, and a honeycomb molded body having a plurality of shapes is formed. There is an advantage that it is not necessary to manufacture the device. In addition, since the outer peripheral coat layer bites into the recess, it is firmly fixed to the honeycomb fired body by the anchor effect, and peeling or the like hardly occurs.
In addition, the fourth embodiment can provide the same effects as those of the second embodiment.

In addition, although the process of bonding 16 honeycomb fired bodies is described from the first embodiment to the fourth embodiment, the number of honeycomb fired bodies constituting the honeycomb structure is equal to the number of the above-described embodiments. It is not limited and may be more or less than 16.

(Fifth embodiment)
Next, a fifth embodiment which is an embodiment of a method for manufacturing a second honeycomb structure of the present invention will be described.
The method for manufacturing a honeycomb structured body according to the fifth embodiment includes inorganic particles on the outer periphery of one honeycomb fired body having a porous cell partition wall and an outer peripheral wall that partition and form a plurality of cells serving as exhaust gas flow paths. And an outer periphery coating material paste layer forming step for forming an outer periphery coating material paste layer using an outer periphery coating material paste containing an inorganic binder composed of at least one of inorganic fibers and a sol, and the formed outer periphery coating material paste layer The outer periphery coating material paste layer freezing treatment step for performing the freezing treatment, and the outer periphery coating material paste layer drying step for drying the outer periphery coating material paste layer subjected to the freezing treatment to form an outer periphery coating layer, To do.

In the method for manufacturing a honeycomb structured body according to the fifth embodiment, first, a honeycomb fired body having a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths is manufactured.
As in the case of the first embodiment, the honeycomb fired body includes (5-1) a molded body raw material preparation step, (5-2) a molded body manufacturing step, (5-3) a degreasing step, and (5-4). Obtained through a firing step. Since the above process is substantially the same as in the first embodiment, detailed description thereof is omitted here, but the shape of the honeycomb fired body to be formed may be a columnar shape, an elliptical columnar shape, etc. in addition to a prismatic shape. Good.

Thereafter, (5-5) outer periphery coating material paste layer forming step, (5-6) outer periphery coating material paste layer freezing treatment step, and (5-7) outer periphery coating material paste layer drying step are performed. Manufacture the body.

(5-5) Outer peripheral coating material paste layer forming step In the outer peripheral coating material paste layer forming step, the outer periphery of one honeycomb fired body includes an inorganic binder composed of at least one of inorganic particles and inorganic fibers and sol. An outer periphery coating material paste layer is formed using the outer periphery coating material paste.
FIG. 11 is a cross-sectional view schematically showing an outer periphery coating material paste layer forming step and an outer periphery coating material paste layer freezing treatment step in the fifth embodiment of the present invention.
In the outer periphery coating material paste layer forming step, the outer periphery coating material paste is applied to the outer periphery of one honeycomb fired body using a coating jig, and the outer periphery coating material paste layer is formed by equalizing to a uniform thickness. However, as shown in FIG. 11, a cylindrical frame 60 having a slightly larger diameter than the honeycomb fired body 80 surrounding the honeycomb fired body 80 is placed around the cylindrical honeycomb fired body 80. It is desirable to form the outer periphery coating material paste layer 82 ′ by filling the outer periphery coating material paste between the frame mold 60 and the honeycomb fired body 80. By providing the coolant circulation part 62 capable of circulating the coolant between the inner frame 61 and the outer frame 63 of the frame mold 60, the outer periphery coating material paste layer freezing process is performed immediately after the outer periphery coating material paste layer 82 'is formed. It is because a process can be performed.

The inorganic particles, inorganic fibers, and inorganic binder used for preparing the outer periphery coating material paste can be the same as those used for preparing the adhesive paste in the first embodiment. The organic binder used for preparing the paste can also be used. However, the blending ratio and the like may be changed according to required characteristics such as viscosity.

(5-6) Peripheral coating material paste layer freezing treatment step Immediately after the formation of the outer peripheral coating material paste layer 82 ', the outer peripheral coating material paste layer 82' is subjected to a freezing treatment by allowing the refrigerant to pass through the refrigerant circulation part 62. Can do.

As a result, the sol contained in the outer peripheral coating material paste layer 82 ′ is gelled, and silica or the like contained in the sol forms a three-dimensional structure. The original structure will not break. Therefore, in the drying step, moisture is removed and a high-periphery outer coat layer is formed without forming large pore marks (macropores) in the outer coat material paste layer 82 '. As a result, a honeycomb structure having excellent mechanical characteristics can be manufactured.

Moreover, since the outer periphery coating material paste layer 82 ′ is frozen when the above freezing treatment is performed, the outer periphery coating material paste layer 82 ′ can be released in a short time without breaking the shape of the outer periphery coating material paste layer 82 ′. Therefore, even in mass production, a honeycomb structure can be manufactured without producing a large number of frame molds, and the production efficiency of the honeycomb structure can be increased.

(5-7) Outer peripheral coat material paste layer drying step The outer peripheral coat material paste layer 82 'formed on the outer periphery of the honeycomb fired body 80 is dried at, for example, a temperature of 100 ° C to 200 ° C to This completes the manufacture of the honeycomb structure.

(Honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention)
FIG. 12 is a perspective view showing a honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention, and FIG. 13 (a) shows a honeycomb fired body constituting the honeycomb structure shown in FIG. FIG. 13B is a cross-sectional view of the honeycomb fired body shown in FIG. 13A, taken along line BB.

In the honeycomb structure 10 manufactured by the method for manufacturing a honeycomb structure of the present invention, a plurality of honeycomb fired bodies 20 shown in FIG. 13 (a) are bundled through the adhesive layer 11 to form a ceramic block 15, Further, an outer peripheral coat layer 12 is formed on the outer periphery of the ceramic block 15.
In FIG. 12, only the outline of the honeycomb fired body 20 is shown, but the honeycomb fired body 20 constituting the honeycomb structure 10 has a large number of cells 21 arranged in the longitudinal direction as shown in FIG. 13 (b). A cell partition wall 23 that separates the cells 21 and functions as a filter.

That is, in the cell 21 formed in the honeycomb fired body 20, as shown in FIG. 13B, either the inlet side or the outlet side end of the exhaust gas is plugged by the sealing material layer 22, The exhaust gas that has flowed into the cell 21 passes through the cell partition wall 23 separating the cells 21 and then flows out from the other cells 21. When the exhaust gas passes through the cell partition wall 23, the particulates are converted into the cell partition wall 23. It is collected in the part and the exhaust gas is purified.

Since the macropores are not formed in the adhesive layer 11 and the outer peripheral coat layer 12 constituting the honeycomb structure 10 and only small pores are formed, the regeneration process for burning PM deposited inside the honeycomb structure 10 In such a case, even if the temperature of the honeycomb structure 10 rapidly increases, cracks are hardly formed in the adhesive layer 11 and the outer peripheral coat layer 12, and the honeycomb structure has excellent durability. Note that the honeycomb structure 10 shown in FIG. 12 is a honeycomb structure corresponding to the honeycomb structure manufactured according to the first embodiment, but the honeycomb structures manufactured according to other embodiments also have the same effect. .

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

Example 1
(Preparation of honeycomb molded body)
A silicon carbide coarse powder of 52.8% by weight having an average particle diameter of 22 μm and a silicon carbide fine powder of 22.6% by weight having an average particle diameter of 0.5 μm were mixed. Acrylic resin 2.1% by weight, organic binder (methylcellulose) 4.6% by weight, lubricant (Unilube made by NOF Corporation) 2.8% by weight, glycerin 1.3% by weight, and the resulting mixture Then, 13.8% by weight of water was added and kneaded to obtain a mixed composition. Extrusion molding was performed using this mixed composition, and a raw honeycomb molded body having the same shape as the honeycomb fired body 20 shown in FIG.

(Preparation of honeycomb fired body)
The raw honeycomb molded body was dried using a microwave dryer to obtain a dried honeycomb molded body. A paste having the same composition as that of the mixed composition was plugged into a predetermined cell of the dried body of the honeycomb formed body. And the drying process was performed using the hot air dryer.

The dried honeycomb formed body was degreased at 400 ° C. and fired under conditions of 2200 ° C. and 3 hours under an atmospheric pressure of argon atmosphere, thereby manufacturing a honeycomb fired body 20 having a shape shown in FIG. The obtained honeycomb fired body 20 has a porosity of 45%, an average pore diameter of 15 μm, a number of cells (cell density) of 300 pieces / inch ² , and a cell partition wall thickness of 0.25 mm (10 mil). A honeycomb fired body made of a silicon carbide sintered body.

In this example, the same method as in the fourth embodiment was used. That is, using the honeycomb fired bodies 20 manufactured by the above steps, each honeycomb fired body 20 is cut into the honeycomb fired bodies 20 using a diamond cutter or the like, and FIGS. A honeycomb fired body having the same shape as that shown in c) was produced. Thereafter, using fixed pins that support both end surfaces of the honeycomb fired body from above and below, the honeycomb fired bodies are arranged vertically and 4 horizontally, and the one shown in FIG. A supply device 70 for filling the paste was mounted around the body assembly, and a frame mold (tubular jig) 60 was disposed.
Thereafter, the inside of the frame mold 60 was filled with the supply device 70 to form an adhesive paste layer and an outer periphery coating material paste layer.

The paste includes 30% by weight of alumina fibers having an average fiber length of 20 μm, 21% by weight of silicon carbide particles having an average particle diameter of 0.6 μm, 15% by weight of silica sol (solid content of 30% by weight), 5.6% by weight of carboxymethyl cellulose, And the paste containing 28.4 weight% of water was used.
Thereafter, the refrigerant was passed through the refrigerant circulation part 62 of the frame 60 and liquid nitrogen was circulated, and after freezing at −196 ° C., the frame was released immediately. In this case, no peeling or the like occurred and a uniform thickness was maintained.

Thereafter, the plurality of honeycomb fired bodies on which the adhesive paste layer and the outer periphery coating material paste layer are formed are heat-treated at 120 ° C., and the adhesive paste layer and the outer periphery coating material paste layer are dried. Layered. Thereby, a cylindrical honeycomb structure (see FIG. 12) was obtained.

FIG. 14 is a photograph showing the result of observing the outer peripheral coat layer with a scanning electron microscope (SEM) for the honeycomb structure obtained in Example 1.
As shown in FIG. 14, no large pore traces (macropores) were observed in the outer peripheral coat layer, and the pore size was 0.05 mm or less. Similarly, the pore size of the adhesive layer was 0.05 mm or less.

(Example 2)
A refrigerant whose temperature is adjusted by immersing dry ice in isopropyl alcohol is used as a refrigerant, and a plurality of honeycomb fired bodies in which the adhesive paste layer and the outer peripheral coating material paste layer are formed by the above filling process are frozen at −30 ° C. A honeycomb structure was manufactured in the same manner as in Example 1 except for the treatment.
When the adhesive layer and the outer peripheral coat layer of the obtained honeycomb structure were observed by SEM, the pore size was 0.05 mm or less.

(Comparative Example 1)
The plurality of honeycomb fired bodies on which the adhesive paste layer and the outer periphery coating material paste layer are formed by the above filling process are heat-treated at 120 ° C. A honeycomb structure was manufactured in the same manner as in Example 1 except that it was dried to form an adhesive layer and an outer peripheral coat layer.

FIG. 15 is a photograph showing the result of observing the outer peripheral coat layer with an SEM of the honeycomb structure obtained in Comparative Example 1.
As shown in FIG. 15, large pore traces (macropores) were observed in the outer peripheral coat layer, and the size of the macropores was 1.0 mm or more.

DESCRIPTION OF SYMBOLS 10 Honeycomb structure 11 Adhesive material layer 11 ', 45' Adhesive paste layer 12 Outer periphery coating layer 12 ', 46', 82 'Outer periphery coating material paste layer 15 Ceramic block 17 Temporary adhesion aggregate 20, 40, 50, 80 Honeycomb Firing body 20a Side surface 21, 41, 51 Cell 22, 42, 52 Sealing material layer 23, 43, 53 Cell partition wall 31 Mounting table 31a, 37, 62 Refrigerant flow part 32 Cooling member 35, 60 Frame mold 36, 61 Inner frame 38, 63 Outer frame 64 Inlet 65 Opening portion 66 Spacer 67, 68 Gap 70 Supply device 71 Paste chamber 72 Extrusion mechanism 75 Fixed pin 200 Honeycomb molded body 201 Cell 202 Sealing portion 203 Wall portion

Claims (11)

Between the outer peripheral wall of a plurality of honeycomb fired bodies having a porous cell partition wall and an outer peripheral wall defining a plurality of cells serving as exhaust gas flow paths, at least one of inorganic particles and inorganic fibers, and sol An adhesive paste layer forming step of forming an adhesive paste layer containing an inorganic binder,
An adhesive paste layer freezing process for freezing the adhesive paste layer present between the plurality of honeycomb fired bodies;
A method for manufacturing a honeycomb structure, comprising: drying an adhesive paste layer existing between the plurality of honeycomb fired bodies to dry the adhesive paste layer as an adhesive layer. Further, an outer periphery coating material paste layer including an inorganic binder made of at least one of inorganic particles and inorganic fibers and a sol is formed on the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer. An outer periphery coating material paste layer forming step,
The outer periphery coating material paste layer freezing process step which freezes the outer periphery coating material paste layer, and the outer periphery coating material paste layer drying step which dries the outer periphery coating material paste layer into the outer periphery coating layer. Method for manufacturing the honeycomb structure. A frame mold is disposed around the periphery of the plurality of honeycomb fired bodies, and an adhesive paste and an outer periphery coating material paste are disposed between the plurality of honeycomb fired bodies and between the honeycomb fired body and the frame mold. The method for manufacturing a honeycomb structured body according to claim 2, wherein the adhesive paste layer forming step and the outer peripheral coating material paste layer forming step are simultaneously performed by filling. In the outer periphery coating material paste layer forming step, a frame mold is disposed around the outer periphery of the plurality of honeycomb fired bodies having the adhesive layer, and the outer periphery coating material paste is disposed between the plurality of honeycomb fired bodies and the frame mold. The method for manufacturing a honeycomb structured body according to claim 2, wherein the outer peripheral coating material paste layer is formed by filling the material. After the adhesive paste layer drying step, and before the outer peripheral coating material paste layer forming step, a cutting step is performed to cut a plurality of honeycomb fired bodies having the adhesive layer into a predetermined shape. The method for manufacturing a honeycomb structured body according to claim 2 or 3. An inorganic substance composed of at least one of inorganic particles and inorganic fibers, and a sol on the outer periphery of one honeycomb fired body provided with a porous cell partition wall and an outer peripheral wall for partitioning a plurality of cells serving as exhaust gas flow paths An outer periphery coating material paste layer forming step of forming an outer periphery coating material paste layer using an outer periphery coating material paste containing a binder,
Peripheral coating material paste layer freezing treatment step for freezing the formed outer peripheral coating material paste layer,
A method for manufacturing a honeycomb structure, comprising: drying the outer periphery coating material paste layer that has been subjected to the freezing treatment to form an outer periphery coating material paste layer drying step. In the outer periphery coating material paste layer forming step, by arranging a frame mold around the outer periphery of one honeycomb fired body, and filling the outer periphery coating material paste between the honeycomb fired body and the frame mold, The method for manufacturing a honeycomb structured body according to claim 6, wherein an outer peripheral coating material paste layer is formed. The method for manufacturing a honeycomb structured body according to any one of claims 1 to 7, wherein in the freezing step, the temperature is cooled to a temperature of -30 to -196 ° C. The method for manufacturing a honeycomb structured body according to claim 8, wherein in the freezing treatment step, cooling is performed so as to pass through a temperature range of -1 to -5 ° C within 30 seconds. The method for manufacturing a honeycomb structure according to any one of claims 1 to 9, wherein drying is performed at 100 to 200 ° C in the adhesive paste layer drying step or the outer peripheral coating material paste layer drying step. The method for manufacturing a honeycomb structure according to any one of claims 1 to 10, wherein the adhesive paste or the outer periphery coating material paste includes an organic binder.