KR20140028705A - Method for producing ceramic honeycomb structure - Google Patents

Abstract

The present invention relates to a method for producing a ceramic honeycomb structure used as a purification apparatus of automobile exhaust gas and a filter for preventing industrial contamination and, more particularly, to a method for producing a ceramic honeycomb structure including a plurality of cells divided by separating walls and forming a flowing way of a fluid by using a ceramic segment molding in which a plurality of combustible cores is buried therein. [Reference numerals] (S10) Raw soil manufacturing process; (S20) Molding process; (S30) Joining process; (S40) Joining process; (S50) Coating process; (S60) Baking process

Description

METHOD FOR PRODUCING CERAMIC HONEYCOMB STRUCTURE [0002]

The present invention relates to a method for manufacturing a ceramic honeycomb structure used as an apparatus for purifying automobile exhaust gas and a filter for preventing industrial pollution, and more particularly, a partition wall using a ceramic segment molded body having a plurality of combustible cores embedded therein. The present invention relates to a method for manufacturing a ceramic honeycomb structure having a plurality of cells which are divided by and constitute a fluid flow path.

[National R & D Project Supporting the Invention]

Assignment number: 2010201010109C-22-1-000

Department name: Ministry of Knowledge Economy

Research Project: Greenhouse Gas Treatment Technology Development Project

Title: Simultaneous reduction catalyst and process development of N2O / NOx with stationary source by using single reducing agent

Organized by: Korea Institute of Energy Research

Project leader: Moon Seung-hyun

Research period: 2010.10.01-2012.09.30

In general, honeycomb structures are formed in a honeycomb or lattice shape and are used in various technical fields. Since the honeycomb structure has a large effective area in the same volume and a large area in contact with harmful gas or wastewater and waste oil, the honeycomb structure has a high structural strength because it has a high purification efficiency and a structurally stable truss structure.

Such a honeycomb structural body is mainly made of a metal material and a ceramic material, and a honeycomb structural body made of a metal is mainly made of aluminum or a thin steel plate to form a honeycomb structure by welding or mechanical joining . A honeycomb structural body made of a metal material may be formed by a corrugated sheet composed of several layers or a metal support composed of a corrugated sheet and a flat sheet and a casing surrounded by the metal support and joined to the metal support by welding or the like, And is used in a purification apparatus, particularly an exhaust gas purification apparatus for a vehicle engine.

The honeycomb structure formed from the ceramic material is used as a catalyst carrier in the catalytic converter of the exhaust part of the internal combustion engine, and also used in a radiator filter, a fine filter of a diesel engine, a molten metal filter, a wood combustor substrate and a heat exchanger.

In the manufacture of honeycomb structures using ceramic materials, aluminum oxide, zirconium, and cordierite are mainly used to form honeycomb structures through an extrusion process by an extruder. Ceramics or ceramics are easy to mold, have excellent heat resistance, and are porous, thus having a surface area larger than that of a honeycomb structure of a metal material.

The ceramic honeycomb structure is composed of a honeycomb structure having a split structure that has a function of dispersing and mitigating thermal stress by integrally joining a plurality of honeycomb segments with a bonding layer in order to improve thermal shock resistance against thermal stress. That is, the ceramic honeycomb structure of the divided structure has a shape each of which constitutes a part of the entire structure, and a plurality of ceramic honeycomb segments each having a shape that constitutes the entire structure by being assembled in a direction perpendicular to the central axis are provided. The ceramic honeycomb segment joined body is molded so that the entire cross-sectional shape integrally joined by the bonding layer and cut in a plane perpendicular to the central axis becomes a predetermined shape such as a circle, and then the outer peripheral surface is covered with a coating material. It is a structure.

The process of manufacturing the ceramic honeycomb structure includes a process of making a ceramic honeycomb segment and a process of making a ceramic honeycomb structure by joining a plurality of ceramic honeycomb segments.

First, the process of making a ceramic honeycomb segment comprises kneading a molding raw material including a ceramic raw material and a processing aid to obtain clay, and molding a ceramic honeycomb segment molded body having a plurality of cells separated by a partition wall using an extruder. And a step of drying the ceramic segment molded body and firing the dried ceramic segment molded body to obtain a ceramic honeycomb segment having a plurality of cells.

The process of making a ceramic honeycomb structure includes manufacturing a ceramic honeycomb segment according to the method described above, and then applying a paste-like binder (sealing material) to an outer circumferential surface of the ceramic honeycomb segment, and assembling a plurality of ceramic honeycomb segments. After pressing in the assembled state, heat drying is performed to obtain a ceramic honeycomb structure.

That is, the method for manufacturing a ceramic honeycomb structure according to the prior art is made of a honeycomb segment molded body having a cell or a cell having a desired shape through an extrusion process by a complicated extruder. That is, conventionally, the ceramic paste is put into a chamber of an extruder and passed through a die for extrusion to be extruded into a honeycomb shape, and then manufactured by cutting after drying. The dried ceramic compact is made of a ceramic honeycomb structure through a sintering process of imparting mechanical and thermal strength to the structure using thermal energy.

The present invention has been made to solve the problems of the prior art, and a main object of the present invention is to provide a method for producing a ceramic honeycomb structure, which can produce a ceramic honeycomb structure without using an extrusion mold having a complicated structure.

In addition, the present invention is to provide a method for producing a ceramic honeycomb structure that can improve the thermal shock resistance to thermal stress by strengthening the bonding between the plurality of ceramic segment molded body constituting the ceramic honeycomb structure.

In addition, the present invention is to provide a method for producing a ceramic honeycomb structure in which a separate catalyst coating process can be omitted by forming a catalyst layer on the partition wall of the cell in the process of molding and firing the ceramic segment molded body.

Method for producing a ceramic honeycomb structure according to the present invention as a means for achieving the above object of the present invention,

A clay preparation process of kneading a molding raw material including a ceramic raw material and a processing aid to obtain clay;

A molding step of molding the clay made of the molding material into a ceramic segment molded body and embedding a plurality of combustible shims in the ceramic segment molded body;

An assembling process of applying an adhesive to an outer circumferential surface of the ceramic segment molded body and assembling a plurality of ceramic segment molded bodies in a direction perpendicular to a central axis to obtain a ceramic segment assembly;

A bonding step of injecting a bonding material into the gap between the ceramic segment molded bodies constituting the ceramic segment assembly and then heating and drying to obtain a ceramic segment bonded body;

A coating step of forming a coating layer on the outer circumferential surface of the ceramic segment joined body with a constant thickness and heating and drying to obtain a ceramic segment structure;

And baking the ceramic segment structure by heating and burning a plurality of combustible shims embedded in the ceramic segment structure to form a ceramic honeycomb structure having a plurality of cells.

In the present invention, the flammable core is a thread of a predetermined length having a cross-sectional shape of a circle, a square, an ellipse, and maintains a fiber state at or below the firing temperature of the ceramic segment structure, and burns at a firing temperature or higher of the ceramic segment structure to obtain a powder. It is characterized by a state change.

The firing process is characterized in that a plurality of cells partitioned by a plurality of partitions are formed in the place where the combustible shim was formed by firing the ceramic segment structure and burning and removing the combustible shim.

A catalyst coating layer including at least one precious metal selected from Pt, Pd and Rh or at least one general metal selected from Fe and Cu is formed on an outer circumferential surface of the combustible shim, and the catalyst coating layer formed on the combustible shim is formed in the forming process. It is characterized in that the transfer to the inside of the ceramic segment molded body, and fixed to the partition wall in the firing step to form a catalyst layer.

According to the manufacturing method of the ceramic honeycomb structure of the present invention, since a complicated extrusion molding machine is not used, it is possible to easily manufacture a ceramic honeycomb structure having various sizes and shapes.

In addition, the present invention has the effect that a separate wash coating (catalyst coating) process can be omitted by forming a catalyst layer on the partition wall when molding and firing the ceramic formed body.

1 is a perspective view showing an example of a ceramic honeycomb structure according to the present invention,
2 is a perspective view showing an example of a ceramic honeycomb molded body according to the present invention;
3 is a perspective view showing an example of a ceramic segment structure according to the present invention;
4 is a perspective view showing an example of a ceramic segment molded body according to the present invention;
5 is an explanatory diagram showing a process of manufacturing a ceramic honeycomb structure according to the present invention;
6 is a flow chart showing a manufacturing process of a ceramic honeycomb structure according to the present invention;
7 is a structural diagram showing an example of an extrusion molding machine suitably applied to a molding process according to the present invention;
8 is a perspective view showing an example of an assembly table that is suitably applied to an assembly process according to the present invention;
9 is a perspective view showing a ceramic segment assembly according to the present invention;
10 is an explanatory view showing an example of a bonding method applied to the bonding process according to the present invention,
11 is a perspective view showing a ceramic segment assembly according to the present invention,
12 is an explanatory diagram showing an example of a kiln suitably applied to a firing process according to the present invention;
13 is a perspective view showing an example of a flammable shim in which a catalyst film layer is formed according to the present invention;
14 is a cross-sectional view showing a ceramic segment molded body in which a catalyst film layer of a flammable shim is transferred according to the present invention;
15 is an enlarged view illustrating a ceramic honeycomb structure in which a catalyst layer is formed on a partition wall according to the present invention.

Hereinafter, a method of manufacturing a ceramic honeycomb structure according to the present invention will be described in detail with reference to the accompanying drawings.

First, an example of the ceramic honeycomb structure 10 according to the present invention is shown in FIG. As shown, the ceramic honeycomb structure 10 of the present invention is an aggregate of a plurality of ceramic honeycomb segments 20. That is, the ceramic honeycomb structure 10 of the present invention is composed of a plurality of ceramic honeycomb segments 20 stacked in a direction perpendicular to the central axis.

As shown in FIG. 2, the ceramic honeycomb segment 20 has an outer circumferential surface 21, and one side end surface 23 and the other end surface 25 formed on the opposite side so as to correspond to the one end surface 23. Has And a plurality of cells 3 disposed inside the outer circumferential surface 21 and penetrating in the axial direction. The cell 3 consists of a partition 24 arranged inside the ceramic honeycomb segment 20 and a fluid passage 26 partitioned by the partition 24. In addition, the cross-sectional shape of the ceramic honeycomb segment 20 may be circular, elliptical, triangular, square, or other shapes, but is preferably circular.

As shown in FIG. 1, the ceramic honeycomb structure 10 again has an outer circumferential surface 11, one end portion 13, and the other end portion 15 formed opposite to the one end portion 13. Has A plurality of ceramic honeycomb segments 20 are integrally bonded to each other via the bonding layer 4 interposed between the ceramic honeycomb segments 20. In addition, the outer circumferential surface 11 of the ceramic honeycomb structure 10 is formed with a coating layer 6 having a constant thickness. In addition, a plurality of cells 3 serving as fluid passages are formed in the ceramic honeycomb structure 10 in parallel with each other in the direction of the central axis. The ceramic honeycomb structure 10 may have a circular cross section, an ellipse, a triangle, a square, and other shapes cut in a plane perpendicular to the central axis, but preferably rectangular.

3 shows an example of the ceramic segment structure 10a according to the present invention. As shown, the ceramic segment structure 01a of the present invention is an aggregate of a plurality of ceramic segment molded bodies 20a. That is, the ceramic segment structure 01a of the present invention is formed by stacking a plurality of ceramic segment molded bodies 20a in a direction perpendicular to the central axis.

As shown in FIG. 4, the ceramic segment molded body 20a is similar to the ceramic honeycomb segment 20, and has a plurality of inner circumferential surfaces 21 and a plurality of inner circumferential surfaces 21 and penetrating in the axial direction. It consists of a flammable shim 31. The flammable shim 31 is embedded inside the ceramic segment molded body 20a. The cross-sectional shape of the ceramic segment molded body 20a may be circular, elliptical, triangular, square, or other shapes, but is preferably circular.

Referring back to FIG. 3, the ceramic segment structure 10a is similar to the ceramic honeycomb structure 10, and the plurality of ceramic segment molded bodies 20a are formed through the bonding layer 4 interposed between the ceramic segment formed bodies 20a. ) Is integrally bonded. In addition, the ceramic segment structure 10a has a coating layer 6 formed at a constant thickness. In addition, a plurality of combustible shims 31 are embedded in parallel in the direction of the central axis. The ceramic segment structure 10a may have a circular cross section, an ellipse, a triangle, a square, and other shapes cut in a plane perpendicular to the central axis, but preferably rectangular.

The core of the manufacturing method of the ceramic honeycomb structure 10 according to the present invention is to sinter the ceramic segment structure 10a to the ceramic honeycomb structure 10. To this end, the present invention comprises the steps of forming a ceramic segment molded body 20a, assembling and bonding the ceramic segment molded body 20a to obtain a ceramic segment structure 10a, and heating the ceramic segment structure 10a. By firing and burning the combustible shim 31 embedded therein to form the cell 3 in its place.

That is, in the conventional method of manufacturing a ceramic honeycomb structure, the ceramic honeycomb structure 10 is obtained by stacking the ceramic honeycomb segments 20, while the method of manufacturing a ceramic honeycomb structure according to the present invention is stacking the ceramic segment molded body 20a. The ceramic honeycomb structure 10 is obtained by forming the ceramic segment structure 10a and then firing the same, and burning and removing the combustible shim 31 embedded therein.

In other words, the present invention does not manufacture the ceramic honeycomb segment 20 in which the cell 3 is formed, but forms the ceramic segment molded body 20a in which the combustible shim 31 is embedded. In addition, instead of manufacturing the ceramic honeycomb structure 10 by laminating the ceramic honeycomb segments 20, the ceramic segment molded body 20a in which the combustible shim 31 is embedded is laminated to form the ceramic segment structure 10a. By combusting the combustible shim 31 embedded in the ceramic segment structure 10a, a ceramic honeycomb structure 10 in which a plurality of cells 3 penetrate in the longitudinal direction in place thereof is manufactured.

As a method for producing a ceramic honeycomb structure according to the prior art, a method of extrusion molding mainly using extrusion molding having a shape complementary to a desired honeycomb structure (cell shape, partition thickness, cell density, etc.) has been mainly used. However, the conventional method for manufacturing a ceramic honeycomb structure requires a high production technology and a high production cost by using a complicated extrusion mold during extrusion. In addition, the mold wears out during the extrusion process, and the life of the mold is shortened. Due to the difficulty in manufacturing the extrusion mold, the shape of the cell is limited to squares, triangles, hexagons, and the like. There is a problem such as falling. However, the production method according to the present invention does not form a cell 3 during the extrusion process, so that a mold having a complicated structure is not required.

Hereinafter, a method for manufacturing a ceramic honeycomb structure according to the present invention will be described in more detail. Figure 5 is a schematic view showing the manufacturing process of the ceramic honeycomb structure according to the present invention, Figure 6 is a flow chart showing a manufacturing method of the ceramic honeycomb structure of the present invention.

First, as shown in FIG. 5, the method for manufacturing a ceramic honeycomb structure according to the present invention includes forming a ceramic segment molded body 20a and assembling the ceramic segment molded body 20a to form a ceramic segment assembly ( Step (b) of obtaining 10c), step (c) of obtaining a ceramic segment joined body 10b by forming a bonding layer 4 on the ceramic segment assembly 10c, and an outer peripheral surface of the ceramic segment joined body 10b. (D) forming the coating layer 6 to obtain the ceramic segment structure 10a, and firing the ceramic segment structure 10a to obtain the ceramic honeycomb structure 10.

Referring back to FIG. 6, in the method of manufacturing the ceramic honeycomb structure 10 according to the present invention, a process of kneading a molding raw material including a ceramic raw material and a processing aid to obtain clay (hereinafter, referred to as a clay preparation process) ( S10), and using the clay made of the molding material to form a ceramic segment molded body (20a), and embedding a plurality of combustible shim 31 in the ceramic segment molded body (20a) to form a segment molded body (20a) An adhesive is applied to the obtained step (hereinafter referred to as a molding step) (S20) and the outer circumferential surface of the plurality of ceramic segment molded bodies 20a in which the combustible shim 31 is embedded and assembled in a direction perpendicular to the central axis. Bonding material is injected between the process of obtaining the ceramic segment assembly 10c (hereinafter, referred to as an assembling process) (S30) and the ceramic segment molded body 20b of the ceramic segment assembly 10c. Process of obtaining the cement bonded body 10b (hereinafter joining process) (S40) and the process of obtaining the ceramic segment structure 10a by forming the coating layer 6 to the outer peripheral surface of the said ceramic segment bonded body 10b to a fixed thickness ( Hereinafter, the coating process S50 and the ceramic segment structure 10a are fired, and a plurality of combustible shims 31 embedded in the ceramic segment structure 10a are burned to burn the plurality of cells 3. It consists of the process (henceforth a baking process) S60 which forms the ceramic honeycomb structure 10 which has it.

In the manufacturing method of the ceramic honeycomb structure 10 according to the present invention, the clay preparation step (S10) is a step of kneading a molding raw material containing a ceramic raw material to obtain clay. The ceramic raw material is not particularly limited as long as it is a ceramic which can form a certain shape by firing or a material of which a certain shape ceramics by firing, for example, a corderite-forming raw material, mullite, zeolite, alumina, aluminum titanate, lithium aluminum One or two or more materials selected from the group consisting of silicates, spinels, silicon carbide, metal silicon, silicon nitride, and the like can be used.

From the viewpoint of thermal shock resistance, it is preferable to use a cordelite raw material as a main component. Here, the cordelite forming raw material means a raw material capable of forming cordelite by itself and / or firing, and the raw material capable of forming cordelite by firing is 42 to 56 mass% of SiO _2, refers to include, for example talc, kaolin, presintering kaolin, alumina, aluminum hydroxide, silica, to provide a chemical composition of 30 to 45% by weight of Al ₂ O _3, 12~16% by weight MgO in a predetermined ratio. In addition, the main component means 50 mass% or more, preferably 70 mass% or more, and more preferably 80 mass% or more of the ceramic raw material.

From the viewpoint of heat resistance, it is preferable to use silicon carbide or silicon carbide and metal silicon as main components. In the case where the ceramic raw material is mainly composed of silicon metal (Si) and silicon carbide (SiC), if the Si content defined by Si / (Si + SiC) is too small, the effect of Si addition is difficult to obtain and 50 mass% It is difficult to obtain the effect of heat resistance and high thermal conductivity, which is characteristic of SiC. The Si content is preferably 5 to 50 mass%, more preferably 10 to 40 mass%.

In addition to the aggregate particles and water, the clay may contain other additives such as an organic binder, a dispersant, an inorganic binder, and the like as necessary. The organic binder is an additive which functions as a reinforcing agent in the form of a gel in the formed body (clay) before baking and maintains the mechanical strength of the formed body. For example, as an organic binder, the organic polymer which can gelatinize in a molded object (soil), for example, hydroxypropyl methyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, etc. can be used suitably. Can be.

The dispersant is an additive for promoting dispersion of the aggregate particles in water, which is a dispersion medium of the aggregate particles. As the dispersing agent, for example, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. The inorganic binder is an additive for reinforcing the bonding between the aggregate particles, and at least one selected from the group consisting of alumina, silica, zirconia, titania, glass frit, feldspar, cordierite having an average particle diameter of 10 탆 or less can be used have. The inorganic binder is preferably added in an amount of 10 to 35 parts by mass based on 100 parts by mass of the aggregate particles. If the amount is less than 10 parts by mass, the strength of the base material is lowered. If the amount exceeds 35 parts by mass, the strength is improved. However, since the inorganic binder remains in the gap of the aggregate particles, Which is undesirable.

In addition, the clay may include a pore-forming agent. A pore forming agent forms a ceramic porous body, and can manufacture a porous ceramic body excellent in dimensional precision using starch or the mixture of starch and foamed resin which completed foaming. That is, 1 to 30 parts by weight of powdered starch, a binder and water are mixed and kneaded with 100 parts by weight of a ceramic raw material which becomes cordierite by firing, followed by extrusion molding and drying and firing to obtain a cordierite ceramic honeycomb structural body . At this time, there is no particular limitation on the amount of the starch to be added, but if it is excessively large, the amount of heat generated by combustion of the starch in the firing step becomes too large to cause cracks in the porous ceramic body, which is not preferable. On the other hand, if the amount of the starch added is too small, it is difficult to obtain sufficient effect of pore action, which is not preferable. The amount of the starch to be added is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass, per 100 parts by mass of the ceramic raw material.

In addition, the above-mentioned molding material, aggregate particles, water, organic binder, and the like can be mixed with a vacuum grinder or the like and kneaded to prepare a clay having a suitable viscosity. There is no restriction | limiting in particular in the method of kneading the said molding raw material, A kneading machine, such as a general kneader, a pressure kneading machine, a single screw continuous extruder, a twin screw continuous kneading extruder, and a vacuum refining machine, can be used. Although clay can be prepared by kneading the molding raw material with such a kneader, when kneading kneaded with a kneader that does not involve a vacuum process, such as a general kneader or a pressure kneader, is again performed using a vacuum grinder or the like, air bubbles are formed in the clay. It is possible to prepare a little or no soil cover, and the plasticity is improved, which is preferable.

Subsequently, the ceramic clay prepared by the above method forms the ceramic segment molded body 20a in the molding step S20. At this time, a plurality of flammable shims 31 are embedded in the ceramic segment molded body 20a. In the molding process S20 of the present invention, a plurality of combustible shims 31 are embedded without forming the cells 3 inside the ceramic segment molded body 20a.

 7 shows an example of an extruder 40 that can be suitably used in the method of manufacturing a ceramic honeycomb structure according to the present invention. The extruder 40 may mold the ceramic segment molded body 20a and simultaneously embed a plurality of flammable shims 31 in the ceramic segment molded body 20a. As shown, the extruder 40 includes a molding part 42 for forming a ceramic segment molded body 20a by injecting and pressing ceramic clay largely, and a ceramic segment formed through the molding part 42. It is comprised by the embedding part 46 for embedding the several flammable shim 31 in the inside of the molded object 20a.

More specifically, the forming part 42 is a screw conveyor (44) for pressing the topsoil to insert the topsoil and the conveyed forwards and a screw conveyor (44) is installed at the tip of the screw conveyors (44) And the extrusion mold 45 for forming the ceramic segment molded body 20a of a predetermined shape by passing through the clay pressurized by 44). The configuration of the molding section 42 is similar to that of a conventional extrusion machine. However, since the extrusion molding machine 40 of the present invention does not form a plurality of cells 3 inside the ceramic segment molded body 20a, the structure is simpler than that of a conventional extrusion mold. In addition, since the extrusion die 45 has a large through hole, extrusion is easily performed, and no clay remains in the molding machine after extrusion.

Subsequently, the buried portion 46 is installed at the rear of the forming portion 42 to supply the combustible shim 31, and is supplied from the supply reel 47, and the screw conveyor 44 is extruded. It consists of the drawing part 48 which pulls the combustible shim 31 which penetrates the metal mold 45 by a constant pressure. The drawing portion 48 pulls the combustible shim 31 forward at a forming speed of the ceramic segment molded body 20a so that the combustible shim 31 penetrating the screw conveyor 44 and the extrusion mold 45 has a constant tension. To keep them aligned at regular intervals. In the present specification, the drawing unit 48 is installed to pull the flammable shim 31, but if necessary, the drawing unit 48 may be omitted or the plurality of flammable shims 31 may be maintained in parallel in another way. It is possible.

Therefore, the clay injected into the inlet 43 of the extruder 40 is transported forward by the screw conveyor 43, and the clay pressurized at a constant pressure passes through the extrusion mold 45 to form a ceramic segment molded body having a predetermined shape ( 20a). And the combustible shim 31 supplied through the screw conveyor 44 and the extrusion die 45 is embedded in the said ceramic segment molding 20a.

In addition, the ceramic segment molded body 20a formed in the extrusion mold 45 is transferred forward through a plurality of rollers 49 installed in front of the extrusion mold 45. And the ceramic segment molded body (20a) made in the extruder 40 can be cut to a certain length. At this time, the cutter for cutting the ceramic segment molded body 20a is composed of an upper blade and a lower blade to facilitate the cutting of the flammable shim 31.

On the other hand, the flammable shim 31 extends from one end surface 23 of the ceramic segment molded body 20a to the other end surface 26 and penetrates through it. The combustible shim 31 maintains a fiber state below the firing temperature of the ceramic segment molded body 20a, and burns above the firing temperature of the ceramic segment molded body 20a to be changed into a powder state and removed. The flammable shim 31 maintains the fiber state in the process of molding or drying the ceramic segment molded body 20a, and burns and removes the ceramic segment molded body 20a when it is heated to a firing temperature of 1000 ° C or higher.

Preferably, the combustible shim 31 is a yarn made by twisting synthetic fibers such as natural fibers such as cotton, hemp, silk, wool, nylon, polyester, spandex, lycra, acrylic, polyvinyl chloride, and olefin in the longitudinal direction. Is done. The flammable shim 31 is manufactured in a compressed state to maintain its shape during extrusion. In addition, the flammable shim 31 may be a wire made by extruding a mixture of organic and inorganic particles and an adhesive material combusting at or below the firing temperature of the ceramic formed body.

The thickness and the number of the combustible shims 31 are determined according to the size and number of the cells 3 to be formed in the ceramic segment molded body 20a. The thickness of the partition wall 24 and the diameter of the flow path 26 of the ceramic honeycomb structure 10 are not particularly limited. However, if the partition wall is too thick, the pressure loss when the fluid to pass through the porous partition wall increases, and the partition wall If the thickness is too thin, the strength is insufficient, which is not preferable. Preferably the thickness of the barrier rib is in the range of 30 to 2000 mu m, more preferably 40 to 1000 mu m, most preferably 50 to 500 mu m. The cell density (the number of the through holes per unit end surface area) is not particularly limited. However, if the cell density is too small, the strength and the effective GSA (geometrical surface area) as honeycomb structural bodies are insufficient. If the cell density is too large, The pressure loss when the processing fluid flows becomes large. The cell density is preferably 6 to 2000 cells / square inch (0.9 to 311 cells / cm2), more preferably 50 to 1000 cells / square inch (7.8 to 155 cells / cm2), most preferably 100 to 400 cells / Square inch (15.5 to 62.0 cells / cm < 2 >). The cross-sectional shape of the cell is not particularly limited, but from the viewpoint of production, it is preferable to use any one of triangular, rectangular, hexagonal, and corrugated shapes.

The ceramic segment molded body 20a is dried to remove moisture, a liquid medium, and the like contained therein. The drying method is not particularly limited, and generally, hot air drying, microwave drying, dielectric drying, vacuum drying, vacuum drying and the like can be carried out. Among them, hot air drying and hot air drying It is preferable to carry out drying in a drying step in which microwave drying or dielectric drying is combined. The drying temperature of hot air drying is preferably in the range of 80 to 150 占 폚 in that it can be dried quickly. The drying method can also be applied to the assembling step (S30), the bonding step (S40), and the coating step (S50) described later.

Meanwhile, in the present specification, a method of embedding the flammable shim 31 by using an extrusion molding machine has been described. However, the ceramic segment molded body 20a according to the present invention may be manufactured using injection molding in addition to extrusion molding. Note that the molding process (S20) is not limited to extrusion.

Subsequently, the plurality of ceramic segment molded bodies 20a obtained in the forming process S20 are assembled to form a ceramic honeycomb structure 10. The assembly step (S30) is made by applying an adhesive composition in the form of a paste or slurry to the outer peripheral surface of the ceramic segment molded body 20a, laminating the ceramic segment molded body 20a coated with the adhesive, and then heating and drying. At this time, the said adhesive composition is the same as the bonding layer composition mentioned later. The plurality of ceramic segment molded bodies 20a are stacked in a direction perpendicular to the central axis thereof. In this case, as shown in FIG. 8, the ceramic segment assembly 10c may be easily assembled using the assembly table 70 in which the two inclined plates 71 and 72 are perpendicular to each other. In the drawing, the ceramic segment molded bodies 20a stacked up and down are arranged in a row, but the ceramic segment molded bodies 20a stacked up and down may be arranged to be offset from each other.

Subsequently, the ceramic segment assembly 10c obtained in the assembly step S30 obtains the ceramic segment assembly 10b through the joining step S50. The bonding step (S50) is performed by filling the bonding material in the gap between the ceramic segment molded body (20a) constituting the ceramic segment assembly (10c) and then heating and drying. To this end, masking films 60 may be attached to both end surfaces of the ceramic segment assembly 10c. As shown in FIG. 9, a plurality of through holes 61 are formed in the masking film 60 so as to correspond to a gap T between neighboring ceramic segment molded bodies 20a.

Therefore, as shown in FIG. 10, the ceramic segment assembly 10c to which the masking film 60 is attached is precipitated in the bonding material container 70 filled with the bonding material in the slurry state. Then, the bonding material is filled in the gap T between the adjacent ceramic segment molded bodies 20a through the through holes 61 of the masking film 60. The ceramic segment assembly 10c filled with the bonding material is heated and dried to obtain a ceramic segment assembly 10b in which a plurality of ceramic segment molded bodies 20a are integrally bonded. In the present specification, the masking film 60 is used to prevent the bonding material from being adhered to both end surfaces 23 and 25 of the ceramic segment assembly 10c. However, the masking film 60 is not used to the both end surfaces 23 and 25. It is also possible to carry out the twisting of the attached bonding material and to remove it.

In the ceramic segment bonded body 10c obtained in the bonding step S50, the coating layer 6 is formed on the outer circumferential surface thereof at a constant thickness through the coating step S50 to obtain the ceramic segment structure 10a as shown in FIG. In other words, the outer circumferential surface of the ceramic segment joined body 10c is not smooth. Therefore, the coating material is applied to the outer circumferential surface of the ceramic segment joined body 10c at a constant thickness and dried by heating to form a coating layer 6 having a constant thickness. As a material of the said coating material, the thing similar to a bonding material can be used. The thickness of the coating layer 6 is suitably selected, for example in the range of 0.1 mm-1.5 mm.

 Finally, the ceramic segment structure 10a having the coating layer 6 formed thereon is heated and baked at or above the firing temperature in the firing step S60 and at the same time burns the combustible shim 31 embedded in the ceramic segment molded body 20a. To form a ceramic honeycomb structure 10 having a plurality of cells 3. That is, in the sintering process S60, the ceramic segment structure 10a is heated to burn and remove the flammable shim 31 embedded therein so that the cell 3 is formed in place.

Firing is an operation for sintering and densifying aggregate particles in a ceramic segment molded body to secure a predetermined strength. The firing conditions (temperature and time) may be suitably selected depending on the kind of the aggregate particles to be used. For example, when silicon carbide is used as the aggregate particles, it is preferable to perform calcination at a temperature of 1300 to 2300 캜 for about 1 to 5 hours. The firing temperature and firing atmosphere of the ceramic dried body 40 vary depending on the ceramic raw material, and those skilled in the art can select an appropriate firing temperature and firing atmosphere for the selected ceramic raw material.

For example, an oxide-based material such as a cordierite-forming raw material, mullite, etc. is preferably fired in an atmospheric environment. In the case of a cordelite-forming raw material, firing is preferably performed at a temperature of 1400 to 1440 ° C. Further, it is preferable that the non-oxide material such as silicon carbide, silicon nitride and the like is fired in a non-oxidizing atmosphere such as nitrogen or argon. When the silicon carbide is bonded to the metal silicon, it is preferable to sinter at 1400 to 1800 ° C. When silicon carbide is bonded with silicon nitride or the like, it is preferable to carry out sintering at a temperature of 1550 to 1800 ° C. When the silicon carbide particles are bonded to each other by the recrystallization method, it is necessary to perform calcination at a temperature of at least 1800 占 폚 or more. Further, in order to produce silicon nitride by firing the metal silicon in a nitrogen atmosphere, it is preferable to perform firing at a temperature of 1200 to 1600 캜.

On the other hand, before firing or in the process of raising the temperature of the firing, a calcination step of burning and removing the combustible shim 31 in the honeycomb molded body can be further performed. The calcination process is preferable in that the removal of the flammable shim 31 can be facilitated. For example, the ceramic segment molded body 20a may be heated at a temperature below a firing temperature for a predetermined time to remove the volatile component or pyrolyze the flammable shim 31. Usually, what is necessary is just to calcination temperature about 200-1000 degreeC. Although calcination time is not specifically limited, Usually, it is about 1 to 10 hours.

As such, the combustible shim 31 is burned and removed in the firing process S60 according to the present invention. As shown in FIG. 12, the combustible shim 31 embedded in the ceramic segment bonding body 10a ignites and becomes powdery above the baking temperature of the ceramic molded object 20, and becomes under the porous plate 81 by gravity. Is removed. In the place where the combustible shim 31 was, a cell 3 corresponding to the shape of the combustible shim 31 is formed.

Further, in the firing step (S60), a porous ceramic body is formed while the pore-forming agent made of starch or a mixture of starch and a foamed resin which has finished foaming is burned. The ceramic honeycomb structure produced by the present invention has pores in the ceramic body. The porosity and the pore diameter are not particularly limited, and appropriate pore diameter and porosity can be selected according to the application.

Subsequently, when the ceramic honeycomb structure produced according to the present invention is to be used as a catalyst carrier for purifying exhaust gas in a combustion apparatus such as a heat engine or a boiler such as an internal combustion engine, or reforming a liquid fuel or a gaseous fuel, the ceramic honeycomb structure A catalyst layer 18 having a catalyst, such as catalytic capacity, is formed on the wall 14 of (10). In the conventional method of forming the catalyst layer, the catalyst layer may be formed by washing the catalyst slurry on the porous ceramic body, drying and baking the same. Typical examples of the metal having a catalytic ability include noble metals such as Pt, Pd, and Rh, and general metals such as Fe and Cu, and those containing at least one of them are preferable. In addition, the catalyst layer may be composed of a first separated lower layer and a second separated overlapping layer superimposed on the lower layer. In addition, the catalyst layer includes ceramics or ceramics constituting the ceramic segment molded body 20a.

That is, in the manufacturing method of the ceramic honeycomb structure according to the present invention, the catalyst layer can be integrally formed on the partition wall 14 of the cell 3 formed in the firing step (S60). To this end, in the present invention, as shown in FIG. 13, the catalyst film layer 38 is coated with a constant thickness on the outer circumferential surface of the combustible shim 31 embedded in the ceramic segment molded body 20a. For example, the tip of the extruder 40 is provided with a catalyst supply tank 90 in which a catalyst in a slurry state containing precious metals and / or common metals and ceramics is stored. Accordingly, the catalyst film layer 38 is formed on the outer circumferential surface of the combustible shim 31 supplied from the supply reel 47 while passing through the catalyst supply cylinder 90. The flammable shim 31 coated with the catalyst film layer 38 passes through the screw conveyor 44 and the extrusion mold 45 to be embedded in the ceramic segment molded body 20a.

At this time, the catalyst coating layer 38 coated on the outer circumferential surface of the combustible core 31 is transferred to the ceramic segment molded body 20a by the pressure applied in the extrusion molding process to transfer the catalyst coating layer 28. Form. The ceramic coating layer 28 transferred to the ceramic segment molded body 20a is sintered and fixed to the partition 14 of the cell 3 as shown in FIG. 15 in the subsequent firing process S60. . As described above, the present invention forms the cell 3 using the combustible shim 31 and simultaneously forms the catalyst layer 18 in the partition 14 of the cell 3. Therefore, the present invention can omit a separate catalyst coating process.

As described above, in the method of manufacturing the ceramic honeycomb structure according to the present invention, in the process of forming the ceramic segment molded body 20a, the combustible shim 31 is embedded in the ceramic segment molded body 20a, and the ceramic segment molded body ( In the process of firing 20a, the flammable shim 31 is burned and removed to form a plurality of cells 3 forming a fluid flow path inside the ceramic segment molded body 20a.

The manufacturing method of the ceramic honeycomb structure according to the present invention can reduce the extrusion cost by using a complicated and expensive extrusion mold, and can be suitable for the production of small quantities of various kinds because it can produce ceramic honeycomb structures of various sizes and shapes. In addition, the diameter and the number of the cells 3 can be changed by changing the diameter and the number of the flammable shims 31 embedded in the ceramic formed body 20a. Further, in the present invention, the bonding layer 4 is formed between the ceramic segment bodies 20a, and the coating layer 6 is formed on the outer circumferential surface to strongly improve the thermal shock resistance as a structure. Especially, the ceramic honeycomb structure excellent in thermal shock resistance can be provided by realizing the molded object excellent stress relaxation function and joining strength for integrally joining many ceramic segment molded objects 20a.

In addition, when the ceramic honeycomb structure manufactured according to the present invention is used for a filter such as a diesel particulate filter (hereinafter referred to as DPF), the opening is formed at one side end surface 13 for a predetermined cell in the cell 3. The remaining cells 3 are sealed at the other end surface 15 of the opening. In such a configuration, when used as a ceramic honeycomb structure filter, the fluid to be processed flows into, for example, the cell 3 opened at one end 13, passes through the porous partition 14, and the other end ( 15 is discharged from the cell 3 opened in this case, and the partition 14 may be a filter to secure a large filtration area. Such cell sealing can be performed by masking the flow hole which did not seal a cell, providing the raw material used for cell sealing in the slurry form to the opening end surface of a ceramic honeycomb structure, and baking after drying.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It is to be understood that both the technical idea and the technical spirit of the invention are included in the scope of the present invention.

3: cell 4: adhesive layer
6: coating layer 10: ceramic honeycomb structure
10a: ceramic segment structure 10b: ceramic segment assembly
10c: ceramic segment assembly 11: outer peripheral surface
13, 15: end face 14: partition wall
18: catalyst layer 20: ceramic honeycomb segment
20a: ceramic segment molded body 21: outer peripheral surface
23, 25: end face 24: partition wall
26: fluid passage 31: flammable seam
38 catalyst layer 40 extruder
42: molding portion 43: inlet
44: screw conveyor 45: extrusion mold
46: buried portion 47: supply reel
48: drawing section 49: roller
50: assembly table 60: masking film
61: through hole 70: bonding cylinder
80: kiln 81: porous plate
90: catalyst feed container

Claims (4)

A clay preparation process of kneading a molding raw material including a ceramic raw material and a processing aid to obtain clay;
A molding step of molding the clay made of the molding material into a ceramic segment molded body and embedding a plurality of combustible shims in the ceramic segment molded body;
An assembling process of applying an adhesive to an outer circumferential surface of the ceramic segment molded body and assembling a plurality of ceramic segment molded bodies in a direction perpendicular to a central axis to obtain a ceramic segment assembly;
A bonding step of injecting a bonding material into the gap between the ceramic segment molded bodies constituting the ceramic segment assembly and then heating and drying to obtain a ceramic segment bonded body;
A coating step of forming a coating layer on the outer circumferential surface of the ceramic segment joined body with a constant thickness and heating and drying to obtain a ceramic segment structure;
And a firing step of heating and firing the ceramic segment structure and burning a plurality of combustible shims embedded in the ceramic segment structure to form a ceramic honeycomb structure having a plurality of cells. Method for producing a structure.
The method of claim 1,
The flammable core is a thread having a predetermined length having a cross-sectional shape of a circle, a square, and an oval, and maintains a fiber state at or below the firing temperature of the ceramic segment structure, and burns above the firing temperature of the ceramic segment structure to change to a powder state. The manufacturing method of the ceramic honeycomb structure made into.
3. The method of claim 2,
The firing step is a method of manufacturing a ceramic honeycomb structure, characterized in that by firing the ceramic segment structure and by burning and removing the combustible shim is formed a plurality of cells partitioned by a plurality of partitions in the place where the combustible shim.
The method of claim 3,
A catalyst coating layer including at least one precious metal selected from Pt, Pd and Rh or at least one general metal selected from Fe and Cu is formed on an outer circumferential surface of the combustible shim, and the catalyst coating layer formed on the combustible shim is formed in the forming process. A method of manufacturing a ceramic honeycomb structure, characterized in that the transfer to the inside of the ceramic segment molded body and fixed to the partition wall in the firing step to form a catalyst layer.

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