JP2009114039A - Method for producing honeycomb segment joined body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a honeycomb segment joined body which prevents the phenomenon that variation is caused in the structure of each joining material layer between a plurality of honeycomb segments integrally joined, so as to deteriorate strength properties. <P>SOLUTION: Honeycomb segments 10 formed by a conductive ceramic, each having a plurality of cells partitioned by bulkheads and passing through to an axial direction are laminated via joining materials, and a higher voltage is applied to the honeycomb segment 10 located at the inside of the honeycomb segment 10 than those located at the outermost circumference of the honeycomb segment 10 among the plurality of laminated honeycomb segments 10. By flowing electric current from either edge face in the axial direction of each honeycomb segment 10 to the other edge face, the honeycomb segments 10 generate heat, thus the joining materials are dried, so as to adhesively fix and join the honeycomb segments 10 to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a joined honeycomb segment in which a plurality of honeycomb segments are integrally joined by a joining material layer.

  In order to improve the environment and prevent pollution, honeycomb structures are frequently used as collection filters for exhaust gas. At present, for example, SiC DPF (Diesel Particulate Filter) is used to bond a base material (honeycomb segment) divided to prevent cracking due to thermal shock by, for example, hot air drying, microwave drying, natural drying, etc. (Ceramic cement) is dried and integrated (see, for example, Patent Document 1), but the bonding material layer structure after drying varies depending on the bonding location, and the characteristics also vary. There was a problem that cracks occurred at low locations.

JP 2000-7455 A

  In general, in a bonded body, it is ideal that the bonding material is dried in the same manner at each bonding point. However, when bonding a plurality of base materials (honeycomb segments) with a bonding material, the outer bonding material is dried first. Then, the bonding material inside solidifies, and the drying method differs between the bonding material outside the bonded body and the bonding material inside, and the drying shrinkage and hardening behavior of the bonding material is different between the outside and the inside. It will be different. The outer bonding material that dries and solidifies first is solidified while the base material moves relatively homogeneously as the bonding material shrinks and cures, so there is little variation in the structure of the bonding material layer, and its characteristics also vary. small. On the other hand, in the internal bonding material, the movement of the honeycomb segments accompanying the drying shrinkage and curing of the bonding material is not uniform, so that the method of forming the bonding material layer varies and the characteristics also vary.

  For example, it hardens while moving in such a direction that the bonding interval of the honeycomb segments becomes smaller as the bonding material shrinks in some places, and one side of the honeycomb segment is already hardened in the other places, which is commensurate with the shrinkage of the bonding material. The structure of the bonding material layer varies due to curing without being able to move as much as possible, or on the contrary, the bonding interval moves, and the characteristics of the bonding material also vary.

  It is an object of the present invention to provide a method for manufacturing a joined honeycomb segment that prevents the structure of a bonding material layer between a plurality of integrally joined honeycomb segments from being varied to reduce strength characteristics. .

  In order to solve the above-mentioned problems, it has been found that, by energizing the honeycomb segments and thereby drying the bonding material, the bonding material can be dried uniformly and the strength characteristics can be prevented from being lowered. That is, according to the present invention, the following method for manufacturing a joined honeycomb segment is provided.

[1] A honeycomb segment formed of conductive ceramics having a plurality of cells partitioned by partition walls and penetrating in the axial direction is laminated through a bonding material, and the bonding material is dried by energizing the honeycomb segment. A method for manufacturing a joined honeycomb segment, in which the honeycomb segments are firmly fixed and joined together.

[2] The method for manufacturing a joined honeycomb segment according to [1], wherein a higher voltage is applied to the honeycomb segment positioned on the inner side than the honeycomb segment positioned on the outermost periphery of the plurality of stacked honeycomb segments.

[3] The above [1] or [2], in which an electric current is passed from one end face in the axial direction of each honeycomb segment to the other end face to generate heat in the honeycomb segment, thereby drying the bonding material. A method for producing a bonded honeycomb segment assembly according to claim 1.

[4] The method for manufacturing a joined honeycomb segment according to any one of [1] to [3], wherein the conductive ceramic includes SiC.

  The bonding material can be dried by heat generated by energizing the honeycomb segments. The inner bonding material can also be dried by the honeycomb segment in the same manner as the outer bonding material, so that the bonding material can be dried uniformly, preventing the occurrence of shrinkage strain, cracks, peeling, voids, etc., and bonding strength Can be prevented. Further, since the bonding material is dried by energizing the honeycomb segments, local drying is possible, and the drying speed can be easily controlled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

  FIG. 1 shows a honeycomb segment 10 to which the method for manufacturing a joined honeycomb segment assembly 1 of the present invention is applied. The honeycomb segment 10 is made of ceramic and includes an outer peripheral wall 7, partition walls 2 disposed inside the outer peripheral wall 7, and a plurality of cells 3 partitioned by the partition walls 2.

  Furthermore, when the joined honeycomb segment assembly 1 of the present invention is used as a filter, it is preferable that some cells 3 are plugged on the end face 8 of the honeycomb segment 10 as shown in FIG. In particular, it is preferable that the adjacent cells 3 are alternately sealed at the end faces 8 on the opposite sides, and the end faces 8 are sealed in a checkered pattern. By sealing in this manner, for example, the fluid to be treated which flows from one end face 8 passes through the partition wall 2 and flows out from the other end face 8, and when the fluid to be treated passes through the partition wall 2, the porous partition wall 2. Can act as a filter and remove the object.

  In the present invention, when the honeycomb segment 10 is used for a DPF, it is preferable to use silicon carbide or a silicon-silicon carbide based composite phase from the viewpoint of strength, heat resistance, and the like. In the present invention, when the honeycomb segment bonded body 1 is made of metal silicon (Si) and silicon carbide (SiC), the Si content defined by Si / (Si + SiC) of the honeycomb segment bonded body 1 is too small. Since the effect of addition of Si cannot be obtained, the strength is weak, and when it exceeds 50% by mass, the effects of heat resistance and high thermal conductivity, which are the characteristics of SiC, cannot be obtained. The Si content is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. The honeycomb segment 10 may be made of conductive ceramics other than SiC.

  A binder such as methylcellulose and hydroxypropoxylmethylcellulose, an organic pore former, a surfactant and water are added to the above raw materials to produce a plastic clay, and the clay is extruded, for example, and partitioned by partition walls 2. A rectangular pillar-shaped honeycomb formed body having a large number of cells 3 penetrating in the axial direction is formed. The honeycomb segment 10 can be manufactured by drying this with, for example, microwaves and hot air, and then calcining to remove the binder and the organic pore former, followed by firing.

  Moreover, it is preferable that the plugged portion in the case where the cell 3 is plugged at the end face 8 includes a crystal phase of the same type as the main crystal phase of the joined honeycomb segment assembly 1 as the main crystal phase.

  FIG. 2 shows a method for joining the joined honeycomb segment assembly 1. First, a plurality of honeycomb segments 10 of a porous ceramic body having a large number of cells 3 that are partitioned by partition walls 2 and penetrate in the axial direction are bundled through a bonding material layer 5 made of a bonding material.

  Specifically, as shown in FIG. 2, each of the honeycomb segments 10 in the housing area A formed in an L-shaped cross section by the vertical receiving plate 20 and the horizontal receiving plate 21, and the outer peripheral wall 7. The bonding surfaces are laminated with a bonding material layer 5 interposed between the bonding surfaces. This lamination is performed with the two surfaces along the vertical receiving plate 20 and the horizontal receiving plate 21.

The bonding material forming the bonding material layer 5 includes inorganic particles and an inorganic adhesive as main components, and includes an organic binder, a surfactant, a foamed resin, water, and the like as subcomponents. As the inorganic particles, plate-like particles, spherical particles, massive particles, fibrous particles, needle-like particles, etc. can be used, and as the inorganic adhesive, colloidal silica (SiO ₂ sol), colloidal alumina (alumina sol), various oxides Sol, ethyl silicate, water glass, silica polymer, aluminum phosphate and the like can be used. As long as the main component does not generate conductivity (the bonding material conductivity is preferably about 1/50 to 1/200 of the segment conductivity), the ceramic powder common to the constituent components of the honeycomb segment 10 is used. From the viewpoint of health problems, those containing no fibrous particles such as ceramic fibers are preferred, and those containing plate-like particles are preferred. As the plate-like particles, for example, mica, talc, boron nitride, glass flakes and the like can be used. The bonding material layer 5 can be formed by attaching the bonding material to the bonding surface of the honeycomb segment 10. The bonding material layer 5 may be formed on the honeycomb segment 10 before lamination or on the exposed bonding surface of the honeycomb segment 10 that has already been laminated. Lamination is performed by stacking the honeycomb segments 10 one by one.

  Next, as shown in FIG. 3, after stacking a predetermined number of honeycomb segments 10 (in this embodiment, 36 in 6 rows × 6 rows), the whole is simultaneously arrowed through the honeycomb segments 10 located in the outermost layer. The main pressure is applied in the directions F1 and F2 (see FIG. 2). Since the two surfaces of the laminated body are covered with the vertical receiving plate 20 and the horizontal receiving plate 21 at this time, the entire other two surfaces are simultaneously simultaneously pressed in the directions of arrows F1 and F2. For the pressurizing power at this time, an air cylinder or a hydraulic cylinder is used.

  As described above, after the honeycomb segments 10 are stacked via the bonding material, the honeycomb segments 10 are energized to dry the bonding material, whereby the honeycomb segments 10 are firmly fixed and bonded. FIG. 4 and FIG. 5 show an embodiment of current drying in the method for manufacturing a joined honeycomb segment assembly of the present invention. 4 is a sectional view in the axial direction, and FIG. 5 is a plan view seen from one end face 8 side. As shown in FIG. 4, electrodes 25 a and 25 b are attached to both end surfaces 8 of the honeycomb segment 10 in the axial direction. The electrode 25 a is disposed in a region outside the end surface 8, and the electrode 25 b is disposed in a region inside the end surface 8. As the electrode material, for example, conductive felt such as metal felt or carbon felt, a conductive plate, or the like can be used. Moreover, you may perform application | coating to the segment surface of an electroconductive substance. By attaching such an electrode, the honeycomb segment 10 is formed of conductive ceramics, and the bonding material is an insulating material. Therefore, current is passed from one end face 8 of the honeycomb segment 10 to the other end face 8. be able to. That is, only the honeycomb segments 10 are energized, and the bonding material layer 5 is not energized.

  Then, as described above, the outermost periphery of the plurality of honeycomb segments 10 stacked by the electrode 25a for energizing the honeycomb segment 10 located on the outer side and the electrode 25b for energizing the honeycomb segment 10 located on the inner side. A higher voltage is applied to the honeycomb segment 10 located on the inner side than the honeycomb segment 10 located on the inner side. By flowing an electric current from one end face 8 in the axial direction of each honeycomb segment 10 to the other end face 8, the honeycomb segment 10 can generate heat, thereby drying the bonding material. Thus, by applying a high voltage to the inner honeycomb segment 10, the inner bonding material that is difficult to dry can be dried to the same extent as the outer bonding material. By doing in this way, generation | occurrence | production of the shrinkage | contraction distortion by the drying difference of an inner side joining material and an outer side joining material, a crack, peeling, a void, etc. can be prevented, and the fall of joining strength can be prevented.

  The electrode shape is not limited to the embodiment described in FIGS. 4 and 5, and an electrode may be attached to each honeycomb segment 10 or an electrode may be attached to each predetermined region. In addition, the current drying method of the present invention can be used in combination with other drying methods.

  Then, after the bonding material is dried, it is calcined. That is, by conducting current drying and making the movement of the honeycomb segment 10 uniform due to drying shrinkage and curing of the bonding material, variation in the method of forming the bonding material layer 5 is reduced, and each bonded honeycomb segment assembly 1 Variations in the characteristics of the bonding material layer 5 can be reduced. In other words, the local drying rate of the inner and outer bonding materials can be controlled by current drying, and the thermal shock resistance of the joined honeycomb segment can be improved by performing uniform drying. Then, the outer periphery is further ground into a cylindrical shape, and the outer peripheral surface is coated with a coating material, and then heat-treated at about 700 ° C. for about 2 hours, whereby a honeycomb structure 1 as shown in FIG. 6 can be obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Manufacture of honeycomb segments)
As a raw material for the honeycomb segment, SiC powder and metal Si powder were mixed at a mass ratio of 80:20, and a pore former, an organic binder, a surfactant and water were added thereto to produce a plastic clay. This kneaded clay is extruded and dried, and the partition wall thickness is 310 μm, the cell density is about 46.5 cells / cm ² (300 cells / in ² ), the cross section is a regular square with a side of 35 mm, and the length is 178 mm. A ceramic molded body was obtained. The ceramic molded body was plugged at both end faces of the cell so that the end faces had a checkered pattern. That is, the sealing was performed so that adjacent cells were sealed at opposite ends. As the plugging material, the same material as the honeycomb segment material was used. After sealing and drying both end faces of the cell, degreasing at about 400 ° C. in an air atmosphere, followed by firing at about 1450 ° C. in an Ar inert atmosphere to bond SiC crystal particles with Si. A honeycomb segment having a porous structure was obtained.

(Preparation of bonding material)
As a bonding material, SiC fine particles 41% by mass, SiC coarse particles 16.5% by mass, mica 22% by mass, colloidal silica 20% by mass, bentonite 0.5% by mass, organic pore former 1.5% by mass (external), Water was further mixed with a mixture of organic binder 0.4% by mass (external) and dispersant 0.04% by mass (external), and kneaded for 30 minutes with a mixer to obtain a paste-like bonding material. . At this time, the amount of water added was adjusted so that the paste viscosity was 20 to 60 Pa · s.

(Joining)
A bonding material was applied to the bonded surfaces of the honeycomb segments, and the process of bonding while pressing one by one in order was repeated to produce a bonded body composed of 36 honeycomb segments combined in six rows and six rows. Thereafter, electrodes were attached to both end faces, and current drying was performed. As for the conditions for the electric drying, a voltage of 20 V was applied to the honeycomb segment in the outermost row and 30 V was applied to the inner honeycomb segment (Example 1).

  Similarly, honeycomb segments were prepared, and the bonding material was dried by hot air drying (Comparative Example 1), microwave drying (Comparative Example 2), and natural drying (Comparative Example 3). The drying conditions are shown in Table 1.

  Then, it heat-processed for 2 hours at 700 degreeC with the electric furnace, and obtained the joined body (Example 1, Comparative Examples 1-3).

(Joint strength)
As shown in FIG. 7, both end faces of some of the honeycomb segments were fixed, and the remaining honeycomb segments were loaded to examine the bonding strength of the bonding material layer. Regarding the measurement of the bonding strength, the measurement was carried out at the bonding site between the outermost honeycomb segment and the second honeycomb segment from the outermost periphery. The results are shown in Table 1. The gap ratio in Table 1 is the ratio 1 / L × 100 (%) of the length l of the gap (delamination) in the bonding material layer to the length L of the bonding material layer in contact with one side of the honeycomb segment. As shown in FIG. 8, the ratio of delamination 5d generated in the bonding material layer 5 between the honeycomb segments 10 is shown.

  As shown in Table 1, the bonding strength was improved in Example 1 by electrodrying compared to Comparative Examples 1 to 3. Further, in Example 1, the gap ratio was small compared to Comparative Examples 1 to 3, and delamination was difficult to occur. This is because, in the conventional method (Comparative Examples 1 to 3), there is a difference in drying speed between the inner bonding material and the outer bonding material, which decreases the bonding strength. In Example 1), it is considered that the bonding strength was improved by reducing the difference between the drying of the inner bonding material and the drying of the outer bonding material.

  The method for manufacturing a joined honeycomb segment according to the present invention is a diesel particulate for capturing and removing particulate matter (particulates) contained in exhaust gas from, for example, a diesel engine as a collection filter for exhaust gas. This is useful as a method for producing a curated filter (DPF).

It is a perspective view which shows a honeycomb segment. It is explanatory drawing which shows the joining method of a honeycomb segment. It is a schematic diagram which shows the end surface of the laminated | stacked honeycomb segment. It is a cross-sectional schematic diagram for demonstrating electroconductive drying. It is a top view for demonstrating energization drying. It is a perspective view of a honeycomb structure. It is explanatory drawing for demonstrating the joining strength measuring method. It is explanatory drawing for demonstrating gap ratio.

Explanation of symbols

1: Honeycomb segment bonded body (honeycomb structure), 2: partition, 3: cell, 5: bonding material layer, 5d: delamination, 7: outer peripheral wall, 8: end face, 10: honeycomb segment, 20: vertical receiving plate , 21: horizontal receiving plate, 25a, 25b: electrodes.

Claims (4)

  A honeycomb segment formed of conductive ceramics having a plurality of cells that are partitioned by partition walls and penetrates in the axial direction is stacked via a bonding material, and the bonding material is dried by energizing the honeycomb segment, whereby the honeycomb A method for manufacturing a joined honeycomb segment, in which the segments are firmly fixed and joined together.   The method for manufacturing a joined honeycomb segment according to claim 1, wherein a high voltage is applied to the honeycomb segment positioned on the inner side of the honeycomb segment positioned on the outermost periphery of the plurality of stacked honeycomb segments.   The honeycomb segment bonding according to claim 1 or 2, wherein an electric current is passed from one end surface in the axial direction of each of the honeycomb segments to the other end surface to generate heat in the honeycomb segment, thereby drying the bonding material. Body manufacturing method.   The method for manufacturing a bonded honeycomb segment assembly according to any one of claims 1 to 3, wherein the conductive ceramic contains SiC.

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