Note: Within nine months of the publication of the mention of the grant of the European patent in the European PatentBulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with theImplementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has beenpaid. (Art. 99(1) European Patent Convention).

Printed by Jouve, 75001 PARIS (FR)

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(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention of the grant of the patent: 02.01.2013 Bulletin 2013/01

(21) Application number: 07831965.4

(22) Date of filing: 09.11.2007

(51) Int Cl.:B28B 11/00 (2006.01) C04B 35/195 (2006.01)

C04B 41/00 (2006.01) C04B 41/45 (2006.01)

(86) International application number: PCT/JP2007/072235

(87) International publication number: WO 2008/081654 (10.07.2008 Gazette 2008/28)

(54) METHOD FOR MANUFACTURING SEALING HONEYCOMB STRUCTURE

VERFAHREN ZUR HERSTELLUNG EINER ABDICHTENDEN WABENSTRUKTUR

PROCD PERMETTANT DE FABRIQUER UNE STRUCTURE NID DABEILLES DTANCHISATION

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR

(30) Priority: 05.01.2007 JP 2007000375

(43) Date of publication of application: 11.11.2009 Bulletin 2009/46

(73) Proprietor: NGK Insulators, Ltd.Nagoya-shi, Aichi 467-8530 (JP)

(72) Inventors: ITO, Koichi

Nagoya-shiAichi 467-8530 (JP)

TOKUNAGA, TakeshiNagoya-shiAichi 467-8530 (JP)

(74) Representative: Paget, Hugh Charles Edward et alMewburn Ellis LLP 33 Gutter LaneLondonEC2V 8AS (GB)

(56) References cited: EP-A- 1 800 730 WO-A1-2006/062141JP-A- 01 221 216 JP-A- 2005 218 209

PATENT ABSTRACTS OF JAPAN 2008, & JP 2008 055346 A (DENSO CORP.), 13 March 2008 (2008-03-13)

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Description

Technical Field

[0001] The present invention relates to a manufacturing method of a plugged honeycomb structure which can preferablybe used in a filter such as a diesel particulate filter and in which predetermined cells at an end surface of the structureare plugged.

Background Art

[0002] As a dust collecting filter typified by a diesel particulate filter (DPF), a filter having a honeycomb structure andmade of a ceramic is used. Such a filter has a honeycomb structure having a large number of cells which are separatedand formed by porous partition walls so as to constitute channels of a fluid, and each cell is plugged on one end portionopposite to that of an adjacent cell so that each end surface of the honeycomb structure has a checkered pattern.[0003] When an exhaust gas including fine particles such as particulates is passed from one end surface of the filter(a plugged honeycomb structure), the exhaust gas flows into the structure from the cells having the end portions whichare not plugged on the one end surface, passes through the porous partition walls and enters the other cells having endportions which are not plugged on the other end surface of the structure. Then, when the exhaust gas passes throughthe partition walls, the fine particles in the exhaust gas are trapped by the partition walls, and the cleaned exhaust gasfrom which the fine particles have been removed is discharged from the other end surface of the honeycomb structure.[0004] Usually, to manufacture the plugged honeycomb structure having such a configuration, a method is employedin which as shown in Fig. 2, a mask film 4 to constitute a mask is attached to an end surface of a honeycomb substrate1, holes 3 are provided at positions corresponding to opening end portions (cell opening end portions 7) of predeterminedcells 2a and 2b of the mask film 4, and an end portion of the honeycomb substrate 1 is submerged into a container 5 inwhich a plugging slurry 6 is stored, whereby the plugging slurry 6 is allowed to permeate the predetermined cell openingend portions 7 through the holes 3 of the mask film 4 (e.g., see Patent Document 1).[0005] In a case where the opening end portions of the predetermined cells are plugged by such a method, the slurry6 for plugging does not sometimes permeate into a desired depth of the cells 2a and 2b. Moreover, the permeation depthof the plugging slurry in the cells 2a and 2b is not sometimes uniform, and there has been a problem that it is difficult tomanufacture a homogeneous plugged honeycomb structure. In a case where the permeation depth of the plugging slurrywhich permeates the respective cells to be plugged is not uniform, fluctuations are generated in a pressure loss of eachcell of the resultant plugged honeycomb structure, and a disadvantage that deviation is generated in a deposited amountof filtered matters or the like easily occurs.[0006] As a concerned conventional technology for solving the above problems, a method is disclosed in which theplugging slurry having thixotropy is used, and the plugging slurry is allowed to permeate the predetermined cells of thehoneycomb substrate while vibrated (e.g., see Patent Documents 2 and 3).[0007] However, even in the methods disclosed in Patent Documents 2 and 3, there is a case where the pluggingslurry 6 does not always permeate into the desired depth of the cells 2a and 2b, and the permeation depth is not uniform.Since a device for vibrating the plugging slurry is required, there is a tendency that manufacturing facilities to be usedbecome huge and complicated.[0008]

WO 2006/062141 describes a method of producing a sealed honeycomb structure body. Sealing sections are formedin cells of the honeycomb structure body. A slurry which is the material for the sealing sections is stored in a storagecontainer, such that a boundary face of the slurry is flat. Then, that end face of a honeycomb structure body which isprovided with a sealing section forming a mask covering opening end sections of cells excluding the sealing cells of thehoneycomb structure body is pressed to the slurry stored in the storage container. Thereby, the slurry is introduced intothe inside of cells to form the sealing sections.JP 01-221216 describes a method for preventing generation of defects such as bubbles in a molded product formedfrom a liquid resin. A product having an undercut is molded by a molding device. A closed mold molding consists of topand bottom parts and a core mold. Casting ports are formed on the lower most parts of a gap in the mold which has theform of the intended product. Air removal holes of fine diameter for discharging air from inside the gap are formed onuppermost parts of the gap. Casting ports and air removal holes are positioned offset from one another. Mixed liquid

[Patent Document 1] JP-A 2001-300922[Patent Document 2] JP-A 6-190218

[Patent Document 3] JP-A 6-190224

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resin is introduced through the casting port. By provision of the air holes, turbulent flow in the mixed liquid resin andinclusion of air are apparently reduced.JP 2005-218209 describes an apparatus for assembling an electric rotating machine. The assembling apparatus has abase for placing frame of the electric rotating machine on a top surface thereof, the base having a hole in the centre. Alower mold is elevatably fitted into the hole in the base and holds a mold material intermediate between the top surfaceof the base and inner and outer faces of the frame. The apparatus further comprises a biasing means for upwardlybiasing the lower mold. An upper mold is disposed above the base, and guides a stator of the electric rotating machineinto the frame. The upper mold abuts the lower mold. A pressing means for elevating the upper mold is also provided.A deaeration bore is formed through the upper mold.

Disclosure of the Invention

[0009] The present invention has been developed in view of such problems of the conventional technology, and anobject thereof is to provide a manufacturing method of a plugged honeycomb structure in which a plugging slurry canuniformly be allowed to permeate into a desired depth of cells, and a product defect such as plugging failure is hardlygenerated easily.[0010] That is, according to the present invention, there is provided the following manufacturing method of a pluggedhoneycomb structure.[0011] [1] A manufacturing method of a plugged honeycomb structure including a cylindrical honeycomb substrate inwhich a plurality of cells having two opening end portions are separated by partition walls and formed so as to communicatewith both end surfaces of the honeycomb substrate, and plugging portions arranged so as to plug one of the two openingend portions of the cells and form a complementary checkered pattern with one end surface and the other end surfaceof the honeycomb substrate, the method comprising: an attaching step of attaching mask films to both the end surfacesof the honeycomb substrate, respectively; a first perforation step of making slurry permeation holes at portions of themask films corresponding to the one opening end portion of each of the predetermined cells; a second perforation stepof making deaeration holes having a diameter of 0.02 to 0.8 mm at portions of the mask films facing the portions providedwith the slurry permeation holes via the cells; a filling step of submerging both the end surfaces of the honeycombsubstrate to which the mask films have been attached into a plugging slurry having a viscosity of 0.5 to 2000 Pas,respectively, and filling the one opening end portion of each of the predetermined cells with the plugging slurry to obtaina slurry filled substrate; and a firing step of firing the resultant slurry filled substrate.[0012] [2] The manufacturing method of the plugged honeycomb structure according to the above [1], wherein thedeaeration holes have a diameter in a range of 0.05 to 0.4 mm.[0013] [3] The manufacturing method of the plugged honeycomb structure according to the above [1] or [2], whereinthe plugging slurry has a viscosity in a range of 1 to 1500 Pas.[0014] [4] The manufacturing method of the plugged honeycomb structure according to any one of the above [1] to[3], wherein the plugging slurry has thixotropy, and the one opening end portion of each of the predetermined cells isfilled with the plugging slurry while vibrating the plugging slurry.[0015] According to the manufacturing method of the plugged honeycomb structure of the present invention, it ispossible to easily manufacture the plugged honeycomb structure in which the plugging slurry can be allowed to uniformlypermeate into a desired depth of the cells and a product defect such as plugging failure is hardly generated easily.

Brief Description of the Drawings

[0016]

[Fig. 1] Fig. 1 is a schematic diagram showing one embodiment of a manufacturing method of a plugged honeycombstructure according to the present invention;[Fig. 2] Fig. 2 is a schematic diagram showing a conventional state in which a plugging slurry is allowed to permeatecell opening end portions;[Fig. 3] Fig. 3 is a perspective view showing one example of the plugged honeycomb structure;[Fig. 4] Fig. 4 is a photograph of a partially sectional structure of a plugged honeycomb structure manufactured inExample 1; and[Fig. 5] Fig. 5 is a photograph of a partially sectional structure of a plugged honeycomb structure manufactured inComparative Example 1.

Description of Reference Numerals

[0017] 1: honeycomb substrate, 2, 2a, 2b: cell, 3: hole, 3a: slurry permeation hole, 3b: deaeration hole, 4: mask film,

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5: container, 6: plugging slurry, 7: cell opening end portion, 10: partition wall, 11: first end surface, 15: plugging portion,20: slurry filled substrate, 21: second end surface, 25: outer peripheral wall, 27, 29: end surface, 30: plugged honeycombstructure, X: diameter of deaeration hole

Best Mode for Carrying out the Invention

[0018] The best mode for carrying out the present invention will hereinafter be described, but it should be understoodthat the present invention is not limited to the following embodiment and that appropriate modification, improvement andthe like added to the following embodiment based on ordinary knowledge of a person skilled in the art fall in the scopeof the present invention.[0019] Fig. 1 is a schematic diagram showing a part of one embodiment of a manufacturing method of a pluggedhoneycomb structure according to the present invention. The manufacturing method of the plugged honeycomb structureaccording to the present embodiment is a method of manufacturing a plugged honeycomb structure 30 in which openingend portions (cell opening end portions 7) of predetermined cells 2 of a cylindrical honeycomb substrate 1 provided witha plurality of cells 2 separated by partition walls 10 between end surfaces (a first end surface 11, a second end surface21) are filled with a plugging slurry 6, and then fired to form plugging portions 15 at the predetermined cell opening endportions 7. Further details of the manufacturing method of the plugged honeycomb structure according to the presentinvention will hereinafter be described.[0020] In the manufacturing method of the plugged honeycomb structure according to the present embodiment, firstthe cylindrical honeycomb substrate 1 provided with the plurality of cells 2 separated by the partition walls 10 so as tocommunicate the first end surface 11 and the second end surface 21 is prepared (Fig. 1(a)).[0021] To prepare the honeycomb substrate 1, first there is used, as a material, powder of one type of material selectedfrom the group consisting of a ceramic such as cordierite, mullite, alumina, spinel, zirconia, silicon carbide, a siliconcarbide-cordierite based composite material, a silicon-silicon carbide based composite material, silicon nitride, lithiumaluminum silicate, aluminum titanate or zeolite; a metal such as an Fe-Cr-Al based metal; and a combination of thesematerials. To this material, a binder such as methyl cellulose or hydroxyl propoxyl methyl cellulose is added, and furthera surfactant and water are added to obtain a mixed material. Subsequently, the resultant mixed material is formed intoa clay having plasticity, extruded and formed into a honeycomb shape, and then dried or fired, so that the honeycombsubstrate 1 can be prepared.[0022] An attaching step attaches mask films 4a and 4b to the first end surface 11 and the second end surface 21 ofthe honeycomb substrate 1, respectively (Fig. 1(b)). There is not any special restriction on a type of the mask films 4aand 4b, but it is preferable that film can be melted by heat and also be perforated by irradiation with laser light. It ispreferable to use, as the mask films 4a and 4b, a film having an adhesive layer so as to be fixed on the end surface (thefirst end surface 11, the second end surface 21) of the honeycomb substrate 1. Specific examples of such a film includea film including a base layer constituted of a polymer material such as polyester, polyolefin or halogenated polyolefin,and the adhesive layer laminated on this base layer and constituted of an acrylic adhesive material. From viewpoints ofstrength and ease of making holes, it is preferable that a thickness of the mask films 4a and 4b is about 10 to 100 mm.[0023] A first perforation step makes slurry permeation holes 3a at portions of the mask films 4a and 4b correspondingto the predetermined cell opening end portions 7 (Fig. 1(c)). The slurry permeation holes 3a function as inflow ports forallowing a plugging slurry to flow into the cell opening end portions 7 in the subsequent step. It is to be noted that it ispreferable to set a diameter of the slurry permeation holes 3a to 30 to 70% of an opening area of the slurry permeationholes 3a, because the plugging slurry having a viscosity described later easily permeates the holes in a satisfactorystate. It is further preferable to set the diameter to 40 to 60%, and it is especially preferable to set the diameter to around50%.[0024] A second perforation step makes deaeration holes 3b at portions of the mask films 4a and 4b facing the portionsprovided with the slurry permeation holes 3a via the cells 2 (Fig. (d)). The deaeration holes 3b function as outflow portsfor discharging, from the cells, air which has been introduced in the cells 2 and which cannot flow outwards, in a casewhere the plugging slurry is passed into the cell opening end portions 7 through the slurry permeation holes 3a.[0025] A diameter X of the deaeration holes is set to 0.02 to 0.8 mm, preferably 0.04 to 0.6 mm, further preferably0.05 to 0.4 mm. The diameter X of the deaeration holes is set to this numerical value range, whereby it is difficult (orimpossible) to allow the plugging slurry having the viscosity described later to flow outwards or inwards through thedeaeration holes 3b, but inflow and outflow of the air are facilitated (or can be performed). Therefore, even in a casewhere the end surfaces of the honeycomb substrate 1 to which the mask films 4a and 4b having the slurry permeationholes 3a and the deaeration holes 3b have been attached are submerged into the plugging slurry 6, the plugging slurry6 easily permeates the cell opening end portions 7 from the slurry permeation holes 3a, but does not easily permeatethe portions from the deaeration holes 3b (Fig. 1(e)).[0026] There is not any special restriction on a method of making the slurry permeation holes 3a and the deaerationholes 3b in the mask films 4a and 4b, but, for example, a method of making the holes by laser irradiation is preferable.

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Moreover, the slurry permeation holes 3a and the deaeration holes 3b may be made one by one in the mask films 4aand 4b with one needle, or a large number of the slurry permeation holes 3a and the deaeration holes 3b may collectivelybe made using bundle needles planted on the plate having a pitch corresponding to that of the cells 2 to be perforated.In addition, it is preferable that images of the first end surface 11 and the second end surface 21 of the honeycombsubstrate 1 are processed to extract positions of the cells 2 in which the slurry permeation holes 3a and the deaerationholes 3b are to be made, and the slurry permeation holes 3a and the deaeration holes 3b are made at the extractedpositions by use of a laser marker, so that even the honeycomb substrate 1 in which the pitch and an opening shape ofthe cells 2 are not constant can flexibly be handled. It is to be noted that in a case where the slurry permeation holesand the deaeration holes are made by the laser irradiation, to regulate diameters of these holes, intensity of laser mayappropriately be regulated.[0027] A filling step first submerges the first end surface 11 and the second end surface 21 to which the mask films4a and 4b of the honeycomb substrate 1 have been attached into the plugging slurry 6 having a predetermined viscosity,respectively, and fills the cell opening end portions 7 with the plugging slurry 6 to obtain a slurry filled substrate 20 (Figs.1(e) and (f)). The plugging slurry has a viscosity of 0.5 to 2000 Pas, preferably 1 to 1500 Pas. The viscosity of theplugging slurry is set to this numerical value range, whereby it is difficult (or impossible) for the plugging slurry to flowinwards or outwards through the deaeration holes 3b having the diameter (X) in the above numerical value range, butthe inflow and outflow of the air are facilitated (or can be performed). Therefore, even when the first end surface 11 andthe second end surface 21 of the honeycomb substrate 1 are submerged into the plugging slurry 6, respectively, theplugging slurry 6 easily permeates the cell opening end portions 7 through the slurry permeation holes 3a, but does notremarkably easily permeate the portions from the deaeration holes 3b. Therefore, the plugging slurry 6 does not remark-ably easily permeate the cells 2 which are not to be permeated by the plugging slurry 6, a plugging defect is not easilygenerated, and hence a manufacturing yield can be improved. Furthermore, with regard to the air in the cells 2, theplugging slurry 6 permeates the cells 2 through the slurry permeation holes 3a, whereby the air is quickly dischargedfrom the deaeration holes 3b. Therefore, a plugged honeycomb structure can easily be manufactured in which theplugging slurry 6 can uniformly permeate into a desired depth of the cells 2 and in which plugging portions have highreliability.[0028] It is to be noted that in a case where the plugging slurry 6 having thixotropy is used, when the plugging slurry6 permeates the cell opening end portions 7, it is preferable to fill the cell opening end portions 7 with the plugging slurry6 while vibrating the slurry by use of an ultrasonic generator or the like, because the plugging slurry 6 can more uniformlypermeate into the desired depth of the cells 2.[0029] The plugging slurry can be prepared by mixing at least ceramic powder and a dispersion medium for the slurry.Preferable examples of the dispersion medium for the slurry include an organic solvent such as acetone, ethanol ormethanol, and water.[0030] To the plugging slurry, if necessary, an additive such as a binder or deflocculant may further be added. Thereis not any special restriction on a type of the ceramic powder, but, for example, silicon carbide powder, cordierite powderor the like may preferably be used. As the binder, a resin such as polyvinyl alcohol (PVA) may be used, but it is morepreferable to use a thermal gel setting binder having a property of gelating by heating. As the thermal gel setting binder,methyl cellulose may preferably be used.[0031] After the slurry filled substrate 20 is obtained, if necessary, the slurry filled substrate is dried, and heated and/orfired, so that the plugged honeycomb structure 30 provided with the plugging portions 15 can be manufactured (Fig. 1(g)). It is to be noted that in general, the plugged honeycomb structure 30 can be manufactured by performing the fillingstep of filling the predetermined cell opening end portions 7 with the plugging slurry 6, and then performing the firing,but the filling step may be performed with respect to an unfired honeycomb structure formed body (a dried body), or afired honeycomb structure body.[0032] For example, as shown in Fig. 3, in the plugged honeycomb structure 30 manufactured according to the man-ufacturing method of the plugged honeycomb structure of the present invention, as long as the plurality of cells 2 areseparated by the porous partition walls and extend from one end surface 27 to the other end surface 29 in an axialdirection and the cells 2 have the plugging portions 15 arranged at either of the end surfaces 27 and 29 so as to plugthe end surfaces, there is not any restriction on a shape of the structure. It is to be noted that reference numeral 25 inFig. 3 is an outer peripheral wall which surrounds an outer periphery of the partition walls.[0033] A sectional shape of the plugged honeycomb structure crossing an extending direction of the cells at rightangles can appropriately be adopted from a circular shape, an elliptic shape, a race-track shape, a quadrangular shapeand the like based on an application and an installation place. A sectional shape of the cell crossing the extendingdirection of the cell at right angles may be selected from a polygonal shape such as a triangular shape, a quadrangularshape or a hexagonal shape, a substantially polygonal shape, a circular shape and a substantially circular shape suchas an elliptic shape. A cell density is usually set to 6 to 2000 cells/square inch (0.9 to 311 cells/cm2), preferably about50 to 1000 cells/square inch (7.8 to 155 cells/cm2). When the plugged honeycomb structure 30 (see Fig. 3) is used asa catalyst carrier or a filter, it is preferable that the partition walls and the outer peripheral wall 25 are porous.

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Example

[0034] The present invention will hereinafter specifically be described in accordance with examples, but the presentinvention is not limited to these examples.

(Preparation of Honeycomb Substrate)

[0035] A mixed material made of cordierite, an organic binder, a pore former and water was formed into a honeycombshape, and then dried to prepare a cylindrical honeycomb substrate having an outer diameter of 140 mm and a lengthof 150 mm. In the prepared honeycomb substrate, a cell had a square sectional shape crossing an extending directionof the cell at right angles, partition walls had a thickness of about 0.3 mm, a cell density was 300 cells/square inch, anda cell pitch was 1.5 mm.

(Preparation of Plugging slurry)

[0036] Appropriate amounts of methyl cellulose, glycerin and water were added to cordierite powder, and kneaded toprepare four types of plugging slurries having viscosities of 1 Pads, 1000 Pads, 1500 Pads and 2000 Pads.

(Example 1)

[0037] Mask films (material: polyester, thickness: mm, trade name "Masking Tape", manufactured by 3M Co.) wereattached to both end surfaces (a first end surface and a second end surface) of one of honeycomb substrates, and slurrypermeation holes were made at portions of the attached mask films corresponding to predetermined cell opening endportions (so as to obtain a checkered pattern) by use of laser. Subsequently, deaeration holes having a diameter of 0.05mm were made at portions of the mask films facing the portions provided with the slurry permeation holes via cells byuse of the laser. Afterward, the first end surface of the honeycomb substrate was submerged into a depth of 5 mm in aplugging slurry having a viscosity of 1 Pas to fill the cell opening end portions with the plugging slurry through the slurrypermeation holes of the mask film.[0038] After pulling up the honeycomb substrate from the plugging slurry, the honeycomb substrate was dried at 100Cfor 120 seconds. Afterward, in the same manner as in the above first end surface, the second end surface of thehoneycomb substrate was submerged into the plugging slurry to fill the cell opening end portions at the other end surfaceof the honeycomb substrate with the plugging slurry. The honeycomb substrate was dried at 100C for 120 seconds,and fired for 50 hours to manufacture a plugged honeycomb structure.[0039] When an average plugging depth (mm) of the plugging portions of the manufactured plugged honeycombstructure was measured, the depth was 5.00 mm at the first end surface, the depth was 4.98 mm at the second endsurface, and an average of the depths of the first and second end surfaces was 4.99 mm. It is to be noted that an averageachievement ratio of the plugging depth with respect to a target depth (5 mm) was 100%. Moreover, a photograph of apartially sectional structure of the plugged honeycomb structure manufactured in Example 1 is shown in Fig. 4.

(Examples 2 to 6 and Comparative Examples 1 to 6)

[0040] Plugged honeycomb structures were manufactured in the same manner as in Example 1 except that a perforationmethod of deaeration holes, a diameter (X) of the deaeration holes, a viscosity of a plugging slurry and a vibrationfrequency were set to a method and numeric values shown in Table 1, respectively. Plugging portions of the manufacturedplugged honeycomb structures were measured in the same manner as in Example 1. Results are shown in Table 1.Moreover, a photograph of a partially sectional structure of the plugged honeycomb structure manufactured in Compar-ative Example 1 is shown in Fig. 5.[0041]

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[Tab

le 1

]

[00

41]

Per

fora

tio

n

met

ho

d o

f d

eaer

atio

n

ho

les

Dia

met

er (X

) o

f dea

erat

ion

h

ole

(m

m)

Vis

cosi

ty o

f p

lug

gin

g

slu

rry

(Pad

s)

Vib

rati

on

fr

equ

ency

(H

z)

Ave

rag

e p

lug

gin

g d

epth

(m

m)

Ave

rag

e ta

rget

d

epth

ac

hie

vem

ent

ratio

(%

)

Rem

arks

Fir

st e

nd

su

rfac

eS

eco

nd

en

d

surf

ace

Ave

rag

e o

f fi

rst

and

se

con

d e

nd

su

rfac

es

Exa

mp

le 1

Las

er0.

020.

5-

4.68

4.35

4.52

90%

Exa

mp

le 2

Pin

0.02

0.5

-4.

704.

334.

5290

%

Exa

mp

le 3

Las

er0.

11

-4.

694.

634.

6693

%

Exa

mp

le 4

Las

er0.

110

0060

5.01

5.00

5.01

100%

Exa

mp

le 5

Las

er0.

120

0060

4.53

4.49

4.51

90%

Exa

mp

le 6

Las

er0.

820

0060

4.64

4.50

4.57

91%

Co

mp

arat

ive

Exa

mp

le 1

--

0.5

-3.

111.

592.

3547

%*1

Co

mp

arat

ive

Exa

mp

le 2

--

0.5

604.

532.

223.

3868

%*2

Co

mp

arat

ive

Exa

mp

le 3

Las

er0.

010.

560

3.64

3.33

3.49

70%

*1

Co

mp

arat

ive

Exa

mp

le 4

Las

er0.

10.

460

5.21

5.12

5.17

103%

*3

Co

mp

arat

ive

Exa

mp

le 5

Las

er0.

125

0060

1.88

1.05

1.47

29%

*1

Co

mp

arat

ive

Exa

mp

le 6

Las

er1

2000

604.

984.

884.

9399

%*3

*1: D

iffic

ult f

or p

lugg

ing

slur

ry to

per

mea

te*2

: Plu

ggin

g sl

urry

slig

htly

eas

ily p

erm

eate

s by

vib

ratin

g sl

urry

, but

it is

diff

icul

t for

slu

rry

to p

erm

eate

*3: P

lugg

ing

slur

ry p

erm

eate

s fr

om d

eaer

atio

n ho

les

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[0042] As shown in Table 1, in the methods of Examples 1 to 5, as compared with the methods of ComparativeExamples 1 to 5, it is clear that the plugging slurry permeates into a desired depth and the plugging portion having asufficient depth is formed. According to the methods of Examples 1 to 5, it is clear that the plugged honeycomb structurehaving an excellent quality can be manufactured without causing the plugging failure. It is to be noted that for reference,in a case where a plugging slurry having a viscosity in excess of 2500 Pas is used, the plugging slurry does not easilyretain properties of the slurry, and it has been difficult for the plugging slurry to permeate the cells.

Industrial Applicability

[0043] A manufacturing method of a plugged honeycomb structure according to the present invention is preferable asa method of manufacturing a plugged honeycomb structure for use in a filter such as DPF.

Claims

1. A manufacturing method of a plugged honeycomb structure (30) including a cylindrical honeycomb substrate (1) inwhich a plurality of cells (2, 2a, 2b) having two opening end portions (7) are separated by partition walls (10) andformed so as to communicate with both end surfaces (11, 21) of the honeycomb substrate (30), and plugging portions(15) arranged so as to plug one of the two opening end portions (7) of the cells (2, 2a, 2b) and form a complementarycheckered pattern with one end surface (11) and the other end surface (21) of the honeycomb substrate (30), themethod comprising:

an attaching step of attaching mask films (4) to both the end surfaces (11, 21) of the honeycomb substrate (1),respectively;a first perforation step of making slurry permeation holes (3a) at portions of the mask films (4) correspondingto the one opening end portion (7) of each of the predetermined cells (2, 2a, 2b);a second perforation step of making deaeration holes (3b) having a diameter of 0.02 to 0.8 mm at portions ofthe mask films (4) facing the portions provided with the slurry permeation holes (3a) via the cells (2, 2a, 2b);a filling step of submerging both the end surfaces (11, 21) of the honeycomb substrate (1) to which the maskfilms (4) have been attached into a plugging slurry (6) having a viscosity of 0.5 to 2000 Pas, respectively, andfilling the one opening end portion (7) of each of the predetermined cells (2, 2a, 2b) with the plugging slurry (6)to obtain a slurry filled substrate (20); anda firing step of firing the resultant slurry filled substrate (20).

2. The manufacturing method of the plugged honeycomb structure (30) according to claim 1, wherein the deaerationholes (3b) have a diameter in a range of 0.05 to 0.4 mm.

3. The manufacturing method of the plugged honeycomb structure (30) according to claim 1 or 2, wherein the pluggingslurry (6) has a viscosity in a range of 1 to 1500 Pas.

4. The manufacturing method of the plugged honeycomb structure (30) according to claim 1 or 2, wherein the pluggingslurry (6) has thixotropy, andthe one opening end portion (7) of each of the predetermined cells (2, 2a, 2b) is filled with the plugging slurry (6)while vibrating the plugging slurry (6).

Patentansprche

1. Herstellungsverfahren fr eine verschlossene Wabenstruktur (30), das Folgendes umfasst: ein zylinderfrmigesWabensubstrat (1), in dem eine Vielzahl von Zellen (2, 2a, 2b) mit zwei ffnungsendabschnitten (7) durch Trenn-wnde (10) getrennt sind und so ausgebildet sind, dass sie mit beiden Endflchen (11, 21) des Wabensubstrats(30) kommunizieren, und Verschlussabschnitte (15), die so angeordnet sind, dass sie einen der beiden ffnungs-endabschnitte (7) der Zellen (2, 2a, 2b) verschlieen und mit der einen Endflche (11) und der anderen Endflche(21) des Wabensubstrats komplementre Schachbrettmuster bilden, wobei das Verfahren Folgendes umfasst:

einen Schritt des Aufbringens von Abdeckfilmen (4) auf beide Endflchen (11, 21) des Wabensubstrats (1);einen ersten Perforationsschritt, bei dem Aufschlmmungseindringlcher (3a) in dem einen ffnungsendab-schnitt (7) jeder der vorbestimmten Zellen (2, 2a, 2b) entsprechenden Teilen der Abdeckfilme (4) hergestellt

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werden;einen zweiten Perforationsschritt, bei dem Entlftungslcher (3b) mit einem Durchmesser von 0,02 bis 0,8 mmin Teilen der Abdeckfilme (4) hergestellt werden, die den mit den Aufschlmmungseindringlchern (3a) bereit-gestellten Teilen durch die Zellen (2, 2a, 2b) hindurch zugewandt sind;einen Befllungsschritt, bei dem beide Endflchen (11, 21) des Wabensubstrats (1), auf die die Abdeckfilme(4) aufgebracht wurden, in eine Verschlussaufschlmmung (6) mit einer Viskositt von 0,5 bis 2.000 Pasgetaucht werden und der eine ffnungsendabschnitt (7) jeder der vorbestimmten Zellen (2, 2a, 2b) mit derVerschlussaufschlmmung (6) gefllt wird, um ein mit Aufschlmmung geflltes Substrat (20) zu erhalten; undeinen Schritt des Brennens des resultierenden mit Aufschlmmung gefllten Substrats (20).

2. Verfahren zur Herstellung einer verschlossenen Wabenstruktur (30) nach Anspruch 1, worin die Entlftungslcher(3b) einen Durchmesser im Bereich von 0,05 bis 0,4 mm aufweisen.

3. Verfahren zur Herstellung einer verschlossenen Wabenstruktur (30) nach Anspruch 1 oder 2, worin die Verschlus-saufschlmmung (6) eine Viskositt im Bereich von 1 bis 1.500 Pas aufweist.

4. Verfahren zur Herstellung einer verschlossenen Wabenstruktur (30) nach Anspruch 1 oder 2, worin die Verschlus-saufschlmmung (6) thixotrop ist undder eine ffnungsendabschnitt (7) jeder der vorbestimmten Zellen (2, 2a, 2b) mit der Verschlussaufschlmmung(6) befllt wird, whrend diese in Vibration versetzt wird.

Revendications

1. Procd de fabrication dune structure en nid dabeilles obture (30) comprenant un substrat de nid dabeilles (1)cylindrique dans lequel une pluralit de cellules (2, 2a, 2b) comportant deux parties dextrmit douverture (7) sontspares par des parois de sparation (10) et sont formes de manire communiquer avec les deux surfacesdextrmit (11, 21) du substrat de nid dabeilles (30), et des parties dobturation (15) agences de manire obturerlune des deux parties dextrmit douverture (7) des cellules (2, 2a, 2b) et former un motif en damier compl-mentaire avec une surface dextrmit (11) et lautre surface dextrmit (21) du substrat de nid dabeilles (30), leprocd comprenant :

une tape de fixation consistant fixer des films de masque (4) aux deux surfaces dextrmit (11, 21) dusubstrat de nid dabeilles (1), respectivement ;une premire tape de perforation consistant raliser des trous de permation de pte (3a) au niveau desparties des films de masque (4) correspondant ladite une partie dextrmit douverture (7) de chacune descellules (2, 2a, 2b) prdtermines ;une deuxime tape de perforation consistant raliser des trous de dsaration (3b) ayant un diamtre de0,02 0,8 mm au niveau des parties des films de masque (4) faisant face aux parties pourvues des trous depermation de pte (3a) via les cellules (2, 2a, 2b) ;une tape de remplissage consistant submerger les deux surfaces dextrmit (11, 21) du substrat de niddabeilles (1) auxquelles les films de masque (4) ont t fixs dans une pte dobturation (6) ayant une viscositde 0,5 2.000 Pa.s, respectivement, et remplir ladite une partie dextrmit douverture (7) de chacune descellules (2, 2a, 2b) prdtermines avec la pte dobturation (6) pour obtenir un substrat rempli de pte (20) ; etune tape de cuisson consistant cuire le substrat rempli de pte (20) rsultant.

2. Procd de fabrication de la structure en nid dabeilles obture (30) selon la revendication 1, dans lequel les trousde dsaration (3b) ont un diamtre dans une plage de 0,05 0,4 mm.

3. Procd de fabrication de la structure en nid dabeilles obture (30) selon la revendication 1 ou 2, dans lequel lapte dobturation (6) a une viscosit dans une plage de 1 1.500 Pa.s.

4. Procd de fabrication de la structure en nid dabeilles obture (30) selon la revendication 1 ou 2, dans lequel lapte dobturation (6) a une thixotropie, etladite une partie dextrmit douverture (7) de chacune des cellules (2, 2a, 2b) prdtermines est remplie avecla pte dobturation (6) tout en faisant vibrer la pte dobturation (6).

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REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the readers convenience only. It does not form part of the Europeanpatent document. Even though great care has been taken in compiling the references, errors or omissions cannot beexcluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

JP 2001300922 A [0008] JP 6190218 A [0008] JP 6190224 A [0008]

WO 2006062141 A [0008] JP 1221216 A [0008] JP 2005218209 A [0008]

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