JP3529051B1 - Ceramic honeycomb structure - Google Patents
Ceramic honeycomb structureInfo
- Publication number
- JP3529051B1 JP3529051B1 JP2003293769A JP2003293769A JP3529051B1 JP 3529051 B1 JP3529051 B1 JP 3529051B1 JP 2003293769 A JP2003293769 A JP 2003293769A JP 2003293769 A JP2003293769 A JP 2003293769A JP 3529051 B1 JP3529051 B1 JP 3529051B1
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb structure
- ceramic honeycomb
- wall portion
- wall
- groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 152
- 238000005192 partition Methods 0.000 claims abstract description 127
- 239000000463 material Substances 0.000 claims description 66
- 239000011800 void material Substances 0.000 claims description 36
- 239000011148 porous material Substances 0.000 claims description 16
- 230000035939 shock Effects 0.000 abstract description 66
- 238000011049 filling Methods 0.000 abstract description 4
- 230000002093 peripheral effect Effects 0.000 description 58
- 239000011248 coating agent Substances 0.000 description 56
- 238000000576 coating method Methods 0.000 description 56
- 230000035882 stress Effects 0.000 description 42
- 229910052878 cordierite Inorganic materials 0.000 description 33
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 33
- 238000001035 drying Methods 0.000 description 20
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 19
- 230000000694 effects Effects 0.000 description 18
- 239000011230 binding agent Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 230000007423 decrease Effects 0.000 description 14
- 239000000843 powder Substances 0.000 description 13
- 238000000746 purification Methods 0.000 description 13
- 239000008119 colloidal silica Substances 0.000 description 11
- 239000002245 particle Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 238000000034 method Methods 0.000 description 10
- 229920000609 methyl cellulose Polymers 0.000 description 10
- 239000001923 methylcellulose Substances 0.000 description 10
- 235000010981 methylcellulose Nutrition 0.000 description 10
- 239000013078 crystal Substances 0.000 description 9
- 239000000835 fiber Substances 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 5
- 238000011161 development Methods 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 229910010293 ceramic material Inorganic materials 0.000 description 4
- 239000010419 fine particle Substances 0.000 description 4
- 230000008646 thermal stress Effects 0.000 description 4
- 239000005995 Aluminium silicate Substances 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- 235000012211 aluminium silicate Nutrition 0.000 description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 238000007602 hot air drying Methods 0.000 description 3
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 229910052863 mullite Inorganic materials 0.000 description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- BQSLGJHIAGOZCD-CIUDSAMLSA-N Leu-Ala-Ser Chemical compound CC(C)C[C@H](N)C(=O)N[C@@H](C)C(=O)N[C@@H](CO)C(O)=O BQSLGJHIAGOZCD-CIUDSAMLSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000004299 exfoliation Methods 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Abstract
【要約】
【課題】 最外周に位置するセルが、外部との間の隔壁
を有しないことによって、外部に開口して軸方向に延び
る凹溝を形成しているセラミックハニカム本体の、凹溝
を充填して外表面を有する外壁部を形成させたセラミッ
クハニカム構造体において、熱衝撃が発生しても、熱衝
撃によるクラックが隔壁にまで進展しにくくした、耐熱
衝撃性、信頼性を併せ持つセラミックハニカム構造体を
提供することにある。
【解決手段】 外部に開口して軸方向に延びる凹溝を形
成しているセラミックハニカム本体の、前記凹溝を充填
して外表面を有する外壁部を形成させたセラミックハニ
カム構造体において、前記外壁部表面の空隙部、或い
は、前記凹溝と外壁部を構成する部材との間に形成され
た応力開放部を少なくとも有することによって、熱衝撃
が作用しても、上記応力開放部で熱衝撃による応力を開
放し、隔壁にクラックが生じにくくしたセラミックハニ
カム構造体。A cell located at the outermost periphery does not have a partition wall between itself and the outside, so that a groove of a ceramic honeycomb body which is formed to open to the outside and extend in the axial direction is formed. In a ceramic honeycomb structure that is filled to form an outer wall portion having an outer surface, even if a thermal shock occurs, cracks due to the thermal shock hardly spread to the partition walls, and the ceramic honeycomb has both thermal shock resistance and reliability It is to provide a structure. SOLUTION: In the ceramic honeycomb structure having an externally opened concave groove extending in the axial direction, a ceramic honeycomb structure having an outer wall portion having an outer surface formed by filling the concave groove. By having at least a stress relief portion formed between the cavity on the surface of the portion or the concave groove and the member constituting the outer wall portion, even if a thermal shock is applied, the stress relief portion causes the stress relief portion. A ceramic honeycomb structure that relieves stress and hardly causes cracks in partition walls.
Description
【０００１】本発明はセラミックハニカム構造体、特に
ディーゼルエンジンの排ガス浄化用触媒担体や微粒子捕
集フィルタに用いられる大型セラミックハニカム構造体
や自動車排ガス浄化用触媒担体に用いられる薄壁セラミ
ックハニカム構造体に関するものである。The present invention relates to a ceramic honeycomb structure, and more particularly to a large-sized ceramic honeycomb structure used for a catalyst carrier for purifying exhaust gas of diesel engines and a particulate collection filter, and a thin-wall ceramic honeycomb structure used for a catalyst carrier for cleaning automobile exhaust gas. It is a thing.
【０００２】地域環境や地球環境の保全面から、自動車
などのエンジンの排気ガスに含まれる有害物質を削減す
るため、セラミックハニカム構造体を使用した排気ガス
浄化用の触媒コンバータや微粒子捕集用フィルタが使用
されている。図１はハニカム構造体の斜視図である。図
１に示すように、通常、ハニカム構造体１は、外周壁３
と、この外周壁３の内周側に各々直交する隔壁により形
成された多数のセルを有する。そして、ハニカム構造体
１は、金属製収納容器（図示せず）内で動かないよう
に、収納容器内周面とハニカム構造体の外周壁外周面と
の間に配置された把持部材により強固に把持されて収納
されている。In order to reduce harmful substances contained in the exhaust gas of engines such as automobiles from the viewpoint of protecting the local environment and the global environment, a catalytic converter for purifying exhaust gas and a filter for collecting fine particles using a ceramic honeycomb structure. Is used. FIG. 1 is a perspective view of a honeycomb structure. As shown in FIG. 1, usually, the honeycomb structure 1 has an outer peripheral wall 3
And a large number of cells formed by partition walls orthogonal to each other on the inner peripheral side of the outer peripheral wall 3. The honeycomb structure 1 is firmly fixed by a gripping member arranged between the inner peripheral surface of the storage container and the outer peripheral wall of the honeycomb structure so as not to move in the metal storage container (not shown). It is gripped and stored.
【０００３】ハニカム構造体１は、従来、以下の工程で
製造されている。コージェライト生成原料粉末と、成形
助剤、造孔剤と水を、混合、混練して得たセラミック坏
土を特殊金型を通じて押出成形することにより、外周壁
３や隔壁４が形成されたハニカム構造を有する成形体を
得る。次に、乾燥炉内で、成形体中の水分などを蒸発乾
燥させ、更に焼成炉内で、成形体中のバインダ等の成形
助剤等を除去した後、所定温度下で焼成して、所定の形
状と強度を持ち、外周壁３や隔壁４に微細な細孔を持つ
ハニカム構造体１を得ていた。The honeycomb structure 1 is conventionally manufactured by the following steps. A honeycomb body in which outer peripheral wall 3 and partition walls 4 are formed by extruding a ceramic kneaded material obtained by mixing and kneading a cordierite forming raw material powder, a molding aid, a pore-forming agent and water through a special mold. A molded body having a structure is obtained. Next, after evaporating and drying the water content in the molded body in a drying furnace and further removing the molding aid such as the binder in the molded body in the firing furnace, it is fired at a predetermined temperature to a predetermined temperature. Thus, the honeycomb structure 1 having the shape and strength and having fine pores in the outer peripheral wall 3 and the partition walls 4 was obtained.
【０００４】ディーゼルエンジン用の、例えば、外径が
１５０ｍｍ以上で長さが１５０ｍｍ以上の大型セラミッ
クハニカム構造体や、隔壁４の厚さが０．２ｍｍ以下と
薄いハニカム構造体１を製造する場合、押出成形時に、
成形体の自重が大きすぎたり、成形体自身の強度が不十
分であったりすることから、自重を支えきれず、外周壁
３の周縁部の隔壁４が潰れたり変形し、焼成後に所定の
強度が得られないという問題があった。In the case of manufacturing a large-sized ceramic honeycomb structure having an outer diameter of 150 mm or more and a length of 150 mm or more, or a honeycomb structure 1 having a thin partition wall 4 of 0.2 mm or less, for example, for a diesel engine, During extrusion,
Since the weight of the molded body is too large or the strength of the molded body itself is insufficient, the weight of the molded body cannot be supported and the partition wall 4 at the peripheral edge portion of the outer peripheral wall 3 is crushed or deformed, and the predetermined strength is obtained after firing. There was a problem that could not be obtained.
【０００５】この問題を解決するため、特許文献１に
は、コージェライト化原料に成形助剤及び／又は造孔材
を加えて調合し、混合混練し押出成形可能に可塑化し、
このセラミック杯土を押出成形、乾燥、焼成してハニカ
ム構造を有する焼成体とした後、このハニカム構造を有
する焼成体の外周壁３とその周縁部を研削加工によって
所定寸法より小さくする除去加工を行い、除去加工した
周縁にコーティング材を塗布、乾燥、硬化させて外壁部
を形成し、ハニカム構造の隔壁と外壁部を一体化させる
方法が開示されている。この方法によれば、ハニカム構
造を有する焼成体の外周壁３とその周縁部を研削加工で
除去しているので、外周壁の周縁部の変形したセルを除
くことができるため、ハニカム構造体の機械的強度を高
くできる、としている。またハニカム構造を有する焼成
体全体の真円度が低い場合にも、研削加工により真円度
を高めた後に外壁部を形成することにより、寸法精度が
向上される、としている。そして、この従来の方法にお
いて使用される外壁部を形成するためのコーティング材
として、セラミックファイバーと無機バインダーとを使
用すると、外壁部の強度を高くすることができ、更にコ
ーティング材にハニカム構造体本体と同種の、例えば、
コージェライト粉末を添加するとハニカム構造を有する
焼成体との熱膨張係数差を少なくすることができるので
好ましいとしている。In order to solve this problem, in Patent Document 1, a cordierite-forming raw material is mixed with a molding aid and / or a pore-forming material, mixed, kneaded, and plasticized to be extrudable,
The ceramic clay is extruded, dried and fired to form a fired body having a honeycomb structure, and then the outer peripheral wall 3 of the fired body having the honeycomb structure and its peripheral portion are removed by grinding so as to be smaller than a predetermined size. A method is disclosed in which a coating material is applied to the peripheral edge that has been subjected to the removal processing, dried, and cured to form the outer wall portion, and the partition walls and the outer wall portion of the honeycomb structure are integrated. According to this method, since the outer peripheral wall 3 of the fired body having the honeycomb structure and the peripheral portion thereof are removed by grinding, the deformed cells in the peripheral portion of the outer peripheral wall can be removed. The mechanical strength can be increased. Further, even when the circularity of the whole fired body having a honeycomb structure is low, the dimensional accuracy is improved by forming the outer wall portion after increasing the circularity by grinding. Then, when a ceramic fiber and an inorganic binder are used as a coating material for forming the outer wall portion used in this conventional method, the strength of the outer wall portion can be increased, and the coating material further has a honeycomb structure body. Similar to, for example,
The addition of cordierite powder is preferred because it can reduce the difference in thermal expansion coefficient with the fired body having a honeycomb structure.
【０００６】更に、上記のような構成のハニカム構造体
における、外壁部のハニカム構造体本体からの耐剥離性
を改善して、耐熱性、耐熱衝撃性に優れたハニカム構造
体を得るため、特許文献２には、外壁部（外殻層）がコ
ージェライト粒子及び／又はセラミックファイバーと、
それらの間に存在する、コロイダルシリカまたはコロイ
ダルアルミナにて形成された非晶質酸化物マトリックス
とから構成してなることを特徴とするセラミックハニカ
ム構造体が開示されている。この従来のセラミックハニ
カム構造体の構成を図２及び図３を用いて以下説明す
る。特許文献２に記載の技術によれば、隔壁４で囲まれ
且つ相互に仕切られた多数のセルのうち、最外周に位置
するものが、外部との間の隔壁を有しないことによっ
て、外部に開口して軸方向に延びる凹溝１２を形成して
いるセラミックハニカム本体１４の、軸方向に伸びる凹
溝１２をコート材にて充填して外壁部（外殻層）１６を
設けていることから、ハニカム本体１４に有効な補強を
しつつ、使用中に外殻層であるコート層の剥離によるハ
ニカム構造体の強度低下を防止し、且つハニカム構造体
の補強の際に惹起されるハニカム構造体の熱衝撃強度の
低下を効果的に抑制せしめることができるとしている。
そして、この技術で使用されるコート材は、コージェラ
イト粒子及び／又はセラミックファイバーと、コロイダ
ルシリカまたはコロイダルアルミナからなるコロイド酸
化物とを主成分として含み、且つコロイド状酸化物を、
前記コージェライト粒子及び／又はセラミックファイバ
−の１００重量部に対して、固形分換算で３〜３５重量
部の割合で配合せしめており、この範囲で、骨材たる、
コージェライト粒子や、セラミックファイバーを充分に
固着せしめ、外壁部（外殻層）１６の熱特性、更には、
ハニカム構造体自体の熱特性の悪化が防げるとしてい
る。[0006] Further, in the honeycomb structure having the above-mentioned structure, the exfoliation resistance of the outer wall portion from the main body of the honeycomb structure is improved to obtain a honeycomb structure excellent in heat resistance and thermal shock resistance. In Reference 2, the outer wall portion (outer shell layer) is cordierite particles and / or ceramic fibers,
Disclosed is a ceramic honeycomb structure characterized by being composed of an amorphous oxide matrix formed of colloidal silica or colloidal alumina existing between them. The structure of this conventional ceramic honeycomb structure will be described below with reference to FIGS. 2 and 3. According to the technique described in Patent Document 2, among a large number of cells that are surrounded by the partition walls 4 and are partitioned from each other, the cells located at the outermost periphery do not have a partition wall with the outside, and Since the axially extending concave groove 12 of the ceramic honeycomb body 14 which is opened and forms the axially extending concave groove 12 is filled with the coating material, the outer wall portion (outer shell layer) 16 is provided. A honeycomb structure that effectively reinforces the honeycomb main body 14 and prevents the strength of the honeycomb structure from lowering due to peeling of a coat layer that is an outer shell layer during use, and that is caused when reinforcing the honeycomb structure It is said that it is possible to effectively suppress the decrease of the thermal shock strength.
The coating material used in this technique contains cordierite particles and / or ceramic fibers as a main component, and a colloidal oxide composed of colloidal silica or colloidal alumina, and a colloidal oxide,
With respect to 100 parts by weight of the cordierite particles and / or the ceramic fiber, it is mixed in a proportion of 3 to 35 parts by weight in terms of solid content, and in this range, it is an aggregate.
Cordierite particles and ceramic fibers are sufficiently fixed, and the thermal characteristics of the outer wall portion (outer shell layer) 16, and further
It is said that the deterioration of the thermal characteristics of the honeycomb structure itself can be prevented.
【０００７】[0007]
【特許文献１】特許第２６０４８７６号公報[Patent Document 1] Japanese Patent No. 2604876
【特許文献２】特許第２６１３７２９号公報[Patent Document 2] Japanese Patent No. 2613729
【０００８】上記特許文献１及び２に記載の従来の技術
を本発明者等で評価した結果、これらの技術手段は、外
径が１５０ｍｍ以上で長さが１５０ｍｍ以上の比較的大
型のセラミックハニカム構造体を押出成形する際に発生
する、外周壁の周縁部の隔壁が潰れたり変形したりする
問題は解消できるものの、以下のような問題点があっ
た。As a result of evaluating the conventional techniques described in the above-mentioned Patent Documents 1 and 2 by the present inventors, these technical means have a relatively large ceramic honeycomb structure having an outer diameter of 150 mm or more and a length of 150 mm or more. Although the problem that the partition wall at the peripheral edge of the outer peripheral wall is crushed or deformed, which occurs when the body is extrusion-molded, can be solved, but there are the following problems.
【０００９】上記従来の特許文献１及び２に記載の技術
に記載されている、外壁部を形成する材料は、ハニカム
本体の隔壁を構成する材料との熱膨張係数差の小さいも
のを選択することが、ハニカム本体と外壁部との境界面
に集中する熱応力を小さくすることができ、好ましいと
されているが、両者の熱膨張係数を実質的に一致させる
ことは困難であったこのようなセラミックハニカム構造
体が排気ガスで急熱されると、セラミックハニカム構造
体の中心部の温度が上昇するが、外壁部は把持部材、金
属容器を介して外気温度に接しており外周壁部の温度は
上昇しにくいため、中心部と外壁部の温度差により、外
表面に引張応力が作用、クラックが発生し、強固に固着
している外壁部と凹溝界面を貫通し、隣接したセルの隔
壁へと連鎖的に進展するようになる。隔壁にクラックが
進展すると、隔壁が脱落して排ガスの浄化性能が低下し
たり、微粒子捕集用フィルタの場合は、入口側と出口側
の流路が連通してしまうため、微粒子の捕集率が低下す
るといった、排気ガス浄化装置の浄化性能に係わる、極
めて重要な問題に発展することがあった。As the material for forming the outer wall portion, which is described in the above-mentioned conventional patent documents 1 and 2, a material having a small difference in coefficient of thermal expansion from the material forming the partition walls of the honeycomb body should be selected. However, since it is possible to reduce the thermal stress concentrated on the boundary surface between the honeycomb main body and the outer wall portion, it is said to be preferable, but it was difficult to substantially match the thermal expansion coefficients of the two. When the ceramic honeycomb structure is rapidly heated by the exhaust gas, the temperature of the central portion of the ceramic honeycomb structure rises, but the outer wall portion is in contact with the outside air temperature through the holding member and the metal container, and the temperature of the outer peripheral wall portion is Since it does not easily rise, tensile stress acts on the outer surface due to the temperature difference between the center part and the outer wall part, cracks occur, penetrate the firmly fixed outer wall part and concave groove interface, and to the partition wall of the adjacent cell And progress in a chain It becomes the way. If cracks develop in the partition walls, the partition walls will fall off and the exhaust gas purification performance will decrease, and in the case of a particulate collection filter, the inlet side and outlet side flow paths will communicate, so the particulate collection rate It sometimes develops into an extremely important problem related to the purification performance of the exhaust gas purification device, such as a decrease in the exhaust gas.
【００１０】従って本発明の目的は、上記問題に鑑みて
なされたもので、最外周に位置するセルが、外部との間
の隔壁を有しないことによって、外部に開口して軸方向
に延びる凹溝を形成しているセラミックハニカム本体
の、凹溝を充填して外表面を形成する外壁部を有するセ
ラミックハニカム構造体において、熱衝撃が発生して
も、熱衝撃によるクラックが隔壁にまで進展しにくくし
た、耐熱衝撃性、信頼性を併せ持つセラミックハニカム
構造体を提供することにある。Therefore, the object of the present invention was made in view of the above problems, and the cells located at the outermost periphery do not have a partition wall with the outside, so that the recesses that are open to the outside and extend in the axial direction are formed. In a ceramic honeycomb structure having an outer wall portion that fills the concave grooves and forms the outer surface of the ceramic honeycomb body forming the grooves, even if a thermal shock occurs, cracks due to the thermal shock propagate to the partition walls. An object of the present invention is to provide a ceramic honeycomb structure having both heat shock resistance and reliability.
【００１１】本発明者らは、従来の技術では達成できな
かった、ハニカム本体に一般的に用いられているコージ
ェライト質セラミックス材料の熱膨張係数と外壁部を構
成するコージェライトを主体とする材料の熱膨張係数の
差異、及びそれに伴い発生する熱衝撃クラックの隔壁へ
の進展について検討した。本発明者等は押出成形法を用
いて、特許文献１及び２を参考にしながら、従来のコー
ジェライト質セラミックハニカム構造体を製造してみた
結果、以下のことが考察された。コージェライトの生原
料を押出してハニカム構造体に成形すると、六角板状結
晶であるカオリンは押出成形用口金の幅の狭いスリット
を通過する際に隔壁の面内に沿って配向する。その後の
焼成過程において、カオリンの結晶に対して、直角方向
に、六角柱状のコージェライト結晶が生成されるため、
コージェライト結晶のｃ軸方向がハニカム構造の隔壁面
に平行になるように形成される。コージェライト結晶の
熱膨張係数は異方性を有しており、ａ軸方向が＋２．９
×１０−６／℃、ｃ軸方向が−１．１×１０−６／℃で
あるため、生原料を押出成形、焼成したハニカム構造体
の熱膨張係数は、隔壁の厚み方向ではａ軸による高い熱
膨張係数を示すが、隔壁と平行な方向ではｃ軸とａ軸の
合成された低い熱膨張を示し、ハニカム本体全体として
低熱膨張係数を示すようになる。このような、コージェ
ライト質セラミックスからなるハニカム本体の最外周に
位置するものが、外部との間の隔壁を有しないことによ
って、外部に開口して軸方向に延びる凹溝に、従来技術
のコージェライト骨材、セラミックファイバー、無機バ
インダー等からなるコート材をスラリー状にして塗布し
た後、乾燥或いは必要に応じて焼成を行うと、コート材
を塗布した外壁部は、コージェライト結晶の配向が得ら
れないこと、及び熱膨張係数の異なるセラミックファイ
バーや無機バインダーを含有していることから、必然的
にコージェライト結晶が配向している隔壁よりその熱膨
張係数が大きくなる。このような熱膨張係数差を有する
外壁部と凹溝が、図３に示すように凹溝の角隅部にまで
外壁部を構成する部材が充填され、しかも外壁部を構成
する部材中の無機バインダ等による接着力により、強固
に固着、一体化せしめられていることから、両者の界面
には接着に伴う残留応力が内在することになる。具体的
には、外壁部の熱膨張係数が隔壁より大きいことから、
外壁部には引張応力、凹溝を構成する隔壁には圧縮応力
が残留する。この残留応力が内在するセラミックハニカ
ム構造体を排気ガス浄化装置に装着し、高温の排気ガス
に曝され、繰り返し熱衝撃を受けると、過大な熱応力が
外壁部と凹溝の境界面に集中し、外壁部から隔壁へと連
通するクラックが発生するようになることをつきとめ
た。特に、このような凹溝と外壁部の固着力は、隔壁の
気孔率が５０％以上、平均細孔径が１０μｍ以上の場
合、外周壁を形成するためのコート材を塗布する際に、
凹溝を構成する隔壁中の細孔の中にコート材が入り込み
やすく、所謂アンカー効果が大きくなり、隔壁と外壁部
の固着力が大きくなることから、残留応力も大きくな
り、外壁部に発生したクラックが隔壁にまで進展し易か
った。以上は、低熱膨張係数を有するコージェライト質
ハニカム本体を一例として説明したが、アルミナ、ムラ
イト、窒化珪素、炭化珪素等のコージェライト以外のセ
ラミックスによりハニカム本体を形成した場合であって
も、外壁部を形成するためのコート材中には、本体と外
壁部を固着させるために、無機バインダー等の本体を構
成するセラミックス材料以外のものを含有させる必要が
あり、本体と外壁部の熱膨張係数を一致させることは困
難であり、熱衝撃によるクラックが外壁部から隔壁にま
で進展する問題は同様に発生する。本発明者等は、熱衝
撃により外壁部表面に発生したクラックを隔壁にまで、
進展させないような外周壁部の形態に注目して検討し、
本発明に想到した。The inventors of the present invention have a thermal expansion coefficient of a cordierite-based ceramic material generally used for a honeycomb main body and a material mainly composed of cordierite that constitutes the outer wall portion, which cannot be achieved by the conventional techniques. Of the difference in the coefficient of thermal expansion of the, and the development of the thermal shock cracks that accompany it to the partition walls were investigated. The present inventors have produced the conventional cordierite-based ceramic honeycomb structure using the extrusion molding method with reference to Patent Documents 1 and 2, and as a result, the following has been considered. When a raw material of cordierite is extruded and formed into a honeycomb structure, kaolin, which is a hexagonal plate crystal, is oriented along the plane of the partition wall when passing through the narrow slit of the extrusion die. In the subsequent firing process, since hexagonal columnar cordierite crystals are generated in the direction perpendicular to the kaolin crystals,
It is formed so that the c-axis direction of the cordierite crystal is parallel to the partition wall surface of the honeycomb structure. The thermal expansion coefficient of the cordierite crystal has anisotropy, and the a-axis direction is +2.9.
Since x10 -6 / ° C and c-axis direction are -1.1 x 10 -6 / ° C, the coefficient of thermal expansion of the honeycomb structure obtained by extrusion molding and firing the raw material depends on the a-axis in the partition wall thickness direction. Although it has a high coefficient of thermal expansion, it exhibits a low coefficient of thermal expansion due to the combination of the c-axis and the axis of a in the direction parallel to the partition walls, and the honeycomb body as a whole exhibits a low coefficient of thermal expansion. Such a honeycomb body made of cordierite-based ceramics located at the outermost periphery has no partition wall with the outside, and thus has a groove extending in the axial direction that is open to the outside and has a cordier according to the related art. After coating a coating material composed of light aggregate, ceramic fiber, inorganic binder, etc. in a slurry form and then drying or firing it as necessary, the outer wall portion coated with the coating material has an orientation of cordierite crystals. Since it is not possible and contains ceramic fibers and inorganic binders having different thermal expansion coefficients, the thermal expansion coefficient is inevitably higher than that of the partition wall in which the cordierite crystals are oriented. The outer wall portion and the concave groove having such a difference in thermal expansion coefficient are filled with the member forming the outer wall portion up to the corners of the concave groove as shown in FIG. Since they are firmly fixed and integrated by the adhesive force of the binder or the like, the residual stress due to the adhesion is inherent in the interface between the two. Specifically, since the coefficient of thermal expansion of the outer wall portion is larger than the partition wall,
Tensile stress remains on the outer wall portion and compressive stress remains on the partition walls forming the groove. When the ceramic honeycomb structure containing the residual stress is installed in the exhaust gas purifying apparatus and exposed to high temperature exhaust gas and repeatedly subjected to thermal shock, excessive thermal stress is concentrated on the boundary surface between the outer wall portion and the concave groove. , It was found that cracks will be generated from the outer wall portion to the partition wall. In particular, when the partition wall has a porosity of 50% or more and an average pore diameter of 10 μm or more, the adhesive force between the concave groove and the outer wall portion is, when applying the coating material for forming the outer peripheral wall,
The coating material easily enters the pores in the partition walls that form the recessed groove, the so-called anchor effect increases, and the fixing force between the partition walls and the outer wall portion increases, so that the residual stress also increases and it occurs in the outer wall portion. It was easy for cracks to reach the partition walls. The above is described as an example of a cordierite honeycomb main body having a low coefficient of thermal expansion. In order to fix the main body and the outer wall portion in the coating material for forming the, it is necessary to include other than the ceramic material constituting the main body such as an inorganic binder, and the thermal expansion coefficient of the main body and the outer wall portion It is difficult to make them coincide with each other, and the problem that cracks due to thermal shock propagate from the outer wall portion to the partition wall similarly occurs. The present inventors, to the partition wall cracks generated on the outer wall surface due to thermal shock,
Pay attention to the shape of the outer peripheral wall that does not progress,
The present invention was conceived.
【００１２】即ち、本発明のセラミックハニカム構造体
は、隔壁で囲まれた多数のセルのうち、最外周に位置す
るセルが、外部との間の隔壁を有しないことによって、
外部に開口して軸方向に延びる凹溝を形成しているセラ
ミックハニカム本体の、前記凹溝を充填して外表面を形
成する外壁部を有するセラミックハニカム構造体におい
て、前記外壁部と凹溝との間の少なくとも一部に応力開
放部を有することを特徴とする。また、本発明のセラミ
ックハニカム構造体は、隔壁で囲まれた多数のセルのう
ち、最外周に位置するセルが、外部との間の隔壁を有し
ないことによって、外部に開口して軸方向に延びる凹溝
を形成しているセラミックハニカム本体の、前記凹溝を
充填して外表面を形成する外壁部を有するセラミックハ
ニカム構造体において、前記外壁部及び外壁部と凹溝と
の間のそれぞれの少なくとも一部に応力開放部を有する
ことを特徴とする。本発明のセラミックハニカム構造体
において、前記外壁部における応力開放部が外表面に開
口した空隙部であることが好ましい。また、本発明のセ
ラミックハニカム構造体において、前記外表面に開口し
た空隙部の長さの合計がセラミックハニカム構造体全長
の１倍以上であることが好ましい。本発明のセラミック
ハニカム構造体において、前記外壁部と凹溝の間の応力
開放部が前記外壁部を構成する部材と凹溝の間に形成さ
れた空隙であることが好ましい。また、本発明のセラミ
ックハニカム構造体において、前記外壁部を構成する部
材と凹溝の間に形成された空隙部を有する凹溝の個数割
合が全凹溝のうちの５％以上であることが好ましく、２
０％以上であることが更に好ましい。さらには、本発明
のセラミックハニカム構造体において、前記隔壁を構成
する材料の気孔率が５０〜８０％、平均細孔径が１０〜
５０μｍであることが好ましい。That is, in the ceramic honeycomb structure of the present invention, among a large number of cells surrounded by partition walls, the cells located at the outermost periphery do not have partition walls with the outside,
In a ceramic honeycomb body having an outer wall portion that is open to the outside and forms a groove extending in the axial direction, and has an outer wall portion that fills the groove and forms an outer surface, the outer wall portion and the groove It has a stress relief part in at least one part between. Further, the ceramic honeycomb structure of the present invention, among a large number of cells surrounded by partition walls, the cells located at the outermost periphery do not have partition walls with the outside, and thus are opened to the outside in the axial direction. In the ceramic honeycomb main body forming the extending concave groove, in the ceramic honeycomb structure having an outer wall portion that fills the concave groove to form an outer surface, each of the outer wall portion and the outer wall portion between the concave groove It is characterized in that it has a stress releasing portion in at least a part thereof. In the ceramic honeycomb structure of the present invention, it is preferable that the stress releasing portion in the outer wall portion is a void portion having an opening on the outer surface. Further, in the ceramic honeycomb structure of the present invention, it is preferable that the total length of the voids opened on the outer surface is not less than 1 time the total length of the ceramic honeycomb structure. In the ceramic honeycomb structure of the present invention, it is preferable that the stress releasing portion between the outer wall portion and the groove is a void formed between the member forming the outer wall portion and the groove. Further, in the ceramic honeycomb structure of the present invention, the number of recessed grooves having voids formed between the member forming the outer wall portion and the recessed grooves is 5% or more of all the recessed grooves. Preferably 2
It is more preferably 0% or more. Furthermore, in the ceramic honeycomb structure of the present invention, the material forming the partition walls has a porosity of 50 to 80% and an average pore diameter of 10 to 10.
It is preferably 50 μm.
【００１３】以下、本発明の作用、効果について説明す
る。本発明のセラミックハニカム構造体は、隔壁で囲ま
れた多数のセルのうち、最外周に位置するセルが、外部
との間の隔壁を有しないことによって、外部に開口して
軸方向に延びる凹溝を形成しているセラミックハニカム
本体の、前記凹溝を充填して外表面を形成する外壁部を
有するセラミックハニカム構造体において、前記外壁部
と凹溝との間の少なくとも一部に応力開放部を有する場
合には、ハニカム構造体の耐熱衝撃性が大幅に向上す
る。即ち、本発明のセラミックハニカム構造体が例えば
排気ガスにより急熱された場合には、熱衝撃により外壁
部に発生する応力を開放するための応力開放部が外壁部
と凹溝との間の少なくとも一部に形成されていると、こ
の応力開放部が熱衝撃応力を開放し、クラックが隔壁に
進展しにくくなるため、隔壁が脱落して排ガスの浄化性
能が低下したり、微粒子捕集用フィルタの場合は、入口
側と出口側の流路が連通し、微粒子の捕集率が低下する
といった、排気ガス浄化装置の浄化性能に係わる、致命
的な問題に発展することを防ぐことが出来るのである。
また、本発明のセラミックハニカム構造体は、隔壁で囲
まれた多数のセルのうち、最外周に位置するセルが、外
部との間の隔壁を有しないことによって、外部に開口し
て軸方向に延びる凹溝を形成しているセラミックハニカ
ム本体の、前記凹溝を充填して外表面を形成する外壁部
を有するセラミックハニカム構造体において、前記外壁
部及び外壁部と凹溝との間のそれぞれの少なくとも一部
に応力開放部を有することから、更にハニカム構造体の
耐熱衝撃性が大幅に向上する。即ち、応力開放部が外壁
部及び外壁部と凹溝との間のそれぞれの少なくとも一部
に存在する場合には、熱衝撃応力を開放する効果がより
大きくなり、熱衝撃によるクラックが隔壁に進展するの
を防止する効果がより大きくなる。このため、隔壁が脱
落して排ガスの浄化性能が低下したり、微粒子捕集用フ
ィルタの場合は、入口側と出口側の流路が連通し、微粒
子の捕集率が低下するといった、排気ガス浄化装置の浄
化性能に係わる、致命的な問題に発展することを防ぐこ
とが出来るのである。本発明のセラミックハニカム構造
体は、前記外壁部における応力開放部が外表面に開口し
た空隙部である場合には、ハニカム構造体の耐熱衝撃性
が大幅に向上する。即ち、本発明のセラミックハニカム
構造体が例えば排気ガスにより急熱された場合には、予
め外壁部の外表面に開口した空隙部が形成されているこ
とから、当該空隙部の開口幅が拡大することによって、
外壁部に作用する熱衝撃応力が開放されるため、熱衝撃
によるクラックが、外壁部と隔壁との接合界面を超え、
隔壁に進展することを防げるのである。ここでいう空隙
部とは外表面における開口幅が代表的には２μｍ以上で
長さ１００μｍ以上の細長い形状のものを指し、外壁部
に形成された、セラミック骨材、無機バインダー等の間
に存在する気孔とは区別されるものである。例えば、図
４に模式図に示すように、空隙部２１は、軸方向に延び
る凹溝１２に充填された外壁部１６の外表面に形成され
ており、その深さ方向の先端は、外壁部内で閉じている
場合や、凹溝１２まで到達している場合等がある。意図
的に形成した、この空隙部を外表面側から観察した走査
型電子顕微鏡写真を図５に示す。また、空隙部は図６
（ａ）（ｂ）（ｃ）に示すように、軸方向に存在する場
合のみならず、図６（ｄ）（ｅ）に示すように円周方向
等に存在しても良いし、図６（ｆ）に示すように亀甲状
に存在しても、前記述べたように熱衝撃による応力を開
放する効果がある。ここで、前記外表面に開口した空隙
部の長さの合計がセラミックハニカム構造体全長の１倍
以上であることが好ましいとしたのは、空隙部が多数存
在すれば、熱衝撃応力を開放する観点からすれば、効果
が大きいのであるが、空隙部の長さの合計がセラミック
ハニカム構造体全長の１倍以上あれば、少なくともハニ
カム構造体の外壁部に発生する熱衝撃応力の円周方向成
分をセラミックハニカム構造体の全長に亘って開放でき
ることから、熱衝撃性向上の効果が得られるためであ
る。ここで、空隙部の長さの合計とは、ハニカム構造体
１ケ中の外表面に開口した空隙部長さの合計のことであ
り、ハニカム構造体１ヶ中に複数存在する場合はこれら
の総和で表す。例えば、図６（ａ）は、空隙部の長さの
合計がセラミックハニカム構造体全長の１倍に相当し、
図６（ｃ）は、空隙部の長さの合計がセラミックハニカ
ム構造体全長の１倍より少し大きい場合に相当する。
尚、空隙部の長さの合計がセラミックハニカム構造体全
長の３倍以上であれば、よりその効果が大きくなる。The operation and effect of the present invention will be described below. The ceramic honeycomb structure of the present invention has, among a large number of cells surrounded by partition walls, the cells located at the outermost periphery have no partition walls with the outside, so that the cells open to the outside and extend in the axial direction. In a ceramic honeycomb structure having an outer wall portion that fills the concave groove to form an outer surface of a ceramic honeycomb body having a groove formed therein, a stress releasing portion is provided at least at a part between the outer wall portion and the concave groove. In the case of having, the thermal shock resistance of the honeycomb structure is significantly improved. That is, when the ceramic honeycomb structure of the present invention is rapidly heated by, for example, exhaust gas, the stress releasing portion for releasing the stress generated in the outer wall portion by thermal shock is at least between the outer wall portion and the concave groove. If partly formed, this stress relief part releases thermal shock stress, and cracks are less likely to propagate to the partition walls, so the partition walls fall off and the exhaust gas purification performance deteriorates, and the particulate collection filter. In the case of, it is possible to prevent the development of a fatal problem relating to the purification performance of the exhaust gas purification device, such as the passage of the inlet side and the flow path of the outlet side, which reduces the collection rate of fine particles. is there.
Further, the ceramic honeycomb structure of the present invention, among a large number of cells surrounded by partition walls, the cells located at the outermost periphery do not have partition walls with the outside, and thus are opened to the outside in the axial direction. In the ceramic honeycomb main body forming the extending concave groove, in the ceramic honeycomb structure having an outer wall portion that fills the concave groove to form an outer surface, each of the outer wall portion and the outer wall portion between the concave groove Since the stress relief portion is provided at least in part, the thermal shock resistance of the honeycomb structure is further significantly improved. That is, when the stress relief portion is present in at least a part of each of the outer wall portion and between the outer wall portion and the concave groove, the effect of releasing the thermal shock stress becomes larger, and cracks due to thermal shock propagate to the partition wall. The effect of preventing this is further increased. For this reason, the partition wall falls off to lower the exhaust gas purification performance, and in the case of a particulate collection filter, the flow path on the inlet side and the outlet side communicates with each other, and the particulate collection rate decreases. It is possible to prevent the development of a fatal problem related to the purification performance of the purification device. In the ceramic honeycomb structure of the present invention, the thermal shock resistance of the honeycomb structure is significantly improved when the stress release part in the outer wall part is a void part opened on the outer surface. That is, when the ceramic honeycomb structure of the present invention is rapidly heated by, for example, exhaust gas, the opening width of the opening portion is expanded because the opening portion is previously formed on the outer surface of the outer wall portion. By
Since the thermal shock stress acting on the outer wall is released, the crack due to the thermal shock exceeds the joint interface between the outer wall and the partition wall,
It is possible to prevent the progress to the partition wall. The term “void” as used herein refers to an elongated shape having an opening width on the outer surface of typically 2 μm or more and a length of 100 μm or more, and is present between the ceramic aggregate, the inorganic binder, etc. formed on the outer wall. It is to be distinguished from the pores. For example, as shown in the schematic view of FIG. 4, the void portion 21 is formed on the outer surface of the outer wall portion 16 filled in the recessed groove 12 extending in the axial direction, and the distal end in the depth direction is inside the outer wall portion. There is a case where it is closed with, or a case where it reaches the groove 12. FIG. 5 shows a scanning electron micrograph of the intentionally formed void portion observed from the outer surface side. In addition, the void is shown in FIG.
As shown in (a), (b) and (c), it may exist not only in the axial direction but also in the circumferential direction as shown in FIGS. Even if it exists in a hexagonal shape as shown in (f), it has an effect of releasing stress due to thermal shock as described above. Here, the total length of the voids opened on the outer surface is preferably 1 time or more of the total length of the ceramic honeycomb structure, because the thermal shock stress is released if there are a large number of voids. From the viewpoint, the effect is great, but if the total length of the voids is at least 1 time the total length of the ceramic honeycomb structure, at least the circumferential component of the thermal shock stress generated in the outer wall of the honeycomb structure This is because the ceramic honeycomb structure can be opened over the entire length, so that the effect of improving the thermal shock resistance can be obtained. Here, the total length of the voids is the total length of the voids opened on the outer surface of one honeycomb structure, and when there are a plurality of honeycomb structures, the total of these is present. It is represented by. For example, in FIG. 6A, the total length of the voids corresponds to one time the total length of the ceramic honeycomb structure,
FIG. 6C corresponds to the case where the total length of the voids is slightly larger than one time the total length of the ceramic honeycomb structure.
If the total length of the voids is at least 3 times the total length of the ceramic honeycomb structure, the effect will be greater.
【００１４】また、本発明のセラミックハニカム構造体
は、前記外壁部と凹溝の間の応力開放部が外壁部を構成
する部材と凹溝の間に形成された空隙である場合には、
ハニカム構造体の耐熱衝撃性が大幅に向上する。即ち、
本発明のセラミックハニカム構造体は、図３に示すよう
な空隙が無く凹溝の角隅部にまで外壁部を構成する部材
が充填されている従来技術に比べて、図７及び図８に示
すように外壁部を構成する部材と凹溝の間に空隙が形成
されていることから、例えば排気ガスにより急熱された
場合には、外壁部外表面に発生する熱衝撃応力により発
生したクラックが外壁部と凹溝を構成する隔壁の間に形
成された空隙で吸収され、結果として熱衝撃応力が開放
することになるため、このクラックが外壁部と隔壁との
接合界面を超え、隔壁に進展することを防げるのであ
る。また、本発明のセラミックハニカム構造体は、外壁
部と凹溝を構成する隔壁の間の接着面積が小さいことか
ら、両者界面の熱膨張係数差により生じる残留応力が低
減できるため、熱衝撃によるクラックが発生しにくいと
いう効果も有している。本発明のセラミックハニカム構
造体において、前記外壁部を構成する部材と凹溝の間に
空隙部を有する凹溝の個数割合が全凹溝のうちの５％以
上であることが好ましいのは、前記外壁部を構成する部
材と凹溝の間に空隙部を有する凹溝が多数存在する場合
には、熱衝撃応力を開放する観点からすれば、効果が大
きいからである。２０％以上であれば更に好ましい。前
記外壁部を構成する部材と凹溝の間に空隙部を有する凹
溝の個数割合が９５％を超えると、凹溝を構成する隔壁
と、外壁部を構成する部材間の接着面積が減少し、アイ
ソスタティック強度が低下すると共に、外壁部がセラミ
ックハニカム本体から剥離し易くなるため好ましくな
い。外壁部を構成する部材と凹溝の間に空隙部を有する
凹溝のより好ましい個数割合は全凹溝のうちの２０〜９
０％である。ここで、外壁部を構成する部材と凹溝の間
に空隙部を有する凹溝とは、図７に断面模式図で示すよ
うに隔壁で囲まれた多数のセルのうち、最外周に位置す
るセルが、外部との間の隔壁を有しないことによって、
外部に開口して軸方向に延びる凹溝を形成しているセラ
ミックハニカム本体の、前記凹溝の全領域が外周壁部材
で充填されていない凹溝のことをいい、図８に示すよう
に、凹溝を構成する隔壁の端部５１、５４と凹溝を構成
する隔壁の交点５２、５３で形成される凹溝長さ５１−
５２−５３−５４のうち、外壁部を構成する部材と接触
している部分の長さ即ち、接触部長さ５１−５５、５６
−５７、５８−５４の合計長さの割合が９５％以下の凹
溝のことをいう。ここで、外壁部を構成する部材と凹溝
の間に形成された空隙について凹溝の一断面を用いて説
明したが、この空隙は、ハニカム構造体の軸方向に連続
的に形成されていると、ハニカム構造体全体に発生する
熱衝撃応力を解法する意味で好ましい。但し、この空隙
の形態は例えば図８に示す形態が、軸方向全長に亘って
全て同一である必要はなく、凹溝長さに対する外壁部を
構成する部材と隔壁の接触長さの割合が異なっても、熱
応力を開放する効果は有している。Further, in the ceramic honeycomb structure of the present invention, when the stress releasing portion between the outer wall portion and the groove is a void formed between the member forming the outer wall portion and the groove,
The thermal shock resistance of the honeycomb structure is significantly improved. That is,
The ceramic honeycomb structure of the present invention is shown in FIGS. 7 and 8 as compared with the prior art in which there is no void as shown in FIG. 3 and the members forming the outer wall portion are filled up to the corners of the groove. Since a gap is formed between the member forming the outer wall portion and the recessed groove, cracks generated by thermal shock stress generated on the outer surface of the outer wall portion are generated, for example, when rapidly heated by exhaust gas. It is absorbed by the voids formed between the outer wall and the partition wall that forms the concave groove, and as a result, the thermal shock stress is released, so this crack propagates to the partition wall beyond the bonding interface between the outer wall part and the partition wall. You can prevent what you do. Further, since the ceramic honeycomb structure of the present invention has a small bonding area between the outer wall portion and the partition wall forming the concave groove, residual stress caused by a difference in thermal expansion coefficient between both interfaces can be reduced, and thus cracks due to thermal shock can be reduced. It also has the effect of being less likely to occur. In the ceramic honeycomb structure of the present invention, it is preferable that the ratio of the number of concave grooves having a void between the member forming the outer wall portion and the concave groove is 5% or more of all the concave grooves. This is because when a large number of recessed grooves having voids are present between the member forming the outer wall portion and the recessed grooves, the effect is great from the viewpoint of releasing the thermal shock stress. 20% or more is more preferable. When the ratio of the number of concave grooves having a void portion between the member forming the outer wall portion and the concave groove exceeds 95%, the adhesion area between the partition wall forming the concave groove and the member forming the outer wall portion decreases. However, it is not preferable because the isostatic strength is lowered and the outer wall portion is easily separated from the ceramic honeycomb body. A more preferable number ratio of the concave grooves having a void between the member forming the outer wall portion and the concave grooves is 20 to 9 of all the concave grooves.
It is 0%. Here, the member forming the outer wall portion and the concave groove having a void portion between the concave grooves are located at the outermost periphery of a large number of cells surrounded by partition walls as shown in the schematic cross-sectional view of FIG. 7. By having no partition between the cell and the outside,
Of the ceramic honeycomb main body that is formed with a groove extending outward in the axial direction and forming a groove extending in the axial direction, it means a groove in which the entire area of the groove is not filled with an outer peripheral wall member, and as shown in FIG. The groove length 51- formed by the intersections 52, 53 of the partition wall ends 51, 54 forming the groove and the partition wall forming the groove.
52-53-54, the length of the portion in contact with the member forming the outer wall portion, that is, the contact portion length 51-55, 56
-57, 58-54: A groove having a total length ratio of 95% or less. Here, the void formed between the member forming the outer wall portion and the concave groove has been described using one cross section of the concave groove, but the void is continuously formed in the axial direction of the honeycomb structure. And is preferable in the sense of solving the thermal shock stress generated in the entire honeycomb structure. However, the shape of the void does not have to be the same over the entire length in the axial direction, for example, in the shape shown in FIG. 8, and the ratio of the contact length between the member forming the outer wall portion and the partition wall to the groove length is different. However, it has the effect of releasing thermal stress.
【００１５】本発明のセラミックハニカム構造体におい
て、前記隔壁を構成する材料の気孔率が５０〜８０％、
平均細孔径が１０〜５０μｍであることが好ましいの
は、以下の理由による。本発明の外部に開口して軸方向
に伸びる凹溝を形成しているハニカム本体の凹溝を充填
して外表面を形成する外壁部を形成し、凹溝を構成する
隔壁と外壁部を一体化させたハニカム構造体において、
気孔率が５０％以上の場合は、外壁部を構成する材料が
隔壁中の気孔に入り込みやすく、所謂アンカー効果が大
きくなり、外壁部と凹溝が一体化され、ハニカム構造体
の機械的強度を大きくできることから好ましいが、気孔
率が８０％を越える場合は、ハニカム構造体の隔壁自体
の強度が低下し、ハニカム構造体の機械的強度が低下す
るから好ましくない。ここで言う、機械的強度は例えば
アイソスタティック強度で代表され、ハニカム構造体の
アイソスタティック強度が低下すると、触媒担体や微粒
子捕集フィルタとして使用された際に、エンジンからの
振動や、路面振動等の機械的応力により破損し、排気ガ
ス浄化性能が低下する場合があるので好ましくない。ま
た、同様に、平均細孔径が１０μｍ以上の場合は、外壁
部を構成する材料が隔壁中の気孔に入り込みやすく、所
謂アンカー効果が大きくなり、外壁部と凹溝が一体化さ
れ、ハニカム構造体の機械的強度を大きくできることか
ら好ましいが、平均細孔径が５０μｍを越える場合は、
ハニカム構造体の隔壁自体の強度が低下し、ハニカム構
造体の機械的強度が低下するから好ましくない。また、
気孔率を５０％以上、平均細孔径を１０μｍ以上とした
場合、上記のように外壁部と凹溝が強固に固着されるこ
とから、特許文献１や特許文献２の従来技術のセラミッ
クハニカム構造体の場合は、耐熱衝撃性が低下するので
あるが、本発明のセラミックハニカム構造体の場合は、
外壁部又は外壁部と凹溝の間に応力開放部を有している
ので、耐熱衝撃性の低下を小さくすることができる。
尚、ハニカム構造体の隔壁の機械的強度低下を防ぐため
には、上記のように気孔率及び平均細孔径の範囲を調整
するのと共に、隔壁中の細孔の形状を略球状にすること
により、粗大な細孔への応力集中を低減できることから
好ましい。In the ceramic honeycomb structure of the present invention, the material forming the partition walls has a porosity of 50 to 80%,
The reason why the average pore size is preferably 10 to 50 μm is as follows. The outer wall portion forming the outer surface is formed by filling the concave groove of the honeycomb main body forming the concave groove that is open to the outside and extends in the axial direction of the present invention, and the partition wall and the outer wall portion that form the concave groove are integrated. In the converted honeycomb structure,
When the porosity is 50% or more, the material forming the outer wall portion easily enters the pores in the partition wall, the so-called anchor effect is increased, the outer wall portion and the concave groove are integrated, and the mechanical strength of the honeycomb structure is improved. It is preferable because the porosity can be increased, but when the porosity exceeds 80%, the strength of the partition walls of the honeycomb structure decreases, and the mechanical strength of the honeycomb structure decreases, which is not preferable. Here, the mechanical strength is represented by, for example, isostatic strength, and when the isostatic strength of the honeycomb structure decreases, vibration from the engine, road surface vibration, etc. when used as a catalyst carrier or a particulate collection filter, etc. It is not preferable because it may be damaged by the mechanical stress and the exhaust gas purification performance is deteriorated. Similarly, when the average pore diameter is 10 μm or more, the material forming the outer wall portion easily enters the pores in the partition wall, the so-called anchor effect is increased, and the outer wall portion and the concave groove are integrated to form a honeycomb structure. Is preferable because the mechanical strength of can be increased, but when the average pore diameter exceeds 50 μm,
This is not preferable because the strength of the partition walls of the honeycomb structure decreases and the mechanical strength of the honeycomb structure decreases. Also,
When the porosity is 50% or more and the average pore diameter is 10 μm or more, the outer wall portion and the concave groove are firmly fixed to each other as described above. Therefore, the conventional ceramic honeycomb structure of Patent Document 1 or Patent Document 2 is used. In the case of, the thermal shock resistance decreases, but in the case of the ceramic honeycomb structure of the present invention,
Since the stress relief portion is provided between the outer wall portion or between the outer wall portion and the concave groove, it is possible to reduce the decrease in thermal shock resistance.
Incidentally, in order to prevent the mechanical strength of the partition walls of the honeycomb structure from decreasing, by adjusting the range of the porosity and the average pore diameter as described above, and by making the shape of the pores in the partition walls substantially spherical, It is preferable because stress concentration on coarse pores can be reduced.
【００１６】本発明のセラミックハニカム構造体を構成
するセラミック材料としては、本発明が主に、自動車エ
ンジンの排気ガス浄化用触媒の担体として或いはディー
ゼルエンジンの排気ガス中の微粒子を除去するためのフ
ィルタとして使用されるため、耐熱性に優れた材料を使
用することが好ましく、コージェライト、アルミナ、ム
ライト、窒化珪素、炭化珪素及びＬＡＳからなる群から
選ばれた少なくとも１種を主結晶とするセラミック材料
を用いることが好ましい。中でも、コージェライトを主
結晶とするセラミックハニカム構造体は、安価で耐熱
性、耐化学性に優れ、また低熱膨張であることから最も
好ましい。本発明のセラミックハニカム構造体におい
て、外壁部を構成する部材としては、本発明が凹溝を構
成する隔壁と、該凹溝に充填された外壁部の熱膨張係数
差があったとしても耐熱衝撃性を改善せしめていること
から、必ずしも熱膨張係数を一致させる必要はなく、凹
溝を構成する隔壁の熱膨張係数に対して外壁部を構成す
る部材の熱膨張係数が大きくても、小さくても良く、例
えばコージェライト、シリカ、アルミナ、ムライト、炭
化珪素、窒化珪素等から選ばれる耐熱性セラミックス骨
材粒子に無機バインダー、必要に応じてセラミックファ
イバー、セメント等を添加したものを適宜選択すれば良
い。As the ceramic material constituting the ceramic honeycomb structure of the present invention, the present invention is mainly used as a carrier for an exhaust gas purifying catalyst of an automobile engine or a filter for removing fine particles in an exhaust gas of a diesel engine. Therefore, it is preferable to use a material having excellent heat resistance, and a ceramic material containing at least one selected from the group consisting of cordierite, alumina, mullite, silicon nitride, silicon carbide and LAS as a main crystal. Is preferably used. Among them, the ceramic honeycomb structure having cordierite as a main crystal is most preferable because it is inexpensive, has excellent heat resistance and chemical resistance, and has low thermal expansion. In the ceramic honeycomb structure of the present invention, as the member constituting the outer wall portion, even if there is a difference in thermal expansion coefficient between the partition wall forming the concave groove of the present invention and the outer wall portion filled in the concave groove, thermal shock resistance Since the thermal expansion coefficient is improved, it is not always necessary to match the thermal expansion coefficient, and even if the thermal expansion coefficient of the member forming the outer wall portion is larger than the thermal expansion coefficient of the partition wall forming the concave groove, It is also possible to appropriately select, for example, a material obtained by adding a heat-resistant ceramic aggregate particle selected from cordierite, silica, alumina, mullite, silicon carbide, silicon nitride, etc., to an inorganic binder, and optionally ceramic fiber, cement, etc. good.
【００１７】本発明のセラミックハニカム構造体の隔壁
厚は０．１〜０．５ｍｍが好ましく、隔壁のピッチは
１．３ｍｍ以上が好ましい。隔壁厚が０．１ｍｍ未満の
場合は、特に外径が１５０ｍｍを越えるようなハニカム
構造体を製造する際に隔壁の強度が低下し、好ましくな
い。一方、隔壁厚が０．５ｍｍを超える場合は、ハニカ
ム構造体の排気ガスに対する隔壁の通気抵抗が大きくな
り、圧力損失が大きくなるからである。より好ましい隔
壁厚さは、０．２〜０．４ｍｍである。また、隔壁のピ
ッチが１．３ｍｍ未満の場合は、ハニカム構造体のセル
の開口面積が小さくなることから、ハニカム構造体の入
口の圧力損失が大きくなるためである。ハニカム構造体
の圧力損失が大きくなると、エンジンの出力低下につな
がることから好ましくない。本発明のセラミックハニカ
ム構造体は、外径１５０ｍｍ以上、全長１５０ｍｍ以上
の所謂大型ハニカム構造体であることが好ましい。大型
ハニカム構造体の場合、熱衝撃が作用した際に、ハニカ
ム構造体の中心と表面の温度差が大きくなるため、クラ
ックが隔壁に進展しやすくなるため、本発明の応力開放
部により耐熱衝撃性を改善する効果が有効に現れるから
である。The partition wall thickness of the ceramic honeycomb structure of the present invention is preferably 0.1 to 0.5 mm, and the partition wall pitch is preferably 1.3 mm or more. When the partition wall thickness is less than 0.1 mm, the strength of the partition wall is reduced, especially when manufacturing a honeycomb structure having an outer diameter of more than 150 mm, which is not preferable. On the other hand, when the partition wall thickness exceeds 0.5 mm, the ventilation resistance of the partition wall with respect to the exhaust gas of the honeycomb structure increases, and the pressure loss increases. A more preferable partition wall thickness is 0.2 to 0.4 mm. Further, when the pitch of the partition walls is less than 1.3 mm, the opening area of the cells of the honeycomb structure becomes small, so that the pressure loss at the inlet of the honeycomb structure becomes large. If the pressure loss of the honeycomb structure increases, it leads to a decrease in the output of the engine, which is not preferable. The ceramic honeycomb structure of the present invention is preferably a so-called large-sized honeycomb structure having an outer diameter of 150 mm or more and a total length of 150 mm or more. In the case of a large-sized honeycomb structure, when a thermal shock acts, the temperature difference between the center and the surface of the honeycomb structure becomes large, so that cracks easily propagate to the partition walls, and therefore the thermal shock resistance of the present invention is improved. This is because the effect of improving
【００１８】本発明の外表面に開口した空隙部を有する
セラミックハニカム構造体を製造するには、例えばセラ
ミックハニカム構造の焼成体の外周壁３とその周縁部を
所定寸法より小さくする除去加工を行った後、最外周に
位置するセルが、外部との間の隔壁を有しないことによ
って、外部に開口して軸方向に延びる凹溝にセラミック
骨材及び無機バインダからなるコート材を塗布、充填さ
せ、例えば７０℃以上に加熱させられた乾燥炉に、投入
してコート材中に含まれる水分を急速乾燥することによ
り、コート材表面に開口した空隙部を形成させることが
できる。この空隙部が発生するのは急速乾燥によりコー
ティングされたコート材の表面と内部の水分量に差が生
じ、表面と内部の乾燥収縮量の差が発生するからであ
る。このコート材としては、コージェライト、シリカ、
アルミナ、ムライト、炭化珪素、窒化珪素等から選ばれ
る耐熱性セラミックス骨材粒子にセラミックファイバ
ー、セメント、無機バインダー、水等を単独で或いは混
合して用いることができ、更に必要に応じて有機バイン
ダー等を混合することもできるが、これらに限定される
ものではない。このとき、コート材中の骨材、無機バイ
ンダ−や有機バインダーの種類や添加量、水分量、或い
は乾燥炉の温度を調整することにより、外表面に開口し
た空隙部の発生割合、空隙部の開口幅、空隙部の形態を
変化させることができるが、無機バインダの添加量や水
分量を増加させると空隙部は発生し易くなる。なお、コ
ート材の乾燥が終了した後は、必要に応じてコート材の
焼成を行っても良い。In order to manufacture the ceramic honeycomb structure having the open voids on the outer surface of the present invention, for example, removal processing is performed to make the outer peripheral wall 3 and the peripheral portion of the fired body of the ceramic honeycomb structure smaller than a predetermined size. After that, since the cells located at the outermost periphery do not have a partition wall with the outside, the coating material composed of the ceramic aggregate and the inorganic binder is applied and filled in the groove that opens to the outside and extends in the axial direction. For example, by pouring it into a drying oven heated to 70 ° C. or higher to rapidly dry the water contained in the coating material, it is possible to form voids opened on the surface of the coating material. The reason why the voids are generated is that a difference in water content between the surface and the inside of the coating material coated by rapid drying causes a difference in the amount of drying shrinkage between the surface and the inside. As the coating material, cordierite, silica,
Heat-resistant ceramic aggregate particles selected from alumina, mullite, silicon carbide, silicon nitride, etc. can be used alone or in combination with ceramic fibers, cement, inorganic binder, water, etc., and further, an organic binder, etc., if necessary. Can be mixed, but is not limited thereto. At this time, by adjusting the aggregate in the coating material, the type and addition amount of the inorganic binder and the organic binder, the water content, or the temperature of the drying furnace, the generation ratio of the voids opened on the outer surface, The opening width and the morphology of the voids can be changed, but the voids are more likely to occur when the addition amount of the inorganic binder and the water content are increased. After the drying of the coating material is completed, the coating material may be fired if necessary.
【００１９】また、本発明の外壁部を構成する部材と凹
溝の間に空隙を有するセラミックハニカム構造体を製造
するには、セラミックハニカム構造の焼成体の外周壁３
とその周縁部を所定寸法より小さくする除去加工を行っ
た後、最外周に位置するセルが、外部との間の隔壁を有
しないことによって、外部に開口して軸方向に延びる凹
溝に粘度を２００００ｃＰ以上に調整したコート材を塗
布、充填させた後、乾燥させる。従来の特許文献１の方
法のように、１００００ｃＰ〜２００００ｃＰの粘度を
有するコート材を塗布した場合には、図３に示すように
凹溝１２の角隅部にまでコート材が充填され易いのであ
るが、コート材の粘度を２００００ｃＰ以上の高粘度と
することにより、図７及び図８に示すように凹溝の角隅
部までコート材が充填されないため、外壁部を構成する
部材と凹溝との間に空隙を有するセラミックハニカム構
造体が得られる。尚、コート材の粘度を２００００ｃＰ
以上の高粘度にするには、骨材、無機バインダ−や有機
バインダーの種類や添加量、水分量等を調整することに
より可能となる。また、コート材の乾燥が終了した後
は、必要に応じてコート材の焼成を行っても良い。In order to manufacture a ceramic honeycomb structure having a void between the member constituting the outer wall portion and the concave groove of the present invention, the outer peripheral wall 3 of the fired body having the ceramic honeycomb structure is manufactured.
After performing the removal process to make the peripheral part smaller than a predetermined size, the cell located at the outermost periphery does not have a partition wall with the outside, so that the viscosity of the groove that opens to the outside and extends in the axial direction is increased. Is coated and filled with the coating material adjusted to 20000 cP or more, and then dried. When a coating material having a viscosity of 10000 cP to 20000 cP is applied as in the conventional method of Patent Document 1, the coating material is likely to be filled up to the corners of the concave groove 12 as shown in FIG. However, by setting the viscosity of the coating material to 20000 cP or higher, the coating material is not filled up to the corners of the groove as shown in FIGS. 7 and 8, so that the member forming the outer wall portion and the groove are formed. A ceramic honeycomb structure having voids between them is obtained. The viscosity of the coating material is 20000 cP
The above-mentioned high viscosity can be obtained by adjusting the kinds and addition amounts of the aggregate, the inorganic binder and the organic binder, the water content and the like. Further, after the drying of the coating material is completed, the coating material may be fired if necessary.
【００２０】尚、本発明のセラミックハニカム構造体を
製造する際の、コート材の塗布については、前記のよう
にセラミックハニカム構造の焼成体の外周壁３とその周
縁部を所定寸法より小さくする除去加工を行った後、最
外周に位置するものが、外部との間の隔壁を有しないこ
とによって、外部に開口して軸方向に延びる凹溝にコー
ト材を充填しても良いし、セラミックハニカム構造の乾
燥体の外周壁３とその周縁部を所定寸法より小さくする
除去加工を行った後、焼成を行った上で、外部に開口し
て軸方向に延びる凹溝にコート材を充填しても良いし、
セラミックハニカム構造の乾燥体の外周壁３とその周縁
部を所定寸法より小さくする除去加工を行った後、外部
に開口して軸方向に延びる凹溝にコート材を充填して、
焼成を行っても良い。As to the coating of the coating material when manufacturing the ceramic honeycomb structure of the present invention, the outer peripheral wall 3 of the fired body of the ceramic honeycomb structure and its peripheral portion are removed by making them smaller than a predetermined size as described above. After processing, the outermost one does not have a partition wall with the outside, so that a groove may be opened to the outside and extended in the axial direction with a coating material, or a ceramic honeycomb. After removing the outer peripheral wall 3 and the peripheral portion of the dried body having a structure smaller than a predetermined dimension, baking is performed, and then, a groove is opened to the outside and extends in the axial direction, and a coating material is filled therein. Is also good
After removing the outer peripheral wall 3 of the dried body having a ceramic honeycomb structure and its peripheral portion to a size smaller than a predetermined size, a groove is formed to be open to the outside and extend in the axial direction with a coating material.
Baking may be performed.
【００２１】以上、説明のとおり、本発明のセラミック
ハニカム構造体によれば、隔壁で囲まれた多数のセルの
うち、最外周に位置するセルが、外部との間の隔壁を有
しないことによって、外部に開口して軸方向に延びる凹
溝を形成しているセラミックハニカム本体の、前記凹溝
を充填して外表面を有する外壁部を形成させたセラミッ
クハニカム構造体において、前記凹溝と外壁部を構成す
る部材との間に形成された空隙といった応力開放部を少
なくとも有することから、熱衝撃が作用しても、熱衝撃
による応力が上記応力開放部で開放され、熱衝撃による
クラックが隔壁にまで進展することを防ぐことにより、
隔壁にクラックが入ることによって、隔壁が脱落して排
ガスの浄化性能が低下したり、特に微粒子捕集用フィル
タの場合は、入口側と出口側の流路が連通してしまうた
め、微粒子の捕集率が低下するといった、排気ガス浄化
装置の浄化性能に係わる、致命的な問題に発展すること
を防ぐことが出来る。As described above, according to the ceramic honeycomb structure of the present invention, among the many cells surrounded by the partition walls, the cell located at the outermost periphery has no partition wall with the outside. A ceramic honeycomb body having an outer wall portion having an outer surface that is filled with the recessed groove of the ceramic honeycomb body that is formed with a recessed groove that is open to the outside and extends in the axial direction. Since it has at least a stress releasing portion such as a void formed between a member forming a portion and a thermal shock, stress due to the thermal shock is released at the stress releasing portion, and cracks due to the thermal shock cause partition walls. By preventing progress to
When the partition walls are cracked, the partition walls fall off and the exhaust gas purification performance deteriorates.In particular, in the case of a particulate collection filter, the inlet side and the outlet side flow paths communicate with each other, so the particulate capture It is possible to prevent the development of a fatal problem related to the purification performance of the exhaust gas purification device, such as a decrease in the collection rate.
【００２２】以下、本発明を実施するための最良の形態
につき説明する。
（参考例）
カオリン、タルク、シリカ、アルミナなどの粉末を調整
して、質量比で、ＳｉＯ2 ：４８〜５２％、Ａｌ2Ｏ3：
３３〜３７％、ＭｇＯ：１２〜１５％を含むようなコー
ジェライト生成原料粉末とし、これにメチルセルロー
ス、ヒドロキシプロピルメチルセルロース等のバインダ
ー、潤滑剤、造孔材としてグラファイトを添加し、乾式
で十分混合した後、規定量の水を添加、十分な混練を行
って可塑化したセラミック杯土を作成した。The best mode for carrying out the present invention will be described below. ( Reference Example ) Powders of kaolin, talc, silica, alumina, etc. are prepared and, by mass ratio, SiO 2 : 48 to 52%, Al 2 O 3 :
A cordierite-forming raw material powder containing 33 to 37% and MgO: 12 to 15% was added, and a binder such as methylcellulose or hydroxypropylmethylcellulose, a lubricant, and graphite as a pore-forming material were added thereto and thoroughly mixed in a dry system. After that, a specified amount of water was added, and sufficient kneading was performed to prepare a plasticized ceramic clay.
【００２３】次いで、坏土を公知の押出成形用口金を通
過させることにより、外周壁３と隔壁４とが一体に形成
されたハニカム構造を有する成形体とした後、乾燥、焼
成操作を加えることにより、隔壁厚０．３ｍｍ、隔壁の
ピッチ１．５ｍｍ、外径寸法２８０ｍｍ、全長３００ｍ
ｍの外周壁３と隔壁４とが一体に形成されたコージェラ
イト質セラミックハニカム焼成体を得た。隔壁の気孔率
は６５％、平均細孔径は２０μｍであった。Next, the kneaded material is passed through a known extrusion die to form a formed body having a honeycomb structure in which the outer peripheral wall 3 and the partition walls 4 are integrally formed, and then drying and firing operations are performed. The partition wall thickness is 0.3 mm, the partition wall pitch is 1.5 mm, the outer diameter is 280 mm, and the total length is 300 m.
A cordierite-based ceramic honeycomb fired body in which the outer peripheral wall 3 of m and the partition wall 4 were integrally formed was obtained. The porosity of the partition walls was 65%, and the average pore diameter was 20 μm.
【００２４】得られたコージェライト質セラミックハニ
カム焼成体の周縁部を円筒研削盤を用いて加工除去する
ことにより、外周面に凹溝を有する、外径２６５．７ｍ
ｍ、全長３００ｍｍのセラミックハニカム本体を準備し
た。The peripheral portion of the obtained cordierite ceramic honeycomb fired body is processed and removed by using a cylindrical grinder to form a groove on the outer peripheral surface and an outer diameter of 265.7 m.
A ceramic honeycomb body having a length of m and a total length of 300 mm was prepared.
【００２５】一方、コート材として、平均粒径１０μｍ
のコージェライト粉末Ａ１００質量部に対して、コロイ
ダルシリカを固形分で１０〜１５質量部配合し、更に、
前記コージェライト粉末とコロイダルシリカの合計１０
０質量部に対して、１．２質量部のメチルセルロースを
配合し、水と共に混練して、粘度１５０００〜１９００
０ｃＰのコート材を準備した。On the other hand, as the coating material, the average particle size is 10 μm.
10 to 15 parts by mass of solid content of colloidal silica is added to 100 parts by mass of cordierite powder A.
A total of 10 cordierite powders and colloidal silica
1.2 parts by weight of methyl cellulose was blended with 0 parts by weight, and the mixture was kneaded with water to give a viscosity of 15000 to 1900.
A coating material of 0 cP was prepared.
【００２６】次いで、前記準備した外周部に凹溝を有す
るハニカム本体の外周部に、前記コート材を塗布したう
えで、表１に示す各種乾燥温度に加熱した乾燥炉に投入
し、熱風乾燥を行った。その後４５０℃まで加熱して、
上記メチルセルロースを分解除去すると共に、凹溝と外
壁部が一体化された外径２６６．７ｍｍ、全長３００ｍ
ｍ、隔壁厚０．３ｍｍ、隔壁のピッチ１．５ｍｍの参考
例１〜６のセラミックハニカム構造体を得た。この参考
例１〜６のセラミックハニカム構造体では、コート材の
粘度を１５０００〜１９０００ｃＰに調整して塗布した
ことから、外壁部を構成する部材は凹溝の角隅部にまで
充填されていた。また、コート材充填直後に、７０℃〜
１２０℃の各温度に加熱した乾燥炉に、投入したため外
壁部の外表面に開口した空隙部が発生していた。なお、
外壁部外表面に開口した空隙部の観察は目視で行い、蛇
行している空隙部については直線に近似して空隙部長さ
を計測し、セラミックハニカム構造体１ヶ中に存在して
いた複数の空隙部長さの合計を算出したうえで、（空隙
部長さの合計）／（ハニカム構造体全長）を計算した。Next, the coating material is applied to the outer peripheral portion of the prepared honeycomb main body having concave grooves on the outer peripheral portion, and the coating material is placed in a drying oven heated to various drying temperatures shown in Table 1 to perform hot air drying. went. Then heat to 450 ° C,
The methyl cellulose is decomposed and removed, and the groove and the outer wall are integrated into an outer diameter of 266.7 mm and a total length of 300 m.
m, a partition wall thickness 0.3mm, reference pitch 1.5mm of the partition wall
The ceramic honeycomb structures of Examples 1 to 6 were obtained. This reference
In the ceramic honeycomb structures of Examples 1 to 6, the viscosity of the coating material was adjusted to 15,000 to 19000 cP and the coating was performed, so that the member forming the outer wall portion was filled up to the corners of the concave groove. Immediately after filling the coating material, 70 ° C-
Since it was put into a drying furnace heated to each temperature of 120 ° C., a void portion was formed on the outer surface of the outer wall portion. In addition,
Visual observation of the voids opened on the outer surface of the outer wall portion was performed. For the meandering voids, the void length was measured by approximating a straight line, and a plurality of voids existing in one ceramic honeycomb structure were measured. After calculating the total length of the voids, (total length of voids) / (total length of honeycomb structure) was calculated.
【００２７】次に、作成した参考例１〜６セラミックハ
ニカム構造体に対して、耐熱衝撃温度及びアイソスタテ
ィック強度の試験を行った。耐熱衝撃温度の評価試験
は、一定温度（室温＋４００℃）に加熱された電気炉中
にセラミックハニカム構造体を挿入して３０分間保持
し、その後室温に急冷した後、セラミックハニカム構造
体の軸方向両端面の目視観察を行い、隔壁に発生したク
ラックの有無を確認した。また、隔壁にクラックが発見
されない場合は、電気炉の温度を２５℃上昇させ同様の
試験を行い、クラックが発生するまで繰り返した。そし
てクラックが発見されなかった最高温度差（加熱温度−
室温）を耐熱衝撃温度とした。アイソスタティック強度
試験は、社団法人自動車技術会発行の自動車規格（ＪＡ
ＳＯ）Ｍ５０５−８７に基づき、セラミックハニカム構
造体の軸方向両端面に厚さ２０ｍｍのアルミ板を当接し
て両端を密閉するとともに、外壁部表面を厚さ２ｍｍの
ゴムで密着したものを、圧力容器に入れ、圧力容器内に
水を導入して、外壁部表面から静水圧を加え、破壊した
ときの圧力を測定して、アイソスタティック強度とし
た。結果を表１に示す。Next, with respect to the prepared reference examples 1 to 6 ceramic honeycomb structures, thermal shock temperature and isostatic strength tests were conducted. The thermal shock resistance evaluation test was carried out by inserting the ceramic honeycomb structure into an electric furnace heated to a constant temperature (room temperature + 400 ° C), holding it for 30 minutes, and then rapidly cooling it to room temperature, and then in the axial direction of the ceramic honeycomb structure. Both ends were visually observed to confirm the presence of cracks in the partition walls. When no crack was found in the partition wall, the temperature of the electric furnace was raised by 25 ° C., the same test was performed, and the test was repeated until a crack was generated. And the maximum temperature difference (heating temperature-
Room temperature) was defined as the thermal shock resistance temperature. The isostatic strength test is based on the automobile standard (JA
SO) M505-87, the ceramic honeycomb structure is abutted with aluminum plates having a thickness of 20 mm on both end faces in the axial direction to seal both ends, and the outer wall surface is adhered with a rubber having a thickness of 2 mm. It was placed in a container, water was introduced into the pressure container, a hydrostatic pressure was applied from the outer wall surface, and the pressure at the time of breakage was measured to obtain the isostatic strength. The results are shown in Table 1.
【００２８】[0028]
【表１】 [Table 1]
【００２９】参考例１〜６のセラミックハニカム構造体
は、外壁部外表面に開口した空隙部を有していることか
ら、この空隙部が熱衝撃による応力を開放することによ
って、熱衝撃によるクラックが隔壁に進展することを防
ぐため、耐熱衝撃温度は、５５０〜６２５℃が得られ
た。一方、アイソスタティック強度は、軸方向に伸びた
凹溝にコート材が充填されていることから実用上問題な
い１ＭＰａ以上が得られた。また（空隙部長さの合計）
／（ハニカム構造体全長）の値が大きい方が、耐熱衝撃
温度の高くなることが確認され、空隙部長さの合計がセ
ラミックハニカム構造体の全長の１倍以上あれば、耐熱
衝撃温度を高める効果のあることも確認された。Since the ceramic honeycomb structures of Reference Examples 1 to 6 have voids opened on the outer surface of the outer wall portion, the voids release cracks due to thermal shock by releasing stress due to thermal shock. The thermal shock resistance temperature of 550 to 625 ° C. was obtained in order to prevent the heat transfer from developing into partition walls. On the other hand, the isostatic strength of 1 MPa or more, which is practically no problem, was obtained because the coating material was filled in the groove extending in the axial direction. Also (total of void length)
It has been confirmed that the larger the value of / (total length of honeycomb structure) is, the higher the thermal shock resistance temperature is, and if the total length of the voids is at least 1 time the total length of the ceramic honeycomb structure, the thermal shock resistance temperature is increased. It was also confirmed that
【００３０】（比較例）参考例
と同様の方法により、コージェライト質セラミッ
クハニカム焼成体の周縁部を円筒研削盤を用いて加工除
去することにより、最外周に位置するセルが外部との間
に隔壁を有しないことによって、外部に開口して軸方向
に伸びる凹溝を有し、隔壁厚０．３ｍｍ、隔壁のピッチ
１．５ｍｍ、外径寸法２６５．７ｍｍ、全長３００ｍｍ
であるコージェライト質セラミックハニカム本体を準備
し、これを比較例１のセラミックハニカム構造体とし
た。一方、同様に外部に開口して軸方向に伸びる凹溝を
有し、隔壁厚０．３ｍｍ、隔壁のピッチ１．５ｍｍ、外
径寸法２６５．７ｍｍ、全長３００ｍｍであるコージェ
ライト質セラミックハニカム本体を準備し、平均粒径１
０μｍのコージェライト粉末Ａ１００質量部に対して、
コロイダルシリカを固形分で１０質量部配合し、更に、
前記コージェライト粉末とコロイダルシリカの合計１０
０質量部に対して、１．２質量部のメチルセルロースを
配合し、水と共に混練して、粘度１５０００ｃＰとした
コート材を、前記外周部に凹溝を有するハニカム本体の
外周部に塗布した。そして塗布直後に４０℃の乾燥炉に
投入し２４時間乾燥したのち、７０℃の乾燥炉で１２時
間乾燥させ、その後４５０℃まで加熱して、凹溝と外壁
部が一体化された比較例２セラミックハニカム構造体を
得た。この比較例１及び２のセラミックハニカム構造体
に対して参考例と同様に、耐熱衝撃温度、アイソスタテ
ィック強度の測定を行った結果を表２に示す。(Comparative Example) In the same manner as in the reference example , the peripheral portion of the cordierite-based ceramic honeycomb fired body was processed and removed by using a cylindrical grinder so that the cells located at the outermost periphery were separated from the outside. Since it has no partition wall, it has a groove that opens to the outside and extends in the axial direction, and has a partition wall thickness of 0.3 mm, a partition wall pitch of 1.5 mm, an outer diameter dimension of 265.7 mm, and an overall length of 300 mm.
The cordierite-based ceramic honeycomb main body was prepared and used as the ceramic honeycomb structure of Comparative Example 1. On the other hand, similarly, a cordierite-based ceramic honeycomb body having a groove that is opened to the outside and extends in the axial direction and has a partition wall thickness of 0.3 mm, partition wall pitch of 1.5 mm, outer diameter dimension of 265.7 mm, and total length of 300 mm is provided. Prepare and average particle size 1
With respect to 100 parts by mass of cordierite powder A of 0 μm,
10 parts by mass of solid content of colloidal silica is added, and further,
A total of 10 cordierite powders and colloidal silica
1.2 parts by mass of methyl cellulose was blended with 0 parts by mass, kneaded with water, and a coating material having a viscosity of 15000 cP was applied to the outer peripheral portion of the honeycomb main body having the groove on the outer peripheral portion. Immediately after coating, the sample was placed in a drying oven at 40 ° C. and dried for 24 hours, then dried in a drying oven at 70 ° C. for 12 hours, and then heated to 450 ° C. to prepare a comparative example 2 in which the groove and the outer wall were integrated. A ceramic honeycomb structure was obtained. Table 2 shows the results obtained by measuring the thermal shock resistance temperature and the isostatic strength of the ceramic honeycomb structures of Comparative Examples 1 and 2 in the same manner as in the Reference Example .
【００３１】[0031]
【表２】 [Table 2]
【００３２】外壁部を形成していない比較例１のセラミ
ックハニカム構造体は、隔壁と外壁部の熱膨張差の問題
は発生しないが、６５０℃を超える熱衝撃を加えると、
外径２６５．７ｍｍ、全長３００ｍｍという大型の構造
体であることから中心部と表面間の温度差による熱応力
により、隔壁にクラックが入るようになり、耐熱衝撃温
度は６５０℃であった。この比較例１のセラミックハニ
カム構造体については、外壁部がないことから、外周部
にゴムを密着させることが困難なためアイソスタティッ
ク強度は求めることは出来なかったが、外壁部が形成さ
れていないハニカム構造体は、金属容器内に把持部材を
使って、収納、保持することが実質的に不可能になるこ
とから、触媒担体や微粒子補修用フィルタとして使用す
ることはできないという課題を抱えている。また、比較
例２のセラミックハニカム構造体は、コート材の粘度を
１５０００ｃＰに調整して塗布したことから、外壁部を
構成する部材は凹溝の角隅部にまで充填されており、コ
ート材の最初の乾燥が４０℃の低温であったため、外壁
部の外表面に開口した空隙部は発生せず、図３に示す形
態となった。従って、凹溝を構成する隔壁と外壁部が強
固に固着一体化されており、アイソスタティック強度は
参考例で示された参考例１〜６のセラミックハニカム構
造体に比べて高くなったが、外壁部の外表面に開口した
空隙部からなる熱衝撃応力開放部を有していないため、
耐熱衝撃温度は４００℃となり、参考例で示した、参考
例１〜６のセラミックハニカム構造体に比べ、耐熱衝撃
性に劣ることがわかった。In the ceramic honeycomb structure of Comparative Example 1 in which the outer wall portion is not formed, the problem of the difference in thermal expansion between the partition wall and the outer wall portion does not occur, but when a thermal shock exceeding 650 ° C. is applied,
Since it was a large structure having an outer diameter of 265.7 mm and a total length of 300 mm, cracks began to form in the partition walls due to thermal stress due to the temperature difference between the central portion and the surface, and the thermal shock resistance temperature was 650 ° C. Since the ceramic honeycomb structure of Comparative Example 1 has no outer wall portion, it is difficult to bring rubber into close contact with the outer peripheral portion, so that the isostatic strength cannot be obtained, but the outer wall portion is not formed. The honeycomb structure has a problem that it cannot be used as a catalyst carrier or a filter for repairing fine particles because it is practically impossible to store and hold it by using a holding member in a metal container. . Further, in the ceramic honeycomb structure of Comparative Example 2, the viscosity of the coating material was adjusted to 15000 cP and the coating was performed, so that the member forming the outer wall portion was filled up to the corners of the recessed groove. Since the initial drying was performed at a low temperature of 40 ° C., voids opened on the outer surface of the outer wall did not occur, and the form shown in FIG. 3 was obtained. Therefore, the partition wall that forms the groove and the outer wall are firmly fixed and integrated, and the isostatic strength is
Although it was higher than the ceramic honeycomb structures of Reference Examples 1 to 6 shown in Reference Example , since it does not have a thermal shock stress release portion composed of a void portion opened to the outer surface of the outer wall portion,
Heat shock temperature is 400 ° C., and the shown in Reference Example, Reference
It was found that the thermal shock resistance was inferior to the ceramic honeycomb structures of Examples 1 to 6.
【００３３】（実施例１）参考例
と同様の方法により、外周面に凹溝を有する、外
径２６５．７ｍｍ、全長３００ｍｍ、隔壁厚０．３ｍ
ｍ、隔壁のピッチ１．５ｍｍのセラミックハニカム本体
を準備した。一方、コート材として、平均粒径２０μｍ
のコージェライト粉末Ｂ１００質量部に対して、コロイ
ダルシリカを固形分で１０質量部配合し、これにメチル
セルロース、水と共に混練して、粘度２５０００〜６７
０００ｃＰのコート材を準備した。次いで、前記準備し
た外周面に凹溝を有するハニカム体の外周部に、前記コ
ート材を塗布したうえで、４０℃で２４時間乾燥したの
ち、７０℃で１２時間乾燥させた。この最初の乾燥温度
が低かったため、参考例に示した外壁部の外表面に開口
した空隙部は発生していない。その後４５０℃まで加熱
して、上記メチルセルロースを分解除去すると共に、凹
溝と外壁部が一体化された外径２６６．７ｍｍ、全長３
００ｍｍ、隔壁厚０．３ｍｍ、隔壁のピッチ１．５ｍ
ｍ、本発明例１〜５のセラミックハニカム構造体を得
た。その後、本発明例１〜５のセラミックハニカム構造
体に対して、参考例と同様に、耐熱衝撃温度及びアイソ
スタティック強度の試験を行った。更に、耐熱衝撃温度
が測定終了したハニカム構造体を軸方向に３当分に切断
し、切断面での凹溝に充填され形成された外壁部形態の
観察を行い、全凹溝のうち外壁部を構成する部材と凹溝
の間に空隙を有する凹溝の個数割合をカウントした。試
験結果を、表３に示す。(Example 1 ) By the same method as in the reference example , an outer diameter of 265.7 mm, a total length of 300 mm, and a partition wall thickness of 0.3 m having a groove on the outer peripheral surface.
A ceramic honeycomb body having m and a partition wall pitch of 1.5 mm was prepared. On the other hand, as the coating material, the average particle diameter is 20 μm.
10 parts by mass of colloidal silica in a solid content is mixed with 100 parts by mass of cordierite powder B of No. 1, and the mixture is kneaded with methyl cellulose and water to give a viscosity of 2,500 to 67.
A coating material of 000 cP was prepared. Next, the coating material was applied to the outer peripheral portion of the prepared honeycomb body having concave grooves on the outer peripheral surface thereof, followed by drying at 40 ° C. for 24 hours and then at 70 ° C. for 12 hours. Since this initial drying temperature was low, no voids were formed in the outer surface of the outer wall portion shown in the reference example . After that, it is heated to 450 ° C. to decompose and remove the methyl cellulose, and the groove and the outer wall are integrated to have an outer diameter of 266.7 mm and a total length of 3
00 mm, partition thickness 0.3 mm, partition pitch 1.5 m
m, inventive ceramic honeycomb structures of Examples 1 to 5 were obtained. Thereafter, the ceramic honeycomb structures of Inventive Examples 1 to 5 were tested for thermal shock resistance and isostatic strength in the same manner as in Reference Example . Further, the honeycomb structure whose thermal shock resistance temperature has been measured is cut into 3 axial portions, and the outer wall portion formed by filling the concave grooves on the cut surface is observed. The number ratio of the concave grooves having voids between the constituent members and the concave grooves was counted. The test results are shown in Table 3.
【００３４】[0034]
【表３】 [Table 3]
【００３５】表３に示すように、本発明例１〜５のセラ
ミックハニカム構造体は、外壁部を構成する部材と凹溝
の間に空隙を有する凹溝を有していることから、熱衝撃
応力によるクラックが外壁部に発生しても、この空隙で
熱衝撃応力が開放され、クラックの進展を防ぐことが出
来ることから、空隙が無く凹溝の角隅部にまで外壁部を
構成する部材が充填されている比較例２のセラミックハ
ニカム構造体に比べて、熱衝撃によるクラックが隔壁に
まで進展しにくく、耐熱衝撃温度は比較例２のセラミッ
クハニカム構造体に対して高くなった。一方、アイソス
タティック強度は、軸方向に伸びた凹溝に外壁部を構成
する部材が充填されており、外壁部を構成する部材と凹
溝の間に空隙を有しているものの、実用上問題ない１Ｍ
Ｐａ以上が得られた。また、外壁部を構成する部材と凹
溝の間に空隙を有する凹溝の全凹溝に対する個数割合が
大きい方が、耐熱衝撃温度の高くなることが確認され、
凹溝の全凹溝に対する個数割合が５％以上あると、耐熱
衝撃温度を高める効果の大きくなることも確認された。As shown in Table 3, since the ceramic honeycomb structures of Examples 1 to 5 of the present invention have the concave groove having a void between the member constituting the outer wall portion and the concave groove, thermal shock is caused. Even if a crack is generated in the outer wall portion due to stress, the thermal shock stress is released in this void, and it is possible to prevent the development of the crack. Therefore, there is no void and the outer wall portion extends to the corners of the groove. As compared with the ceramic honeycomb structure of Comparative Example 2 in which C was filled, cracks due to thermal shock were less likely to propagate to the partition walls, and the thermal shock resistance temperature was higher than that of the ceramic honeycomb structure of Comparative Example 2. On the other hand, isostatic strength is a problem in practical use, although the groove that extends in the axial direction is filled with the member that forms the outer wall, and there is a gap between the member that forms the outer wall and the groove. Not 1M
Pa or more was obtained. Further, it was confirmed that the thermal shock temperature becomes higher when the number ratio of the concave grooves having the voids between the member forming the outer wall portion and the concave grooves to the total concave grooves is higher.
It was also confirmed that the effect of increasing the thermal shock resistance temperature is increased when the number ratio of the grooves to the total grooves is 5% or more.
【００３６】（実施例２）参考例
と同様の方法により、外周面に凹溝を有する、外
径２６５．７ｍｍ、全長３００ｍｍ、隔壁厚０．３ｍ
ｍ、隔壁のピッチ１．５ｍｍのハニカム構造体本体を準
備した。コート材は参考例と同様に、平均粒径１０μｍ
のコージェライト粉末Ａ１００質量部に対して、コロイ
ダルシリカを固形分で１０質量部配合し、更に、前記コ
ージェライト粉末とコロイダルシリカの合計１００質量
部に対して、１．２質量部のメチルセルロースを配合
し、水と共に混練して、粘度５２０００ｃＰのコート材
を準備した。次いで、前記準備した外周部に凹溝を有す
るハニカム体の外周部に、前記コート材を塗布したうえ
で、表４に示すように、７０℃或いは１００℃に加熱し
た乾燥炉に投入し、急熱を加え、熱風乾燥を行った。そ
の後４５０℃まで加熱して、上記メチルセルロースを分
解除去すると共に、凹溝と外壁部が一体化された外径２
６６．７ｍｍ、全長３００ｍｍ、隔壁厚０．３ｍｍ、隔
壁のピッチ１．５ｍｍの本発明例６及び７のセラミック
ハニカム構造体を得た。また、参考例と同様の方法によ
り、外周面に凹溝を有する、外径２６５．７ｍｍ、全長
３００ｍｍ、隔壁厚０．３ｍｍ、隔壁のピッチ１．５ｍ
ｍのハニカム構造体本体を準備した。コート材は、平均
粒径１５μｍの非晶質シリカ粉末Ａ１００質量部に対し
て、コロイダルシリカを固形分で７０質量部配合し、更
に、前記非晶質シリカ粉末とコロイダルシリカの合計１
００質量部に対して、１．２質量部のメチルセルロース
を配合し、水と共に混練して、粘度４５０００ｃＰのコ
ート材を準備した。次いで、前記準備した外周部に凹溝
を有するハニカム体の外周部に、前記コート材を塗布し
たうえで、表４に示すように、７０℃或いは１００℃に
加熱した乾燥炉に投入し、急熱を加え、熱風乾燥を行っ
た。その後４５０℃まで加熱して、上記メチルセルロー
スを分解除去すると共に、凹溝と外壁部が一体化された
外径２６６．７ｍｍ、全長３００ｍｍ、隔壁厚０．３ｍ
ｍ、隔壁のピッチ１．５ｍｍの本発明例８及び９のセラ
ミックハニカム構造体を得た。これら本発明例６〜９の
セラミックハニカム構造体の外表面に開口した空隙部の
形態、セラミックハニカム構造体１ヶ中に存在していた
外表面に開口した空隙部の（空隙部長さの合計）／（ハ
ニカム構造体全長）、外壁部を構成する部材と凹溝の間
に空隙を有する凹溝の全凹溝に対する個数割合は表４の
通りであった。その後、作成した本発明例６〜９のセラ
ミックハニカム構造体に対して、参考例と同様に、耐熱
衝撃温度及びアイソスタティック強度の試験を行った。
試験結果を、表４に示す。(Embodiment 2 ) By the same method as in the reference example , an outer diameter is 265.7 mm, a total length is 300 mm, and a partition wall thickness is 0.3 m.
m, a honeycomb structure body having a partition wall pitch of 1.5 mm was prepared. Similar to the reference example , the coating material has an average particle size of 10 μm.
10 parts by mass of colloidal silica as a solid content is mixed with 100 parts by mass of cordierite powder A, and 1.2 parts by mass of methyl cellulose is further mixed with 100 parts by mass of the cordierite powder and colloidal silica. Then, the mixture was kneaded with water to prepare a coating material having a viscosity of 52000 cP. Next, as shown in Table 4, after applying the coating material to the outer peripheral portion of the prepared honeycomb body having concave grooves in the outer peripheral portion, the coating material was put into a drying furnace heated to 70 ° C. or 100 ° C. Heat was applied and hot air drying was performed. After that, it is heated up to 450 ° C. to decompose and remove the methyl cellulose, and also the outer diameter 2 in which the groove and the outer wall are integrated.
66.7 mm, a total length of 300 mm, partition wall thickness of 0.3 mm, and partition wall pitch of 1.5 mm were obtained to obtain ceramic honeycomb structures of Inventive Examples 6 and 7 . Further, by the same method as in the reference example , an outer diameter is 265.7 mm, an overall length is 300 mm, a partition wall thickness is 0.3 mm, and a partition wall pitch is 1.5 m.
m honeycomb structure body was prepared. As the coating material, 100 parts by mass of the amorphous silica powder A having an average particle diameter of 15 μm was mixed with 70 parts by mass of colloidal silica in a solid content, and further, the total amount of the amorphous silica powder and the colloidal silica was 1%.
1.2 parts by mass of methyl cellulose was mixed with 100 parts by mass and kneaded with water to prepare a coating material having a viscosity of 45,000 cP. Next, as shown in Table 4, after applying the coating material to the outer peripheral portion of the prepared honeycomb body having concave grooves in the outer peripheral portion, the coating material was put into a drying furnace heated to 70 ° C. or 100 ° C. Heat was applied and hot air drying was performed. After that, it is heated to 450 ° C. to decompose and remove the methyl cellulose, and the groove and the outer wall are integrated into an outer diameter of 266.7 mm, a total length of 300 mm, and a partition wall thickness of 0.3 m.
m, the pitch of the partition walls was 1.5 mm, and the ceramic honeycomb structures of Inventive Examples 8 and 9 were obtained. The form of the voids opened on the outer surface of the ceramic honeycomb structures of Examples 6 to 9 of the present invention, the voids opened on the outer surface that were present in one ceramic honeycomb structure (total void length) Table 4 shows / (total length of honeycomb structure), and the number ratio of the concave grooves having voids between the members forming the outer wall portion and the concave grooves to all the concave grooves. Thereafter, the produced ceramic honeycomb structures of Inventive Examples 6 to 9 were tested for thermal shock resistance temperature and isostatic strength in the same manner as in Reference Example .
The test results are shown in Table 4.
【００３７】[0037]
【表４】 [Table 4]
【００３８】表４に示すように、本発明例６〜９のセラ
ミックハニカム構造体は、外壁部に外表面に開口した空
隙部を有しており、且つ外壁部を構成する部材と凹溝の
間に空隙を有する凹溝を有していることから、この外表
面の空隙部及び、外壁部を構成する部材と凹溝の間の空
隙が熱衝撃による応力を開放することによって、熱衝撃
によるクラックが隔壁に進展することを防ぐことが出来
るため、耐熱衝撃温度は、比較例２のセラミックハニカ
ム構造体の４００℃に比べて高くなった。しかも、外表
面の空隙部及び、外壁部を構成する部材と凹溝の間の空
隙の二種類の応力開放部を有していることから、参考例
１〜６及び本発明例１〜６のハニカム構造体に比べて
も、耐熱衝撃温度は高くなった。一方、アイソスタティ
ック強度は、軸方向に伸びた凹溝に外壁部を構成する部
材が充填されており、外壁部を構成する部材と凹溝の間
に空隙を有しているものの、実用上問題ない１ＭＰａ以
上が得られた。As shown in Table 4, the ceramic honeycomb structures of Examples 6 to 9 of the present invention have a void portion opened to the outer surface in the outer wall portion, and the members constituting the outer wall portion and the concave groove are formed. Since there is a concave groove having a gap between them, the void portion of this outer surface and the gap between the member forming the outer wall portion and the concave groove release stress due to thermal shock, so that Since the cracks can be prevented from propagating to the partition walls, the thermal shock resistance temperature was higher than 400 ° C. of the ceramic honeycomb structure of Comparative Example 2. Moreover, since there are two types of stress releasing portions, that is, the void portion on the outer surface and the void between the member forming the outer wall portion and the concave groove, there are two types of stress relief portions of Reference Examples 1 to 6 and Inventive Examples 1 to 6 . The thermal shock resistance temperature was higher than that of the honeycomb structure. On the other hand, isostatic strength is a problem in practical use, although the groove that extends in the axial direction is filled with the member that forms the outer wall, and there is a gap between the member that forms the outer wall and the groove. A value of 1 MPa or more was obtained.
【００３９】以上はセラミックハニカム焼成体の周縁部
を加工除去することにより、外周面に凹溝を有する、ハ
ニカム構造体の外周面に外壁部を形成する製造工程例で
説明したが、本発明の作用効果からすれば、セラミック
ハニカム乾燥体の周縁部を加工除去した後、焼成をする
ことにより、外周面に凹溝を有するハニカム構造体の外
周面に外壁部を形成する製造方法、或いはセラミックハ
ニカム乾燥体の周縁部を加工除去した後、外周面の凹溝
に外壁部を形成するコート材を塗布後、ハニカム乾燥体
と外壁部を同時に焼成する製造方法を採用しても同様の
効果が得られることは言うまでもない。The manufacturing process example of forming the outer wall portion on the outer peripheral surface of the honeycomb structure having the groove on the outer peripheral surface by processing and removing the peripheral portion of the ceramic honeycomb fired body has been described above. According to the effect, a manufacturing method of forming an outer wall portion on the outer peripheral surface of a honeycomb structure having concave grooves on the outer peripheral surface by processing and removing the peripheral portion of the dried ceramic honeycomb body, or a ceramic honeycomb After processing and removing the peripheral portion of the dried body, the same effect can be obtained by adopting the manufacturing method in which the honeycomb dried body and the outer wall portion are simultaneously fired after applying the coating material for forming the outer wall portion to the groove on the outer peripheral surface. It goes without saying that it will be done.
【００４０】[0040]
【図１】ハニカム構造体の斜視図である。FIG. 1 is a perspective view of a honeycomb structure.
【図２】本発明に用いられるセラミックハニカム本体の
一例を示す、外部に開口して軸方向に延びる凹溝の拡大
図である。FIG. 2 is an enlarged view of a groove that is open to the outside and extends in the axial direction, showing an example of a ceramic honeycomb body used in the present invention.
【図３】図２に示されるセラミックハニカム本体の凹溝
に外壁部が設けられた状態を示す従来技術の説明図であ
る。FIG. 3 is an explanatory diagram of a conventional technique showing a state in which an outer wall portion is provided in a concave groove of the ceramic honeycomb main body shown in FIG.
【図４】図２に示されるセラミックハニカム本体の凹溝
に外壁部が設けられた状態を示す本発明の説明図であ
る。4 is an explanatory view of the present invention showing a state where an outer wall portion is provided in a concave groove of the ceramic honeycomb main body shown in FIG.
【図５】本発明のセラミックハニカム構造体の外壁部に
形成された空隙部を外表面から観察した走査型顕微鏡写
真である。FIG. 5 is a scanning micrograph of a void portion formed in the outer wall portion of the ceramic honeycomb structure of the present invention observed from the outer surface.
【図６】本発明の外壁部に空隙部を有するセラミックハ
ニカム構造体の空隙部の形態を示す説明図である。[Fig. 6] Fig. 6 is an explanatory view showing a form of a void portion of a ceramic honeycomb structure having a void portion in an outer wall portion of the present invention.
【図７】図２に示されるセラミックハニカム本体の凹溝
に外壁部が設けられた状態を示す本発明の説明図であ
る。FIG. 7 is an explanatory diagram of the present invention showing a state where the outer wall portion is provided in the concave groove of the ceramic honeycomb main body shown in FIG.
【図８】図７に示されるセラミックハニカム本体の凹溝
に外壁部が設けられた状態を示す図面において、外壁部
を構成する部材と凹溝の間に形成された空隙を示す図で
ある。FIG. 8 is a view showing a void formed between a member forming the outer wall portion and the concave groove in the drawing showing the outer wall portion provided in the concave groove of the ceramic honeycomb main body shown in FIG. 7.
【００４１】
１：ハニカム構造体
３：外周壁
４：隔壁
６；セル
１２：凹溝
１４：セラミックハニカム本体
１６：外壁部
１８：セラミックハニカム構造体
２１：外壁部の外表面に形成された空隙部
２２；外壁部を構成する部材と凹溝の間に形成された空
隙
５１、５４；凹溝を構成する隔壁の端部
５２、５３；凹溝を構成する隔壁の交点
５５、５６、５７、５８；凹溝断面における外壁部を構
成する部材と隔壁の交点1: Honeycomb structure 3: Outer peripheral wall 4: Partition wall 6; Cell 12: Groove 14: Ceramic honeycomb body 16: Outer wall portion 18: Ceramic honeycomb structure 21: Void portion formed on the outer surface of the outer wall portion 22; voids 51, 54 formed between the member forming the outer wall portion and the concave groove; end portions 52, 53 of partition walls forming the concave groove; intersection points 55, 56, 57, 58 of partition walls forming the concave groove. The intersection of the partition wall and the member forming the outer wall in the groove cross section
Claims (7)
周に位置するセルが、外部との間の隔壁を有しないこと
によって、外部に開口して軸方向に延びる凹溝を形成し
ているセラミックハニカム本体の、前記凹溝を充填して
外表面を形成する外壁部を有するセラミックハニカム構
造体において、前記外壁部と凹溝との間の少なくとも一
部に応力開放部を有することを特徴とするセラミックハ
ニカム構造体。1. Out of a large number of cells surrounded by partition walls, the cells located at the outermost periphery have no partition walls with the outside, so that a groove that is open to the outside and extends in the axial direction is formed. In a ceramic honeycomb main body having an outer wall portion that fills the concave groove to form an outer surface, a ceramic honeycomb structure having a stress release portion at least at a part between the outer wall portion and the concave groove. Characteristic ceramic honeycomb structure.
に位置するセルが、外部との間の隔壁を有しないことに
よって、外部に開口して軸方向に延びる凹溝を形成して
いるセラミックハニカム本体の、前記凹溝を充填して外
表面を形成する外壁部を有するセラミックハニカム構造
体において、前記外壁部及び外壁部と凹溝との間のそれ
ぞれの少なくとも一部に応力開放部を有することを特徴
とするセラミックハニカム構造体。2. Out of a large number of cells surrounded by partition walls, the cells located at the outermost periphery have no partition walls with the outside, so that a groove that is open to the outside and extends in the axial direction is formed. In a ceramic honeycomb structure having an outer wall portion of the ceramic honeycomb main body that fills the recessed groove to form an outer surface, stress is released to at least a part of each of the outer wall portion and the outer wall portion and the recessed groove. A ceramic honeycomb structure having a portion.
に開口した空隙部であることを特徴とする請求項２に記
載のセラミックハニカム構造体。3. The ceramic honeycomb structure according to claim 2, wherein the stress releasing portion in the outer wall portion is a void portion opened on the outer surface.
がセラミックハニカム構造体全長の１倍以上であること
を特徴とする請求項３に記載のセラミックハニカム構造
体。4. The ceramic honeycomb structure according to claim 3, wherein the total length of the voids opened on the outer surface is not less than 1 time the total length of the ceramic honeycomb structure.
部を構成する部材と凹溝の間に形成された空隙であるこ
とを特徴とする請求項１乃至４に記載のセラミックハニ
カム構造体。5. The ceramic according to claim 1, wherein the stress releasing section between the outer wall and the groove is gap formed between the member and the groove constituting the outer wall portion Honeycomb structure.
成された空隙を有する凹溝の個数割合が全凹溝のうちの
５％以上であることを特徴とする請求項５に記載のセラ
ミックハニカム構造体。6. The number of recessed grooves having voids formed between the member forming the outer wall portion and the recessed grooves is 5% or more of all the recessed grooves. The described ceramic honeycomb structure.
８０％、平均細孔径が１０〜５０μｍであることを特徴
とする請求項１乃至６のいずれかに記載のセラミックハ
ニカム構造体。7. The porosity of the material forming the partition wall is 50 to 50.
80% and an average pore diameter of 10 to 50 μm, The ceramic honeycomb structure according to claim 1.
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| JP2002326852 | 2002-11-11 | ||
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4421858B2 (en) * | 2003-09-12 | 2010-02-24 | 日本碍子株式会社 | Honeycomb structure and manufacturing method thereof |
| JP4737594B2 (en) * | 2004-02-18 | 2011-08-03 | 日立金属株式会社 | Ceramic honeycomb filter |
| JP4537238B2 (en) * | 2005-03-24 | 2010-09-01 | 日本碍子株式会社 | Method for measuring cleavage index of kaolin particles and method for producing cordierite honeycomb structure |
| JP5532606B2 (en) * | 2006-12-27 | 2014-06-25 | 日立金属株式会社 | Ceramic honeycomb structure and manufacturing method thereof |
| JP4402732B1 (en) * | 2008-07-16 | 2010-01-20 | 東京窯業株式会社 | Honeycomb structure |
| JP5053224B2 (en) * | 2008-10-09 | 2012-10-17 | 本田技研工業株式会社 | Exhaust purification filter |
| JP2012170935A (en) * | 2011-02-24 | 2012-09-10 | Denso Corp | Honeycomb structure |
| JP2013043138A (en) * | 2011-08-25 | 2013-03-04 | Denso Corp | Catalyst carrier and method for producing the same |
| WO2013054793A1 (en) | 2011-10-11 | 2013-04-18 | 日立金属株式会社 | Method for producing ceramic honeycomb structure, and ceramic honeycomb structure |
| JP6623648B2 (en) * | 2015-09-30 | 2019-12-25 | 日立金属株式会社 | Ceramic honeycomb structure, method for manufacturing the same, and coating material |
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