JPH06165943A - Cordierite honeycomb structure - Google Patents
Cordierite honeycomb structureInfo
- Publication number
- JPH06165943A JPH06165943A JP5127781A JP12778193A JPH06165943A JP H06165943 A JPH06165943 A JP H06165943A JP 5127781 A JP5127781 A JP 5127781A JP 12778193 A JP12778193 A JP 12778193A JP H06165943 A JPH06165943 A JP H06165943A
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb structure
- high specific
- surface area
- specific surface
- catalyst
- 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.)
- Pending
Links
- 229910052878 cordierite Inorganic materials 0.000 title claims abstract description 42
- 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 title claims abstract description 42
- 239000011148 porous material Substances 0.000 claims abstract description 50
- 239000000463 material Substances 0.000 claims abstract description 30
- 239000011247 coating layer Substances 0.000 claims abstract description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 27
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 239000003054 catalyst Substances 0.000 abstract description 42
- 238000000151 deposition Methods 0.000 abstract description 3
- 230000006866 deterioration Effects 0.000 abstract description 2
- 230000008093 supporting effect Effects 0.000 description 18
- 239000002245 particle Substances 0.000 description 14
- 230000035939 shock Effects 0.000 description 14
- 238000009826 distribution Methods 0.000 description 9
- 239000000919 ceramic Substances 0.000 description 8
- 239000002994 raw material Substances 0.000 description 8
- 238000010304 firing Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 5
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000000454 talc Substances 0.000 description 4
- 229910052623 talc Inorganic materials 0.000 description 4
- 239000005995 Aluminium silicate Substances 0.000 description 3
- 235000012211 aluminium silicate Nutrition 0.000 description 3
- 239000004927 clay Substances 0.000 description 3
- 238000010438 heat treatment 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
- 239000010410 layer Substances 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000006255 coating slurry Substances 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000004901 spalling Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- INJRKJPEYSAMPD-UHFFFAOYSA-N aluminum;silicic acid;hydrate Chemical compound O.[Al].[Al].O[Si](O)(O)O INJRKJPEYSAMPD-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 235000013339 cereals Nutrition 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 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 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 235000013312 flour Nutrition 0.000 description 1
- 239000005350 fused silica glass Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000010443 kyanite Substances 0.000 description 1
- 229910052850 kyanite Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 229910001753 sapphirine Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Landscapes
- Porous Artificial Stone Or Porous Ceramic Products (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はコージェライトハニカム
構造触媒担体、特に自動車排ガスの浄化用触媒担体に用
いられる高比表面積材料および触媒の担持性に優れた低
膨脹性のハニカム構造体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordierite honeycomb structure catalyst carrier, especially a high specific surface area material used as a catalyst carrier for purifying automobile exhaust gas, and a low expansion honeycomb structure excellent in catalyst carrying property. is there.
【０００２】[0002]
【従来の技術】一般に自動車排ガス浄化に用いられるハ
ニカム触媒は一体構造で低膨脹性のコージェライトハニ
カム構造触媒担体の表面に活性アルミナ等の高比表面積
材料と白金等の触媒金属を担持することにより製造され
る。2. Description of the Related Art Generally, a honeycomb catalyst used for purification of automobile exhaust gas is formed by supporting a high specific surface area material such as activated alumina and a catalyst metal such as platinum on the surface of an integrated structure and low expansion cordierite honeycomb structure catalyst carrier. Manufactured.
【０００３】高比表面積材料及び触媒の担持性即ちコー
タビリティはコージェライトハニカム触媒担体に要求さ
れる重要な特性の一つであり、コージェライトハニカム
触媒の量産性のためコージェライトハニカム構造体には
これを解決する手段として従来より多孔性が要求され続
けていた。A material having a high specific surface area and supportability of a catalyst, that is, coatability is one of important characteristics required for a cordierite honeycomb catalyst carrier. As a means for solving this, porosity has been conventionally required.
【０００４】一方、耐熱衝撃性も上記ハニカム触媒に要
求される重要な特性の一つで、排気ガス中の未燃焼炭化
水素、一酸化炭素の触媒反応による急激な発熱やエンジ
ン始動、停止時の急熱、急冷により温度変化を受け、ハ
ニカム構造体内に生じる温度差により引き起こされる熱
応力に耐える高い耐熱衝撃性が要求される。On the other hand, thermal shock resistance is also one of the important characteristics required for the above-mentioned honeycomb catalyst, and it is characterized by a rapid heat generation due to the catalytic reaction of unburned hydrocarbons and carbon monoxide in the exhaust gas, engine start and stop. High thermal shock resistance is required to withstand the thermal stress caused by the temperature difference generated in the honeycomb structure due to the temperature change caused by the rapid heating and the rapid cooling.
【０００５】この耐熱衝撃性は急熱急冷耐久温度差で表
わされ、その耐久温度差はハニカムの特性のうち熱膨脹
係数に逆比例することが判明しており、熱膨脹係数が小
さいほどその耐久温度差が大きく、ハニカム触媒用のセ
ラミックハニカム構造触媒担体として低膨脹のコージェ
ライトが用いられる最大の理由となっている。This thermal shock resistance is represented by the difference between the rapid heating and quenching endurance temperature, and it has been found that the endurance temperature difference is inversely proportional to the coefficient of thermal expansion among the characteristics of the honeycomb. The smaller the coefficient of thermal expansion, the more the endurance temperature. The difference is large, which is the main reason why low expansion cordierite is used as a ceramic honeycomb structure catalyst carrier for a honeycomb catalyst.
【０００６】従来、コージェライトセラミックが低膨脹
性を示すことは公知であり、例えば米国特許第3885977
号明細書（特開昭50-75611号公報) に開示されているよ
うに、25℃〜1000℃の間での熱膨脹係数が少なくとも一
方向で11×10-7（１／℃）より小さい配向したコージェ
ライトセラミックが知られており、そこではこの配向性
を起させる原因としてカオリン等の板状粘土、積層粘土
に起因する平面的配向を記述している。It is known in the past that cordierite ceramics exhibit low expansion properties, eg US Pat. No. 3,885,977.
As disclosed in Japanese Patent Application Laid-Open No. 50-75611, orientation in which the coefficient of thermal expansion between 25 ° C and 1000 ° C is less than 11 × 10 -7 (1 / ° C) in at least one direction. A known cordierite ceramic is described therein, which describes planar orientation caused by plate-like clay such as kaolin and laminated clay as a cause of causing this orientation.
【０００７】さらに特開昭53-82822号公報では、タルク
等のマグネシア源原料を10〜50μmの限定された粗粒域
で用いることにより、コージェライトセラミックが極め
て低熱膨脹を示すことが開示されている。Further, JP-A-53-82822 discloses that cordierite ceramic exhibits extremely low thermal expansion by using a magnesia source material such as talc in a limited coarse grain region of 10 to 50 μm. There is.
【０００８】しかしながら、ハニカム触媒は低膨脹のコ
ージェライト材質の表面にこれに比べてはるかに熱膨脹
率の大きい活性アルミナ等の高比表面積材料を担持する
ため、コージェライトハニカム担体の低熱膨脹化のみで
はハニカム触媒の耐熱衝撃性を改善することはできな
い。即ち、高比表面積材料の担持による熱膨脹上昇をで
きる限り小さくする技術が要求されているのである。However, since the honeycomb catalyst carries a high specific surface area material such as activated alumina having a much higher thermal expansion coefficient than the surface of a low expansion cordierite material, it is not possible to reduce the thermal expansion of the cordierite honeycomb carrier. The thermal shock resistance of the honeycomb catalyst cannot be improved. That is, there is a demand for a technique for minimizing the increase in thermal expansion due to the loading of the high specific surface area material.
【０００９】[0009]
【発明が解決しようとする課題】コージェライトハニカ
ム担体の多孔性向上、触媒担持性改良、高比表面積材料
の担持に関する耐熱衝撃性改善については、次のような
内容が提案されている。The following contents have been proposed for improving the porosity of a cordierite honeycomb carrier, improving the catalyst supporting property, and improving the thermal shock resistance related to supporting a high specific surface area material.
【００１０】 米国特許第3,950,175 号明細書（特開
昭50- 75612 号) には、原料中のタルク又は粘土の一部
又は全量を、パイロフェライト、カイアナイト、石英、
溶融シリカのようなシリカ又はシリカアルミナ源原料に
よって置換することにより少なくとも20％の10μm より
大きな径の開孔を有するコージェライト系多孔質セラミ
ックスが得られることが開示されている。US Pat. No. 3,950,175 (Japanese Patent Laid-Open No. 50-75612) discloses that a part or the whole amount of talc or clay in a raw material is replaced with pyroferrite, kyanite, quartz,
It is disclosed that substitution with silica such as fused silica or a silica-alumina source material yields at least 20% cordierite-based porous ceramics with open pores larger than 10 μm.
【００１１】 特公昭51-44913号公報では、セラミッ
ク材料よりなるハニカム構造体の薄壁表面にセラミック
粉末を被着焼成して、孔径５μm 以上の細孔容積 0.1cm
3/g 以上を有する表面層を形成し、触媒担持性を改良す
ることを開示している。In Japanese Patent Publication No. 51-44913, a ceramic powder is adhered and fired on a thin wall surface of a honeycomb structure made of a ceramic material, and a pore volume of 0.1 cm or more having a pore diameter of 5 μm or more.
It is disclosed that a surface layer having a content of 3 / g or more is formed to improve the catalyst supporting property.
【００１２】 特開昭58-14950号公報では、コージェ
ライトハニカム構造体への高比表面積材料である活性ア
ルミナのコーティングに際して、予めメチルセルロース
等の有機物質をプレコートしてコージェライトハニカム
のマイクロクラックに活性アルミナが浸入することによ
るコージェライトハニカム触媒の耐熱衝撃性改善を開示
している。上記〜の技術については、以下のような
種々の問題点が存在する。In Japanese Patent Laid-Open No. 58-14950, when a cordierite honeycomb structure is coated with activated alumina, which is a material having a high specific surface area, an organic substance such as methylcellulose is pre-coated in advance to activate the microcrack of the cordierite honeycomb. It discloses the improvement of thermal shock resistance of cordierite honeycomb catalyst by infiltration of alumina. The above-mentioned technologies (1) to (3) have the following various problems.
【００１３】については、新たに10μm 以上の細孔に
熱膨脹の高い活性アルミナ等の高比表面積材料が浸入し
やすく、10μm 以上の細孔容積が多いほどハニカム触媒
の耐熱衝撃性が劣化することが判明した。つまり、10μ
m 以上の細孔による多孔性はコーティング後の耐熱衝撃
性を損う欠点が有る。With respect to the above, a new material having a high specific surface area such as activated alumina having a high thermal expansion is easily infiltrated into the pores of 10 μm or more, and the thermal shock resistance of the honeycomb catalyst may deteriorate as the pore volume of 10 μm or more increases. found. In other words, 10μ
Porosity due to pores of m or more has a drawback that the thermal shock resistance after coating is impaired.
【００１４】については、セラミックス粉末の被着工
程が必要であり、大幅なコストアップとなり、また本願
発明で示すような0.5 〜５μm の微細気孔は付与しにく
い欠点が有る。With respect to the above, there is a drawback that a step of depositing the ceramic powder is required, resulting in a large increase in cost, and it is difficult to provide the fine pores of 0.5 to 5 μm as shown in the present invention.
【００１５】については、活性アルミナ等の高比表面
積材料とコージェライトハニカム担体との付着性が劣化
し、コート層がハクリしやすい欠点が有る。また、コー
ティングに関する工数が増加し、大幅なコストアップと
なる。With respect to the above, there is a drawback that the adhesion between the high specific surface area material such as activated alumina and the cordierite honeycomb carrier is deteriorated and the coat layer is easily peeled off. In addition, the number of man-hours related to coating increases, resulting in a significant cost increase.
【００１６】以上のように、高比表面積材料及び触媒成
分の担持性とコーティング後のコージェライトハニカム
触媒の耐熱衝撃性向上を同時に満足するコージェライト
ハニカム構造触媒担体が望まれている。[0016] As described above, there is a demand for a cordierite honeycomb structure catalyst carrier which simultaneously satisfies the support of the high specific surface area material and the catalyst component and the improvement of the thermal shock resistance of the cordierite honeycomb catalyst after coating.
【００１７】本発明の目的は上述した不具合を解消し
て、コージェライト担体よりも熱膨脹係数の大きい高比
表面積材料及び触媒成分の担持により耐熱衝撃性劣化の
少ないコージェライトハニカム構造体を提供しようとす
るものである。An object of the present invention is to solve the above-mentioned problems and to provide a cordierite honeycomb structure having a small thermal shock resistance deterioration by supporting a high specific surface area material having a larger thermal expansion coefficient than a cordierite carrier and a catalyst component. To do.
【００１８】[0018]
【課題を解決するための手段】本発明のコージェライト
ハニカム構造体は、高比表面積材料のコート層が実質的
に表面に均一にコートされ、前記高比表面積材料が実質
的に表面気孔中に存在しないことを特徴とするものであ
る。In the cordierite honeycomb structure of the present invention, a coating layer of a high specific surface area material is substantially uniformly coated on the surface, and the high specific surface area material is substantially coated in surface pores. It is characterized by not existing.
【００１９】[0019]
【作用】本発明のハニカム構造体の化学組成は、従来低
膨脹コージェライトセラミックスの組成として知られて
いるコージェライト理論組成点(2MgO ・ 2Al2O3・5SiO
2)を中心とした重量基準でSiO2 42 〜56％、好ましくは
47〜53％、Al2O3 30〜45％好ましくは32〜38％、MgO 12
〜16％好ましくは12.5〜15％の領域で、種々の製造条件
変更、即ち原料銘柄、原料粒度の変更、焼成条件の変更
により、目的とする30〜42％の気孔率、直径0.5 〜５μ
m の細孔の総細孔容積が全細孔容積の70％以上かつ直径
10μm 以上の細孔容積が全細孔容積の10％以下を達成す
ることが可能である。The chemical composition of the honeycomb structure of the present invention is the theoretical composition point of the cordierite (2MgO 2 Al 2 O 3 5SiO), which is conventionally known as the composition of low expansion cordierite ceramics.
2 ) SiO 2 42-56% based on the weight basis, preferably
47-53%, Al 2 O 3 30-45%, preferably 32-38%, MgO 12
-16%, preferably in the range of 12.5-15%, by changing various manufacturing conditions, that is, changing the raw material brand, raw material particle size, and firing conditions, the target porosity of 30-42%, diameter 0.5-5 μm
The total pore volume of m pores is 70% or more of the total pore volume and the diameter
It is possible for a pore volume of 10 μm or more to achieve 10% or less of the total pore volume.
【００２０】主成分以外の化学成分は熱膨脹特性に悪影
響を及ぼす場合が多く、TiO2 , CaO, K2O , Na2O , Fe2
O3 , P2O5等の不純物は全体として2.5 ％以下に抑える
ことが望ましく、特にCaO , K2O , Na2Oのアルカリ成分
が少ないほど熱膨脹特性に好影響を及ぼす。Chemical components other than the main component often adversely affect the thermal expansion characteristics, and TiO 2 , CaO, K 2 O, Na 2 O, Fe 2
Impurities such as O 3 and P 2 O 5 are preferably suppressed to 2.5% or less as a whole, and particularly, the smaller the alkali components of CaO, K 2 O and Na 2 O, the better the thermal expansion characteristics.
【００２１】結晶相は実質的にコージェライト結晶から
成ることが好ましく、コージェライト結晶量として90重
量％以上、他の含有結晶としてのムライト、及びスピネ
ル（サフィリンを含む）を含む。The crystal phase preferably consists essentially of cordierite crystals, and contains 90 wt% or more of cordierite crystals, mullite as other contained crystals, and spinel (including sapphirine).
【００２２】活性アルミナ等高比表面積材料の触媒担持
性に関して、従来より吸水率、気孔率との相関が指摘さ
れていたが、その気孔率の要因以上に今回、特にある一
定の細孔径領域即ち0.5 〜５μm が担持性に著しく寄与
することが明らかになった。また、従来多孔性を維持す
るためにコージェライト担体に導入していた10μm 以上
の細孔は逆に触媒担持性を劣化させ、さらに担持量のバ
ラツキを増大することが判明した。Regarding the catalyst-supporting property of a high specific surface area material such as activated alumina, a correlation with water absorption rate and porosity has been conventionally pointed out. It was revealed that 0.5 to 5 μm significantly contributes to the supporting property. Further, it was found that pores of 10 μm or more, which were conventionally introduced into the cordierite carrier to maintain the porosity, adversely deteriorate the catalyst supporting property and further increase the dispersion of the supporting amount.
【００２３】0.5 〜５μm の細孔の寄与の理由として
は、活性アルミナ等の高比表面積材料の粒子径と毛細管
吸水現象より付着速度がこの領域の細孔径に対して最大
になるものと考えられる。また、10μm 以上の細孔につ
いては、表面気孔への高比表面積材料の浸入によって担
持量のバラツキが出るものと考えられる。The reason for the contribution of the pores of 0.5 to 5 μm is considered to be that the adhesion rate becomes maximum with respect to the pore diameter in this region due to the particle diameter of the high specific surface area material such as activated alumina and the capillary water absorption phenomenon. . In addition, regarding pores with a diameter of 10 μm or more, it is considered that the amount of supported particles varies due to the infiltration of the high specific surface area material into the surface pores.
【００２４】触媒担持性と気孔率の相関も認められ、気
孔率30％以下で触媒担持性が劣化する。一方、0.5 〜５
μm 細孔容積の比率を維持し気孔率を向上することは触
媒担持性を向上させるが、ハニカム触媒に要求されるも
う一つの重要な特性である機械的強度が劣化する。A correlation between the catalyst supportability and the porosity is also recognized, and the catalyst supportability deteriorates when the porosity is 30% or less. On the other hand, 0.5-5
Maintaining the ratio of the pore volume of μm to improve the porosity improves the catalyst supporting property, but deteriorates the mechanical strength which is another important property required for the honeycomb catalyst.
【００２５】工業的に最も数多く採用されているリブ厚
150μm 、１平方センチ当り62セルのハニカム構造体で
流路方向の圧縮強度は実用上 100kgf/cm2 以上、好まし
くは200kgf/cm2 以上が必要であり、気孔率に対応させ
るとそれぞれ42％、36％にあたる。Rib thickness most industrially adopted
150 [mu] m, 1 compressive strength in the flow path direction in the honeycomb structure of square centimeter per 62 cells practically 100 kgf / cm 2 or more, preferably requires 200 kgf / cm 2 or more, respectively 42% made to correspond to the porosity, It corresponds to 36%.
【００２６】担持後の耐熱衝撃性に関して、新たに10μ
m 以上の細孔が重要な役割を果すことが判明した。触媒
活性を維持するために通常使用される高比表面積の活性
アルミナ粒径は、５〜10μm の粒子径を有している。こ
のため、活性アルミナの付着速度は低いものの10μm 以
上の気孔にはこの活性アルミナ粒子が浸入しやすく、特
にハニカム隔壁の内部にまで浸入してしまうために、担
体の大幅な熱膨脹上昇をもたらす。よって、従来より触
媒担持性向上のため導入が図られてきた10μm以上の細
孔は、触媒担持性および担持後の耐熱衝撃性両面で好ま
しくない要因であることが明らかとなった。Regarding the thermal shock resistance after loading, a new value of 10 μm
It was found that pores of m or larger play an important role. The high specific surface area activated alumina particles commonly used to maintain catalytic activity have a particle size of 5 to 10 .mu.m. For this reason, although the deposition rate of activated alumina is low, the activated alumina particles easily infiltrate into pores of 10 μm or more, and particularly penetrate into the inside of honeycomb partition walls, resulting in a large increase in thermal expansion of the carrier. Therefore, it has been clarified that the pores of 10 μm or more, which have been conventionally introduced to improve the catalyst supporting property, are unfavorable factors in both the catalyst supporting property and the thermal shock resistance after the supporting.
【００２７】本発明の構成において、0.5 〜５μm 細孔
容積は全細孔容積の70％以上より好ましくは80％以上占
めることにより、良好な触媒担持性が得られる。また、
10μm 以上の細孔容積を全細孔容積の10％以下に抑える
ことによって、触媒担持性の向上及びバラツキ抑制、担
持後の熱膨脹上昇を最小限に抑えることが可能となる。
担体の熱膨脹係数は、この効果を明確に得るためには40
〜800 ℃の間の熱膨脹係数が1.0 ×10-6／℃以下である
必要がある。上述した条件をともに満足する細孔分布を
有することにより、触媒担持性、コート後の耐熱衝撃性
の大幅な向上が可能となる。In the constitution of the present invention, good catalyst-supporting property can be obtained by making the pore volume of 0.5 to 5 μm account for 70% or more, preferably 80% or more of the total pore volume. Also,
By suppressing the pore volume of 10 μm or more to 10% or less of the total pore volume, it becomes possible to improve the catalyst supportability and suppress the dispersion, and to minimize the increase in thermal expansion after the support.
The coefficient of thermal expansion of the carrier is 40 to obtain this effect clearly.
The coefficient of thermal expansion between ~ 800 ° C must be 1.0 × 10 -6 / ° C or less. By having a pore size distribution that satisfies both of the above conditions, it becomes possible to greatly improve the catalyst supporting property and the thermal shock resistance after coating.
【００２８】[0028]
【実施例】本発明の好ましい細孔分布を有するコージェ
ライトハニカム構造体の製造にあたっては、従来公知の
種々の方法から選択して製造することが可能である。例
えば、所定粒度の原料を混合し、この混合物に可塑剤及
び粘結剤を加えて可塑化した変形可能なバッチとし、こ
の可塑化したバッチを押出し成形法により成形後乾燥
し、次いで所定の温度で焼成して得ることができる。こ
のとき、以下の点に注意すると好ましい。EXAMPLES In producing the cordierite honeycomb structure having the preferable pore distribution of the present invention, it is possible to select and produce from various conventionally known methods. For example, a raw material having a predetermined particle size is mixed, a plasticizer and a binder are added to the mixture to make a plasticized deformable batch, and the plasticized batch is molded by an extrusion molding method and then dried, and then at a predetermined temperature. It can be obtained by firing at. At this time, it is preferable to pay attention to the following points.
【００２９】原料特にタルク原料の粒度分布カーブで特
定の粗粒分をカットすることおよび微粒のアルミナ原料
を使用することが有効である。気孔率の適正化には微粒
のグラファイト、小麦粉、でんぷん粉の使用も有効であ
る。It is effective to cut a specific coarse particle portion in the particle size distribution curve of the raw material, especially the talc raw material, and to use a fine alumina raw material. The use of fine graphite, wheat flour, and starch powder is also effective for optimizing the porosity.
【００３０】また、焼成工程において1000〜1400℃の昇
温速度を制御すること、即ち50℃/Hr 以下に抑制した昇
温を選択することが有効である。さらに、最高温度と保
持時間を変更することにより0.5 〜５μm の細孔量を増
加させることができる。Further, it is effective to control the temperature rising rate of 1000 to 1400 ° C. in the firing step, that is, to select the temperature rising suppressed to 50 ° C./Hr or less. Further, by changing the maximum temperature and the holding time, it is possible to increase the pore amount of 0.5 to 5 μm.
【００３１】焼成条件変更による0.5 〜５μm 細孔増加
では、その方向がコージェライトハニカム担体の熱膨脹
係数増加に対応するため担体の熱膨脹係数を1.0 ×10-6
／℃以下に抑えなければならない。When the pore size is increased by 0.5 to 5 μm by changing the firing conditions, the direction corresponds to the increase in the coefficient of thermal expansion of the cordierite honeycomb carrier, so the coefficient of thermal expansion of the carrier is 1.0 × 10 −6.
Must be kept below / ° C.
【００３２】なお、活性アルミナによる高比表面積材料
のコーティング（ウォッシュコート）に限定されるもの
ではなくCeO2等の希土類酸化物又はPt等の貴金属触媒成
分を含んだ活性アルミナウォッシュコート、さらにZrO2
等この他の高比表面積材料のウォッシュコートに対して
も有効である。The coating of the high specific surface area material with activated alumina (wash coat) is not limited, but an activated alumina wash coat containing a rare earth oxide such as CeO 2 or a noble metal catalyst component such as Pt, and further ZrO 2
It is also effective for washcoats of other high specific surface area materials.
【００３３】以下、実際の例について説明する。実施例１ 表１に示す化学組成のタルク、カオリン、仮焼カオリ
ン、アルミナを使用して表２に示す調合割合で原料の粒
度変更、焼成条件として1000〜1400℃の昇温速度、最高
温度、保持時間を変更して、公知の押出製法により表３
No. １〜No. 13の細孔分布を有するリブ厚 150μm 、１
平方センチ当りのセル数62ケの直径 101mm、長さ 152mm
の円筒形コージェライトハニカム構造触媒担体を得た。An actual example will be described below. Example 1 Talc, kaolin, calcined kaolin, and alumina having the chemical compositions shown in Table 1 were used to change the particle size of the raw materials at the compounding ratio shown in Table 2, the heating rate of 1000 to 1400 ° C., the maximum temperature as firing conditions, The holding time was changed and the known extrusion method was used.
Rib thickness 150 μm with pore distribution of No. 1 to No. 13, 1
62 cells per square centimeter, diameter 101mm, length 152mm
Thus, a cylindrical cordierite honeycomb structure catalyst carrier was obtained.
【００３４】一方、高比表面積材料として、平均粒子径
９μm のベーマイト相活性アルミナ95重量部とアルミナ
ゾル５重量部及びpH調整剤として希硝酸を使用して固型
分30％のコーティング用スラリーを調整した。前記No.
１〜No. 13のハニカム構造体各５個をこのスラリー20リ
ットル中にそれぞれ各２分間浸漬し、空気気流中で余分
なスラリーを吹き出し、120 ℃で乾燥した。スラリーへ
の浸漬〜乾燥の工程をそれぞれ２回実施の後 700℃で焼
成した。On the other hand, as a high specific surface area material, 95 parts by weight of boehmite phase activated alumina having an average particle diameter of 9 μm, 5 parts by weight of alumina sol and dilute nitric acid as a pH adjuster were used to prepare a coating slurry having a solid content of 30%. did. Said No.
Five honeycomb structures of Nos. 1 to 13 were each immersed in 20 liters of this slurry for 2 minutes each, and excess slurry was blown out in an air stream and dried at 120 ° C. The steps of dipping in the slurry to drying were each performed twice, and then firing was performed at 700 ° C.
【００３５】焼成後の重量を測定し、合計２回のディッ
ピングによる担持量を測定した。ｎ= ５の担持量の平均
値と0.5 〜５μm 細孔量との関係を図１に、担持量と10
μm以上細孔量との関係を図２にそれぞれ示す。The weight after firing was measured, and the supported amount by a total of two dippings was measured. The relationship between the average value of the amount of n = 5 and the amount of pores of 0.5 to 5 μm is shown in FIG.
FIG. 2 shows the relationship with the pore size of μm or more.
【００３６】また、担持前後のコージェライトハニカム
構造体の熱膨脹係数及びコーティング品の電気炉スポー
リング破壊温度についても表３に示す。Table 3 also shows the coefficient of thermal expansion of the cordierite honeycomb structure before and after the supporting and the electric furnace spalling breakdown temperature of the coated product.
【００３７】[0037]
【表１】 [Table 1]
【００３８】[0038]
【表２】 [Table 2]
【００３９】[0039]
【表３】 [Table 3]
【００４０】上述した結果から、0.5 〜５μm および10
μm 以上の細孔容積の全細孔容積に占める割合が本発明
の規定内である試験No. ３〜５，７〜10および12は、担
持量、熱膨脹係数、電気炉スポーリング破壊温度の点
で、本発明の規定外の細孔容積分布を有する試験No.
１，２，６，11, 13と比べて良好であることがわかっ
た。From the above results, 0.5-5 μm and 10
Test Nos. 3 to 5, 7 to 10 and 12, in which the ratio of the pore volume of μm or more to the total pore volume is within the regulations of the present invention, are points of the supported amount, the coefficient of thermal expansion, and the electric furnace spalling fracture temperature. In, the test No. having a pore volume distribution outside the specifications of the present invention.
It was found to be better than 1, 2, 6, 11, and 13.
【００４１】実施例２ 実施例１と同様にして、表４、３，４（表３、３，４と
同バッチ）、14, 20,21さらに造孔剤として微粒グラフ
ァイトを用いて表４、15〜19, 22の細孔分布を有するリ
ブ厚 150μm 、１平方センチ当りセル数62ケの直径 101
mm、長さ 152mmの円筒形コージェライトハニカム構造触
媒担体を得た。実施例１で使用したコーティング用スラ
リーを用いて同様の実験方法にて活性アルミナ担持量を
測定した。この結果と活性アルミナ担持前の圧縮強度測
定結果を表４に示す。また、図３に気孔率と担持量、圧
縮強度の関係を示す。 Example 2 In the same manner as in Example 1, Tables 4, 3 and 4 (the same batch as Tables 3, 3 and 4), 14, 20 and 21 were used, and Table 4 was prepared using fine graphite as a pore-forming agent. Rib thickness 150μm with pore distribution of 15 to 19 and 22, diameter of 62 cells per square centimeter 101
A cylindrical cordierite honeycomb structure catalyst carrier having a length of mm and a length of 152 mm was obtained. Using the coating slurry used in Example 1, the amount of active alumina supported was measured by the same experimental method. Table 4 shows this result and the result of compressive strength measurement before supporting activated alumina. Further, FIG. 3 shows the relationship between the porosity, the supported amount, and the compressive strength.
【００４２】[0042]
【表４】 上述した結果から、気孔率および細孔容積分布が本発明
の規定内である試験No. 3, 4, 14〜18, 21は、担持量、
圧縮強度の点で、本発明の規定外の気孔率および細孔容
積分布を有する試験No. 19, 20と比べて良好であること
がわかった。[Table 4] From the above-mentioned results, the porosity and the pore volume distribution of the test No. 3, 4, 14 to 18, 21 which are within the definition of the present invention, the supported amount,
In terms of compressive strength, it was found to be better than Test Nos. 19 and 20 having the porosity and the pore volume distribution outside the limits of the present invention.
【００４３】また、本発明の試験No. ３と参考例の試験
No. １, ２についてCeO2及び活性アルミナを触媒として
担持させたときの界面の様子をSEM により撮影した。図
４〜図６は、それぞれ本発明の試験No. ３および参考例
試験No. ２，１の粒子構造を示す図である。図４に示す
本発明の例では活性アルミナ層が表面に均一に形成され
ているのに対し、図５，図６に示す参考例では活性アル
ミナ層が表面に均一に形成されず、また図６では担体内
部にまで浸透している様子がわかる。Further, the test No. 3 of the present invention and the test of the reference example
Regarding Nos. 1 and 2, the state of the interface when CeO 2 and activated alumina were supported as a catalyst was photographed by SEM. 4 to 6 are views showing the particle structures of Test No. 3 and Reference Example Test Nos. 2 and 1 of the present invention, respectively. In the example of the present invention shown in FIG. 4, the activated alumina layer is uniformly formed on the surface, whereas in the reference examples shown in FIGS. 5 and 6, the activated alumina layer is not uniformly formed on the surface, and FIG. Shows that it has penetrated into the inside of the carrier.
【００４４】[0044]
【発明の効果】以上詳細に説明したところから明らかな
ように、本発明のコージェライトハニカム構造体によれ
ば、所定の気孔率および細孔容積分布を有するコージェ
ライトハニカム構造体をハニカム構造触媒担体として使
用することにより、高比表面材料及び触媒成分の担持性
が良好でコーティング後のコージェライトハニカム触媒
の耐熱衝撃性も良好なコージェライトハニカム構造触媒
担体を得ることができる。As is clear from the above description in detail, according to the cordierite honeycomb structure of the present invention, a cordierite honeycomb structure having a predetermined porosity and pore volume distribution is used as a honeycomb structure catalyst carrier. As a result, it is possible to obtain a cordierite honeycomb structure catalyst carrier having a high specific surface material and good supportability of a catalyst component, and a coated cordierite honeycomb catalyst having good thermal shock resistance.
【図１】触媒担持量と0.5 〜５μm 細孔容積の全細孔容
積に占める割合との関係を示したグラフである。FIG. 1 is a graph showing the relationship between the amount of catalyst supported and the ratio of 0.5-5 μm pore volume to the total pore volume.
【図２】触媒担持量と10μm 以上の細孔容積の全細孔容
積に占める割合との関係を示したグラフである。FIG. 2 is a graph showing the relationship between the amount of catalyst supported and the ratio of the pore volume of 10 μm or more to the total pore volume.
【図３】気孔率と触媒担持量および圧縮強度との関係を
示したグラフである。FIG. 3 is a graph showing the relationship between the porosity, the catalyst loading amount, and the compression strength.
【図４】本発明の担体と活性アルミナの担持界面の粒子
構造を示すSEM 写真である。FIG. 4 is an SEM photograph showing a particle structure of a supporting interface between the carrier of the present invention and activated alumina.
【図５】参考例の担体と活性アルミナの担持界面の粒子
構造を示すSEM 写真である。FIG. 5 is an SEM photograph showing a particle structure at a supporting interface between a carrier of Reference Example and activated alumina.
【図６】参考例の担体と活性アルミナの担持界面の粒子
構造を示すSEM 写真である。FIG. 6 is an SEM photograph showing a particle structure of a supporting interface between a carrier of Reference Example and activated alumina.
Claims (3)
面に均一にコートされ、前記高比表面積材料が実質的に
表面気孔中に存在しないことを特徴とするコージェライ
トハニカム構造体。1. A cordierite honeycomb structure, wherein a coating layer of a high specific surface area material is substantially uniformly coated on the surface, and the high specific surface area material is substantially absent in surface pores.
る請求項１記載のコージェライトハニカム構造体。2. The cordierite honeycomb structure according to claim 1, wherein the high specific surface area material is activated alumina.
構造体において、高比表面積材料をコートする前の気孔
率が30％を超え42％以下であって、直径0.5〜５μｍの
総細孔容積が全細孔容積の70％以上で、直径10μｍ以上
の細孔容積が全細孔容積の10％以下であることを特徴と
するコージェライトハニカム構造体。3. The cordierite honeycomb structure according to claim 1, wherein the porosity before coating the high specific surface area material is more than 30% and 42% or less, and the total pore volume of 0.5 to 5 μm in diameter is A cordierite honeycomb structure characterized by being 70% or more of the total pore volume and 10% or less of the total pore volume of the pores having a diameter of 10 μm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5127781A JPH06165943A (en) | 1987-02-12 | 1993-05-06 | Cordierite honeycomb structure |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62028365A JPH0669534B2 (en) | 1987-02-12 | 1987-02-12 | Cordierite honeycomb structure |
| JP5127781A JPH06165943A (en) | 1987-02-12 | 1993-05-06 | Cordierite honeycomb structure |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62028365A Division JPH0669534B2 (en) | 1987-02-12 | 1987-02-12 | Cordierite honeycomb structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06165943A true JPH06165943A (en) | 1994-06-14 |
Family
ID=26366452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5127781A Pending JPH06165943A (en) | 1987-02-12 | 1993-05-06 | Cordierite honeycomb structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06165943A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06165939A (en) * | 1987-02-12 | 1994-06-14 | Ngk Insulators Ltd | Cordierite honeycomb structure |
| JPH1015351A (en) * | 1996-07-05 | 1998-01-20 | Takasago Thermal Eng Co Ltd | Catalyst medium for air cleaning and air cleaner |
| JP2008062216A (en) * | 2006-09-11 | 2008-03-21 | Denso Corp | Ceramic catalyst object |
| CN115259843A (en) * | 2022-06-17 | 2022-11-01 | 四会市康荣新材料有限公司 | Low expansion coefficient's extrusion porcelain pipe |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5417388A (en) * | 1977-07-08 | 1979-02-08 | Mitsui Mining & Smelting Co | Catalyst carrier |
| JPS63197550A (en) * | 1987-02-12 | 1988-08-16 | Ngk Insulators Ltd | Cordierite honeycomb structural body |
| JPH06165939A (en) * | 1987-02-12 | 1994-06-14 | Ngk Insulators Ltd | Cordierite honeycomb structure |
-
1993
- 1993-05-06 JP JP5127781A patent/JPH06165943A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5417388A (en) * | 1977-07-08 | 1979-02-08 | Mitsui Mining & Smelting Co | Catalyst carrier |
| JPS63197550A (en) * | 1987-02-12 | 1988-08-16 | Ngk Insulators Ltd | Cordierite honeycomb structural body |
| JPH06165939A (en) * | 1987-02-12 | 1994-06-14 | Ngk Insulators Ltd | Cordierite honeycomb structure |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06165939A (en) * | 1987-02-12 | 1994-06-14 | Ngk Insulators Ltd | Cordierite honeycomb structure |
| JPH1015351A (en) * | 1996-07-05 | 1998-01-20 | Takasago Thermal Eng Co Ltd | Catalyst medium for air cleaning and air cleaner |
| JP2008062216A (en) * | 2006-09-11 | 2008-03-21 | Denso Corp | Ceramic catalyst object |
| CN115259843A (en) * | 2022-06-17 | 2022-11-01 | 四会市康荣新材料有限公司 | Low expansion coefficient's extrusion porcelain pipe |
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