JP2010260787A - Method for manufacturing porous honeycomb structure - Google Patents
Method for manufacturing porous honeycomb structure Download PDFInfo
- Publication number
- JP2010260787A JP2010260787A JP2010137900A JP2010137900A JP2010260787A JP 2010260787 A JP2010260787 A JP 2010260787A JP 2010137900 A JP2010137900 A JP 2010137900A JP 2010137900 A JP2010137900 A JP 2010137900A JP 2010260787 A JP2010260787 A JP 2010260787A
- Authority
- JP
- Japan
- Prior art keywords
- less
- honeycomb structure
- talc
- fused silica
- cordierite
- 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.)
- Granted
Links
Landscapes
- Porous Artificial Stone Or Porous Ceramic Products (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Exhaust Gas After Treatment (AREA)
- Processes For Solid Components From Exhaust (AREA)
- Filtering Materials (AREA)
Abstract
Description
本発明は、ディーゼル機関から排出される炭素を主成分とする微粒子であるパティキュレートを捕集するフィルターに用いるコーディエライト製のハニカム構造体の製造方法に関する。 The present invention relates to a method for manufacturing a cordierite honeycomb structure used for a filter that collects particulates that are fine particles mainly composed of carbon discharged from a diesel engine.
ディーゼル機関から排出されるパティキュレートを捕集する目的とし、コーディエライト製のハニカム構造体を用いたフィルターが利用されている。従来のハニカム構造体は、円柱形状であって、その長手方向に設けた多数の導入通路及び排出通路を有する。 For the purpose of collecting particulates discharged from a diesel engine, a filter using a cordierite honeycomb structure is used. A conventional honeycomb structure has a cylindrical shape and has a large number of introduction passages and discharge passages provided in the longitudinal direction thereof.
上記導入通路は、排出ガス導入側を開口しており、一方排出側を閉塞材によって閉塞してある。また、上記排出通路は、排出ガス導入側を閉塞材によって閉塞してあり、一方排出側を開口してある。そして、導入通路と排出通路とは、縦方向及び横方向に交互に、いわゆる市松模様状に配置してある。また、上記導入通路及び排出通路を構成する隔壁は、多孔質であって、多数の細孔を有する。 The introduction passage is open on the exhaust gas introduction side, while the discharge side is closed with a closing material. The exhaust passage is closed on the exhaust gas introduction side with a closing material, and on the other hand, the exhaust side is opened. The introduction passage and the discharge passage are alternately arranged in the vertical direction and the horizontal direction in a so-called checkered pattern. The partition walls constituting the introduction passage and the discharge passage are porous and have a large number of pores.
次に、上記従来のハニカム構造体を用いたフィルターによってパティキュレートを捕集する際には、まず、パティキュレートを含有した排出ガスが上記導入通路内に進入する。この時、上記隔壁は、排出ガス中のパティキュレートを捕獲し、排出ガスを浄化する。次いで、浄化された排出ガスは排出通路の開口端から排出される。
このようなハニカム構造体を用いたフィルターは、各貫通孔間の隔壁に形成される細孔径をどのように設計するかにより捕集効率、圧力損失等の性能が異なり、フィルター壁の細孔分布を制御することが求められている。
Next, when particulates are collected by the filter using the conventional honeycomb structure, first, exhaust gas containing particulates enters the introduction passage. At this time, the partition wall captures particulates in the exhaust gas and purifies the exhaust gas. Next, the purified exhaust gas is exhausted from the open end of the exhaust passage.
A filter using such a honeycomb structure has different performance such as collection efficiency and pressure loss depending on how the pore diameter formed in the partition wall between the through holes is designed. Is required to control.
従来、多孔質ハニカムフィルターとしては、耐熱性に優れる炭化ケイ素製は、細孔径の制御が容易であるものの、焼成に際し特殊な雰囲気で焼成せねばならず、また、大型化一体フィルターの作製が困難で小ブロックを張り合わせた後、円筒状に作製せねばならず、コストがかかるという問題を有していた。 Conventionally, as a porous honeycomb filter, silicon carbide, which has excellent heat resistance, can easily control the pore diameter, but it must be fired in a special atmosphere during firing, and it is difficult to produce a large integrated filter Then, after the small blocks are pasted together, they have to be manufactured in a cylindrical shape, which has a problem of cost.
これに対し、コーディエライト製は特殊な雰囲気焼成もいらず、また、大型化一体フィルターの作製が容易でコストパフォーマンスが優れていることに加え、熱膨張を低く制御できることから使用環境における安定性に優れることからコーディエライト製多孔質ハニカムフィルターの開発が進められている。 On the other hand, cordierite does not require special atmosphere firing, is easy to manufacture a large-sized integrated filter, has excellent cost performance, and has low thermal expansion control, so it can be used in a stable environment. The development of cordierite porous honeycomb filters is being promoted.
このフィルターとして、カオリンと酸化アルミニウムをコーディエライト化原料に含有させないことにより気孔率を向上させると共に、粒径を特定範囲で制御した水酸化アルミニウム（粒径が０．５〜３μｍの粉末と、粒径が５〜１５μｍの粉末とが水酸化アルミニウム全体の５０〜１００％を占める）と、溶融シリカ（平均粒径が３０〜１００μｍ）と、タルクからなるコーディエライト原料に、所定の有機発泡剤又は可燃性物質を添加した原料を用いる製造方法により得られた、平均孔径が２５〜４０μｍのハニカムフィルターが開示されている（特許文献１）。しかし、このハニカムフィルターでは、細孔径を、主に、水酸化アルミニウムと、有機発泡剤、又は可燃性物質により制御する為、平均細孔径は大きな径となり、パティキュレートがすり抜けてしまい、捕集率が低下してしまうという問題がある。 As this filter, the porosity is improved by not containing kaolin and aluminum oxide in the cordierite forming raw material, and the aluminum hydroxide whose particle size is controlled in a specific range (powder having a particle size of 0.5 to 3 μm, A powder having a particle size of 5 to 15 μm occupies 50 to 100% of the whole aluminum hydroxide), a fused silica (average particle size of 30 to 100 μm), and a cordierite raw material made of talc, with a predetermined organic foam A honeycomb filter having an average pore diameter of 25 to 40 μm obtained by a production method using a raw material to which an agent or a combustible material is added is disclosed (Patent Document 1). However, in this honeycomb filter, since the pore diameter is mainly controlled by aluminum hydroxide and an organic foaming agent or a combustible substance, the average pore diameter becomes large and particulates slip through and the collection rate There is a problem that will decrease.
また、細孔分布を制御したコーディエライトを主結晶相とする材料からなる多孔質ハニカムフィルターであって、細孔分布が、細孔径１０μｍ未満の細孔容積：全細孔容積の１５％以下、細孔径１０〜５０μの細孔容積：全細孔容積の７５％以上、細孔径５０μｍを超える細孔容積：全細孔容積の１０％以下であることを特徴とする多孔質ハニカムフィルター及びその製造方法が開示されている（特許文献２）。 Also, a porous honeycomb filter made of a material having cordierite as a main crystal phase with controlled pore distribution, wherein the pore distribution is a pore volume having a pore diameter of less than 10 μm: 15% or less of the total pore volume A porous honeycomb filter having a pore diameter of 10 to 50 μm: 75% or more of the total pore volume and a pore volume exceeding 50 μm of the pore diameter: 10% or less of the total pore volume, and A manufacturing method is disclosed (Patent Document 2).
しかし、ディーゼルエンジンの改良並びに燃料噴射系の著しい技術革新に伴い、排ガス中の微粒子は、排出量低減化に加え微粒子化され、細孔径を極めて高度に制御したハニカムフィルターが強く要望されている。これに対して、従来法によるこのハニカムフィルターでは、微粒子化したパティキュレートを完全に捕集できないという問題がある。 However, with the improvement of the diesel engine and the remarkable technological innovation of the fuel injection system, there is a strong demand for a honeycomb filter in which the fine particles in the exhaust gas are made fine in addition to reducing the emission amount and the pore diameter is extremely controlled. On the other hand, this honeycomb filter according to the conventional method has a problem that the particulates cannot be completely collected.
本発明は、かかる従来の問題点に鑑みてなされたものであって、微粒子（Ｐａｒｔｉｃｕｌａｔｅ Ｍａｔｔｅｒ：ＰＭ、パティキュレート）等の捕集効率が高く、かつ細孔の目詰まりによる圧力損失の増大を防止することができる多孔質ハニカム構造体の製造方法を提供することを目的とする。 The present invention has been made in view of such conventional problems, and has a high collection efficiency of particulates (Particulate Matter: PM), and prevents an increase in pressure loss due to clogging of pores. It is an object of the present invention to provide a method for manufacturing a porous honeycomb structure that can be made.
ハニカム状のセル壁と該セル壁に囲まれた多数のセルとを有する多孔質のハニカム構造体であって、
上記セル壁は、化学組成がＳｉＯ2：４５〜５５重量％、Ａｌ2Ｏ3：３３〜４２重量％、ＭｇＯ：１２〜１８重量％よりなるコーディエライトを主成分とし、
上記セル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満であることを特徴とする多孔質ハニカム構造体がある。
A porous honeycomb structure having a honeycomb-shaped cell wall and a large number of cells surrounded by the cell wall,
The cell walls, chemical composition SiO 2: 45 to 55 wt%, Al 2 O 3: 33~42 wt%, MgO: a main component from the consisting cordierite 12-18 wt%,
In the distribution of the pores formed in the cell wall, the pore volume having a pore diameter of 5 μm or less is less than 15% of the total pore volume, and the pore volume exceeding 25 μm is 10% of the total pore volume. There is a porous honeycomb structure characterized in that it is less than.
上記多孔質ハニカム構造体は、上記セル壁における細孔の分布を特定範囲に制限することにより、微粒子等の捕集効率が高く、かつ細孔の目詰まりによる圧力損失の増大を防止することができる。
多孔質ハニカム構造体は、微粒子化したパティキュレートを高効率で捕集するために、パティキュレートがすり抜け易い粗大孔を存在させず、かつ、細孔径を小さくすることが有効である。そのため、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満とすることにより、高い捕集効率が得られる。
The porous honeycomb structure has a high collection efficiency of fine particles and the like, and prevents an increase in pressure loss due to pore clogging by limiting the distribution of pores in the cell wall to a specific range. it can.
In the porous honeycomb structure, in order to collect particulates with high efficiency, it is effective not to have coarse pores that easily pass through the particulates and to reduce the pore diameter. Therefore, a high collection efficiency can be obtained by setting the pore volume exceeding the pore diameter of 25 μm to less than 10% of the total pore volume.
また、上記のように、高捕集率のために細孔径を小さくすることが望ましい。しかし、微細孔は、触媒層付与による細孔の閉塞を招き、圧力損失を増大させるという問題がある。そのため、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満とすることにより、細孔の目詰まりによる圧力損失の増大を防ぐことができる。 Further, as described above, it is desirable to reduce the pore diameter for high collection rate. However, the micropores cause a problem that the pores are blocked due to the provision of the catalyst layer and the pressure loss is increased. Therefore, when the pore volume having a pore diameter of 5 μm or less is less than 15% of the total pore volume, an increase in pressure loss due to pore clogging can be prevented.
つまり、細孔径５〜２５μｍの狭い範囲の細孔が占める割合を極めて高い率となるように細孔の分布を制御することにより、微粒子化したパティキュレートをも捕集することができ、かつ、圧力損失や目詰まりなどの問題の発生も抑制することができる。
このように、微粒子等の捕集効率が高く、かつ細孔の目詰まりによる圧力損失の増大を防止することができる多孔質ハニカム構造体を提供することができる。
That is, by controlling the distribution of the pores so that the proportion of pores in a narrow range of 5 to 25 μm is extremely high, it is possible to collect fine particulates, and The occurrence of problems such as pressure loss and clogging can also be suppressed.
As described above, it is possible to provide a porous honeycomb structure having a high collection efficiency of fine particles and the like and capable of preventing an increase in pressure loss due to clogging of pores.
第１及び第２の発明は、上記の多孔質ハニカム構造体を製造する方法である。
第１の発明は、ハニカム状のセル壁と該セル壁に囲まれた多数のセルとを有し、上記セル壁は、化学組成がＳｉＯ2：４５〜５５重量％、Ａｌ2Ｏ3：３３〜４２重量％、ＭｇＯ：１２〜１８重量％よりなるコーディエライトを主成分とし、上記セル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満である多孔質ハニカム構造体を製造する方法であって、
コーディエライト化原料を押出成形し上記ハニカム構造体を成形する成形工程と、上記ハニカム構造体を乾燥させる乾燥工程と、上記ハニカム構造体を焼成する焼成工程とを有し、
上記コーディエライト化原料は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であることを特徴とする多孔質ハニカム構造体の製造方法にある（請求項１）。
1st and 2nd invention is a method of manufacturing said porous honeycomb structure.
The first invention has a honeycomb-shaped cell wall and a large number of cells surrounded by the cell wall. The cell wall has a chemical composition of SiO 2 : 45 to 55% by weight, Al 2 O 3 : 33. The distribution of pores formed in the cell wall is composed of cordierite consisting of ˜42 wt% and MgO: 12 to 18 wt%, and the pore volume of the pore diameter of 5 μm or less is the total pore volume. A method for producing a porous honeycomb structure having a pore volume of less than 15% and having a pore diameter exceeding 25 μm is less than 10% of the total pore volume,
A molding step of extruding a cordierite forming raw material to form the honeycomb structure, a drying step of drying the honeycomb structure, and a firing step of firing the honeycomb structure,
The cordierite-forming raw material is mainly composed of talc, fused silica, and aluminum hydroxide, and is the sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 8.7 μm or less by a particle size distribution meter. Is 15% or less, and the sum of the coarse particle accumulation frequency of talc of 31.3 μm or more and the coarse particle accumulation frequency of fused silica of 31.3 μm or more is 10% or less, (Claim 1).
また、第２の発明は、ハニカム状のセル壁と該セル壁に囲まれた多数のセルとを有し、上記セル壁は、化学組成がＳｉＯ2：４５〜５５重量％、Ａｌ2Ｏ3：３３〜４２重量％、ＭｇＯ：１２〜１８重量％よりなるコーディエライトを主成分とし、上記セル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満である多孔質ハニカム構造体を製造する方法であって、
コーディエライト化原料を押出成形し上記ハニカム構造体を成形する成形工程と、上記ハニカム構造体を乾燥させる乾燥工程と、上記ハニカム構造体を焼成する焼成工程とを有し、
上記コーディエライト化原料は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であることを特徴とする多孔質ハニカム構造体の製造方法にある（請求項２）。
The second invention has a honeycomb-shaped cell wall and a large number of cells surrounded by the cell wall, and the cell wall has a chemical composition of SiO 2 : 45 to 55% by weight, Al 2 O 3. : Cordierite composed of 33 to 42% by weight, MgO: 12 to 18% by weight, and the pores formed in the cell wall have a pore volume of 5 μm or less. A method for producing a porous honeycomb structure having a pore volume of less than 15% of the volume and a pore volume exceeding 25 μm in pore diameter of less than 10% of the total pore volume,
A molding step of extruding a cordierite forming raw material to form the honeycomb structure, a drying step of drying the honeycomb structure, and a firing step of firing the honeycomb structure,
The cordierite-forming raw material is mainly composed of talc, fused silica, and aluminum hydroxide. The sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 6.25 μm or less by a particle size distribution meter. Is 15% or less, and the sum of the coarse particle accumulation frequency of talc 43.8 μm or more and the coarse particle accumulation frequency of fused silica 31.3 μm or more is 10% or less, (Claim 2).
上記多孔質ハニカム構造体を得るためには、製造過程において、細孔の形成を制御する必要がある。
そこで、コーディエライト化原料としてタルク、溶融シリカ、水酸化アルミニウムを選定し、細孔形成メカニズムを解析したところ、後で詳しく説明するが、多孔質ハニカム構造体のセル壁の気孔率は、水酸化アルミニウムの体積比率によって決定され、細孔径は、タルク及びシリカの粒子径によって決定されることが分かった。
そして、コーディエライト化原料中の、シリカ、タルクの収縮率を考慮し、粒子径を最適化することで、細孔径分布を所望範囲で高度に制御できることを見出した。
In order to obtain the porous honeycomb structure, it is necessary to control the formation of pores in the manufacturing process.
Therefore, talc, fused silica, and aluminum hydroxide were selected as the cordierite forming raw materials, and the pore formation mechanism was analyzed. As will be described in detail later, the porosity of the cell wall of the porous honeycomb structure is It was determined by the volume ratio of aluminum oxide, and the pore size was found to be determined by the particle size of talc and silica.
The inventors have found that the pore size distribution can be highly controlled within a desired range by optimizing the particle size in consideration of the shrinkage rate of silica and talc in the cordierite forming raw material.
そのため、上記特定のコーディエライト化原料を用いて、上記成形工程、乾燥工程、及び焼成工程を行うことにより、細孔径５〜２５μｍの狭い範囲の細孔を極めて高率で形成することができ、捕集高率が高く、かつ細孔の目詰まりによる圧力損失の増大のないハニカム構造体を製造することができる。
このように、本発明によれば、微粒子（パティキュレート）等の捕集効率が高く、かつ細孔の目詰まりによる圧力損失の増大を防止することができる多孔質ハニカム構造体を製造することができる。
Therefore, by performing the molding step, the drying step, and the firing step using the specific cordierite forming raw material, it is possible to form pores in a narrow range with a pore diameter of 5 to 25 μm at an extremely high rate. A honeycomb structure having a high collection rate and no increase in pressure loss due to clogging of pores can be produced.
As described above, according to the present invention, it is possible to manufacture a porous honeycomb structure that has high collection efficiency of fine particles (particulates) and the like and can prevent an increase in pressure loss due to pore clogging. it can.
また、従来は、カオリンやアルミナによって比較的孔の少ない骨格部が形成されていた。上記製造方法においては、タルク、溶融シリカ、水酸化アルミニウムを基本原料として用いている。上記水酸化アルミニウムは、その中に含まれる結晶水が蒸発し、多数の孔が形成する。また、溶融シリカ及びタルクは、焼成工程で分解し、その際の体積収縮により、その部分が気孔になる。そのため、本発明においては、形成される骨格部は従来よりも多孔質となる。 Conventionally, a skeleton having relatively few pores has been formed from kaolin or alumina. In the above production method, talc, fused silica, and aluminum hydroxide are used as basic raw materials. In the aluminum hydroxide, the crystal water contained therein evaporates to form a large number of pores. Further, the fused silica and talc are decomposed in the firing step, and the portion becomes pores due to the volume shrinkage at that time. Therefore, in the present invention, the skeleton formed is more porous than before.
上記多孔質ハニカム構造体は、上述したように、上記セル壁は、化学組成がＳｉＯ2：４５〜５５重量％、Ａｌ2Ｏ3：３３〜４２重量％、ＭｇＯ：１２〜１８重量％よりなるコーディエライトを主成分とし、上記セル壁中に形成された細孔の分布が、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満である。
上記細孔径５μｍ以下の細孔容積が１５％以上の場合には、触媒担持で細孔が詰まり、圧損が増加するという問題がある。一方、上記細孔径２５μｍを超える細孔容積が１０％以上の場合には、微粒子がすり抜け易く、捕集率が低下するという問題がある。
なお、細孔径分布の測定は、ポロシメータを用いた水銀圧入法により細孔容積を求める方法等により行うことができる。
As described above, in the porous honeycomb structure, the cell wall has a chemical composition of SiO 2 : 45 to 55 wt%, Al 2 O 3 : 33 to 42 wt%, and MgO: 12 to 18 wt%. The pore volume of cordierite as a main component and the pore distribution formed in the cell wall is such that the pore volume with a pore diameter of 5 μm or less is less than 15% of the total pore volume and the pore diameter exceeds 25 μm. Is less than 10% of the total pore volume.
When the pore volume with the pore diameter of 5 μm or less is 15% or more, there is a problem that the pores are clogged by catalyst loading and the pressure loss increases. On the other hand, when the pore volume exceeding the pore diameter of 25 μm is 10% or more, there is a problem that the fine particles are easily slipped through and the collection rate is lowered.
The pore size distribution can be measured by a method for obtaining the pore volume by a mercury intrusion method using a porosimeter.
また、上記ハニカム構造体は、例えば円柱状の外径を有し、その長手方向に、排出ガスを導入、排出するための、隔壁によって形成される多数の通路を有する形状にすることができる。
上記外径は、円柱形状以外に、直方体、その他の形状にすることもできる。
また、上記通路の断面形状は、四角形にすることが構成上最も容易であるが、六角形、三角形、その他の形状にしても問題はない。
The honeycomb structure has, for example, a cylindrical outer diameter, and can have a shape having a large number of passages formed by partition walls for introducing and discharging exhaust gas in the longitudinal direction.
The said outer diameter can also be made into a rectangular parallelepiped and other shapes besides cylindrical shape.
In addition, the cross-sectional shape of the passage is the easiest in terms of configuration, but there is no problem even if it is a hexagonal shape, a triangular shape, or other shapes.
また、上記セル壁の気孔率は、４０〜６０％であることが好ましい。
この場合には、特に、高捕集率かつ低圧損を得ることができる。
上記気孔率が４０％未満の場合には、圧損が高くなるおそれがある。一方、上記気孔率が６０％を超える場合には、捕集効率が低下するおそれがある。より好ましくは、上記気孔率は、４５〜５５％である。
Moreover, it is preferable that the porosity of the said cell wall is 40 to 60%.
In this case, in particular, a high collection rate and low pressure loss can be obtained.
When the porosity is less than 40%, the pressure loss may increase. On the other hand, when the porosity exceeds 60%, the collection efficiency may decrease. More preferably, the porosity is 45 to 55%.
また、上記セル壁の４０〜８００℃における熱膨張係数は、０．７×１０-6／℃以下であることが好ましい。
この場合には、非常に優れた耐熱衝撃性を示し、急激な温度変化が繰返し発生しても、破損することはない。
上記セル壁の４０〜８００℃における熱膨張係数が０．７×１０-6／℃を超える場合には、耐熱衝撃性が悪化するおそれがある。
Moreover, it is preferable that the thermal expansion coefficient in 40-800 degreeC of the said cell wall is 0.7 * 10 < -6 > / degrees C or less.
In this case, the thermal shock resistance is excellent, and even if a rapid temperature change occurs repeatedly, it will not be damaged.
When the thermal expansion coefficient at 40 to 800 ° C. of the cell wall exceeds 0.7 × 10 −6 / ° C., the thermal shock resistance may be deteriorated.
第１の発明、及び第２の発明の多孔質ハニカム構造体の製造方法は、上述したように、成形工程と、乾燥工程と、焼成工程とを有する。
上記成形工程では、コーディエライト化原料に水等を加えて混練し、これを押し出し成形し、ハニカム構造体に成形する。ハニカム形状に押し出し成形後、切断することにより、容易に所望寸法のハニカム成形体を得ることができる。連続成形が可能であると共に、コーディエライト結晶を配向させて低膨張性にできる。
また、上記成形工程では、コーディエライト化原料と水とを混練するだけでなく、必要に応じて、さらに可燃性物質等を加えてもよい。
As described above, the method for manufacturing the porous honeycomb structure according to the first invention and the second invention includes the forming step, the drying step, and the firing step.
In the forming step, water or the like is added to the cordierite-forming raw material and kneaded, and this is extruded and formed into a honeycomb structure. By extruding into a honeycomb shape and then cutting, a honeycomb formed body having a desired size can be easily obtained. Continuous molding is possible, and cordierite crystals can be oriented to have low expansion.
In the molding step, not only the cordierite-forming raw material and water are kneaded, but a combustible substance or the like may be further added as necessary.
また、上記乾燥工程では、上記成形工程で成形されたハニカム構造体を、上記水分などを蒸発させるために、熱風乾燥、マイクロ波乾燥、誘電乾燥、減圧乾燥、真空乾燥、凍結乾燥等で乾燥させる。中でも、全体を迅速かつ均一に乾燥することができる点で、熱風乾燥と、マイクロ波乾燥又は誘電乾燥とを組み合わせた乾燥工程を行うことが好ましい。また、上記乾燥工程は、例えば約８０℃〜１００℃で加熱することにより行う。加熱時間は、ハニカム成形体の大きさ等に合わせて適宜選択することが好ましい。 In the drying step, the honeycomb structure formed in the forming step is dried by hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, or the like in order to evaporate the moisture or the like. . Especially, it is preferable to perform the drying process which combined hot air drying and microwave drying or dielectric drying at the point which can dry the whole rapidly and uniformly. Moreover, the said drying process is performed by heating at about 80 to 100 degreeC, for example. It is preferable that the heating time is appropriately selected according to the size of the honeycomb formed body.
また、上記焼成工程は、従来と同様に行えば、約１３００〜１５００℃の温度において５〜２０時間保持することにより行う。ただし、焼成温度及び時間は、ハニカム成形体の大きさ等によって適宜変更することが好ましい。
なお、上記乾燥工程と焼成工程とは、別々の工程として行ってもよいが、乾燥温度から連続的に焼成温度に変更することによって、一つの工程にまとめることもできる。
Moreover, the said baking process will be performed by hold | maintaining at the temperature of about 1300-1500 degreeC for 5 to 20 hours, if it carries out similarly to the past. However, it is preferable to appropriately change the firing temperature and time depending on the size of the honeycomb formed body.
In addition, although the said drying process and a baking process may be performed as a separate process, it can also be put together into one process by changing from a drying temperature to baking temperature continuously.
そして、第１の発明の製造方法において、上記コーディエライト化原料を、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク、溶融シリカ８．７μｍ以下の微小粒累積頻度の和を１５％以下、３１．３μｍ以上の粗大粒累積頻度の和を１０％以下とした。 In the production method of the first invention, the cordierite-forming raw material is mainly composed of talc, fused silica, and aluminum hydroxide, talc by a particle size distribution meter, and the cumulative frequency of fine particles of fused silica of 8.7 μm or less. The sum is 15% or less, and the sum of the cumulative frequency of coarse grains of 31.3 μm or more is 10% or less.
ここで、累積頻度について説明する。粒度分布測定器では各粒子径毎の存在比率分布が得られるが、累積頻度は、この分布の総和であり、１００％となる。グラフとしては横軸を粒子径、縦軸を頻度（％）で表すことができ、ある粒子径範囲までの累積頻度として求めることが可能である。狙いの粒子径よりも細かい累積頻度の総和を微小粒累積頻度とし、逆に狙いの粒子径よりも粗い粒子径の累積頻度の総和を粗大粒累積頻度と定義する。
そして、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和とは、８．７μｍ以下のタルクと８．７μｍ以下の溶融シリカのそれぞれが占める体積比率にタルクと溶融シリカ各々の累積頻度との積をとり、得られたタルク、溶融シリカそれぞれの値の和をいう。
また、タルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和とは、上記と同様、３１．３μｍ以上のものに対して同様の手順にて求めた和ということである。
Here, the cumulative frequency will be described. In the particle size distribution measuring instrument, an abundance ratio distribution for each particle diameter is obtained, but the cumulative frequency is the sum of this distribution, which is 100%. In the graph, the horizontal axis can be represented by the particle diameter and the vertical axis can be represented by the frequency (%), and can be obtained as the cumulative frequency up to a certain particle diameter range. The sum of the cumulative frequencies finer than the target particle size is defined as the fine particle cumulative frequency, and conversely, the sum of the cumulative frequencies of the particle sizes coarser than the target particle size is defined as the coarse particle cumulative frequency.
The sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 8.7 μm or less as measured by the particle size distribution meter is talc of 8.7 μm or less and fused silica of 8.7 μm or less, respectively. The product of the talc and the accumulated frequency of each fused silica is taken as the volume ratio occupied by, and the sum of the values of the obtained talc and fused silica is said.
Also, the sum of the coarse particle accumulation frequency of talc of 31.3 μm or more and the coarse particle accumulation frequency of fused silica of 31.3 μm or more is the sum obtained by the same procedure for those having a particle size of 31.3 μm or more as described above That's what it means.
また、第２の発明の製造方法において、上記コーディエライト化原料を、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和を１５％以下、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和を１０％以下とした。 In the production method of the second invention, the cordierite-forming raw material is mainly composed of talc, fused silica, and aluminum hydroxide, and the cumulative frequency of fine particles of talc of 8.7 μm or less and fused silica 6 by a particle size distribution meter. The sum of the cumulative frequency of fine particles of 0.25 μm or less is 15% or less, and the sum of the cumulative frequency of coarse particles of talc 43.8 μm or more and the cumulative frequency of coarse particles of 31.3 μm or more of fused silica is 10% or less.
粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和とは、対象とする粒子径が異なるだけで、上記と同様の手順にて求めた和ということである。
また、粒度分布計によるタルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和とは、対象とする粒子径が異なるだけで、上記と同様の手順にて求めた和ということである。
The sum of the cumulative frequency of fine particles of talc 8.7 μm or less and the cumulative frequency of fine particles of fused silica 6.25 μm or less as determined by the particle size distribution meter is obtained by the same procedure as described above, except for the target particle size. It is a sum.
Further, the sum of the coarse particle accumulation frequency of talc 43.8 μm or more by the particle size distribution meter and the coarse particle accumulation frequency of fused silica 31.3 μm or more is similar to the above procedure except that the target particle diameter is different. It is the sum that I asked for.
第１の発明は、タルクと溶融シリカの粒径を同じ基準で制御することができ、管理が容易である。この場合において、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和が１５％を超える場合には、得られる多孔質ハニカム構造体のセル壁に、細孔径５μｍ以下の細孔が多く形成されやすくなり、触媒担持で細孔が詰まり、圧損が増加するという問題がある。一方、粒度分布計によるタルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％を超える場合には、細孔径２５μｍを超える細孔が形成されやすくなり、微粒子がすり抜け易く、捕集率が低下するという問題や、強度を低下させてしまうという問題がある。 In the first invention, the particle sizes of talc and fused silica can be controlled on the same basis, and management is easy. In this case, when the sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 8.7 μm or less by a particle size distribution meter exceeds 15%, the resulting porous honeycomb structure There are problems that many pores having a pore diameter of 5 μm or less are likely to be formed on the cell wall, and the pores are clogged by supporting the catalyst and the pressure loss increases. On the other hand, when the sum of the coarse particle accumulation frequency of talc of 31.3 μm or more by the particle size distribution meter and the coarse particle accumulation frequency of fused silica of 31.3 μm or more exceeds 10%, pores having a pore diameter of more than 25 μm are easily formed. Thus, there are problems that the fine particles are easily slipped through and the collection rate is lowered, and that the strength is lowered.
第２の発明は、粒径の制御を、タルクと溶融シリカについてそれぞれの基準で細かく行う方法である。この場合には、タルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和が１５％を超える場合に、得られる多孔質ハニカム構造体のセル壁に、細孔径５μｍ以下の細孔が多く形成されやすくなり、触媒担持で細孔が詰まり、圧損が増加するという問題がある。また、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％を超える場合に、細孔径２５μｍを超える細孔が形成されやすくなり、微粒子がすり抜け易く、捕集率が低下するという問題や、強度が低下するという問題がある。 The second invention is a method for finely controlling the particle diameter based on the respective standards for talc and fused silica. In this case, when the sum of the fine particle accumulation frequency of talc of 8.7 μm or less and the fine particle accumulation frequency of fused silica of 6.25 μm or less exceeds 15%, the cell wall of the obtained porous honeycomb structure is There are problems that many pores having a pore diameter of 5 μm or less are likely to be formed, the pores are clogged by supporting the catalyst, and the pressure loss increases. In addition, when the sum of the coarse particle accumulation frequency of talc 43.8 μm or more and the coarse particle accumulation frequency of fused silica 31.3 μm or more exceeds 10%, pores having a pore diameter of more than 25 μm are easily formed, and the fine particles pass through. There is a problem that the collection rate is low and the strength is low.
そして、上記タルク及び溶融シリカの微小粒は、気流分級により取り除く等して制御することができる。また、上記タルク及び溶融シリカの粗大粒は、メッシュ分級により取り除く等して制御することができる。
また、上記コーディエライト化原料は、不純物として、Ｆｅ2Ｏ3、ＣａＯ、Ｎａ2Ｏ、Ｋ2Ｏ等を含有してもよい。
The fine particles of talc and fused silica can be controlled by removing them by air classification. The coarse particles of talc and fused silica can be controlled by removing them by mesh classification.
The cordierite forming raw material may contain Fe 2 O 3 , CaO, Na 2 O, K 2 O, etc. as impurities.
ここで、上記第１の発明及び第２の発明の製造方法によって、上記多孔質ハニカム構造体を容易に製造することができる理由について考察する。
上述したように、コーディエライト化原料としてタルク、溶融シリカ、水酸化アルミニウムを選定した際の細孔形成メカニズムを解析したところ、多孔質ハニカム構造体のセル壁の気孔率は、水酸化アルミニウムの体積比率によって決定され、細孔径は、タルク及びシリカの粒子径によって決定されることが分かった。
Here, the reason why the porous honeycomb structure can be easily manufactured by the manufacturing method of the first invention and the second invention will be considered.
As described above, the pore formation mechanism was analyzed when talc, fused silica, and aluminum hydroxide were selected as the cordierite forming raw material. As a result, the porosity of the cell wall of the porous honeycomb structure was It was determined by the volume ratio, and it was found that the pore size was determined by the particle size of talc and silica.
具体的には、焼成工程において、１２００℃付近において、水酸化アルミニウムの脱水・収縮反応が起こり、収縮に伴い微小気孔が発生する。この時点で、得られる多孔質ハニカム構造体の気孔率がほぼ決定する。また、水酸化アルミニウムの脱水により生成したＡｌ2Ｏ3がコーディエライトの骨格となる。 Specifically, in the firing step, dehydration / shrinkage reaction of aluminum hydroxide occurs at around 1200 ° C., and micropores are generated with shrinkage. At this point, the porosity of the resulting porous honeycomb structure is almost determined. Further, Al 2 O 3 produced by dehydration of aluminum hydroxide becomes a cordierite skeleton.
その後、さらに加熱をしていくと、１３００〜１４００℃付近で、タルク、シリカが溶融する。溶融したタルク及びシリカは微小気孔に入り込み、微細気孔を埋める。そして、１４３０℃で骨格を中心にコーディエライト化する。そのため、タルクや溶融シリカが存在していた部分には、これらの粒子径に応じた空洞（細孔）が形成され、細孔径が決定する。
このように、気孔率は水酸化アルミニウムの体積比率によって決定され、また、細孔の細孔径は、シリカ及びタルクの粒子径と相関関係があることが分かった。
Thereafter, when further heating is performed, talc and silica melt at around 1300 to 1400 ° C. Molten talc and silica enter the micropores and fill the micropores. Then, cordierite is formed around the skeleton at 1430 ° C. Therefore, cavities (pores) corresponding to these particle sizes are formed in the portions where talc and fused silica were present, and the pore size is determined.
Thus, the porosity was determined by the volume ratio of aluminum hydroxide, and the pore diameter was found to correlate with the particle diameters of silica and talc.
すなわち、原料中の上記タルク及び溶融シリカの粒子径を制御することによって、得られるハニカム構造体のセル壁中の細孔の細孔径を制御することが可能であると予想された。 That is, it was expected that the pore diameters of the pores in the cell walls of the resulting honeycomb structure could be controlled by controlling the particle diameters of the talc and fused silica in the raw material.
そして、発明者の種々の実験により、コーディエライト化原料に用いたタルク、溶融シリカのそれぞれの平均粒子径と、セル壁中の細孔の分布で最頻値を示す細孔径との関係を求めた。具体的には、（平均粒子径）＝（粒子径収縮率ｋ）・（細孔径）の式を用いて、タルク、溶融シリカのそれぞれの粒子径収縮率ｋを算出した。その結果、タルクの粒子径収縮率ｋ＝１．７５、シリカの粒子径収縮率ｋ＝１．２５となった。 And by various experiments of the inventor, the relationship between the average particle diameter of talc and fused silica used as the cordierite forming raw material and the pore diameter showing the mode value in the distribution of pores in the cell wall Asked. Specifically, the respective particle diameter shrinkage ratios k of talc and fused silica were calculated using the formula (average particle diameter) = (particle diameter shrinkage ratio k) · (pore diameter). As a result, the particle size shrinkage k of talc k = 1.75 and the particle size shrinkage k of silica = 1.25.
求めた粒子径収縮率ｋを用いて、細孔径５μｍ未満の細孔を形成すると考えられる５・ｋ（μｍ）未満の粒子径を求めた。細孔径５μｍ未満の細孔を形成すると考えられるタルクの粒子径は８．７５未満、溶融シリカの粒子径は６．２５μｍ未満となった。
また、求めた粒子径収縮率ｋを用いて、細孔径２５μｍを超える細孔を形成すると考えられる２５・ｋ（μｍ）超えの粒子径を求めた。細孔径２５μｍを超える細孔を形成すると考えられるタルクの粒子径は４３．７５μｍ超え、溶融シリカの粒子径は３１．２５μｍ超えとなった。
Using the obtained particle diameter shrinkage k, a particle diameter of less than 5 · k (μm), which is considered to form pores having a pore diameter of less than 5 μm, was determined. The particle diameter of talc, which is considered to form pores having a pore diameter of less than 5 μm, was less than 8.75, and the particle diameter of fused silica was less than 6.25 μm.
Further, using the obtained particle diameter shrinkage k, a particle diameter exceeding 25 · k (μm), which is considered to form pores exceeding 25 μm, was determined. The particle diameter of talc, which is considered to form pores with a pore diameter exceeding 25 μm, exceeded 43.75 μm, and the particle diameter of fused silica exceeded 31.25 μm.
以上の結果から、タルクと溶融シリカの粒径を同じ基準で制御して簡素化する場合には、上記第１の発明が成立し、より細かい制御を行う場合には、第２の発明が成立することが分かる。 From the above results, when the particle sizes of talc and fused silica are controlled by the same standard and simplified, the first invention is established, and when finer control is performed, the second invention is established. I understand that
また、第１の発明及び第２の発明において、タルクの平均粒子径を溶融シリカの平均粒子径よりも大きくすることが好ましい（請求項３）。
上述したように、上記タルクは、上記溶融シリカと比較すると、低温度で細孔を形成する。そのため、タルクが存在していた部分に形成される細孔は、タルクが溶融した後、高い温度にさらされた際の溶融シリカの溶融によって、その細孔が小さくなる。そのため、予め、タルクの平均粒子径を溶融シリカの平均粒子径よりも大きくすることにより、適当な大きさの細孔を形成させることができる。
In the first and second inventions, it is preferable that the average particle size of talc is larger than the average particle size of fused silica.
As described above, the talc forms pores at a lower temperature than the fused silica. Therefore, the pores formed in the portion where talc was present become smaller due to melting of the fused silica when the talc is melted and then exposed to a high temperature. Therefore, pores having an appropriate size can be formed in advance by making the average particle size of talc larger than the average particle size of fused silica.
また、上記溶融シリカは、球状又は破砕状としたことが好ましい（請求項４）。
上記溶融シリカは、コーディエライト生成温度域でも高温度域で母材に溶け込み、自らの形骸が細孔の形となる。そして、細孔径の制御に対して球状又は破砕状がコントロールし易いため好ましい。
The fused silica is preferably spherical or crushed (claim 4).
The fused silica dissolves in the base material at a high temperature range even in the cordierite generation temperature range, and its own shape becomes a pore shape. And since spherical or a crushing shape is easy to control with respect to control of a pore diameter, it is preferable.
（実施例１）
本例では、本発明の実施例にかかる多孔質ハニカム構造体の製造方法について説明する。
図１に示すように、本例の多孔質ハニカム構造体１は、ハニカム状のセル壁２とセル壁２に囲まれた多数のセル３と外周側面を覆う筒状の外周スキン４とを有する多孔質のハニカム構造体１である。そして、上記セル壁２は、化学組成がＳｉＯ2：４５〜５５重量％、Ａｌ2Ｏ3：３３〜４２重量％、ＭｇＯ：１２〜１８重量％よりなるコーディエライトを主成分とし、上記セル壁２中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満である。
以下、これを詳説する。
Example 1
In this example, a method for manufacturing a porous honeycomb structure according to an example of the present invention will be described.
As shown in FIG. 1, a porous honeycomb structure 1 of this example includes a honeycomb-shaped cell wall 2, a large number of cells 3 surrounded by the cell wall 2, and a cylindrical outer peripheral skin 4 covering the outer peripheral side surface. This is a porous honeycomb structure 1. Then, the cell walls 2, chemical composition SiO 2: 45 to 55 wt%, Al 2 O 3: 33 to 42 wt%, MgO: 12 to 18 consisting wt% cordierite as a main component, the cell The distribution of the pores formed in the wall 2 is that the pore volume having a pore diameter of 5 μm or less is less than 15% of the total pore volume, and the pore volume exceeding the pore diameter of 25 μm is less than 10% of the total pore volume. It is.
This will be described in detail below.
まず、多孔質ハニカム構造体１を作製するに当たって、まず、タルク３５．４質量％、溶融シリカ１９．４質量％、及び水酸化アルミニウム４５．２質量％からなるコーディエライト原料を２６種類（原料１〜原料２６）用意した。
コーディエライト化原料中の水酸化アルミニウムは、平均粒子径５μｍの原料を用いた。
また、上記タルクと溶融シリカは、表１及び表２に示す粒子径を有するものを用いた。
その後、上記コーディエライト化原料と、可燃性物質とを表３に示す割合で混合し、さらに、表３に示す量の水を加えて混練することにより２６種類のスラリーを得た。
First, in producing the porous honeycomb structure 1, first, 26 kinds of cordierite raw materials (raw materials) composed of 35.4% by mass of talc, 19.4% by mass of fused silica, and 45.2% by mass of aluminum hydroxide were used. 1 to 26) prepared.
As the aluminum hydroxide in the cordierite forming raw material, a raw material having an average particle diameter of 5 μm was used.
The talc and fused silica used had the particle sizes shown in Tables 1 and 2.
Thereafter, the cordierite-forming raw material and the combustible substance were mixed at a ratio shown in Table 3, and further, 26 kinds of slurries were obtained by adding and kneading the amount of water shown in Table 3.
その後、成形工程において、得られたスラリーを周知のハニカム押出し成形機にて押出し成形し、所望の長さに切断した。
そして、乾燥工程において、切断した成形体を電子レンジにより水分の８０％以上を蒸発させ、さらに８０℃の熱風で１２時間乾燥させた。
次いで、焼成工程において、乾燥した成形体を１４２０℃で２０時間焼成して図１に示す、φ１４０×２２０ｍｍ、壁厚み：１５ＭＩＬ、メッシュ：＃２５０のハニカム構造体１（試料Ｅ１〜試料Ｅ１６、試料Ｃ１〜試料Ｃ１０）を得た。
Thereafter, in the forming step, the obtained slurry was extruded using a well-known honeycomb extruder, and cut into a desired length.
Then, in the drying step, 80% or more of the moisture was evaporated from the cut molded body with a microwave oven, and further dried with hot air at 80 ° C. for 12 hours.
Next, in the firing step, the dried formed body was fired at 1420 ° C. for 20 hours, and the honeycomb structure 1 (φ140 × 220 mm, wall thickness: 15 MIL, mesh: # 250 shown in FIG. 1 (sample E1 to sample E16, sample) C1-sample C10) were obtained.
次に、得られた２６種類のすべてのハニカム構造体に対して、細孔径分布並び熱膨張率の測定を行った。
細孔径分布の測定は、ポロシメータを用いた水銀圧入法により細孔容積を求めて行った。測定した細孔径分布から、５μｍ以下の細孔容積率並び２５μｍ以上の細孔容積率を算出した。結果を表４に示す。
また熱膨張率の測定は、熱膨張計により行った。熱膨張率測定結果も表４に併記する。
Next, the pore size distribution and the coefficient of thermal expansion were measured for all of the 26 types of honeycomb structures obtained.
The pore diameter distribution was measured by determining the pore volume by mercury porosimetry using a porosimeter. From the measured pore size distribution, a pore volume ratio of 5 μm or less and a pore volume ratio of 25 μm or more were calculated. The results are shown in Table 4.
The coefficient of thermal expansion was measured with a thermal dilatometer. The thermal expansion coefficient measurement results are also shown in Table 4.
表４より知られるように、試料Ｅ１〜試料Ｅ８は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であるコーディエライト化原料を用いて、成形工程と、乾燥工程と、焼成工程とを行うことにより得られたハニカム構造体である。そして、これらのハニカム構造体のセル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満となり、細孔径５〜２５％の狭い範囲の細孔を極めて高率で形成されていることができることがわかる。図２に、試料Ｅ７のセル壁の細孔の細孔径分布（分布曲線Ａ）を示し、図３（ａ）に、そのハニカム体のミクロ構造を示す。 As is known from Table 4, samples E1 to E8 are mainly composed of talc, fused silica, and aluminum hydroxide, and have a fine particle accumulation frequency of talc of 8.7 μm or less and a fused silica of 8.7 μm or less by a particle size distribution meter. A cordierite-forming raw material having a sum of fine particle accumulation frequencies of 15% or less and a sum of coarse particle accumulation frequencies of 31.3 μm or more of talc and coarse particle accumulation frequencies of 31.3 μm or more of fused silica is 10% or less. And a honeycomb structure obtained by performing a forming process, a drying process, and a firing process. The distribution of pores formed in the cell walls of these honeycomb structures is such that the pore volume with a pore diameter of 5 μm or less is less than 15% of the total pore volume, and the pore volume with a pore diameter exceeding 25 μm. It can be seen that it is less than 10% of the total pore volume, and narrow pores having a pore diameter of 5 to 25% can be formed at an extremely high rate. FIG. 2 shows the pore size distribution (distribution curve A) of the pores in the cell wall of sample E7, and FIG. 3 (a) shows the microstructure of the honeycomb body.
一方、表４より知られるように、試料Ｃ１〜試料Ｃ５は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和が１５％超えであり、タルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であるコーディエライト化原料を用いて、成形工程と、乾燥工程と、焼成工程とを行うことにより得られたハニカム構造体である。そして、これらのハニカム構造体のセル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％以上、及び／又は、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満となっていることがわかる。
比較のために、図２に、特許文献１に開示される従来技術を模擬した方法により作製した試料のセル壁の細孔の細孔径分布（分布曲線Ｂ）を示し、図３（ｂ）に、そのハニカム構造体のミクロ構造を示す。
On the other hand, as is known from Table 4, samples C1 to C5 are mainly composed of talc, fused silica, and aluminum hydroxide, and have a fine particle accumulation frequency of 8.7 μm or less of talc and a fused silica of 8.7 μm by a particle size distribution meter. The sum of the following fine particle accumulation frequency is over 15%, and the sum of the coarse particle accumulation frequency of talc 31.3 μm or more and the coarse particle accumulation frequency of fused silica 31.3 μm or more is 10% or less. A honeycomb structure obtained by performing a forming process, a drying process, and a firing process using raw materials. The distribution of pores formed in the cell walls of these honeycomb structures is such that the pore volume with a pore diameter of 5 μm or less is 15% or more of the total pore volume and / or the pore diameter exceeds 25 μm. It can be seen that the volume is less than 10% of the total pore volume.
For comparison, FIG. 2 shows the pore size distribution (distribution curve B) of the pores of the cell wall of a sample prepared by a method simulating the prior art disclosed in Patent Document 1, and FIG. The microstructure of the honeycomb structure is shown.
また、表４より知られるように、試料Ｅ９〜試料Ｅ１６は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であるコーディエライト化原料を用いて、成形工程と、乾燥工程と、焼成工程とを行うことにより得られたハニカム構造体である。そして、これらのハニカム構造体のセル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％未満であり、細孔径２５μｍを超える細孔容積が全細孔容積の１０％未満となり、細孔径５〜２５％の狭い範囲の細孔を極めて高率で形成されていることができることがわかる。 Further, as is known from Table 4, samples E9 to E16 are mainly composed of talc, fused silica, and aluminum hydroxide, and have a cumulative frequency of fine particles of talc of 8.7 μm or less measured by a particle size distribution meter and fused silica of 6.25 μm. The sum of the following fine particle accumulation frequency is 15% or less, and the sum of the coarse particle accumulation frequency of talc 43.8 μm or more and the coarse particle accumulation frequency of fused silica 31.3 μm or more is 10% or less. A honeycomb structure obtained by performing a forming process, a drying process, and a firing process using raw materials. The distribution of pores formed in the cell walls of these honeycomb structures is such that the pore volume with a pore diameter of 5 μm or less is less than 15% of the total pore volume, and the pore volume with a pore diameter exceeding 25 μm. It can be seen that it is less than 10% of the total pore volume, and narrow pores having a pore diameter of 5 to 25% can be formed at an extremely high rate.
一方、表４より知られるように、試料Ｃ６〜試料Ｃ１０は、タルク、溶融シリカ、水酸化アルミニウムを主成分とするが、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和が１５％超えであり、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％超えであるコーディエライト化原料を用いて、成形工程と、乾燥工程と、焼成工程とを行うことにより得られたハニカム構造体である。そして、これらのハニカム構造体のセル壁中に形成された細孔の分布は、細孔径５μｍ以下の細孔容積が全細孔容積の１５％以上、細孔径２５μｍを超える細孔容積が全細孔容積の１０％以上となっていることができることがわかる。 On the other hand, as can be seen from Table 4, Sample C6 to Sample C10 are mainly composed of talc, fused silica, and aluminum hydroxide, but the cumulative frequency of fine particles of talc of 8.7 μm or less by the particle size distribution meter and fused silica 6 The sum of the cumulative frequency of fine particles of 0.25 μm or less exceeds 15%, and the sum of the cumulative frequency of coarse particles of talc 43.8 μm or more and the cumulative frequency of coarse particles of 31.3 μm or more of fused silica exceeds 10%. A honeycomb structure obtained by performing a forming step, a drying step, and a firing step using a lightening raw material. The distribution of the pores formed in the cell walls of these honeycomb structures is such that the pore volume having a pore diameter of 5 μm or less is 15% or more of the total pore volume, and the pore volume exceeding 25 μm is completely fine. It can be seen that it can be 10% or more of the pore volume.
続いて、試料Ｅ７に触媒を担持させ、ディーゼル機関から排出されるパティキュレートの捕集を行い、Ｓｏｏｔ Ｍａｓｓ Ｌｉｍｉｉｔ（最大ＰＭ堆積量）及び圧損の測定を行った。最大ＰＭ堆積量は、目標値が６ｇ／Ｌ以上であるところ、８．６ｇ／Ｌと良好な結果を示した。また、圧損についても、目標値が１２ｋＰａ以下（ａｔ２．５ｍ3／ｍｉｎ、ＰＭ：５．０ｇ／Ｌ）であるところ、１０．５ｋＰａと良好な結果を示した。 Subsequently, the catalyst was supported on the sample E7, the particulates discharged from the diesel engine were collected, and the soot mass limit (maximum PM deposition amount) and the pressure loss were measured. The maximum PM deposition amount was 8.6 g / L when the target value was 6 g / L or more, and showed a good result. Further, regarding the pressure loss, when the target value was 12 kPa or less (at 2.5 m 3 / min, PM: 5.0 g / L), a favorable result of 10.5 kPa was shown.
このように、本発明によれば、微粒子（パティキュレート）等の捕集効率が高く、かつ細孔の目詰まりによる圧力損失の増大を防止することができる多孔質ハニカム構造体を得ることができることがわかる。 As described above, according to the present invention, it is possible to obtain a porous honeycomb structure having a high collection efficiency of fine particles (particulates) and the like and capable of preventing an increase in pressure loss due to pore clogging. I understand.
１ 多孔質ハニカム構造体
２ セル壁
３ セル
1 porous honeycomb structure 2 cell wall 3 cell
Claims (4)
コーディエライト化原料を押出成形し上記ハニカム構造体を成形する成形工程と、上記ハニカム構造体を乾燥させる乾燥工程と、上記ハニカム構造体を焼成する焼成工程とを有し、
上記コーディエライト化原料は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ８．７μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク３１．３μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であることを特徴とする多孔質ハニカム構造体の製造方法。 It has a honeycomb-shaped cell wall and a large number of cells surrounded by the cell wall, and the cell wall has a chemical composition of SiO 2 : 45 to 55% by weight, Al 2 O 3 : 33 to 42% by weight, MgO The distribution of the pores formed in the cell wall based on cordierite consisting of 12 to 18% by weight is such that the pore volume with a pore diameter of 5 μm or less is less than 15% of the total pore volume, A method for producing a porous honeycomb structure in which the pore volume exceeding a pore diameter of 25 μm is less than 10% of the total pore volume,
A molding step of extruding a cordierite forming raw material to form the honeycomb structure, a drying step of drying the honeycomb structure, and a firing step of firing the honeycomb structure,
The cordierite-forming raw material is mainly composed of talc, fused silica, and aluminum hydroxide, and is the sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 8.7 μm or less by a particle size distribution meter. Is 15% or less, and the sum of the coarse particle accumulation frequency of talc of 31.3 μm or more and the coarse particle accumulation frequency of fused silica of 31.3 μm or more is 10% or less, .
コーディエライト化原料を押出成形し上記ハニカム構造体を成形する成形工程と、上記ハニカム構造体を乾燥させる乾燥工程と、上記ハニカム構造体を焼成する焼成工程とを有し、
上記コーディエライト化原料は、タルク、溶融シリカ、水酸化アルミニウムを主成分とし、粒度分布計によるタルク８．７μｍ以下の微小粒累積頻度と溶融シリカ６．２５μｍ以下の微小粒累積頻度との和が１５％以下であり、タルク４３．８μｍ以上の粗大粒累積頻度と溶融シリカ３１．３μｍ以上の粗大粒累積頻度の和が１０％以下であることを特徴とする多孔質ハニカム構造体の製造方法。 It has a honeycomb-shaped cell wall and a large number of cells surrounded by the cell wall, and the cell wall has a chemical composition of SiO 2 : 45 to 55% by weight, Al 2 O 3 : 33 to 42% by weight, MgO The distribution of the pores formed in the cell wall based on cordierite consisting of 12 to 18% by weight is such that the pore volume with a pore diameter of 5 μm or less is less than 15% of the total pore volume, A method for producing a porous honeycomb structure in which the pore volume exceeding a pore diameter of 25 μm is less than 10% of the total pore volume,
A molding step of extruding a cordierite forming raw material to form the honeycomb structure, a drying step of drying the honeycomb structure, and a firing step of firing the honeycomb structure,
The cordierite-forming raw material is mainly composed of talc, fused silica and aluminum hydroxide, and is the sum of the cumulative frequency of fine particles of talc of 8.7 μm or less and the cumulative frequency of fine particles of fused silica of 6.25 μm or less by a particle size distribution meter. Is 15% or less, and the sum of the coarse particle accumulation frequency of talc 43.8 μm or more and the coarse particle accumulation frequency of fused silica 31.3 μm or more is 10% or less, .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010137900A JP5413310B2 (en) | 2008-03-31 | 2010-06-17 | Method for manufacturing porous honeycomb structure |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008090393 | 2008-03-31 | ||
| JP2008090393 | 2008-03-31 | ||
| JP2010137900A JP5413310B2 (en) | 2008-03-31 | 2010-06-17 | Method for manufacturing porous honeycomb structure |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2008320699A Division JP2009262125A (en) | 2008-03-31 | 2008-12-17 | Porous honeycomb structure and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2010260787A true JP2010260787A (en) | 2010-11-18 |
| JP5413310B2 JP5413310B2 (en) | 2014-02-12 |
Family
ID=43359195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2010137900A Expired - Fee Related JP5413310B2 (en) | 2008-03-31 | 2010-06-17 | Method for manufacturing porous honeycomb structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5413310B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013047908A1 (en) | 2011-09-29 | 2013-04-04 | 日本碍子株式会社 | Honeycomb filter and production method for same |
| US11850541B2 (en) | 2019-07-31 | 2023-12-26 | Denso Corporation | Exhaust gas purification filter |
| US11878258B2 (en) | 2019-07-31 | 2024-01-23 | Denso Corporation | Exhaust gas purification filter |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002219319A (en) * | 2000-11-24 | 2002-08-06 | Ngk Insulators Ltd | Porous honeycomb filter and method for manufacturing the same |
| JP2004250324A (en) * | 2003-01-30 | 2004-09-09 | Hitachi Metals Ltd | Method for producing ceramic honeycomb structure, and cordierite raw material |
| WO2007064497A1 (en) * | 2005-11-30 | 2007-06-07 | Corning Incorporated | Porous cordierite ceramic honeycomb article with improved strength and method of manufacturing same |
| WO2007108428A1 (en) * | 2006-03-17 | 2007-09-27 | Ngk Insulators, Ltd. | Process for producing honeycomb structure |
| WO2008027302A2 (en) * | 2006-08-25 | 2008-03-06 | Corning Incorporated | Narrow pore size distribution cordierite ceramic honeycomb articles and methods for manufacturing same |
-
2010
- 2010-06-17 JP JP2010137900A patent/JP5413310B2/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002219319A (en) * | 2000-11-24 | 2002-08-06 | Ngk Insulators Ltd | Porous honeycomb filter and method for manufacturing the same |
| JP2004250324A (en) * | 2003-01-30 | 2004-09-09 | Hitachi Metals Ltd | Method for producing ceramic honeycomb structure, and cordierite raw material |
| WO2007064497A1 (en) * | 2005-11-30 | 2007-06-07 | Corning Incorporated | Porous cordierite ceramic honeycomb article with improved strength and method of manufacturing same |
| WO2007108428A1 (en) * | 2006-03-17 | 2007-09-27 | Ngk Insulators, Ltd. | Process for producing honeycomb structure |
| WO2008027302A2 (en) * | 2006-08-25 | 2008-03-06 | Corning Incorporated | Narrow pore size distribution cordierite ceramic honeycomb articles and methods for manufacturing same |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013047908A1 (en) | 2011-09-29 | 2013-04-04 | 日本碍子株式会社 | Honeycomb filter and production method for same |
| US8747511B2 (en) | 2011-09-29 | 2014-06-10 | Ngk Insulators, Ltd. | Honeycomb filter, and manufacturing method of the same |
| US11850541B2 (en) | 2019-07-31 | 2023-12-26 | Denso Corporation | Exhaust gas purification filter |
| US11878258B2 (en) | 2019-07-31 | 2024-01-23 | Denso Corporation | Exhaust gas purification filter |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5413310B2 (en) | 2014-02-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7141089B2 (en) | Magnesium aluminum silicate structures for DPF applications | |
| JP3806975B2 (en) | Manufacturing method of honeycomb structure | |
| KR101894341B1 (en) | Ceramic honeycomb structure and process for producing same | |
| KR101949299B1 (en) | Ceramic honeycomb filter and its production method | |
| JP5372494B2 (en) | Manufacturing method of honeycomb structure | |
| US7473464B2 (en) | Porous material and method for production thereof | |
| KR101677486B1 (en) | Ceramic honeycomb structure and process for producing same | |
| JP5831453B2 (en) | Method for manufacturing ceramic honeycomb structure | |
| JP2014166635A (en) | Method for manufacturing ceramic honeycomb structure | |
| CN107129318B (en) | Method for manufacturing honeycomb structure | |
| JP2010138770A (en) | Ceramic filter, and its manufacturing method and evaluation method | |
| JP2008037722A (en) | Method of manufacturing honeycomb structure | |
| JP2009262125A (en) | Porous honeycomb structure and method for manufacturing the same | |
| WO2004060830A1 (en) | Method of baking ceramic honeycomb structure | |
| JP2005272158A (en) | Method for producing cordieritic honeycomb structure | |
| JP2007045686A (en) | Method for manufacturing porous ceramic structure | |
| JPWO2006006667A1 (en) | Method for manufacturing porous honeycomb structure | |
| CN113272042B (en) | Cordierite-containing ceramic bodies, batch composition mixtures, and methods of making cordierite-containing ceramic bodies | |
| JP5413310B2 (en) | Method for manufacturing porous honeycomb structure | |
| JP4571775B2 (en) | Method for manufacturing porous honeycomb structure, and honeycomb formed body | |
| JP2011178607A (en) | Porous honeycomb structure and method for producing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20120130 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20130122 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20130311 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20130702 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20130711 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20131015 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20131028 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 5413310 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |