JPH0362672B2 - - Google Patents
Info
- Publication number
- JPH0362672B2 JPH0362672B2 JP60292986A JP29298685A JPH0362672B2 JP H0362672 B2 JPH0362672 B2 JP H0362672B2 JP 60292986 A JP60292986 A JP 60292986A JP 29298685 A JP29298685 A JP 29298685A JP H0362672 B2 JPH0362672 B2 JP H0362672B2
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb structure
- alumina
- weight
- raw material
- silicic acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000835 fiber Substances 0.000 claims description 56
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 47
- 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 claims description 27
- 229910052863 mullite Inorganic materials 0.000 claims description 27
- 239000002994 raw material Substances 0.000 claims description 24
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 23
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 23
- 235000012239 silicon dioxide Nutrition 0.000 claims description 21
- 238000010304 firing Methods 0.000 claims description 20
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 17
- 239000000203 mixture Substances 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 239000010431 corundum Substances 0.000 claims description 9
- 229910052593 corundum Inorganic materials 0.000 claims description 9
- 239000000945 filler Substances 0.000 claims description 9
- 239000008119 colloidal silica Substances 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 6
- 229910000323 aluminium silicate Inorganic materials 0.000 claims description 5
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 5
- 239000006185 dispersion Substances 0.000 claims description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 2
- 230000001476 alcoholic effect Effects 0.000 claims description 2
- 229910003002 lithium salt Inorganic materials 0.000 claims description 2
- 159000000002 lithium salts Chemical class 0.000 claims description 2
- 159000000003 magnesium salts Chemical class 0.000 claims description 2
- BSVBQGMMJUBVOD-UHFFFAOYSA-N trisodium borate Chemical compound [Na+].[Na+].[Na+].[O-]B([O-])[O-] BSVBQGMMJUBVOD-UHFFFAOYSA-N 0.000 claims 1
- 239000000919 ceramic Substances 0.000 description 15
- 239000013078 crystal Substances 0.000 description 10
- 239000011230 binding agent Substances 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 7
- 229910052906 cristobalite Inorganic materials 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 229910052810 boron oxide Inorganic materials 0.000 description 5
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 239000000377 silicon dioxide Substances 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 4
- 239000002657 fibrous material Substances 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000035939 shock Effects 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 2
- 239000004327 boric acid Substances 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000005416 organic matter Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000002648 laminated material Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Porous Artificial Stone Or Porous Ceramic Products (AREA)
- Catalysts (AREA)
Description
〔産業上の利用分野〕
本発明は、1000℃上の高温で使われる触媒の担
体や熱交換素子等に有用な、高度の耐熱性を有す
るハニカム構造体の製造法に関するものである。
〔従来の技術〕
各種セラミツク繊維を主原料にして紙を作り、
これを加工してハニカム構造体にしたものは、特
開昭52−127663号公報、同56−136656号公報等に
記載されている。セラミツク繊維紙からなるハニ
カム構造体は、耐熱性（特に耐熱衝撃性）および
耐食性にすぐれているので、押出成形によるセラ
ミツクハニカム構造体よりも軽量で圧力損失の少
ない気相反応用触媒担体や熱交換素子として近年
注目されているものである。
これら従来のハニカム構造体において、セラミ
ツク繊維は、必要に応じて繊維間間隙に充填され
た無機質粉末とともに、個々の紙の中で、また紙
同志の接合点において、コロイダルシリカ、コロ
イダルアルミナ等の無機質接着剤の硬化物により
互いに接着されており、それによつてハニカム構
造体の形状安定性が確保されている。
〔発明が解決しようとする問題点〕
セラミツク繊維紙からなるハニカム構造体は、
上述のようにすぐれた特性を有するが、その用途
開発が進むにつれて、一部の用途においてはより
高度の耐熱性を有するものが望まれるようになつ
た。
格別耐熱性のよいハニカム構造体を得るには、
セラミツク繊維紙の骨格を形成するセラミツク繊
維としてできる限り耐熱性のよいものを使用する
ことがまず必要である。このような観点から、従
来特に高度の耐熱性を有するハニカム構造体が望
まれる場合はセラミツク繊維の中でも最高度の耐
熱性を示すアルミナ繊維が繊維素材として選ばれ
ている。
しかしながら、アルミナ繊維自身は最高約1600
℃の高温にも耐えるものの、これから作られた従
来のハニカム構造体は、約1200℃以上での使用に
は到底耐えられないものであつた。これは、ハニ
カム構造体の形状保持に重要な役割を演じている
結合剤の熱劣化が比較的低い温度で始まるため、
耐熱温度の高い繊維を用いてもその耐熱度があま
り生かされないことによるものである。たとえば
ケイ酸ゲルで結合されたものは1000℃付近から始
まるケイ酸ゲルの軟化溶融により、またアルミナ
ゲルにより結合されたものは1000℃付近から始ま
るアルミナゲルの結晶化に基づく脆化により、そ
れぞれ接合強度が低下してしまうので、繊維部分
は劣化していないのにハニカム構造が崩壊し易く
なつてしまう。
本発明は、従来のセラミツク繊維紙製ハニカム
構造体における上記問題点を解決し、アルミナ繊
維のすぐれた耐熱性が充分生かされた高度耐熱性
ハニカム構造体を提供しようとするものである。
〔問題点を解決するための手段〕
上記目的を達成することに成功した本発明は、
セラミツク繊維またはセラミツク繊維と耐熱性充
填材との混合物よりなる紙から作られたハニカム
構造体において、セラミツク繊維の少なくとも50
重量％がα−Al2O3型多結晶質アルミナ繊維であ
り、且つセラミツク繊維同士がムライトにより結
合されているものである耐熱性ハニカム構造体の
製造法、すなわち、α−Al2O3型アルミナ繊維ま
たはθ−Al2O3型アルミナ繊維からなる群から選
ばれた多結晶質高アルミナ繊維が50重量％以上を
占める繊維混合物から紙を抄造し、これをハニカ
ム構造体に成形し、得られたハニカム構造体に固
形分重量比で３：７ないし６：４の易反応性ケイ
酸原料およびアルミナゾルの混合物またはこれに
耐熱性充填材を加えた材料の水分散液を含浸さ
せ、次いでハニカム構造体を1100〜1500℃で焼成
することにより該ハニカム構造体に付着した易反
応性ケイ酸原料およびアルミナゾルからムライト
を生成させることを特徴とする耐熱性ハニカム構
造体の製造法を提供するものである。
以下、この製造法について詳述する。
まず繊維質原料について述べると、多結晶質ア
ルミナ繊維としてはα−Al2O3型またはθ−Al2
O3型のものを用いる。α−Al2O3型でも単結晶質
のアルミナ繊維は、剛直で、紙にした後のコルゲ
ート加工が困難なため使用することができない。
また、幾分非晶質なものであるγ−Al2O3型のア
ルミナ繊維は、最後の焼成工程において易反応性
ケイ酸原料やアルミナゾルとよく反応する傾向が
あり、その結果、最終製品中にα−Al2O3型アル
ミナ繊維からなる骨格構造を確実に残すことがで
きないので適当でない。α−Al2O3型やθ−Al2
O3型の多結晶質アルミナ繊維の中でも、90重量
％をこえる高率でAl2O3を含有する高度に結晶質
のものは、製造工程における変性を起こしにくい
ので特に好ましい。
上述の多結晶質高アルミナ繊維および併用する
他の繊維質材料から紙を抄造するが、その場合、
抄造性を高めるために、有機質結合材等を用いる
ことができる。紙の厚さは最終製品の用途に応じ
て適宜選ばれるが、製造と加工が容易な厚さは
0.2〜0.8mm程度である。
得られた紙は、任意の方法により型付け加工
し、さらに積層加工して、生ハニカム体を製造す
る。ハニカム構造の態様は特に限定されるもので
はなく、第１図に示すような、波板状の紙１と平
板状の紙２との交互積層体など、任意の構成のも
のとすることができる。なお、ハニカム構造を得
るための紙の接着には、後にハニカム構造体に含
浸させる易反応性ケイ酸原料とアルミナゾルとの
混合物を用いることが望ましい。
次いで、ムライト質結合剤の原料である易反応
性ケイ酸原料およびアルミナゾル、その他充填材
等、粉体状材料の水分散液をハニカム構造体に含
浸させる。含浸処理は、上記の水分散液に生ハニ
カム体を浸漬することにより容易に行うことがで
きる。
易反応性ケイ酸原料としては、コロイダルシリ
カ、アルコール性シリカゾルなどを用いることが
できる。これらのほか、約1100℃以上に加熱され
たときシリカ（クリストバライト）を遊離するア
ルミリシリケート繊維をケイ酸原料の一部として
併用することも可能であるが、これを用いるとき
は紙の抄造原料中に配合する必要がある。
易反応性ケイ酸原料と反応させるアルミナ原料
としてはアルミナゾルを用いるが、この材料は、
ハニカム構造体への均一含浸性が良く、また上述
の易反応性ケイ酸原料との反応性が特に優れてい
る点で、アルミナ微粉末など他のアルミナ原料よ
りも好ましい。
易反応性ケイ酸原料とアルミナゾルとの使用比
率は、重量比で３：７ないし６：４が適当であ
る。これ以上にシリカの比率が高いと過剰のシリ
カがクリストバライトとなつて製品の耐熱性を下
げ、一方アルミナが過剰の場合は十分な結合力が
得られず、製品の強度が不足する。易反応性ケイ
酸原料および易反応性アルミナは、それらから生
成するムライトが製品中で20〜80重量％を占める
程度に使用する。
耐熱性充填材は、従来の耐熱性ハニカム構造体
の場合と同様に、紙の強度を高め、また通気性を
調節するために、必要に応じて加えられるが、ハ
ニカム構造体に基体される耐熱度が高くなつてい
るのにあわせて、十分な耐熱性を有するものから
選ばれる。好ましい充填材としては、平均粒径が
0.2〜10μの微粉末状であるコランダム、ムライ
ト、ジルコニア、ジルコン、炭化ケイ素、窒化ケ
イ素などである。
なお、ハニカム構造体を構成するセラミツク繊
維紙の通気性は、紙の気孔率によつて決まる。触
媒担体として用いられるハニカム構造体の場合、
気孔率は40〜85％程度が適当であり、また熱交換
素子として用いられるものの場合、気孔率は30〜
75％程度であることが望ましい。気孔率は繊維質
材料に対するムライト質結合剤および充填材の量
比によつて決まるので、用途および要求される強
度等も考慮しながら、約20〜80重量％の範囲で結
合剤の量を、また０〜約70重量％の範囲で充填材
の量を、それぞれ選定することが望ましい。
含浸処理を終わつた生ハニカム体の焼成は、電
気炉中で1100〜1500℃に加熱することにより行
う。これにより、ケイ酸原料およびアルミナから
からムライト（3Al2O3・2SiO2）が生成して、ハ
ニカム構造を強固に固定する。なお、焼成に先立
つて生ハニカム体に約３％迄の酸化ホウ素、ナト
リウム塩、リチウム塩、マグネシウム塩、フッ化
物等をアルコール溶液などの形で吸収させておく
と、ムライトの生成が促進されて焼成が低温度か
つ短時間ですむほか、焼成にともなうハニカム構
造体の収縮が少なくなる。最適焼成条件は、酸化
ホウ素を１％程度添加した場合、約1200〜1400℃
て約３〜10時間、酸化ホウ素無添加の場合、約
1300〜1500℃で約６〜20時間である。酸化ホウ素
を添加した場合は、焼成温度が高すぎるとムライ
トの結晶粒子が成長して粗大になり、繊維間接合
強度の低い製品となるので、最高焼成温度に注意
し、ムライトの平均結晶長さ（後記測定法によ
る）が4μ以下、望ましくは1μ以下になるように
する。
原料のアルミナ繊維としてα−Al2O3型以外の
ものを使用した場合は、焼成条件に応じて、α−
Al2O3型への転移が進む。また易反応性ケイ酸原
料としてアルミノシリケート繊維を用いた場合
は、アクミノシリケートからシリカとともにムラ
イトが生成するので、シリカがアルミナゾルと反
応した後でも主としてムライトからなる繊維状物
が製品中に残る。
〔実施例〕
以下、実施例および比較例を示して本発明を説
明する。
実施例 １
組成がAl2O395重量％、SiO2５重量％のアルミ
ナ繊維（θ型のもの；平均繊維径3μ）85重量％
と有機質結合材15重量％とからなる紙（厚さ0.35
mm、坪量100ｇ／m2）を常法により抄造した。次
いで、得られた紙の半量を段ボール加工機により
コルゲート加工し（ピツチ7.6mm、段高さ3.7mm）
未加工の平板状のものと交互に重ねて接着し、第
１図のようなハニカム構造にした。接着には、固
形分20重量％のコロイダルシリカ20重量％の固形
分10重量％のアルミナゾル60重量部との混合物を
用いた。得られた生ハニカム体を、次いで下記組
成の含浸易反応性ケイ酸原料に20分間浸漬したの
ち、110℃で乾燥して硬化させ、更に450℃で加熱
して有機質分を分解させた。
コロイダルシリカ（固形分20重量％）35重量部
アルミナゾル（固形分10重量％） 105重量部
コランダム粉（平均粒径2μ） 84重量部
水 100重量部
上記含浸、乾燥の各処理を再度施して、繊維間
間隙に含浸液成分が固定された生ハニカム体を得
たのち、これを電気炉に入れて1450℃で６時間焼
成することにより、１辺が約200mmの立方体状ハ
ニカム構造体を得た。なお焼成による収縮率は、
積層方向２％、面方向（タテ、ヨコとも）1.2％
であつた。
第２図はこのハニカム構造体の表面の電子顕微
鏡写真（倍率500倍）である。
このハニカム構造体の結晶組成を粉末Ｘ線回折
法により調べたところ、第３図に示したとおり、
ムライトとコランダム（α−Al2O3）からなるも
のであつた。
比較例 １
実施例１で作製したアルミナ繊維紙を実施例１
の場合と同様にコルゲート加工し、更に積層加工
したものを、下記組成の含浸液に20分間浸漬した
後、110℃で乾燥し、さらに450℃で加熱して有機
質分を分解させた。
コロイダルシリカ（固形分20重量％）
100重量部
コランダム粉（平均粒径2μ） 83重量部
水 100重量部
上記含浸、乾燥の各処理を再度施して、アルミ
ナ繊維およびコランダム粉がケイ酸ゲルで結合さ
れたハニカム構造体を得た。
実施例 ２
実施例１で用いたものと同じアルミナ繊維45重
量部と組成がAl2O348重量％、SiO249重量％のア
ルミノシリケート繊維（平均繊維径4μ）40重量
部とを有機質結合材15重量部とともに抄造して、
厚さ0.4mm、坪量100ｇ／m2の紙を製造した。以
下、実施例１と同様にして生ハニカム体の製造と
含浸処理を行い、最後に、1300℃で10時間焼成し
た。焼成による収縮率（３方向平均値）は1.3％
であつた。
得られたハニカム構造体の結晶組成は、ムライ
ト、コランダムおよび少量のクリストバライトか
らなるものであつた。
比較例 ２
実施例２で用いたものと同じアルミノシリケー
ト繊維85重量部を有機質結合材15重量部とともに
抄造して、厚さが0.4mm、坪量が90ｇ／m2の紙を
製造した。以下、実施例１と同様にして生ハニカ
ム体の製造と含浸処理を行い、最後に1300℃で10
時間焼成した。焼成による収縮率（３方向平均
値）は3.2％であつた。
得られたハニカム構造体の結晶組成は、ムライ
トおよびクリストバライトからなるものであつ
た。電子顕微鏡で観察したところ、この構造体に
は反応で生成したムライトのほかに、アルミノシ
リケート繊維からの析出ムライトおよび析出クリ
ストバライトが多数認められた。
実施例 ３
実施例１と同様にしてコロイダルシリカ等が固
定された生ハニカム体を製造し、これをホウ酸の
飽和アルコール溶液に浸漬して、生ハニカム体に
対して１重量％のB2O3を吸収させた。この後
1200℃で６時間焼成して、結晶組成がムライトお
よびコランダムであるハニカム構造体を得た。焼
成による収縮率（３方向平均値）は0.3％であつ
た。
実施例 ４
ホウ酸溶液浸漬を行わないほかは実施例３と同
様にして、ハニカム構造体を製造した。焼成によ
る収縮率（３方向平均値）は0.6％であつた。結
晶組成は、ムライト、コランダムおよび少量のク
リストバライトからなるものであつた。
以上の各例によるハニカム構造体および下記参
考例１，２の特性値および性能試験の結果を第１
表に示す。
参考例 １
市販の自動車排気浄化用ハニカム構造担体（コ
ーデイライト質押出成形品）
壁厚0.3mm、セルピツチ1.5mm、開口率79％
参考例 ２
市販の脱硝用ハニカム構造担体（ムライト質押
出成形品）
壁厚0.45mm、セルピツチ4.25mm、開口率79％
なお荷重破壊温度および熱衝撃試験の試験法と
ムライトの平均結晶長さの測定法の次の通りであ
る。
荷重破壊温度：15Kg／cm2の荷重を試験体（30×30
×30mm）のフルート方向に加えながら５℃／
minで昇温し、試験体が破壊または軟化変形し
た時の温度を測定する。
[Industrial Application Field] The present invention relates to a method for manufacturing a honeycomb structure having a high degree of heat resistance and useful as a catalyst carrier, a heat exchange element, etc. used at high temperatures of 1000°C or higher. [Conventional technology] Paper is made using various ceramic fibers as the main raw material.
Honeycomb structures obtained by processing this material are described in Japanese Patent Application Laid-open Nos. 52-127663 and 56-136656. Honeycomb structures made of ceramic fiber paper have excellent heat resistance (especially thermal shock resistance) and corrosion resistance, so they are lighter and have less pressure loss than extrusion-molded ceramic honeycomb structures, making them suitable for gas-phase application catalyst carriers and heat exchange elements. This has attracted attention in recent years. In these conventional honeycomb structures, ceramic fibers are filled with inorganic powder such as colloidal silica and colloidal alumina within each paper and at the bonding points between the papers, along with inorganic powder filled in the gaps between the fibers as necessary. They are bonded to each other by a cured adhesive, thereby ensuring the shape stability of the honeycomb structure. [Problems to be solved by the invention] A honeycomb structure made of ceramic fiber paper is
Although it has excellent properties as described above, as the development of its uses progresses, it has become desirable for some uses to have a higher degree of heat resistance. To obtain a honeycomb structure with exceptional heat resistance,
It is first necessary to use ceramic fibers that form the skeleton of ceramic fiber paper and have as good heat resistance as possible. From this point of view, when a honeycomb structure having particularly high heat resistance is desired, alumina fiber, which exhibits the highest heat resistance among ceramic fibers, has been selected as the fiber material. However, the alumina fiber itself has a maximum
Although it can withstand high temperatures of 1,200 degrees Celsius, conventional honeycomb structures made from this material could not withstand use at temperatures above about 1,200 degrees Celsius. This is because the thermal deterioration of the binder, which plays an important role in maintaining the shape of the honeycomb structure, begins at relatively low temperatures.
This is because even if fibers with a high heat resistance temperature are used, their heat resistance is not fully utilized. For example, those bonded with silicic acid gel are bonded by softening and melting of the silicic acid gel that starts at around 1000℃, and those bonded with alumina gel are bonded by embrittlement due to crystallization of alumina gel that starts around 1000℃. Since the strength decreases, the honeycomb structure becomes prone to collapse even though the fiber portions have not deteriorated. The present invention aims to solve the above-mentioned problems in conventional honeycomb structures made of ceramic fiber paper and to provide a highly heat-resistant honeycomb structure in which the excellent heat resistance of alumina fibers is fully utilized. [Means for solving the problems] The present invention, which has succeeded in achieving the above object, has the following features:
In a honeycomb structure made from paper consisting of ceramic fibers or a mixture of ceramic fibers and a heat-resistant filler, at least 50% of the ceramic fibers are
A method for producing a heat-resistant honeycomb structure in which the weight percent is α-Al 2 O 3 type polycrystalline alumina fibers and ceramic fibers are bonded together by mullite, that is, α-Al 2 O 3 type Paper is made from a fiber mixture in which polycrystalline high alumina fibers selected from the group consisting of alumina fibers or θ-Al 2 O 3 type alumina fibers account for 50% by weight or more, and this is formed into a honeycomb structure. The obtained honeycomb structure is impregnated with a mixture of easily reactive silicic acid raw material and alumina sol in a solid content weight ratio of 3:7 to 6:4, or an aqueous dispersion of a material in which a heat-resistant filler is added thereto, and then the honeycomb structure is This invention provides a method for producing a heat-resistant honeycomb structure, characterized in that mullite is generated from the easily reactive silicic acid raw material and alumina sol attached to the honeycomb structure by firing the structure at 1100 to 1500°C. be. This manufacturing method will be described in detail below. First, regarding fibrous raw materials, polycrystalline alumina fibers are α-Al 2 O 3 type or θ-Al 2
Use O 3 type. Single-crystal alumina fibers of the α-Al 2 O 3 type cannot be used because they are rigid and difficult to corrugate after being made into paper.
In addition, the somewhat amorphous γ-Al 2 O 3 type alumina fibers tend to react well with the easily reactive silicic acid raw materials and alumina sol during the final firing process, resulting in This is not suitable because it is not possible to reliably leave a skeleton structure made of α-Al 2 O 3 type alumina fibers. α-Al 2 O 3 type and θ-Al 2
Among the O 3 type polycrystalline alumina fibers, highly crystalline fibers containing Al 2 O 3 at a high proportion of more than 90% by weight are particularly preferred because they are less susceptible to modification during the manufacturing process. Paper is made from the above-mentioned polycrystalline high alumina fibers and other fibrous materials used in combination;
An organic binder or the like can be used to improve papermaking properties. The thickness of the paper is selected appropriately depending on the use of the final product, but the thickness that is easy to manufacture and process is
It is about 0.2 to 0.8 mm. The obtained paper is molded by any method and then laminated to produce a raw honeycomb body. The form of the honeycomb structure is not particularly limited, and may have any structure, such as an alternate laminate of corrugated paper 1 and flat paper 2 as shown in FIG. . Note that for bonding paper to obtain a honeycomb structure, it is desirable to use a mixture of an easily reactive silicic acid raw material and alumina sol, which will be impregnated into the honeycomb structure later. Next, the honeycomb structure is impregnated with an aqueous dispersion of powdered materials such as a readily reactive silicic acid raw material that is a raw material for a mullite binder, alumina sol, and other fillers. The impregnation treatment can be easily carried out by immersing the raw honeycomb body in the above-mentioned aqueous dispersion. As the easily reactive silicic acid raw material, colloidal silica, alcoholic silica sol, etc. can be used. In addition to these, it is also possible to use aluminum silicate fibers, which liberate silica (cristobalite) when heated to over 1100°C, as part of the silicic acid raw material; It needs to be mixed in. Alumina sol is used as the alumina raw material to be reacted with the easily reactive silicic acid raw material, but this material is
It is preferable to other alumina raw materials such as alumina fine powder because it has good uniform impregnation into a honeycomb structure and particularly excellent reactivity with the above-mentioned easily reactive silicic acid raw material. The appropriate weight ratio of the easily reactive silicic acid raw material to the alumina sol is 3:7 to 6:4. If the proportion of silica is higher than this, excess silica will turn into cristobalite and reduce the heat resistance of the product, while if alumina is excessive, sufficient bonding strength will not be obtained and the strength of the product will be insufficient. The easily reactive silicic acid raw material and the easily reactive alumina are used to the extent that the mullite produced from them accounts for 20 to 80% by weight in the product. Heat-resistant fillers are added as needed to increase paper strength and adjust air permeability, as in the case of conventional heat-resistant honeycomb structures. The material is selected from those that have sufficient heat resistance as temperatures are increasing. The preferred filler has an average particle size of
These include corundum, mullite, zirconia, zircon, silicon carbide, silicon nitride, etc., which are in the form of fine powders of 0.2 to 10μ. Note that the air permeability of the ceramic fiber paper constituting the honeycomb structure is determined by the porosity of the paper. In the case of honeycomb structures used as catalyst carriers,
Appropriate porosity is about 40 to 85%, and in the case of devices used as heat exchange elements, the porosity should be 30 to 85%.
It is desirable that it be around 75%. Porosity is determined by the ratio of the mullite binder and filler to the fibrous material, so the amount of binder can be adjusted in the range of about 20 to 80% by weight, taking into consideration the application and required strength. It is also desirable to select the amount of filler in the range of 0 to about 70% by weight. After the impregnation treatment, the raw honeycomb body is fired by heating it to 1100 to 1500°C in an electric furnace. As a result, mullite (3Al 2 O 3 .2SiO 2 ) is generated from the silicic acid raw material and alumina, and the honeycomb structure is firmly fixed. In addition, if the raw honeycomb body is made to absorb up to about 3% of boron oxide, sodium salt, lithium salt, magnesium salt, fluoride, etc. in the form of an alcohol solution before firing, the formation of mullite will be promoted. In addition to being able to fire at a low temperature and in a short time, the honeycomb structure shrinks less during firing. The optimum firing conditions are approximately 1200 to 1400℃ when approximately 1% boron oxide is added.
for about 3 to 10 hours, without boron oxide addition, about 3 to 10 hours.
It is about 6 to 20 hours at 1300 to 1500°C. When boron oxide is added, if the firing temperature is too high, the mullite crystal grains will grow and become coarse, resulting in a product with low fiber-to-fiber bonding strength. Pay attention to the maximum firing temperature and increase the average crystal length of the mullite. (according to the measurement method described below) is 4μ or less, preferably 1μ or less. If alumina fiber other than α-Al 2 O 3 type is used as the raw material alumina fiber, α-
The transition to Al 2 O 3 type progresses. Furthermore, when aluminosilicate fibers are used as the easily reactive silicic acid raw material, mullite is produced from the acuminosilicate together with silica, so even after the silica reacts with the alumina sol, fibrous materials mainly consisting of mullite remain in the product. [Example] The present invention will be described below with reference to Examples and Comparative Examples. Example 1 Alumina fiber (θ type; average fiber diameter 3μ) 85% by weight with a composition of 95% by weight of Al 2 O 3 and 5% by weight of SiO 2
and 15% by weight of organic binder (thickness 0.35
mm, basis weight 100 g/m 2 ) was produced by a conventional method. Next, half of the obtained paper was corrugated using a corrugated board processing machine (pitch 7.6 mm, corrugation height 3.7 mm).
They were layered alternately with unprocessed flat plates and glued together to form a honeycomb structure as shown in Figure 1. For bonding, a mixture of 20 weight % colloidal silica with a solid content of 20 weight % and 60 parts by weight of alumina sol with a solid content of 10 weight % was used. The obtained raw honeycomb body was then immersed in an easily impregnated and reactive silicic acid raw material having the following composition for 20 minutes, dried and hardened at 110°C, and further heated at 450°C to decompose the organic matter. Colloidal silica (solid content 20% by weight) 35 parts by weight Alumina sol (solid content 10% by weight) 105 parts by weight Corundum powder (average particle size 2 μ) 84 parts by weight Water 100 parts by weight The above impregnation and drying treatments were performed again. After obtaining a raw honeycomb body in which the impregnating liquid component was fixed in the gaps between the fibers, this was placed in an electric furnace and fired at 1450°C for 6 hours to obtain a cubic honeycomb structure with a side of approximately 200 mm. . The shrinkage rate due to firing is
2% in the stacking direction, 1.2% in the surface direction (both vertically and horizontally)
It was hot. Figure 2 is an electron micrograph (500x magnification) of the surface of this honeycomb structure. When the crystal composition of this honeycomb structure was investigated by powder X-ray diffraction method, as shown in Figure 3,
It consisted of mullite and corundum (α-Al 2 O 3 ). Comparative Example 1 The alumina fiber paper produced in Example 1 was
The corrugated and laminated material was immersed in an impregnating solution with the following composition for 20 minutes, dried at 110°C, and further heated at 450°C to decompose the organic matter. Colloidal silica (solid content 20% by weight)
100 parts by weight Corundum powder (average particle size 2μ) 83 parts by weight Water 100 parts The above impregnation and drying treatments were performed again to obtain a honeycomb structure in which alumina fibers and corundum powder were bonded with silicic acid gel. Example 2 45 parts by weight of the same alumina fibers used in Example 1 and 40 parts by weight of aluminosilicate fibers (average fiber diameter 4μ) having a composition of 48% by weight Al 2 O 3 and 49% by weight SiO 2 were organically bonded. It is made into paper together with 15 parts by weight of wood.
Paper with a thickness of 0.4 mm and a basis weight of 100 g/m 2 was produced. Thereafter, a raw honeycomb body was manufactured and impregnated in the same manner as in Example 1, and finally, it was fired at 1300°C for 10 hours. Shrinkage rate due to firing (average value in 3 directions) is 1.3%
It was hot. The crystal composition of the obtained honeycomb structure consisted of mullite, corundum, and a small amount of cristobalite. Comparative Example 2 85 parts by weight of the same aluminosilicate fibers used in Example 2 were made into paper together with 15 parts by weight of an organic binder to produce paper with a thickness of 0.4 mm and a basis weight of 90 g/m 2 . Hereinafter, a raw honeycomb body was manufactured and impregnated in the same manner as in Example 1, and finally it was heated to 1300℃ for 10 hours.
Baked for an hour. The shrinkage rate (average value in three directions) due to firing was 3.2%. The crystal composition of the obtained honeycomb structure consisted of mullite and cristobalite. When observed with an electron microscope, in addition to the mullite produced by the reaction, a large amount of mullite and cristobalite precipitated from the aluminosilicate fibers were observed in this structure. Example 3 A raw honeycomb body with colloidal silica etc. fixed thereon was produced in the same manner as in Example 1, and this was immersed in a saturated alcohol solution of boric acid to add 1% by weight of B 2 O to the raw honeycomb body. 3 was absorbed. After this
By firing at 1200° C. for 6 hours, a honeycomb structure having a crystal composition of mullite and corundum was obtained. The shrinkage rate (average value in three directions) due to firing was 0.3%. Example 4 A honeycomb structure was manufactured in the same manner as in Example 3 except that immersion in a boric acid solution was not performed. The shrinkage rate (average value in three directions) due to firing was 0.6%. The crystal composition consisted of mullite, corundum and a small amount of cristobalite. The characteristic values and performance test results of the honeycomb structures according to each of the above examples and Reference Examples 1 and 2 below are
Shown in the table. Reference example 1 Commercially available honeycomb structure carrier for automobile exhaust purification (cordeirite extrusion molded product) Wall thickness 0.3 mm, cell pitch 1.5 mm, aperture ratio 79% Reference example 2 Commercially available honeycomb structure carrier for denitrification (mullite extrusion product) Wall thickness: 0.45 mm, cell pitch: 4.25 mm, aperture ratio: 79% The test methods for the load failure temperature and thermal shock tests and the method for measuring the average crystal length of mullite are as follows. Load failure temperature: A load of 15Kg/ cm2 was applied to the test specimen (30×30
×30mm) while adding 5℃/
Raise the temperature to 1 min and measure the temperature when the specimen breaks or softens and deforms.
本発明の製法によれば、抄造された紙の中で易
反応性ケイ酸原料と易反応性アルミナとからムラ
イトが形成されるため、繊維表面もムライト等の
生成反応に関与し、強固な結合が得られる。特
に、焼成前に酸化ホウ素などムライト生成促進作
用を有する物質を吸収させるときは焼成温度の低
下と焼成時間の短縮が可能であり、これにより、
焼成コストが低減されることはもちろん、焼成中
の変形や繊維の劣化が少なくなつて、一段と高品
質のハニカム構造体が得られる。
そして、本発明の製造法によつて得られるハニ
カム構造体は、第１表のデータが示すようにきわ
めて高性能のものである。すなわち、1000℃以上
でも他の結晶形に転移しないα−Al2O3型アルミ
ナ繊維とムライトからなることにより1000℃以上
の高温における強度等の物性および耐久性におい
て従来のセラミツク繊維紙系ハニカム構造体より
も格段にすぐれている。また、細いアルミナ繊維
を骨格とする柔構造およびアルミナ繊維表面とム
ライト質結合材との強固な結合に基づき、耐熱衝
撃性においても最高度の性能を示す。
上述のような特徴により、本発明の製造法によ
るハニカム構造体は高温気相触媒反応触媒担体や
熱交換素子として使つた場合に従来品よりもはる
かにすぐれた耐久性を示すものであり、では使用
困難であつたような苛酷な条件での使用たとえば
触媒接触焼成用素子としての使用も可能なもので
ある。
According to the manufacturing method of the present invention, since mullite is formed from the easily reactive silicic acid raw material and the easily reactive alumina in the paper, the fiber surface also participates in the production reaction of mullite etc., resulting in a strong bond. is obtained. In particular, when absorbing a substance that promotes mullite formation, such as boron oxide, before firing, it is possible to lower the firing temperature and shorten the firing time.
Not only is the firing cost reduced, but deformation and fiber deterioration during firing are also reduced, resulting in a honeycomb structure of even higher quality. The honeycomb structure obtained by the manufacturing method of the present invention has extremely high performance, as shown in the data in Table 1. In other words, since it is made of α-Al 2 O 3 type alumina fibers and mullite, which do not transform into other crystal forms even at temperatures above 1000°C, the structure has superior physical properties such as strength and durability at temperatures above 1000°C compared to conventional ceramic fiber-paper honeycomb structures. Much better than the body. It also exhibits the highest performance in terms of thermal shock resistance due to its flexible structure with thin alumina fibers as its backbone and the strong bond between the surface of the alumina fibers and the mullite binder. Due to the above-mentioned characteristics, the honeycomb structure produced by the manufacturing method of the present invention exhibits far superior durability than conventional products when used as a catalyst carrier for a high-temperature gas phase catalytic reaction or a heat exchange element. It is also possible to use it under severe conditions that would otherwise be difficult to use, for example, as an element for catalytic catalytic firing.
第１図：本発明によるハニカム構造体の一例の
斜視図、第２図：実施例１によるハニカム構造体
の表面の電子顕微鏡写真、第３図：実施例１によ
るハニカム構造体のＸ線回折図。
Figure 1: A perspective view of an example of the honeycomb structure according to the present invention, Figure 2: Electron micrograph of the surface of the honeycomb structure according to Example 1, Figure 3: X-ray diffraction diagram of the honeycomb structure according to Example 1. .
Claims (1)
型アルミナ繊維からなる群から選ばれた多結晶質
高アルミナ繊維が50重量％以上を占める繊維混合
物から紙を抄造し、これをハニカム構造体に成形
し、得られたハニカム構造体に固形分重量比で
３：７ないし６：４の易反応性ケイ酸原料および
アルミナゾルの混合物またはこれに耐熱性充填材
を加えた材料の水分散液を含浸させ、次いでハニ
カム構造体を1100〜1500℃で焼成することにより
該ハニカム構造体に付着した易反応性ケイ酸原料
およびアルミナゾルからムライトを生成させるこ
とを特徴とする耐熱性ハニカム構造体の製造法。 ２ 易反応性ケイ酸原料としてコロイダルシリ
カ、アルコール性シリカゾルまたはアルミノシリ
ケート繊維を用いる特許請求の範囲第１項記載の
製造法。 ３ 耐熱性充填材として微粒子状コランダムを用
いる特許請求の範囲第１項記載の製造法。 ４ 焼成前のハニカム構造体にホウ酸、ナトリウ
ム塩、リチウム塩、マグネシウム塩またはフッ化
物を吸収させる特許請求の範囲第１項記載の製造
法。[Claims] 1 α-Al 2 O 3 type alumina fiber or θ-Al 2 O 3
A paper is made from a fiber mixture in which polycrystalline high alumina fibers selected from the group consisting of alumina fibers account for 50% by weight or more, and this is formed into a honeycomb structure, and the solid content weight is added to the obtained honeycomb structure. The honeycomb structure is impregnated with a mixture of easily reactive silicic acid raw material and alumina sol in a ratio of 3:7 to 6:4, or an aqueous dispersion of a material in which a heat-resistant filler is added, and then the honeycomb structure is fired at 1100 to 1500°C. A method for producing a heat-resistant honeycomb structure, characterized in that mullite is produced from the easily reactive silicic acid raw material and alumina sol attached to the honeycomb structure. 2. The production method according to claim 1, in which colloidal silica, alcoholic silica sol, or aluminosilicate fiber is used as the easily reactive silicic acid raw material. 3. The manufacturing method according to claim 1, in which particulate corundum is used as the heat-resistant filler. 4. The manufacturing method according to claim 1, wherein boric acid, sodium salt, lithium salt, magnesium salt, or fluoride is absorbed into the honeycomb structure before firing.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60292986A JPS62153175A (en) | 1985-12-27 | 1985-12-27 | Heat resistant honeycomb structure and manufacture |
| JP2102783A JPH03193336A (en) | 1985-12-27 | 1990-04-20 | Heat-resistant honeycomb structural body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60292986A JPS62153175A (en) | 1985-12-27 | 1985-12-27 | Heat resistant honeycomb structure and manufacture |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2102783A Division JPH03193336A (en) | 1985-12-27 | 1990-04-20 | Heat-resistant honeycomb structural body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62153175A JPS62153175A (en) | 1987-07-08 |
| JPH0362672B2 true JPH0362672B2 (en) | 1991-09-26 |
Family
ID=17788989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60292986A Granted JPS62153175A (en) | 1985-12-27 | 1985-12-27 | Heat resistant honeycomb structure and manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62153175A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01148764A (en) * | 1987-12-03 | 1989-06-12 | Nichias Corp | Lightweight refractory and its manufacture |
| JPH01148765A (en) * | 1987-12-07 | 1989-06-12 | Nichias Corp | Lightweight refractory and its manufacture |
| JPH0288452A (en) * | 1988-09-26 | 1990-03-28 | Nichias Corp | Heat-resistant inorganic compact |
| JPH02164455A (en) * | 1988-12-15 | 1990-06-25 | Matsushita Electric Ind Co Ltd | Exhaust gas purifying catalyst |
| JP2760439B2 (en) * | 1989-06-30 | 1998-05-28 | 松下電器産業株式会社 | Exhaust gas purification catalyst body and method for producing the same |
| US5078818A (en) * | 1990-04-18 | 1992-01-07 | Hexcel Corporation | Method for producing a fiber-reinforced ceramic honeycomb panel |
| JP2015123426A (en) * | 2013-12-27 | 2015-07-06 | 株式会社エフ・シー・シー | Method for manufacturing catalyst structure, and catalyst structure |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5121807A (en) * | 1974-08-15 | 1976-02-21 | Torio Kk | TEEPUHENSHUKAIRO |
| JPS52127663A (en) * | 1976-04-19 | 1977-10-26 | Sanyo Electric Co Ltd | All heat exchange element and the manufacturing method |
| JPS537447A (en) * | 1976-07-05 | 1978-01-23 | Setsuo Kataoka | Breeding method for new kind of one generation crossbreed plant crossbred compound diploid plant of crossbreed or reciprocal hibrid crossbred cabbages and other vegitables seed and brassica genuses ha |
| JPS56136656A (en) * | 1980-03-26 | 1981-10-26 | Nichias Corp | Carrier for catalyst and its production |
| JPS60122777A (en) * | 1983-12-07 | 1985-07-01 | 三菱化学株式会社 | Manufacture of refractory heat insulative board precursor |
-
1985
- 1985-12-27 JP JP60292986A patent/JPS62153175A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5121807A (en) * | 1974-08-15 | 1976-02-21 | Torio Kk | TEEPUHENSHUKAIRO |
| JPS52127663A (en) * | 1976-04-19 | 1977-10-26 | Sanyo Electric Co Ltd | All heat exchange element and the manufacturing method |
| JPS537447A (en) * | 1976-07-05 | 1978-01-23 | Setsuo Kataoka | Breeding method for new kind of one generation crossbreed plant crossbred compound diploid plant of crossbreed or reciprocal hibrid crossbred cabbages and other vegitables seed and brassica genuses ha |
| JPS56136656A (en) * | 1980-03-26 | 1981-10-26 | Nichias Corp | Carrier for catalyst and its production |
| JPS60122777A (en) * | 1983-12-07 | 1985-07-01 | 三菱化学株式会社 | Manufacture of refractory heat insulative board precursor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62153175A (en) | 1987-07-08 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |