JP4339426B2 - Method for producing inorganic cured body - Google Patents

Description

(i)表１における材料について
この表１において、無機質粉体１，２，３、アルカリ金属珪酸塩水溶液１，２、ワラストナイト、ビニロン、珪石粉等の単位は重量部である。また、表１における無機粉体は１，２，３の３種類があり、アルカリ金属珪酸塩水溶液等は、以下の様になっている。
【００４７】
（無機質粉体１）
カオリン（組成：ＳｉＯ₂ ４５．７％、Ａｌ₂Ｏ₃ ３８．３ ％ 平均粒径：８μｍ ＢＥＴ比表面積５．８ｍ²／ｇ） の原料粉を燃焼温度２５００℃、噴射粒子速度５０ｍ／秒で溶射し、活性無機質粉体（組成：ＳｉＯ₂ ４９．７％、Ａｌ₂Ｏ₃ ４７．０ ％ 平均粒径：４９μｍ ＢＥＴ比表面積６４．３ｍ²／ｇ）を得た。
【００４８】
（無機質粉体２）
フライアッシュ（関電化工社製、平均粒径２０μｍ；ＪＩＳ Ａ ６２０１に準ずる）を分級機（日清エンジニアリング社製、型式；ＴＣ−１５）により分級し、粒径が１０μｍ以下の粉末を１００重量％含有するもの
（無機質粉体３）
カオリン（組成：ＳｉＯ２ ４５．７％、Ａｌ₂Ｏ₃ ３８．３％ 平均粒径：８μm ＢＥＴ比表面積５．８ｍ²／ｇ）９５重量部と珪石粉５重量部及びトリエタノールアミン２５重量％とエタノール７５重量％の混合溶液０．５重量部をウルトラファインミルＡＴ−２０（三菱重工業社製、ジルコニアボール直径１０ｍｍ使用、ボール充填率８５体積％）に供給し２５ｋｗｈ／ｋｇの機械的エネルギーを作用させ、無機質粉体６を得た。尚、作用させた機械的エネルギーはボールミルに供給した電力を処理粉体単位重量あたりで表した。
【００４９】
（アルカリ金属珪酸塩１）
アルカリ金属珪酸塩１として、ＳｉＯ₂ ／K₂Ｏ＝１．４の珪酸カリウムを濃度４５重量％の水溶液にして使用した。
【００５０】
（アルカリ金属珪酸塩２）
また、アルカリ金属珪酸塩２として、ＳｉＯ₂ ／Na₂Ｏ＝１．４の珪酸ナトリウムを濃度４２重量％の水溶液にして使用した。
【００５１】
(ii)材料の混合方法及び得られた素板の試験方法
これらを他材料と混合する前に冷却し、混合したペーストが所定の温度になるように調整した。
【００５２】
この水溶液とワラストナイト、ビニロン繊維（クラレ社製、商品名；ＲＭ１８２×３）、珪石粉、ＳｉＯ₂-Ａｌ₂Ｏ₃系無機質粉体（１〜３）、をオムニミキサー（千代田技研工業株式会社製）で混合し、無機質硬化性組成物を含む均一なペーストとした。
【００５３】
さらに、この無機質硬化性組成物を含む材料を６００×６００×３０mmの型枠に注型し、テーブルバイブレーター（振動数１２００回／分、振幅０．５ｍｍ、縦振動）で１分振動を加えた後、蓋をして、所定の加熱を行い、得られた硬化体の曲げ強度、耐凍結融解試験（ＡＳＴＭ Ｃ−６６６ Ａ法）１００サイクルを測定した。
【００５４】
(iii)試験結果
表１の実施例の１〜７の様に、加熱温度を６５〜８５゜Ｃ，加熱温度到達時間を８〜１５分，温度保持時間を略１５〜３０分，硬化所要時間を２７〜４２とした場合、硬化体の曲げ強度は[kgｆ/cm²]で表すとそれぞれ２１０，２１５，２０４，１９８，２２５，１９５，２２０[kgｆ/cm²]（即ちＭＰａで表すと２０.６，２１.１，２０.０，１９.４，２２.１，１９.１，２１.６[ＭＰａ]）であり、耐凍結融解試験結果は異常なしであった。従って、実施例１〜７では、短時間で良好な結果が得られた。尚、比較例１でも長時間を要したものの、良い性能が得られた。この比較例１は、短時間で良好な結果が得られた実施例１〜７と比較したので、比較例として示したが、実際には本発明の実施例の一つである。
【００５５】
また、比較例の２〜４においては、加熱温度到達時間を６５分と長くした比較例４や温度保持時間を「０」とした比較例２が僅かに破損の△であり、又、加熱温度到達時間を１２分と短くすると同時に温度保持時間を「０」とし且つ硬化所用時間を１２分と短くした比較例３が破損の×であった。
【００５６】
この結果、実施例の１〜７の本願発明の製造方法の条件は比較例２〜３に比べて良好であった。
【００５７】
（２）．実施の形態２
＜基本的製造方法２＞
実施の形態２において、無機質発泡体（無機質硬化体）の製造に用いられる無機質硬化性組成物の原料は次の通りである。即ち、この原料としては、例えば、ＳｉＯ₂-Ａｌ₂Ｏ₃系反応無機質粉体(A)１００重量部、アルカリ金属珪酸塩(B)０．２〜１５０重量部、水(C)３５〜１５００重量部が用いられる。
【００５８】
そして、この様な原料及び発泡剤０．０１〜２重量部を図１（ａ）の如くミキサー１に投入して、この原料及び発泡剤をミキサー１で均一に混合することにより、発泡性の組成物である無機質硬化性組成物（無機質硬化性混合物）のペーストを得る。
【００５９】
次に、この無機質硬化性組成物のペーストをホッパー２を介して材料出口２ａから成形型（型枠）３内に流し込み、必要に応じてレベリングや脱泡のために成形型３に振動をかける。その後、図１（ｂ）の如く成形型３の上部開放端を蓋体４で密閉する。尚、成形型３の上部開放端は必ずしも蓋体４で密閉する必要はない。
【００６０】
この後、無機質硬化性組成物６の発泡・硬化を促進させるために、無機質硬化性組成物６を加熱するが、この加熱開始までの時間を制御する。すなわち、混合終了後の無機質硬化性組成物６は、混合後に直ちに加熱せず、加熱までの時間を制御する。この際、通常は、無機質硬化性組成物６を成形型３内に入れた状態で加熱開始まで待機するが、混合後の無機質硬化性組成物６を加熱開始までの間保存する場所としてはミキサー１内であってもよいし他の場所でもよい。
【００６１】
この様に無機質硬化性組成物６を、混合直後から所定時間保存しておいて、所定時間経過後に図１(C)において加熱することにより、発泡硬化させる。この後、発泡硬化した無機質発泡体を成型型３から取り出す脱型を行なう。尚、脱型後の無機質発泡体は、必要に応じて図１(d)のアフターキュアにより冷却した後、図１(e)で乾燥させて、建物の外壁等の素板７とする。
【００６２】
＜無機質発泡体の原料等の例＞
まず、無機質硬化性組成物（硬化性無機質組成物）を説明する。
【００６３】
この実施の形態の無機質硬化性組成物としては、例えば、ＳｉＯ₂-Ａｌ₂Ｏ₃系反応性無機質粉体１００重量部と、アルカリ金属珪酸塩０．２〜４５０重量部と、水３５〜１５００重量部と、発泡剤０．０１〜２重量部とを含有する熱硬化性組成物が好ましい。なお、この熱硬化性組成物に限定されるものでは無い。
【００６４】
［反応性無機質粉体］
反応性無機質粉体としては、ＳｉＯ₂：５〜８５重量％とＡｌ₂Ｏ₃：９０〜１０重量％のものが好適に使用される。
【００６５】
このような反応性無機質粉体としては、フライアッシュ、メタカオリン、カオリン、ムライト、コランダム、アルミナ系研磨材を製造する際に生成されるダスト、粉砕焼成ボーキサイト等が使用できるが、組成と粒度とが適当であれば、これらに限定されるものではない。
【００６６】
また、これらの反応性無機質粉体をそのまま用いてもよいが、活性化させるために、溶射処理、粉砕分級、機械的エネルギーを作用させてもよい。
【００６７】
「溶射処理方法」としては、セラミックコーティングに適用される溶射技術が応用される。この溶射技術は、好ましくは溶射粉末が３０〜８００ｍ／秒の速度で噴霧されつつ、２０００〜１６０００℃の温度で溶融されるものであり、プラズマ溶射法、高エネルギーガス溶射法、アーク溶射法等が可能である。なお、得られた粉体の比表面積は、０．１〜１００ｍ²／ｇ が好ましい。
【００６８】
「分級、粉砕方法」としては、従来公知の任意の方法が採用され、篩、比重、風力、湿式沈降等による分級、ジェットミル、ロールミル、ボールミルによる粉砕などが挙げられる。なお、これらの手段は併用されてもよい。
【００６９】
「機械的エネルギーによる作用方法」としては、ボール媒体ミル、媒体撹拌型ミル、ローラミル等が使用され、作用させる機械的エネルギーとしては０．５ｋｗｈ／ｋｇ〜３０ｋｗｈ／ｋｇが好ましい。なお、作用する機械的エネルギーが小さいと粉体を活性化しにくく、大きいと装置への負荷が大きい。
【００７０】
そして、「フライアッシュ」は、必要に応じて、焼成されたものでもよい。フライアッシュの焼成温度は、低いと、フライアッシュの黒色が残り、高いと、アルカリ金属珪酸塩との反応性が低くなるので、４００℃〜１０００℃であることが好ましい。
【００７１】
［アルカリ金属珪酸塩］
アルカリ金属珪酸塩とは、Ｍ₂Ｏ・ｎＳｉＯ₂ （Ｍ＝Ｋ，Ｎａ，Ｌｉから選ばれる１種以上の金属）で表される塩である。
【００７２】
このｎの値は、小さくなると緻密な発泡体が得られず、大きくなると水溶液の粘度が上昇し混合が困難になるので、０．０５〜８が好ましく、さらに、好ましくは０．５〜２．５である。
【００７３】
また、アルカリ金属珪酸塩は、水溶液で添加されるのが好ましい。この水溶液の水溶液濃度は、特に限定されないが、薄くなると反応性無機質粉体との反応性が低下し、濃くなると固形分が生じやすくなる。そこで、アルカリ金属珪酸塩は１０〜６０重量％が好ましい。
【００７４】
この水溶液の添加されたアルカリ金属珪酸塩水溶液は、アルカリ金属珪酸塩をそのまま加圧、加熱下で水に溶解してもよいが、アルカリ金属水酸化物水溶液に珪砂、珪石粉などのＳｉＯ₂ 成分をｎが所定の量となるように加圧、加熱下で溶解してもよい。
【００７５】
そして、アルカリ金属珪酸塩の量は、少なくなると硬化が十分になされず、多くなると得られる発泡体の耐水性が低下する。そこで、アルカリ金属珪酸塩の量は、反応性無機質粉体１００重量部に対して０．２〜４５０重量部に限定され、好ましくは１０〜３５０重量部、さらに、好ましくは２０〜２５０重量部である。［水］
水は、アルカリ金属珪酸塩水溶液として添加されてもよいし、独立して添加されてもよい。
【００７６】
また、水の量は、少なくなると十分に硬化しないとともに、混合が困難となり、多くなると硬化体の強度が低下しやすくなる。そこで、反応性無機質粉体１００重量部に対して３５〜１５００重量部に限定され、好ましくは４５〜１０００重量部、さらに、好ましくは５０〜５００重量部である。
【００７７】
［発泡剤］
発泡剤は、過酸化物（過酸化水素、過酸化ソーダ、過酸化カリ、過ほう酸ソーダ等）、金属粉末（Ｍｇ，Ｃａ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ａｌ、Ｇａ、Ｓｎ、Ｓｉ、フェロシリコン）等が用いられる。
【００７８】
この発泡剤は、多すぎると発泡ガスが過剰となり破泡し、少なすぎると発泡倍率が小さすぎて発泡体の意味を失う。そこで、発泡剤は０．０１〜１０重量部とする。
【００７９】
また、過酸化水素を発泡剤として用いるときは、安全性、安定した発泡を考慮すると水溶液として用いるのが好ましい。
【００８０】
そして、金属粉末を用いる場合は、安定した発泡を得るために、粒径２００μm以下であることが好ましい。
【００８１】
［発泡助剤］
この実施の形態では、硬化性無機質組成物に必要に応じて発泡助剤が添加されてもよい。この発泡助剤としては、例えば、ステアリン酸亜鉛、ステアリン酸カルシウム、パルミチン酸亜鉛等の脂肪酸金属塩、シリカゲル、ゼオライト、活性炭、アルミナ粉末等の多孔質粉体などが挙げられる。
【００８２】
＜原料の添加方法＞
［発泡助剤の添加］
これらのステアリン酸亜鉛、ステアリン酸カルシウム、パルミチン酸亜鉛等の脂肪酸金属塩、シリカゲル、ゼオライト、活性炭、アルミナ粉末等の多孔質粉体等の発泡助剤は、単独で使用されてもよいし、２種類以上併用されてもよい。なお、発泡助剤は発泡を均一に生じさせるものなら特に限定され無い。
【００８３】
発泡助剤の量は、多くなると組成物の粘度が上昇し、破泡が発生しやすくなる。そこで、発泡助剤の量は反応性無機質粉体１００重量部に対して１０重量部以下が好ましい。
【００８４】
［無機質充填材の添加］
この実施の形態では、硬化性無機質組成物に必要に応じて無機質充填材が添加されてもよい。
【００８５】
無機質充填材は、例えば、珪砂、川砂、ジルコンサンド、結晶質アルミナ、岩石粉末、火山灰、シリカフラワー、シリカフューム、ベントナイト、高炉スラグ等の混合セメント用混合材、セピオライト、ウォラストナイト、マイカ等の天然鉱物、炭酸カルシウム、珪藻土などが挙げられる。これらの各無機質充填材は、単独で添加されてもよいし、２種類以上併用されてもよい。なお、無機質充填材は、水に溶解せず、硬化性無機質組成物の硬化反応を阻害せず、アルカリ金属珪酸塩と反応しないものであれば特に限定され無い。
【００８６】
無機質充填材の量は、多くなると得られる硬化体の強度が低下する。そこで、無機質充填材の量は反応性無機質粉体１００重量部に対して７００重量部以下が好ましい。
【００８７】
［補強繊維の添加］
この実施の形態では、硬化性無機質組成物に必要に応じて補強繊維が添加されてもよい。
【００８８】
補強繊維は、成形体に付与したい性能に応じ任意のものが使用でき、例えば、ビニロン繊維、ポリアミド繊維、ポリエステル繊維、ポリプロピレン繊維、カーボン繊維、アラミド繊維、ガラス繊維、チタン酸カリウム繊維、鋼繊維などが使用できる。
【００８９】
この補強繊維は、繊維径が細くなると、混合時に再凝集し、交絡によりファイバーボールが形成されやすくなり、最終的に得られる強度が改善されない。また、繊維径が太くなるか又は短くなると、引張強度の向上などの補強効果が小さい。そして、繊維径が長くなると、繊維の分散性及び配向性が低下する。そこで、補強繊維の繊維径は繊維径１〜５００μｍ、繊維長１〜１５ｍｍが好ましい。
【００９０】
また、補強繊維の添加量は多くなると繊維の分散性が低下する。そこで、添加量は反応性無機質粉体１００重量部に対して１０重量部以下が好ましい。これらの各補強繊維は、単独で添加されてもよいし、２種類以上併用されてもよい。
【００９１】
［その他の添加物］
この実施の形態では、硬化性無機質組成物に必要に応じて、アルミナセメント、γ−アルミナ、溶射されたアルミナ、アルミン酸アルカリ金属塩及水酸化アルミニウムを加えてもよい。
【００９２】
【第２実施例】
無機質粉体としては、メタカオリン（エンゲルハード社製のSATINTＯNE SP ３３、平均粒径３．３ミクロン、比表面積１３．９ｍ²／ｇ）１００重量部を用いた。そして、このメタカリオンを、トリエタノールアミン２５重量部％、及びエタノール７５重量部％の混合溶液０．５重量部と共に混合して、機械的エネルギーを作用させた。この混合では、ウルトラファインミルAT−２０（三菱重工業社製、ジルコニアボール直径１０ｍｍ使用、ボール重点率８５体積％）を用い、２５kwh／kgの機械的エネルギーを作用させて、無機質粉体４を得た。尚、この無機質粉体４を得るために用いた上述のメタカオリンは、表３では無機質粉体５である。また、作用させた機械的エネルギーは、ボールミルに供給した電力を処理粉体単位重量当たりで表した。
【００９３】
しかも、所定量のｎＳｉＯ₂／Ｍ₂Ｏ（ｎ＝１．５、Ｍ＝Ｋ）をオートクレーブ中において１３０°Ｃ、７kgｆ／cm²で所定量の水に溶解させると共に、ワラストナイト、ビニロン繊維、珪石粉、上述の無機質粉体又はメタカオリン、ステアリン酸亜鉛をオムニミキサーで混合し、無機質硬化性組成物を含む均一なペーストとした。
【００９４】
この際、ワラストナイトにはカキウチ（株）製のものを用い、ビニロン繊維にはクラレ社製、商品名：RM182×３を用い、珪石粉には増岡窯業原料（株）製、商品名：錦印磁珪砂を用い、ステアリン酸亜鉛には堺化学社製、商品名：Ｓz-2000）を用い、オムニミキサーには千代田技研工業株式会社製のものを用いた。
【００９５】
そして、この様な原料を混合して得られた上述のペーストに発泡剤を添加して更に２分混合し、原料を発泡剤入りのペースト状態とした。この発泡剤としては、Ｓi（キンセイマテック社製、商品名：＃６００）を用いた。
【００９６】
この様な無機発泡硬化性混合物のペーストにおける各原料の配合は、以下の表２及び表３に示してある。
【００９７】
【表２】

【表３】

この表２，表３における原料を配合して得たペーストを成形型（型枠）に流し込んだ後に、成形型の上部開放端を蓋体で閉成し、混合終了後から時間Ｔ１後にペーストの加熱を開始した。そして、６５°Ｃ蒸気中で加熱し発泡・硬化させ無機質発泡体を得た。
【００９８】
この無機質発泡体は、次の表４，表５の条件で評価した。尚、表２の配合における混合終了から加熱開始までの時間T1は表４（実施例１〜７、及び比較例１，２）に示す通りであり、表３の配合における混合終了から加熱開始までの時間T1は表５（実施例８〜１２、及び比較例３，４）に示すとおりである。
【００９９】
【表４】

【表５】

この表４，表５における独泡性，吸水率，強度維持率等は、次の(i)〜(iii)に述べる基準で観察や測定，試験をした。即ち、
(i)独泡性
得られた無機質発泡体は切断面を顕微鏡で観察して判断し、判断の結果、独泡性が良好であれば○とし、不良であれば×、良好と不良の中間であれば△とした。
【０１００】
(ii)吸水率
１２×１２×３（cm）のサンプルを１０日間水中に浸漬させた後に重量Ｇ１を測定し、その後、サンプルを１０５°Ｃのオーブン中で２４時間乾燥させたときの重量をＧ２を測定し、｛（Ｇ１−Ｇ２）／Ｇ２｝×１００の値を１０日後の吸水率とした。
【０１０１】
(iii)耐久試験後の強度維持率（％）
得られた無機質発泡体は、耐久試験として、凍結融解試験（JIS A 1435 水中凍結水中融解試験）前に圧縮試験（JIS A １１０８）を行うとともに、その後、凍結融解試験を行った。凍結融解試験後の圧縮強度を凍結融解試験前の圧縮強度で除して１００を掛けることにより得られた値を強度維持率として表に記載した。
【０１０２】
上述の表４によれば、原料（材料）の混合終了後から加熱開始までの時間T1を実施例１〜実施例７でそれぞれ９０分，６０分，５０分，４０分，３０分，２０分，１０分と変化させた場合、独泡性はいずれも良好の「○」であった。また、吸水率も、１０分では３９，２０分では３６，３０分では３５，４０分では３５、５０分では３２，６０分では３１、９０分では２８であった。更に、耐久試験後の強度維持率は実施例１〜実施例７とも１００％であった。
【０１０３】
これに対して、比較例１では、原料（材料）の混合終了後から加熱開始までの時間T1を５分とした場合、独泡性は不良と良の中間の「△」であった。また、比較例２では、原料（材料）の混合終了後から加熱開始までの時間T1を１分とした場合、即ち混合終了後に直ちに加熱した場合、独泡性は不良の「×」であった。
【０１０４】
しかも、比較例２では、吸水率が実施例１〜実施例７の２８〜３９に比べて４５と高いものであった。更に、比較例１及び比較例２では、耐久試験後の強度維持率が実施例１〜実施例７の１００％に対して９０％及び８３％とそれぞれ低いものであった。
【０１０５】
上述の表５によれば、原料（材料）の混合終了後から加熱開始までの時間T1を実施例８〜実施例１２でそれぞれ５０分，４０分，３０分，２０分，１０分と変化させた場合、独泡性はいずれも良好の「○」であった。また、吸水率も、１０分では３１、２０分では３０、３０分では２８、４０分では２６、５０分では２５であった。更に、耐久試験後の強度維持率は実施例８〜実施例１２とも１００％であった。
【０１０６】
これに対して、また、比較例３では、原料（材料）の混合終了後から加熱開始までの時間T1を５分とした場合、独泡性は良好と不良の中間の「△」であったまた、比較例４では、原料（材料）の混合終了後から加熱開始までの時間T1を１分とした場合、即ち混合終了後に直ちに加熱した場合、独泡性不良の「×」であった。 比較例３及び比較例４では、吸水率が実施例８〜実施例１２の２５〜３１に比べて３５及び３９とそれぞれ高いものであった。更に、比較例３及び比較例４では、耐久試験後の強度維持率が実施例８〜実施例１２の１００％に対して９５％及び９０％とそれぞれ低いものであった。
【０１０７】
【発明の効果】
以上説明したように、請求項１に記載の発明は、ＳｉＯ₂-Ａｌ₂Ｏ₃系無機質粉体、アルカリ金属珪酸塩、水からなる無機質硬化性組成物を加熱して、無機質硬化体を製造する方法において、前記無機質硬化性組成物の原料を混合した後、前記無機質硬化性組成物の加熱開始までの時間を制御するようにしたので、混合後に昇温を開始することにより短時間で無機質硬化体に十分な強度を持たせることができる。
【０１０８】
また、請求項２の発明は、前記無機質硬化性組成物を混合した後に昇温を開始し、昇温開始後２０分以下の時間で６０℃以上に加熱するようにしたので、無機質硬化体に短時間で十分な強度を持たせることができる。
【０１０９】
請求項３の発明は、前記無機質硬化性組成物を昇温開始後、６０°Ｃ以上の温度で１０分以上保持するようにしたので、より強度を高めることができる。
【０１１０】
更に、請求項４の発明は、前記無機質硬化性組成物を発泡性の無機質硬化性組成物として混合した後、７分経過後に加熱開始する様にしたので、
短時間で独立気泡を生成した高耐久性の無機質発泡体を無機質硬化体として得ることができる。
【０１１１】
また、請求項５の発明は、前記無機質硬化性組成物は、ＳｉＯ₂-Ａｌ₂Ｏ₃系無機質粉体１００重量部、アルカリ金属珪酸塩０．２〜４５０重量部、水３５〜１５００重量部からなる構成としたので、無機質硬化体に短時間で十分な強度を持たせるのに好ましい。
【図面の簡単な説明】
【図１】無機質硬化体を製造するシステムの説明図である。
【図２】実施例及び比較例に基づく加熱温度及びＤＳＣと時間との関係を示す特性曲線図ある。
【符号の説明】
１…ミキサー
２…ホッパー
３…成形型
４…蓋体
５…冷却乾燥装置
Ａ…反応性無機質粉体
Ｂ…アルカリ金属珪酸塩
Ｃ…水[0001]
[Industrial application fields]
The present invention relates to a method for producing an inorganic cured body used for an outer wall of a building material or the like.
[0002]
[Prior art]
A method for producing this kind of inorganic cured body is disclosed in Japanese Patent Publication No. 4-45471. This manufacturing method manufactures an inorganic hardened | cured material by heat-curing the mixture of the oxide mixture containing an amorphous silicon dioxide and aluminum oxide, and an alkali metal silicate. The inorganic hardened body obtained by this method can be cured in a shorter time than that using a cement-based material. That is, it is possible to perform demolding by curing in a short time of about 30 minutes.
[0003]
Some inorganic compositions that have been cured and foamed by heat in the presence of alkali have been proposed. For example, a method of obtaining a foam by generating water vapor under heating without using a foaming agent is known. As another method, a method of obtaining a foam by adding metal powder to generate gas is known. An example of this method is, for example, as described in JP-A-57-77062.
[0004]
[Problems to be solved by the invention]
However, in the production method disclosed in Japanese Examined Patent Publication No. 4-45471, with a curing time of about 30 minutes, the strength of the inorganic cured body cannot be sufficiently secured, and the performance is not sufficiently exhibited. Further, by prolonging the curing time of the inorganic cured body disclosed in this publication, it is possible to give the inorganic cured body sufficient strength and to fully exhibit its performance. However, in order to give the inorganic cured body sufficient strength, it takes two hours or more, which causes a problem in production.
[0005]
In addition, in the production method as disclosed in JP-A-57-77062, heating is performed to improve productivity, foaming is broken when foaming / curing is promoted, water foam is easily absorbed and poor in durability. It was not obtained.
[0006]
Then, the 1st objective of this invention is to provide the manufacturing method of the inorganic hardening body which can give an inorganic hardening body sufficient intensity | strength in a short time.
[0007]
A second object of the present invention is to provide a method for producing an inorganic cured body that can solve the above-mentioned problems and can obtain a highly durable inorganic foam in which closed cells are generated.
[0008]
[Means for Solving the Problems]
  In order to solve the above problems, the invention of claim 1 ₂ -Al ₂ O ₃ In the method of heating an inorganic curable composition comprising an inorganic inorganic powder, an alkali metal silicate, and water to produce an inorganic cured body, the temperature rise is started after mixing the raw materials of the inorganic curable composition. Heat to 60 ° C or higher in 20 minutes or less after temperature starts, and then hold at temperature of 60 ° C or higher for 10 minutes or longer and within 30 minutesIt is characterized by that.
[0009]
In this production method, when producing a dense inorganic cured body, it is preferable to heat in a short time in order to cure quickly. Further, when producing a foamed inorganic cured body, it is preferable to take a long time to start heating in order to generate uniform bubbles.
[0010]
   The invention of claim 2The inorganic curable composition is characterized in that the SiO—AlO inorganic powder is 100 parts by weight, the alkali metal silicate is 0.2 to 450 parts by weight, and the water is 35 to 1500 parts by weight.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
(1). Embodiment 1
<Basic manufacturing method 1>
FIG. 1 is an explanatory diagram of a system for producing an inorganic cured body. In FIG. 1, 1 is a mixer for kneading materials, 1a is a material discharge port at the bottom of the mixer 1, 2 is a hopper disposed below the material discharge port 1a, and 2a is a fixed position of the mixed material from the hopper 2. 3 is a mold that opens upward, 4 is a lid that closes the open end of the mold 3, and 5 is a cooling and drying device. A is a reactive inorganic powder (SiO 2₂-Al₂O_ThreeSystem inorganic powder), B is an alkali metal silicate, and C is water.
[0016]
In the present invention, basically, in FIG.₂-Al₂O_Three100 parts by weight of inorganic inorganic powder (A), 0.2 to 450 parts by weight of alkali metal silicate (B), and 35 to 1500 parts by weight of water (C) are mixed in a mixer 1 at a temperature of 20 ° C. or less to paste A shaped inorganic curable composition is prepared. At this time, a foaming agent or a foaming aid may be added as necessary, and inorganic fillers, reinforcing fibers, inorganic foams, synthetic resin foams, vinylidene chloride, acrylic balloons, and the like are necessary. It may be added. These may be added alone or in combination of two or more.
[0017]
Thereafter, the mixed inorganic curable composition (mixture) is supplied into the mold 3 from the mixed material outlet 2a through the hopper 2, and the open end of the mold 3 is closed as shown in FIG. 1 (b). Seal with 4.
[0018]
Next, the mold 3 is vibrated for the purposes of leveling and defoaming. 1 (c), the inorganic curable composition 6 in the mold 3 is heated and heated. This heating and heating is started within 1 hour after mixing the inorganic curable composition 6. At this time, the heating temperature of the inorganic curable composition 6 is preferably 60 ° C. or higher, and the temperature of the inorganic curable composition 6 is set to 60 ° C. or higher in a time of 20 minutes or less after the start of temperature increase. The heating time is kept for 10 minutes or more.
[0019]
After the inorganic curable composition 6 is cured by this heating, the mold is removed from the mold 3, and the demolded inorganic curable composition 6 is cooled by after-curing in FIG. 1 (d), and (e) In step (d), the base plate 7 such as the wall panel of the building is formed.
[0020]
<More specific conditions>
The above-mentioned reactive inorganic powder (SiO₂-Al₂O_Three(Based inorganic powder) (A) includes SiO₂ 5 to 85% by weight and Al₂O_Three 90 to 10% by weight is preferably used. Examples of such powders include fly ash, metakaolin, kaolin, mullite, corundum, dust when producing alumina abrasives, pulverized calcined bauxite, etc., but are limited to these if the composition and particle size are appropriate. It is not something. These powders may be used as they are, but in order to activate them, thermal spraying treatment, pulverization classification, and mechanical energy may be applied.
[0021]
As a thermal spraying method, a thermal spraying technique applied to a ceramic coating is applied. The thermal spraying technique is preferably such that the material powder is melted at a temperature of 2000 to 16000 ° C. and sprayed at a speed of 30 to 800 m / second, such as a plasma spraying method, a high energy gas spraying method, and an arc spraying method. Is possible. The specific surface area of the obtained powder is 0.1 to 100 m.²/ G is preferred.
[0022]
As a method of classification and pulverization, any conventionally known method is adopted, and classification by sieving, specific gravity, wind force, wet sedimentation, etc., pulverization by a jet mill, a roll mill, a ball mill and the like can be mentioned. These means may be used in combination.
[0023]
As a method for applying mechanical energy, a ball medium mill, a medium stirring mill, a roller mill or the like is used, and the mechanical energy to be applied is preferably 0.5 kwh / kg to 30 kwh / kg. If it is small, it is difficult to activate the powder, and if it is large, the load on the apparatus is large.
[0024]
The fly ash may be fired as necessary. If the firing temperature is low, fly ash black remains and coloring becomes difficult. If the firing temperature is high, the reactivity with the alkali metal silicate (B) is low, and therefore it is preferably 400 ° C to 1000 ° C.
[0025]
The above-mentioned alkali metal silicate (B) is M₂O · nSiO₂(M = one or more metals selected from K, Na, and Li). When the value of n is small, a dense foam cannot be obtained, and when it is large, the viscosity of the aqueous solution is increased and mixed. Therefore, the value of n is preferably 0.05 to 8, and more preferably 0.5 to 2.5.
[0026]
Moreover, water (C) may be added as the said alkali metal silicate aqueous solution, and may be added independently. If the amount of water (C) is reduced, it will not be sufficiently cured and mixing will be difficult, and if it is increased, the strength of the cured product will tend to be reduced, so 35 to 100 parts by weight of the reactive inorganic powder (A). The amount is limited to 1500 parts by weight, preferably 45 to 1000 parts by weight, and more preferably 50 to 500 parts by weight.
[0027]
Furthermore, a foaming agent may be added as necessary. As foaming agents, peroxides (hydrogen peroxide, sodium peroxide, potassium peroxide, sodium perborate, etc.), metal powders (Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga) , Sn, Si, ferrosilicon) and the like are used, and if it is too much, the foaming gas becomes excessive and breaks bubbles. It is preferable.
[0028]
When hydrogen peroxide is used as a foaming agent, it is preferably used as an aqueous solution in consideration of safety and stable foaming. When metal powder is used, the particle size is preferably 200 μm or less in order to obtain stable foaming.
[0029]
In the present invention, a foaming aid may be added as necessary. The foaming aid is not particularly limited as long as it causes foaming uniformly, and examples thereof include fatty acid metal salts such as zinc stearate, calcium stearate, and zinc palmitate, porous powders such as silica gel, zeolite, activated carbon, and alumina powder. can give. These may be used alone or in combination of two or more.
[0030]
When the amount of the foaming aid increases, the viscosity of the composition increases and foam breakage easily occurs. Therefore, the amount is preferably 10 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder (A).
[0031]
In the present invention, an inorganic filler may be added as necessary. The inorganic filler is not particularly limited as long as it does not dissolve in water, does not inhibit the curing reaction of the foamable inorganic composition, and does not react with the alkali metal silicate. For example, silica sand, river sand, zircon sand, crystalline Examples include alumina, rock powder, volcanic ash, silica flour, silica fume, bentonite, mixed cement materials such as blast furnace slag, natural minerals such as sepiolite, wollastonite, mica, calcium carbonate, diatomaceous earth, and the like. These may be added alone or in combination of two or more.
[0032]
The inorganic filler preferably has a viscosity of the composition when the average particle size becomes small, a high-magnification foam cannot be obtained, and foaming becomes unstable when the average particle size becomes large, so 0.01 to 1000 μm is preferable. When the amount of the inorganic filler is increased, the strength of the obtained foam is lowered, and therefore the amount is preferably 700 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder (A).
[0033]
In the present invention, reinforcing fibers may be added as necessary. Any fiber can be used depending on the performance to be imparted to the molded body. For example, vinylon fiber, polyamide fiber, polyester fiber, polypropylene fiber, carbon fiber, aramid fiber, glass fiber, potassium titanate fiber, steel fiber, etc. Can be used.
[0034]
When the fiber diameter of the reinforcing fiber is thin, it re-aggregates during mixing, and fiber balls are easily formed by entanglement, and the strength of the foam obtained finally is not further improved, and when it becomes thicker or shorter, the tensile strength The reinforcing effect such as improvement is small, and if the length is longer, the dispersibility and orientation of the fiber are lowered. Since the dispersibility of the fibers decreases as the amount of the reinforcing fibers added increases, the amount is preferably 10 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder (A).
[0035]
Furthermore, for the purpose of reducing the weight of the cured product, inorganic foams such as silica balloons, perlites, fly ash balloons, shirasu balloons, glass balloons, foamed and fired clay, and foams of synthetic resins such as polystyrene, phenol resin, urethane resin, and polyethylene. , Vinylidene chloride, acrylic balloons and the like may be added. These may be added alone or in combination of two or more.
[0036]
Further, if necessary, alumina cement, γ-alumina, sprayed alumina, alkali metal aluminate or aluminum hydroxide may be added.
[0037]
In the present invention, as described above, the curing of the mixed material is started during one hour or less after mixing, and heated to 60 ° C. or more in 20 minutes or less after the start of temperature rising. It is good to hold for more than 10 minutes above the temperature.
[0038]
Cement, which is a commonly used inorganic curable material, is an exothermic reaction. Therefore, if the temperature is suddenly increased, reaction heat accumulates and cracks occur in the cured product due to thermal distortion, resulting in a decrease in strength. To do. For this reason, in cementitious material, the low temperature curing called precuring is performed in advance before heat curing.
[0039]
On the other hand, in the material system according to the present invention, the same thing was inferred, but SiO₂-Al₂O_ThreeIn many cases, the dissolution of the inorganic inorganic powder in the alkali metal silicate aqueous solution is an exothermic reaction, but the dehydration condensation reaction of the dissolved product, which is a curing reaction, is an endothermic reaction (FIG. 1, differential scanning calorimeter). There is a possibility that distortion due to heat does not occur even when abrupt heating is performed, and as a result of actual testing, it was found.
[0040]
Furthermore, since the exothermic reaction no longer occurs even if the temperature after heating is maintained, distortion due to heat or a rapid curing reaction does not occur, and the curing reaction is immediately terminated, and necessary performance is exhibited.
[0041]
In order to obtain the inorganic foamable material of the present invention, alkali metal silicate or an aqueous solution thereof (A) and SiO₂-Al₂O_ThreeThe inorganic powder (B), if necessary, the remaining water (C) foaming aid, reinforcing fibers, inorganic filler and the like and silicon powder are mixed to form a paste.
[0042]
In the case of foaming, the foaming agent may be added later after mixing other materials. When the foaming agent is a powder, the powder may be added alone, or may be added after being dispersed in water for easier dispersion. The paste is poured into a mold and, if necessary, vibrated for leveling and defoaming.
[0043]
Thereafter, heating is performed. As the heating means, a method of directly heating the mold with a large heat capacity such as a hot plate or hot water can be used.
[0044]
These results will be described with reference to the graph shown in FIG. 2. From the temperature change curve T and the DSC (differential scanning calorimeter) curve, when the heating temperature is about 85 ° C. and the heating temperature arrival time is 15 minutes, It can be seen that a stable result is obtained when the temperature holding time is 10 minutes or more.
[0045]
[First embodiment]
Next, examples of the present invention will be described in more detail with reference to the following Table 1 and FIG.
[0046]
[Table 1]

(i) Materials in Table 1
In Table 1, the units of inorganic powders 1, 2, 3, alkali metal silicate aqueous solutions 1, 2, wollastonite, vinylon, silica powder and the like are parts by weight. In addition, the inorganic powder in Table 1 has 1, 2 and 3 types, and the alkali metal silicate aqueous solution and the like are as follows.
[0047]
(Inorganic powder 1)
Kaolin (composition: SiO₂ 45.7%, Al₂O_Three 38.3% Average particle diameter: 8 μm BET specific surface area 5.8 m²/ G) of the raw material powder is sprayed at a combustion temperature of 2500 ° C. and an injection particle speed of 50 m / second to obtain an active inorganic powder (composition: SiO₂ 49.7%, Al₂O_Three 47.0% Average particle diameter: 49 μm BET specific surface area 64.3 m²/ G).
[0048]
(Inorganic powder 2)
Fly ash (manufactured by Kandenka Kogyo Co., Ltd., average particle size 20 μm; conforming to JIS A 6201) is classified by a classifier (Nisshin Engineering Co., Ltd., model: TC-15), and 100% by weight of powder having a particle size of 10 μm or less. Contains
(Inorganic powder 3)
Kaolin (Composition: SiO2 45.7%, Al₂O_Three  38.3% Average particle size: 8 μm BET specific surface area 5.8 m²/ G) Ultrafine mill AT-20 (manufactured by Mitsubishi Heavy Industries, Ltd., zirconia ball diameter 10 mm) using 95 parts by weight, 5 parts by weight of silica powder, and 0.5 parts by weight of a mixed solution of 25% by weight of triethanolamine and 75% by weight of ethanol And a ball filling rate of 85% by volume) was applied with mechanical energy of 25 kwh / kg to obtain an inorganic powder 6. The mechanical energy applied was expressed as the power supplied to the ball mill per unit weight of the processed powder.
[0049]
(Alkali metal silicate 1)
As alkali metal silicate 1, SiO₂ / K₂O = 1.4 potassium silicate was used in an aqueous solution having a concentration of 45% by weight.
[0050]
(Alkali metal silicate 2)
Further, as alkali metal silicate 2, SiO₂ / Na₂Sodium silicate with O = 1.4 was used in an aqueous solution with a concentration of 42% by weight.
[0051]
(ii) Material mixing method and test method of the obtained base plate
These were cooled before mixing with other materials, and adjusted so that the mixed paste had a predetermined temperature.
[0052]
This aqueous solution, wollastonite, vinylon fiber (Kuraray Co., Ltd., trade name: RM182 × 3), silica powder, SiO₂-Al₂O_ThreeThe system inorganic powders (1 to 3) were mixed with an omni mixer (manufactured by Chiyoda Giken Co., Ltd.) to obtain a uniform paste containing the inorganic curable composition.
[0053]
Furthermore, the material containing this inorganic curable composition was cast into a 600 × 600 × 30 mm mold, and vibration was applied for 1 minute with a table vibrator (frequency: 1200 times / min, amplitude: 0.5 mm, longitudinal vibration). Then, the lid was capped and subjected to predetermined heating, and the bending strength of the obtained cured product and 100 cycles of freeze-thaw resistance test (ASTM C-666 A method) were measured.
[0054]
(iii) Test results
As in Examples 1 to 7 in Table 1, the heating temperature is 65 to 85 ° C., the heating temperature reaching time is 8 to 15 minutes, the temperature holding time is approximately 15 to 30 minutes, and the curing time is 27 to 42. The bending strength of the cured product is [kgf / cm²], 210, 215, 204, 198, 225, 195, 220 [kgf / cm, respectively]²(That is, 20.6, 21.1, 20.0, 19.4, 22.1, 19.1, 12.6 [MPa] in terms of MPa) there were. Therefore, in Examples 1 to 7, good results were obtained in a short time. In Comparative Example 1, good performance was obtained although it took a long time. Since this comparative example 1 was shown as a comparative example because it was compared with examples 1 to 7 in which good results were obtained in a short time, it is actually one of the examples of the present invention.
[0055]
Further, in Comparative Examples 2 to 4, Comparative Example 4 in which the heating temperature arrival time was increased to 65 minutes and Comparative Example 2 in which the temperature holding time was “0” were slightly damaged Δ, and the heating temperature Comparative Example 3 in which the arrival time was shortened to 12 minutes and the temperature holding time was set to “0” and the curing time was shortened to 12 minutes was a failure X.
[0056]
As a result, the conditions of the production methods of the present invention of Examples 1 to 7 of Examples were better than those of Comparative Examples 2 to 3.
[0057]
(2). Embodiment 2
<Basic manufacturing method 2>
In Embodiment 2, the raw materials of the inorganic curable composition used for the production of the inorganic foam (inorganic cured body) are as follows. That is, as this raw material, for example, SiO₂-Al₂O_Three100 parts by weight of the system reaction inorganic powder (A), 0.2 to 150 parts by weight of the alkali metal silicate (B), and 35 to 1500 parts by weight of water (C) are used.
[0058]
Then, 0.01 to 2 parts by weight of such a raw material and foaming agent are put into the mixer 1 as shown in FIG. A paste of an inorganic curable composition (inorganic curable mixture) as a composition is obtained.
[0059]
Next, the paste of the inorganic curable composition is poured into the molding die (form frame) 3 from the material outlet 2a through the hopper 2, and the molding die 3 is vibrated for leveling and defoaming as necessary. . Thereafter, the upper open end of the mold 3 is sealed with the lid 4 as shown in FIG. Note that the upper open end of the mold 3 is not necessarily sealed with the lid 4.
[0060]
Thereafter, in order to promote foaming / curing of the inorganic curable composition 6, the inorganic curable composition 6 is heated, and the time until the heating is started is controlled. That is, the inorganic curable composition 6 after mixing is not heated immediately after mixing, but the time until heating is controlled. In this case, usually, the inorganic curable composition 6 is placed in the mold 3 and waits until the start of heating. A mixer is used as a place for storing the mixed inorganic curable composition 6 until the start of heating. It may be within 1 or another place.
[0061]
In this way, the inorganic curable composition 6 is stored for a predetermined time immediately after mixing, and is heated and foamed by heating in FIG. 1C after the predetermined time has elapsed. Thereafter, demolding is performed by taking out the foam-cured inorganic foam from the mold 3. The inorganic foam after demolding is cooled by after-curing in FIG. 1 (d) as necessary, and then dried in FIG. 1 (e) to form a base plate 7 such as an outer wall of a building.
[0062]
<Examples of inorganic foam materials>
First, an inorganic curable composition (curable inorganic composition) will be described.
[0063]
As the inorganic curable composition of this embodiment, for example, SiO₂-Al₂O_ThreeThermosetting composition containing 100 parts by weight of a reactive inorganic powder, 0.2 to 450 parts by weight of an alkali metal silicate, 35 to 1500 parts by weight of water, and 0.01 to 2 parts by weight of a blowing agent Is preferred. In addition, it is not limited to this thermosetting composition.
[0064]
[Reactive inorganic powder]
Examples of reactive inorganic powder include SiO₂: 5 to 85% by weight and Al₂O_Three: 90 to 10% by weight is preferably used.
[0065]
As such a reactive inorganic powder, fly ash, metakaolin, kaolin, mullite, corundum, dust generated when producing an alumina-based abrasive, pulverized calcined bauxite, etc. can be used. If appropriate, it is not limited to these.
[0066]
These reactive inorganic powders may be used as they are, but in order to activate them, thermal spraying treatment, pulverization classification, and mechanical energy may be applied.
[0067]
As the “thermal spraying method”, a thermal spraying technique applied to ceramic coating is applied. This thermal spraying technique is preferably one in which a thermal spray powder is melted at a temperature of 2000 to 16000 ° C. while being sprayed at a speed of 30 to 800 m / second, such as a plasma spraying method, a high energy gas spraying method, an arc spraying method, etc. Is possible. The specific surface area of the obtained powder is 0.1 to 100 m.²/ G is preferred.
[0068]
As the “classification and pulverization method”, any conventionally known method is adopted, and classification by sieving, specific gravity, wind force, wet sedimentation, etc., pulverization by a jet mill, a roll mill, a ball mill, etc. may be mentioned. These means may be used in combination.
[0069]
As the “method of action by mechanical energy”, a ball medium mill, a medium stirring mill, a roller mill or the like is used, and the mechanical energy to be applied is preferably 0.5 kwh / kg to 30 kwh / kg. If the acting mechanical energy is small, it is difficult to activate the powder, and if it is large, the load on the apparatus is large.
[0070]
The “fly ash” may be fired as necessary. If the calcination temperature of fly ash is low, the black color of fly ash remains, and if it is high, the reactivity with alkali metal silicate is low, so it is preferably 400 ° C to 1000 ° C.
[0071]
[Alkali metal silicate]
Alkali metal silicate is M₂O · nSiO₂ (M = one or more metals selected from K, Na, and Li).
[0072]
When the value of n is small, a dense foam cannot be obtained, and when it is large, the viscosity of the aqueous solution increases and mixing becomes difficult, so 0.05-8 is preferable, and 0.5-2. 5.
[0073]
The alkali metal silicate is preferably added as an aqueous solution. The aqueous solution concentration of this aqueous solution is not particularly limited, but when it is thinned, the reactivity with the reactive inorganic powder is lowered, and when it is thickened, solid content tends to be generated. Therefore, the alkali metal silicate is preferably 10 to 60% by weight.
[0074]
The alkali metal silicate aqueous solution to which this aqueous solution is added may be dissolved in water under pressure and heating as it is, but the alkali metal hydroxide aqueous solution may contain SiO, such as silica sand and silica powder.₂ The components may be dissolved under pressure and heating so that n is a predetermined amount.
[0075]
And if the quantity of an alkali metal silicate decreases, hardening will not fully be performed, but when it increases, the water resistance of the foam obtained will fall. Therefore, the amount of the alkali metal silicate is limited to 0.2 to 450 parts by weight with respect to 100 parts by weight of the reactive inorganic powder, preferably 10 to 350 parts by weight, and more preferably 20 to 250 parts by weight. is there. [water]
Water may be added as an alkali metal silicate aqueous solution or may be added independently.
[0076]
Further, when the amount of water decreases, the water does not sufficiently cure, and mixing becomes difficult. Therefore, the amount is limited to 35 to 1500 parts by weight with respect to 100 parts by weight of the reactive inorganic powder, preferably 45 to 1000 parts by weight, and more preferably 50 to 500 parts by weight.
[0077]
[Foaming agent]
Foaming agents are peroxides (hydrogen peroxide, sodium peroxide, potassium peroxide, sodium perborate, etc.), metal powders (Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga) , Sn, Si, ferrosilicon) or the like.
[0078]
If this foaming agent is too much, the foaming gas becomes excessive and breaks, and if it is too little, the foaming ratio is too small and the meaning of the foam is lost. Therefore, the foaming agent is 0.01 to 10 parts by weight.
[0079]
Further, when hydrogen peroxide is used as a foaming agent, it is preferably used as an aqueous solution in consideration of safety and stable foaming.
[0080]
And when using metal powder, in order to obtain the stable foaming, it is preferable that it is a particle size of 200 micrometers or less.
[0081]
[Foaming aid]
In this embodiment, a foaming aid may be added to the curable inorganic composition as necessary. Examples of the foaming aid include fatty acid metal salts such as zinc stearate, calcium stearate and zinc palmitate, and porous powders such as silica gel, zeolite, activated carbon and alumina powder.
[0082]
<Method of adding raw materials>
[Addition of foaming aid]
These foaming assistants such as fatty acid metal salts such as zinc stearate, calcium stearate and zinc palmitate, and porous powders such as silica gel, zeolite, activated carbon and alumina powder may be used alone or in two kinds. You may use together. The foaming aid is not particularly limited as long as foaming occurs uniformly.
[0083]
When the amount of the foaming aid increases, the viscosity of the composition increases, and foam breakage is likely to occur. Therefore, the amount of the foaming aid is preferably 10 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder.
[0084]
[Addition of inorganic filler]
In this embodiment, an inorganic filler may be added to the curable inorganic composition as necessary.
[0085]
Examples of inorganic fillers include silica sand, river sand, zircon sand, crystalline alumina, rock powder, volcanic ash, silica flour, silica fume, bentonite, blast furnace slag, and other mixed cement materials, sepiolite, wollastonite, mica, etc. Minerals, calcium carbonate, diatomaceous earth and the like can be mentioned. Each of these inorganic fillers may be added alone or in combination of two or more. The inorganic filler is not particularly limited as long as it does not dissolve in water, does not inhibit the curing reaction of the curable inorganic composition, and does not react with the alkali metal silicate.
[0086]
When the amount of the inorganic filler is increased, the strength of the obtained cured product is lowered. Therefore, the amount of the inorganic filler is preferably 700 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder.
[0087]
[Addition of reinforcing fibers]
In this embodiment, reinforcing fibers may be added to the curable inorganic composition as necessary.
[0088]
Any fiber can be used as the reinforcing fiber depending on the performance to be imparted to the molded body. For example, vinylon fiber, polyamide fiber, polyester fiber, polypropylene fiber, carbon fiber, aramid fiber, glass fiber, potassium titanate fiber, steel fiber, etc. Can be used.
[0089]
When the fiber diameter of the reinforcing fiber is reduced, the reinforcing fiber is re-aggregated at the time of mixing, and a fiber ball is easily formed by entanglement, and the finally obtained strength is not improved. Further, when the fiber diameter becomes thicker or shorter, the reinforcing effect such as improvement in tensile strength is small. And if a fiber diameter becomes long, the dispersibility and orientation of a fiber will fall. Therefore, the fiber diameter of the reinforcing fiber is preferably 1 to 500 μm and a fiber length of 1 to 15 mm.
[0090]
Moreover, the dispersibility of a fiber will fall, if the addition amount of a reinforcement fiber increases. Therefore, the addition amount is preferably 10 parts by weight or less with respect to 100 parts by weight of the reactive inorganic powder. Each of these reinforcing fibers may be added alone or in combination of two or more.
[0091]
[Other additives]
In this embodiment, alumina cement, γ-alumina, sprayed alumina, alkali metal aluminate and aluminum hydroxide may be added to the curable inorganic composition as necessary.
[0092]
[Second embodiment]
As the inorganic powder, metakaolin (SATINTONE SP 33 manufactured by Engelhard, average particle size 3.3 microns, specific surface area 13.9 m)²/ G) 100 parts by weight were used. Then, this metacaryon was mixed with 0.5 parts by weight of a mixed solution of 25 parts by weight of triethanolamine and 75 parts by weight of ethanol to act mechanical energy. In this mixing, an ultrafine mill AT-20 (Mitsubishi Heavy Industries, Ltd., using a zirconia ball diameter of 10 mm, a ball emphasis rate of 85% by volume) is applied with mechanical energy of 25 kwh / kg to obtain an inorganic powder 4. It was. The above-mentioned metakaolin used for obtaining the inorganic powder 4 is the inorganic powder 5 in Table 3. Further, the mechanical energy applied was expressed by the electric power supplied to the ball mill per unit weight of the processed powder.
[0093]
Moreover, a predetermined amount of nSiO₂/ M₂O (n = 1.5, M = K) in an autoclave at 130 ° C., 7 kgf / cm²In addition to dissolving in a predetermined amount of water, wollastonite, vinylon fiber, silica stone powder, the above-mentioned inorganic powder or metakaolin, and zinc stearate are mixed with an omni mixer to obtain a uniform paste containing an inorganic curable composition. .
[0094]
At this time, the wollastonite manufactured by Kakiuchi Co., Ltd. is used, the vinylon fiber is manufactured by Kuraray Co., Ltd., trade name: RM182 × 3, and the silica stone powder is manufactured by Masuoka Ceramics Co., Ltd., trade name: Nishiki magnetic silica sand was used, Zinc Chemical Co., Ltd., trade name: Sz-2000) was used, and an omni mixer manufactured by Chiyoda Giken Co., Ltd. was used.
[0095]
And the foaming agent was added to the above-mentioned paste obtained by mixing such raw materials, and further mixed for 2 minutes, and the raw material was made into the paste state containing the foaming agent. As this foaming agent, Si (manufactured by Kinsei Matec Co., Ltd., trade name: # 600) was used.
[0096]
The blending of each raw material in the paste of such an inorganic foam curable mixture is shown in Tables 2 and 3 below.
[0097]
[Table 2]

[Table 3]

After pouring the paste obtained by blending the raw materials in Tables 2 and 3 into a mold (form frame), the upper open end of the mold is closed with a lid, and after time T1 from the end of mixing, Heating was started. And it heated in 65 degreeC vapor | steam, and it foamed and hardened and obtained the inorganic foam.
[0098]
This inorganic foam was evaluated under the conditions shown in Tables 4 and 5 below. The time T1 from the end of mixing to the start of heating in the formulations shown in Table 2 is as shown in Table 4 (Examples 1 to 7, and Comparative Examples 1 and 2), and from the end of mixing to the start of heating in the formulations shown in Table 3. The time T1 is as shown in Table 5 (Examples 8 to 12 and Comparative Examples 3 and 4).
[0099]
[Table 4]

[Table 5]

The foamability, water absorption rate, strength maintenance rate, etc. in Tables 4 and 5 were observed, measured and tested according to the criteria described in the following (i) to (iii). That is,
(i) Cell foam
The obtained inorganic foam was judged by observing the cut surface with a microscope. As a result of the judgment, it was evaluated as ◯ if the foamability was good, x if it was poor, and △ if it was between good and bad. .
[0100]
(ii) Water absorption
The weight G1 was measured after a 12 × 12 × 3 (cm) sample was immersed in water for 10 days, and then the weight when the sample was dried in an oven at 105 ° C. for 24 hours was measured for G2. The value of {(G1-G2) / G2} × 100 was taken as the water absorption after 10 days.
[0101]
(iii) Strength maintenance rate after durability test (%)
The obtained inorganic foam was subjected to a compression test (JIS A 1108) before a freeze-thaw test (JIS A 1435 in-water frozen water melt test) as a durability test, and then a freeze-thaw test. The value obtained by dividing the compressive strength after the freeze-thaw test by the compressive strength before the freeze-thaw test and multiplying by 100 is shown in the table as the strength maintenance ratio.
[0102]
According to Table 4 above, the time T1 from the end of mixing the raw materials (materials) to the start of heating is 90 minutes, 60 minutes, 50 minutes, 40 minutes, 30 minutes, and 20 minutes in Examples 1 to 7, respectively. , 10 minutes, all the foam properties were good “◯”. Also, the water absorption was 39 for 10 minutes, 36 for 30 minutes, 35 for 30 minutes, 35 for 40 minutes, 32 for 50 minutes, 31 for 60 minutes, and 28 for 90 minutes. Furthermore, the strength maintenance rate after the durability test was 100% in both Examples 1 to 7.
[0103]
On the other hand, in Comparative Example 1, when the time T1 from the end of mixing of the raw materials (materials) to the start of heating was 5 minutes, the closed cell property was “Δ” between poor and good. Further, in Comparative Example 2, when the time T1 from the end of mixing the raw materials (materials) to the start of heating was set to 1 minute, that is, when heated immediately after the end of mixing, the foamability was poor “x”. .
[0104]
Moreover, in Comparative Example 2, the water absorption was as high as 45 as compared with 28 to 39 in Examples 1 to 7. Furthermore, in Comparative Example 1 and Comparative Example 2, the strength retention after the durability test was 90% and 83% lower than 100% of Examples 1 to 7, respectively.
[0105]
According to Table 5 above, the time T1 from the end of mixing the raw materials (materials) to the start of heating was changed to 50 minutes, 40 minutes, 30 minutes, 20 minutes, and 10 minutes in Examples 8 to 12, respectively. In this case, the cell foaming property was “good”. Also, the water absorption was 31 at 10 minutes, 30 at 20 minutes, 28 at 30 minutes, 26 at 40 minutes, and 25 at 50 minutes. Furthermore, the strength maintenance rate after the durability test was 100% in all of Examples 8 to 12.
[0106]
On the other hand, in Comparative Example 3, when the time T1 from the end of mixing of the raw materials (materials) to the start of heating was 5 minutes, the self-foaming property was “△” between good and bad. Further, in Comparative Example 4, when the time T1 from the end of mixing the raw materials (materials) to the start of heating was set to 1 minute, that is, when heating was performed immediately after the end of mixing, the result was “×” indicating poor foamability. In Comparative Example 3 and Comparative Example 4, the water absorption was 35 and 39 higher than those in Examples 8 to 12, respectively. Furthermore, in Comparative Example 3 and Comparative Example 4, the strength maintenance rate after the durability test was as low as 95% and 90% with respect to 100% in Examples 8 to 12, respectively.
[0107]
【The invention's effect】
As described above, the invention according to claim 1 is made of SiO.₂-Al₂O_ThreeIn the method for producing an inorganic cured body by heating an inorganic curable composition composed of an inorganic inorganic powder, an alkali metal silicate, and water, after mixing the raw materials of the inorganic curable composition, the inorganic curable composition Since the time until the heating of the product is started is controlled, the inorganic hardened body can be given sufficient strength in a short time by starting the temperature rise after mixing.
[0108]
In the invention of claim 2, since the temperature rise is started after mixing the inorganic curable composition, and heated to 60 ° C. or more in a time of 20 minutes or less after the temperature rise start, Sufficient strength can be given in a short time.
[0109]
According to the invention of claim 3, since the inorganic curable composition is held at a temperature of 60 ° C. or more for 10 minutes or more after the start of temperature increase, the strength can be further increased.
[0110]
Furthermore, in the invention of claim 4, since the inorganic curable composition is mixed as a foamable inorganic curable composition, heating is started after 7 minutes.
A highly durable inorganic foam in which closed cells are generated in a short time can be obtained as an inorganic cured body.
[0111]
In the invention of claim 5, the inorganic curable composition is made of SiO.₂-Al₂O_ThreeSince the composition is composed of 100 parts by weight of inorganic inorganic powder, 0.2 to 450 parts by weight of alkali metal silicate, and 35 to 1500 parts by weight of water, it is preferable to give the inorganic cured body sufficient strength in a short time.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a system for producing an inorganic cured body.
FIG. 2 is a characteristic curve diagram showing the relationship between heating temperature and DSC and time based on examples and comparative examples.
[Explanation of symbols]
1 ... Mixer
2 ... Hopper
3 ... Mold
4 ... Lid
5 ... Cooling and drying device
A ... Reactive inorganic powder
B ... Alkali metal silicate
C ... Water

Claims (2)

In a method for producing an inorganic cured body by heating an inorganic curable composition comprising an SiO ₂ -Al ₂ O ₃ inorganic powder, an alkali metal silicate, and water,
After mixing the raw materials of the inorganic curable composition, the temperature starts to be raised, heated to 60 ° C. or higher for 20 minutes or less after the temperature rising starts, and then held at a temperature of 60 ° C. or higher for 10 minutes or longer and within 30 minutes. The manufacturing method of the inorganic hardened | cured material characterized by doing. The inorganic curable composition includes the SiO ₂ -Al ₂ O _Three The method for producing an inorganic cured body according to claim 1, wherein the inorganic inorganic powder is 100 parts by weight, the alkali metal silicate is 0.2 to 450 parts by weight, and the water is 35 to 1500 parts by weight.

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