JP3786291B2

JP3786291B2 - Calcium silicate plate manufacturing method

Info

Publication number: JP3786291B2
Application number: JP16995195A
Authority: JP
Inventors: 正人崎山; 琢也浅見; 朋来岩永; 正章小田
Original assignee: A&A Material Corp
Current assignee: A&A Material Corp
Priority date: 1995-07-05
Filing date: 1995-07-05
Publication date: 2006-06-14
Anticipated expiration: 2015-07-05
Also published as: JPH0920576A

Description

【０００１】
【発明の属する技術分野】
本発明は、珪酸カルシウム板の製造方法に関し、更に詳細には軽量（例えば嵩比重１．０以下）珪酸カルシウム板の製造方法に関する。
【０００２】
【従来の技術・課題】
従来、珪酸カルシウム板は、軽量で、優れた加工性及び寸法安定性をもち、更に不燃性であるという特徴を有し、建築材料として主として内装用に広く使用されている。このような珪酸カルシウム板の成形法として、抄造法、プレスモールド法及び単層成形法などが利用され、石灰質原料、珪酸質原料、無機質充填剤を含有してなる原料スラリーから成形された成形体を、通常は圧力容器内で飽和水蒸気により反応硬化することにより珪酸カルシウム板が製造されている。
【０００３】
しかし、特に抄造法において、軽量珪酸カルシウム板を製造する場合には、水熱反応前の成形体の層間強度が弱く、また、含有水分量が多いため、水熱反応中に余剰水の熱膨張が生じたり、蒸気圧が高くなり、層間剥離やパンクといった問題を生ずることがある。
【０００４】
これらの問題を防止するために、成形後にプレスを行い、その後に水熱反応を行ったり、水熱反応中にターンバックルを用いて締め付けるという方法が行われているが、これらの方法を講ずると嵩比重が高くなったり、製造に人手が掛かるといった欠点があった。
【０００５】
また、特開平６−２８７０８３号公報に示されている余剰水の除去方法もあるが、特殊な容器あるいは蒸気の過熱器を必要とするため一般的な方法とは言えない。
【０００６】
更に、本発明者らは、既に特願平６−323225号及び特願平７−5013号に、珪酸質原料の一部として石灰質原料との反応性が良い非晶質珪酸原料や珪酸塩原料を用いたり、ポルトランドセメントや高炉水砕スラグといった硬化剤を添加する方法を提案しているが、高価な原料を使用したり、嵩比重を高くするといった欠点がある。
【０００７】
従って、本発明の目的は、非晶質珪酸原料や珪酸塩原料あるいはポルトランドセメントや高炉水砕スラグといった硬化剤を添加しないでも、II型無水石膏を用いることにより水熱反応前の成形体(グリーンシート)の強度及び層間強度を向上し、水熱反応中に層間剥離やパンクを生ずることがない軽量珪酸カルシウム板の製造方法及び該方法により得られた珪酸カルシウム板を提供することにある。
【０００８】
【課題を解決するための手段】
即ち、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られる成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、原料スラリーがII型無水石膏を固形分として５〜３０重量％及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【０００９】
また、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られた成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうち少なくとも一方がII型無水石膏を固形分として５〜３０重量％及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【００１０】
更に、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られた成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、抄造機のリターンロールとメーキングロールの間の抄造フィルム上に、ＩＩ型無水石膏とＩＩ型無水石膏に対して外割で０．５〜５重量％の硬化促進剤を含有してなるスラリーをＩＩ型無水石膏として１０〜５０ｇ／ｍ^２の割合で散布しながら積層して所定の厚さに積層後、抄造により得られた成形体を１次養生することによりＩＩ型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【００１１】
また、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られた成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうちのどちらか一方が固形分としてII型無水石膏９２〜９８重量％、繊維質原料２〜８重量％及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、該スラリーによる抄造厚を丸網式抄造機のフェルトが一周する間に抄造される全抄造厚の１〜１０％とし、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【００１２】
更に、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られた成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうちのどちらか一方が固形分としてII型無水石膏３０重量％超え９８重量％未満、繊維質原料２〜８重量％、石灰質原料及び無機質充填剤からなる群から選択される１種または２種以上の成分を５８重量％以下及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、該スラリーによる抄造厚を丸網式抄造機のフェルトが一周する間に抄造される全抄造厚の１〜１０％とし、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【００１３】
また、本発明は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる原料スラリーを抄造法により積層して得られる成形体を、圧力容器中で水熱反応させることからなる珪酸カルシウム板の製造方法において、原料スラリーがＩＩ型無水石膏を固形分として５〜３０重量％含有してなり、且つ抄造機のリターンロールとメーキングロールの間の抄造フィルム上に、固形分濃度５〜１５重量％の硬化促進剤溶液を固形分換算量１〜５ｇ／ｍ^２の割合で散布しながら積層して所定の厚さに積層後、抄造により得られた成形体を１次養生することによりＩＩ型無水石膏を水和させ、次に、水熱反応を行うことを特徴とする軽量珪酸カルシウム板の製造方法に係る。
【００１５】
【発明の実施の形態】
本発明の軽量珪酸カルシウム板（以下、単に「珪酸カルシウム板」と記載する）の製造方法に使用される原料スラリーの基本組成は、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％及び無機質充填剤５〜３０重量％を含有してなる慣用のものである。
【００１６】
ここで、石灰質原料としては、例えば消石灰、生石灰などを使用することができる。なお、石灰質原料の配合量が１７重量％未満であったり、５０重量％を超えると曲げ強度が低く、吸水による寸法変化率が大きくなるために好ましくない。
【００１７】
また、珪酸質原料としては例えば珪砂、珪藻土、フライアッシュ等を使用することができる。なお、珪素質原料の配合量が１５重量％未満であったり、４５重量％を超えると曲げ強度が低く、吸水による寸法変化率が大きくなるために好ましくない。
【００１８】
また、石灰質原料と珪酸質原料については、上記割合のうち、石灰質原料２〜２０重量％と珪酸質原料３〜２５重量％を予めゲル化して使用することができる。ゲル化条件の例としては、７５〜９０℃の温度で１.５〜４時間が挙げられる。
【００１９】
更に、繊維質原料としては、例えばセルロース繊維、ポリプロピレン、ビニロン、ガラスファイバー、カーボンファイバー等を使用することができる。なお、繊維質原料の配合量が２重量％未満であると、曲げ強度が低くなるために好ましくなく、８重量％を超えると不燃性でなくなるために好ましくない。また、ポリプロピレン、ビニロン、ガラスファイバー、カーボンファイバー等を使用する場合、それらの配合量は５重量％以下とすることが好ましい。
【００２０】
また、無機質充填剤としては、例えばパーライト、ウォラストナイト、マイカ、タルク、炭酸カルシウム、２水石膏などを使用することができる。なお、無機質充填剤の配合量が５重量％未満であると、吸水による寸法変化率が大きくなるために好ましくなく、３０重量％を超えると曲げ強度が低下するために好ましくない。
【００２１】
本発明の特徴は、珪酸カルシウム板の製造方法としての以下の６つの方法である：
本発明の第１発明に係る製造方法によれば、上述のような成分配合を有する原料スラリーにII型無水石膏を５〜３０重量％及びII型無水石膏に対し外割で０.５〜５重量％の硬化促進剤を含有させ、この原料スラリーを抄造法により積層して成形し、次に、得られた成形体を１次養生することによりII型無水石膏を水和させたのち、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００２２】
なお、本発明に使用するII型無水石膏は、１０００〜９０００ｃｍ²／ｇ、好ましくは３０００〜８０００ｃｍ²／ｇの範囲内の比表面積を有するものが好ましい。II型無水石膏の比表面積が１０００ｃｍ²／ｇ未満では、初期水和反応が遅く、また、抄造時に沈降が速くなり、配合割合通りの抄き上げが困難となるために好ましくない。また、比表面積が８０００ｃｍ³／ｇを超えても、比表面積の増加に見合うII型無水石膏の水和速度が増加が得られず、逆に、抄造時の濾水性低下、抄造フィルムあるいはグリーンシートのしわ等の原因となるために好ましくない。
【００２３】
即ち、第１発明で使用する原料スラリーは、固形分として石灰質原料１７〜５０重量％、珪酸質原料１５〜４５重量％、繊維質原料２〜８重量％、II型無水石膏５〜３０重量％、無機質充填剤５〜３０重量％、及びII型無水石膏に対し外割で０.５〜５重量％の硬化促進剤を含有してなるものである。ここで、II型無水石膏の配合量が５重量％未満であると、グリーンシートの層間強度の発現性が悪いために好ましくなく、３０重量％を超えるとそれに伴い使用する硬化促進剤の使用量も増え、原料費が高くなり、また、曲げ強度が低くなるために好ましくない。なお、II型無水石膏の配合量は１０〜２０重量％が好ましい。
【００２４】
なお、II型無水石膏をスラリー状態で使用する場合、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。ここで、硬化促進剤の配合量がII型無水石膏に対して外割で０.５重量％未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤の配合量が５重量％を超えると、スラリーを抄造する前に水和が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくなく、更に、硬化促進剤の添加量が多くなると、成形体表面への硬化促進剤成分の析出による、シミ、色むらや、水熱反応器内の金属腐食等の原因となるために好ましくない。即ち、II型無水石膏に対して０.５〜５重量％の硬化促進剤を配合することにより、II型無水石膏の水和反応をスラリー調製後約１０〜２０時間程度で完了することができので、スラリー調製後約６〜１５時間の間にグリーンシートの作製を完了すれば本発明の効果を得ることができる。
【００２５】
次に、本発明の第２発明に係る製造方法によれば、上述のような成分配合を有する原料スラリーを抄造法により積層して成形するにあたり、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうち少なくとも一方がII型無水石膏を固形分として５〜３０重量％及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００２６】
即ち、第２発明においては、上記第１発明に使用する原料スラリーと同一組成のスラリーを丸網式抄造機の１番目及び／または最後の抄箱のスラリーとして使用するものである。ここで、１番目及び／または最後の抄箱に使用するスラリー中のII型無水石膏の配合量が固形分として５重量％未満であると、グリーンシートの層間強度の発現性が悪いために好ましくなく、また、３０重量％を超えるとそれに伴い使用する凝結遅延剤の使用量も増え、原料費が高くなり、また、曲げ強度が低くなるために好ましくない。
【００２７】
なお、II型無水石膏をスラリー状態で使用する場合、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。ここで、硬化促進剤の配合量がII型無水石膏に対して外割で０.５重量％未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤の配合量が５重量％を超えると、スラリーを抄造する前に水和が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくない。即ち、II型無水石膏に対して０.５〜５重量％の硬化促進剤を配合することにより、II型無水石膏の水和反応をスラリー調製後約１０〜２０時間程度で完了することができので、スラリー調製後約６〜１５時間の間にグリーンシートの作製を完了すれば本発明の効果を得ることができる。
【００２８】
本発明の第２発明によれば、基本配合の原料スラリーに、更にII型無水石膏及び硬化促進剤を添加してなるスラリーを丸網式抄造機の１番目及び／または最後の抄箱へ入れ、抄造法により積層して成形する。このスラリーの抄造機の１番目及び／または最後の抄箱への入れ方は、特に限定されるものではなく、例えば他の抄箱と配合割合の異なるスラリーを作製し、専用のチェストから送っても良いし、チェストと抄箱の間の樋で、II型無水石膏及び硬化促進剤それぞれのスラリーを他のスラリーに添加しても良い。
【００２９】
次に、本発明の第３発明に係る製造方法によれば、上述のような基本組成を有する原料スラリーを抄造法により積層して成形するにあたり、抄造機のリターンロールとメーキングロールの間の抄造フィルム上に、ＩＩ型無水石膏とＩＩ型無水石膏に対して外割で０．５〜５重量％の硬化促進剤を含有してなるスラリーをＩＩ型無水石膏として１０〜５０ｇ／ｍ^２の割合で散布しながら積層して所定の厚さに積層後、抄造により得られた成形体を１次養生することによりＩＩ型無水石膏を水和させ、次に、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００３０】
ここで、II型無水石膏の散布量が固形分換算で１０ｇ／ｍ²未満では層間強度の発現性が悪いために好ましくなく、また、II型無水石膏の散布量が５０ｇ／ｍ²を超えるとII型無水石膏の層ができ、乾燥時にクラックが入ったり、曲げ強度が低くなるために好ましくない。
【００３１】
なお、本発明の第３発明に使用可能な丸網式抄造機の一例を図１に示す。この丸網式抄造機によれば、抄箱(6)中に設けられた丸網シリンダー(8)によりスラリー(7)を抄き上げフェルト(3)に転写し、この操作を抄箱(丸網シリンダー)の数だけ反復して抄造フィルム(4)とし、更に、この抄造フィルム(4)をメーキングロール(1)で所定の厚さまで所定回数巻き付けた後切断することにより、グリーンシートを得ることができる。一般に、層間剥離やパンクは、メーキングロール(1)で重ね合わせたフィルム間で起こるため、リターンロール(2)とメーキングロール(1)の間に散布装置(5)を設置してII型無水石膏及び硬化促進剤よりなる散布用スラリーを散布することにより、上記フィルム間の密着力(層間強度)を向上することにより層間剥離やパンクを防止することができる。
【００３２】
なお、散布用スラリーにてII型無水石膏を散布する場合にも、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。ここで、硬化促進剤の配合量がII型無水石膏に対して外割で０.５重量％未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤の配合量が５重量％を超えると、スラリーを抄造する前に水和が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくない。即ち、II型無水石膏に対して０.５〜５重量％の硬化促進剤を配合することにより、II型無水石膏の水和反応をスラリー調製後約１０〜２０時間程度で完了することができので、スラリー調製後約６〜１５時間の間にグリーンシートの作製を完了すれば本発明の効果を得ることができる。
【００３３】
次に、本発明の第４発明に係る製造方法によれば、上述のような基本組成を有する原料スラリーを抄造法により積層して成形するにあたり、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうちのどちらか一方が固形分としてII型無水石膏９２〜９８重量％、繊維質原料２〜８重量％及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、該スラリーによる抄造厚を丸網式抄造機のフェルトが一周する間に抄造される全抄造厚の１〜１０％、好ましくは１〜５％とし、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００３４】
ここで、前記スラリーによる抄造厚が１％未満では、層間強度の発現性が悪いために剥離が起こり易く好ましくない。また、II型無水石膏の含有量が９２〜９８重量％と高含量であるスラリーを使用する場合に、抄造厚が１０％を超えるとII型無水石膏の層が厚くなり、水熱反応後の曲げ強度が低下するために好ましくない。
【００３５】
また、繊維質原料としては、セルロース繊維等を用いることができる。なお、II型無水石膏の配合割合が９８重量％を超えると繊維質原料の配合割合が少なくなり、抄造時に粉体ロスが多くなるために好ましくない。また、繊維質原料の配合割合が８重量％を超えると、繊維質原料の層ができ、剥離し易くなるために好ましくない。
【００３６】
なお、II型無水石膏をスラリー状態で使用する場合、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。ここで、硬化促進剤の配合量がII型無水石膏に対して外割で０.５重量％未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤の配合量が５重量％を超えると、スラリーを抄造する前に水和が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくない。即ち、II型無水石膏に対して０.５〜５重量％の硬化促進剤を配合することにより、II型無水石膏の水和反応をスラリー調製後約１０〜２０時間程度で完了することができので、スラリー調製後約６〜１５時間の間にグリーンシートの作製を完了すれば本発明の効果を得ることができる。
【００３７】
II型無水石膏をスラリー状態で使用する場合、このスラリーの濃度は、他の抄箱の原料スラリーの濃度と同一か、またはそれ以下とするのが好ましく、固形分濃度で１〜１０％、好ましくは３〜７％とするのが好ましい。ただし、丸網へのスラリー固形分の乗り量のロスをできるだけ少なくするように調節するために、抄箱内のスラリー水位を下げたり、シリンダーメッシュを適当な大きさに変更することが必要な場合もある。
【００３８】
次に、本発明の第５発明に係る製造方法によれば、上述のような基本組成を有する原料スラリーを抄造法により積層して成形するにあたり、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうちのどちらか一方が固形分としてII型無水石膏３０重量％超え９８重量％未満、繊維質原料２〜８重量％、石灰質原料及び無機質充填剤からなる群から選択される１種または２種以上の成分を６８重量％以下、及びII型無水石膏に対して外割で０.５〜５重量％の硬化促進剤を含有してなり、該スラリーによる抄造厚を丸網式抄造機のフェルトが一周する間に抄造される全抄造厚の１〜１０％、好ましくは１〜５％とし、抄造により得られた成形体を１次養生することによりII型無水石膏を水和させ、次に、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００３９】
該スラリーによる抄造厚が１％未満では、層間強度の発現性が悪いため剥離が起こり易く好ましくない。また、II型無水石膏の含有量が３０重量％超え９８重量％未満と比較的高含量であるスラリーを使用する場合にも、抄造厚が１０％を超えるとII型無水石膏の層が厚くなり、水熱反応後の曲げ強度が低下する傾向があるために好ましくない。
【００４０】
繊維質原料としては、セルロース繊維等を用いることができる。石灰質原料としては、例えば消石灰、生石灰等を使用することができる。更に、無機質充填剤としては、例えばパーライト、ウォラストナイト、マイカ、タルク、炭酸カルシウム、珪砂、２水石膏等を使用することができる。この石灰質原料及び無機質充填剤からなる群から選択された１種または２種以上を配合することにより、層間強度を維持しつつ、珪酸カルシウム板の原料コストを低下させることができる。II型無水石膏の配合割合が９８重量％を超えると繊維質原料の配合割合が少なくなり、粉体のロスが多くなるために好ましくなく、また、II型無水石膏の配合割合が３０重量％以下の場合には、丸網式抄造機の１番目及び最後の抄箱に入れるスラリーのうちのどちらか一方のみのスラリーにII型無水石膏を配合する場合には配合効果が顕著に現れないために好ましくない。繊維質原料の配合割合が８重量％を超えると繊維質原料の層ができ剥離し易くなるために好ましくない。更に、石灰質原料及び／または無機質充填剤の配合割合が６８重量％を超えるとそれに伴ってII型無水石膏や繊維質原料を充分に配合することができないために好ましくない。
【００４１】
なお、II型無水石膏をスラリー状態で使用する場合、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。ここで、硬化促進剤の配合量がII型無水石膏に対して外割で０.５重量％未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤の配合量が５重量％を超えると、スラリーを抄造する前に水和が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくない。即ち、II型無水石膏に対して０.５〜５重量％の硬化促進剤を配合することにより、II型無水石膏の水和反応をスラリー調製後約１０〜２０時間程度で完了することができので、スラリー調製後約６〜１５時間の間にグリーンシートの作製を完了すれば本発明の効果を得ることができる。
【００４２】
上記スラリーの濃度は、他の抄箱の原料スラリーの濃度と同一か、またはそれ以下とするのが好ましく、固形分濃度で１〜１０％、好ましくは３〜７％とするのが好ましい。ただし、丸網へのスラリー固形分の乗り量のロスをできるだけ少なくするように調節するために、抄箱内のスラリー水位を下げたり、シリンダーメッシュを適当な大きさに変更することが必要な場合もある。
【００４３】
次に、本発明の第６発明に係る製造方法によれば、上述のような成分配合を有する原料スラリーにＩＩ型無水石膏５〜３０重量％を含有させ、且つ抄造機のリターンロールとメーキングロールの間の抄造フィルム上に、固形分濃度５〜１５重量％の硬化促進剤溶液を固形分換算量１〜５ｇ／ｍ^２の割合で散布しながら積層して所定の厚さに積層後、抄造により得られた成形体を１次養生することによりＩＩ型無水石膏を水和させ、次に、水熱反応を行うことにより珪酸カルシウム板を製造することができる。
【００４４】
ここで、II型無水石膏の配合量が５重量％未満であると、グリーンシートの層間強度の発現性が悪いために好ましくなく、３０重量％を超えるとそれに伴い使用する硬化促進剤の使用量も増え、原料費が高くなり、また、曲げ強度が低くなるために好ましくない。なお、II型無水石膏の配合量は１０〜２０重量％が好ましい。
【００４５】
なお、II型無水石膏をスラリー状態で使用する場合、II型無水石膏の水和反応が発現しないため、硬化促進剤の原料スラリーへの添加が必須となる。本発明の第６発明においては、硬化促進剤を溶液として抄造機のリターンロールとメーキングロールの間の抄造フィルム上に、散布しながら積層するところに特徴がある。散布用の硬化促進剤溶液の濃度は２〜１５重量％の範囲が好ましい。ここで、硬化促進剤溶液の濃度が２重量％未満の場合には硬化促進剤の添加効果が少ないために好ましくなく、また、該濃度が１５重量％を超えると散布量が少なくなり、均一な散布がしにくくなるために好ましくなく。また、硬化促進剤溶液の散布量は、固形分換算量で１〜５ｇ／ｍ²の範囲内である。硬化促進剤溶液の散布量が１ｇ／ｃｍ²未満であると、硬化促進効果を発現できず原料スラリーを抄造してもなかなか水和反応が完了せず、抄造後、成形体中のII型無水石膏を水和するための１次養生に非常に時間が掛かり、充分な水和を行うことができず、また、成形体強度も弱くなるために好ましくない。また、硬化促進剤溶液の散布量が５ｇ／ｍ²を超えると、抄造工程が終了する前に水和反応が完了してしまい、グリーンシートの層間強度の発現に寄与しないために好ましくなく、更に、硬化促進剤の添加量が多くなると、成形体表面への硬化促進剤成分の析出による、シミ、色むらや、水熱反応器内の金属腐食等の原因となるために好ましくない。即ち、抄造フィルム上に５〜１５重量％濃度の硬化促進剤溶液を１〜５ｇ／ｍ²の量で散布することにより、II型無水石膏の水和反応を抄造工程後約１０〜２０時間程度で完了することができる。なお、本発明の第６発明もまた図１に示す丸網式抄造機を使用して実施することができる。
【００４６】
本発明に使用する硬化促進剤は特に限定されるものではなく、アルカリ金属硫酸塩(例えばＫ₂ＳＯ₄、Ｎａ₂ＳＯ₄等)、アルミニウム硫酸塩及びミョウバン類［例えばＡｌ₂(ＳＯ₄)₃、ＫＡｌ(ＳＯ₄)₂・１２Ｈ₂Ｏ、ＮａＡｌ(ＳＯ₄)₂・１２Ｈ₂Ｏ、ＮＨ₄Ａｌ(ＳＯ₄)₂・１２Ｈ₂Ｏ等］等の公知のものを単独あるいは併用して用いることができる。
【００４７】
抄造により得られた成形体は、１次養生によりII型無水石膏の水和反応を行った後、水熱反応を行う。１次養生の条件は特に限定されるものではなく、II無水石膏が水和反応する慣用の条件、好ましくは２０〜６０℃で３時間以上の時間にわたり行うことができる。
【００４８】
上述のような１次養生を行った後の成形体は、慣用の水熱反応条件下で水和反応させ、その後の慣用の工程を経て珪酸カルシウム板とすることができる。なお、水熱反応は、圧力容器中、飽和水蒸気圧下で温度１５０〜２００℃、好ましくは１７０〜１９０℃で５〜２０時間、好ましくは８〜１２時間の条件で行うことができる。
【００４９】
上述のような本発明の第１発明ないし第６発明に係る製造方法により製造された珪酸カルシウム板は、層間剥離強度が曲げ強度(絶乾状態)の３％以上と非常に優れた値を示すものとなる。なお、曲げ強度は、ＪＩＳＡ５４１８に準じて３号試験片で試験した結果であり、層間剥離強度試験は３０×３０ｍｍで行った結果である。
【００５０】
【実施例】
実施例１
表１に示す割合で原料を配合し、１２倍の水で撹拌、混合した。なお、ゲルは消石灰１０重量％、珪藻土１０重量％(重量比１：１)を９０℃、２時間の条件で合成した。更に、水を加えて固形分濃度約３重量％の原料スラリーとし、６ｍｍの厚さに抄造した。なお、本例においては、硬化促進剤として硫酸カリウムを使用した。
次に、湿空雰囲気中、３０℃で８時間にわたり１次養生を行った後、圧力容器中、飽和水蒸気下１８０℃、１０時間の条件で水熱反応を行った。
表１に水熱反応後の嵩比重、曲げ強度並びに層間剥離強度(共に絶乾状態)を示す。
【００５１】
【表１】

【００５２】
実施例２
表２に示す割合で原料を配合し、１２倍の水で撹拌、混合した。なお、ゲルは消石灰１０重量％、珪藻土１０重量％(重量比１：１)を９０℃、２時間の条件で合成した。更に、水を加えて固形分濃度約３重量％の原料スラリーとした。また、１番目または最後の抄箱は、別に調製した固形分濃度１０重量％のII型無水石膏及び硬化促進剤を含有してなるスラリーとし、６ｍｍの厚さに抄造した。なお、本例において、硬化促進剤として硫酸カリウムを使用した。
次に、湿空雰囲気中、３０℃で８時間の１次養生を行った後、圧力容器中、飽和水蒸気下１８０℃、１０時間の条件で水熱反応を行った。
表２に水熱反応後の嵩比重、曲げ強度並びに層間剥離強度(共に絶乾状態)を示す。
【００５３】
【表２】

【００５４】
実施例３
表３に示す割合で原料を配合し、１２倍の水で撹拌、混合した。なお、ゲルは消石灰１０重量％、珪藻土１０重量％(重量比１：１)を９０℃、２時間の条件で合成した。更に、水を加えて、固形分濃度約３重量％の原料スラリーとし、６ｍｍの厚さに抄造した。抄造にあたり、リターンロールとメーキングロールの間の抄造フィルム上に、表３に示す量のII型無水石膏と硬化促進剤とのスラリーとして散布した。散布スラリー濃度は、固形分濃度１０重量％とした。なお、本例において、硬化促進剤としては硫酸カリウムを使用した。
次に、湿空雰囲気中、３０℃で８時間の１次養生を行った後、圧力容器中、飽和水蒸気下１８０℃、１０時間の条件で水熱反応を行った。
表３に水熱反応後の嵩比重、曲げ強度並びに層間剥離強度(共に絶乾状態)を示す。
【００５５】
【表３】

【００５６】
実施例４
表４に示す割合で原料を配合し、１２倍の水で撹拌、混合した。なお、ゲルは消石灰１０重量％、珪藻土１０重量％(重量比１：１)を９０℃、２時間の条件で合成した。更に、水を加えて、固形分濃度約３重量％の原料スラリーとした。また、１番目の抄箱あるいは最後の抄箱も同様に配合、混合して固形分濃度約２重量％の原料スラリーとし、６ｍｍの厚さに抄造した。なお、本例において、硬化促進剤として硫酸カリウムを使用した。
次に、湿空雰囲気中、３０℃で８時間の１次養生を行った後、圧力容器中、飽和水蒸気下で１８０℃、１０時間の条件で水熱反応を行った。
表４に水熱反応後の嵩比重、曲げ強度並びに層間剥離強度(共に絶乾状態)を示す。
【００５７】
【表４】

【００５８】
表５に示す割合で原料を配合し、１２倍の水で撹拌、混合した。なお、ゲルは消石灰１０重量％、珪藻土１０重量％(重量比１：１)を９０℃、２時間の条件で合成した。更に、水を加えて、固形分濃度約３重量％の原料スラリーとし、６ｍｍの厚さに抄造した。この際、抄造機のリターンロールとメーキングロールの間のフェルト上で、固形分濃度２重量％の硫酸カリウム溶液を硬化促進剤溶液として散布した。
次に、湿空雰囲気中、３０℃で８時間の１次養生を行った後、圧力容器中、飽和水蒸気下で１８０℃、１０時間の条件で水熱反応を行った。
表５に水熱反応後の嵩比重、曲げ強度並びに層間剥離強度(共に絶乾状態)を示す。
【００５９】
【表５】

【００６０】
【発明の効果】
以上のように、本発明の珪酸カルシウム板の製造方法を用い、原料スラリーを抄造法により成形すれば、水熱反応前の成形体の強度及び層間強度を向上することができ、それによって水熱反応中の成形体の剥離、パンクを防止すると共に、得られる珪酸カルシウム板の層間剥離強度を向上させることができるという効果を奏するものである。
【図面の簡単な説明】
【図１】本発明の第３発明に使用可能な丸網式抄造機の一例を示す図である。
【符号の説明】
１メーキングロール
２リターンロール
３フェルト
４抄造フィルム
５散布装置
６抄箱
７原料スラリー
８丸網シリンダー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a calcium silicate plate, and more particularly to a method for manufacturing a lightweight (for example, bulk specific gravity of 1.0 or less) calcium silicate plate .
[0002]
[Conventional technologies and issues]
Conventionally, calcium silicate plates are lightweight, have excellent workability and dimensional stability, and are non-flammable, and are widely used mainly as interior materials for interiors. As a forming method of such a calcium silicate plate, a papermaking method, a press mold method, a single layer forming method, etc. are utilized, and a formed body formed from a raw material slurry containing a calcareous raw material, a siliceous raw material, and an inorganic filler. In general, a calcium silicate plate is produced by reaction hardening with saturated steam in a pressure vessel.
[0003]
However, especially in the papermaking method, when manufacturing a lightweight calcium silicate plate, the interlaminar strength of the molded body before the hydrothermal reaction is weak and the water content is high, so the thermal expansion of excess water during the hydrothermal reaction. May occur, the vapor pressure may increase, and problems such as delamination and puncture may occur.
[0004]
In order to prevent these problems, a method of performing pressing after molding and then performing a hydrothermal reaction or tightening with a turnbuckle during the hydrothermal reaction is performed, but when these methods are taken There were drawbacks such as high bulk specific gravity and man-hours for production.
[0005]
There is also a method of removing excess water are disclosed in JP-A-6 -287083, but not be a general method requires a superheater special container or steam.
[0006]
Furthermore, the present inventors have already disclosed in Japanese Patent Application No. 6-323225 and Japanese Patent Application No. 7-5013 an amorphous silicic acid raw material and a silicate raw material which have good reactivity with a calcareous raw material as part of the siliceous raw material. Or a method of adding a curing agent such as Portland cement or granulated blast furnace slag has been proposed, but there are drawbacks such as using expensive raw materials and increasing the bulk specific gravity.
[0007]
Therefore, the object of the present invention is to use a type II anhydrous gypsum before the hydrothermal reaction (green) without adding a curing agent such as amorphous silicate raw material, silicate raw material, Portland cement or granulated blast furnace slag. It is an object of the present invention to provide a lightweight calcium silicate plate production method and a calcium silicate plate obtained by the method, which improve the strength of the sheet) and interlayer strength, and do not cause delamination or puncture during hydrothermal reaction.
[0008]
[Means for Solving the Problems]
That is, the present invention is a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. In the method for producing a calcium silicate plate, which is obtained by laminating a molded body obtained by laminating a sheet by a papermaking method in a pressure vessel, the raw material slurry has a solid content of type II anhydrous gypsum in an amount of 5 to 30% by weight and II Type II anhydrous gypsum is hydrated by primary curing of the molded body obtained by papermaking, containing 0.5 to 5% by weight of a hardening accelerator. In addition, the present invention relates to a method for producing a lightweight calcium silicate plate characterized by performing a hydrothermal reaction.
[0009]
The present invention also provides a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. In a method for producing a calcium silicate plate, which is obtained by laminating a molded body obtained by laminating by a papermaking method in a pressure vessel, the slurry put in the first and last boxmaking box of a round netting machine At least one of these contained 5 to 30% by weight of type II anhydrous gypsum as a solid content and 0.5 to 5% by weight of a hardening accelerator based on type II anhydrous gypsum, and was obtained by papermaking. The present invention relates to a method for producing a lightweight calcium silicate plate characterized by hydrating a type II anhydrous gypsum by primary curing of a molded body and then performing a hydrothermal reaction.
[0010]
Furthermore, the present invention provides a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. In the manufacturing method of a calcium silicate board which consists of carrying out the hydrothermal reaction of the molded object obtained by laminating by a papermaking method, on a papermaking film between the return roll of a papermaking machine, and a making roll, II Lamination of slurry containing 0.5 to 5% by weight of a hardening accelerator with respect to type anhydrous gypsum and type II anhydrous gypsum as type II anhydrous gypsum at a rate of 10 to 50 g / m ² after to lamination to a predetermined thickness, to hydrate the type II anhydrous gypsum by primary curing the resulting formed form a paper-making, then lightweight calcium silicate board and performing hydrothermal reaction Involved in the manufacturing method The
[0011]
The present invention also provides a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. In a method for producing a calcium silicate plate, which is obtained by laminating a molded body obtained by laminating by a papermaking method in a pressure vessel, the slurry put in the first and last boxmaking box of a round netting machine Either one of them contains 92 to 98% by weight of type II anhydrous gypsum as a solid content, 2 to 8% by weight of fiber raw material, and 0.5 to 5% by weight of an accelerator based on type II anhydrous gypsum. By making the papermaking thickness of the slurry 1 to 10% of the total papermaking thickness produced while the felt of the round net type papermaking machine makes a round, and primarily curing the molded body obtained by papermaking Hydrate type II anhydrous gypsum, then hydrothermal reaction It is related with the manufacturing method of the lightweight calcium-silicate board characterized by performing.
[0012]
Furthermore, the present invention provides a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. In a method for producing a calcium silicate plate, which is obtained by laminating a molded body obtained by laminating by a papermaking method in a pressure vessel, the slurry put in the first and last boxmaking box of a round netting machine One or more selected from the group consisting of more than 30% by weight and less than 98% by weight of type II anhydrous gypsum, 2-8% by weight of fibrous raw material, calcareous raw material and inorganic filler, The amount of the composition is 58% by weight or less, and 0.5 to 5% by weight of a hardening accelerator is added to the type II anhydrous gypsum. The total thickness of paper to be made during A method for producing a lightweight calcium silicate board characterized by hydrating a type II anhydrous gypsum by primary curing of a molded body obtained by papermaking to 1 to 10% and then performing a hydrothermal reaction. Related.
[0013]
The present invention also provides a raw material slurry containing 17-50% by weight of a calcareous raw material, 15-45% by weight of a siliceous raw material, 2-8% by weight of a fibrous raw material, and 5-30% by weight of an inorganic filler. the molded body obtained by laminating the paper-making method, in the manufacturing method of a calcium silicate plate which comprises reacting hydrothermal in a pressure vessel, 5 to 30 wt% containing organic feedstock slurry of type II anhydrous gypsum as solids And a curing accelerator solution having a solid content concentration of 5 to 15% by weight is sprayed on the papermaking film between the return roll and the making roll of the papermaking machine at a solid content conversion rate of 1 to 5 g / m ^2. after lamination by laminating a predetermined thickness while, to hydrate the type II anhydrous gypsum by primary curing the resulting formed form a paper-making, then lightweight silicate which is characterized in that the hydrothermal reaction Manufacture of calcium plate Related to the method.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The basic composition of the raw material slurry used in the method for producing a lightweight calcium silicate plate (hereinafter simply referred to as “calcium silicate plate”) of the present invention is 17 to 50% by weight of calcareous raw material as solid content and 15 to 15% of silicic raw material. 45 wt%, are conventional comprising a 2-8% by weight fibrous material and from 5 to 30 wt% inorganic filler.
[0016]
Here, as the calcareous raw material, for example, slaked lime, quick lime and the like can be used. In addition, when the compounding quantity of a calcareous raw material is less than 17 weight% or exceeds 50 weight%, since bending strength is low and the dimensional change rate by water absorption becomes large, it is not preferable.
[0017]
Moreover, as a siliceous raw material, for example, silica sand, diatomaceous earth, fly ash and the like can be used. In addition, when the compounding quantity of a silicon raw material is less than 15 weight% or exceeds 45 weight%, since bending strength is low and the dimensional change rate by water absorption becomes large, it is unpreferable.
[0018]
Moreover, about a calcareous raw material and a siliceous raw material, 2-20 weight% of calcareous raw materials and 3-25 weight% of siliceous raw materials can be previously gelatinized and used among the said ratios. Examples of gelling conditions include 1.5 to 4 hours at a temperature of 75 to 90 ° C.
[0019]
Furthermore, as the fiber material, for example, cellulose fiber, polypropylene, vinylon, glass fiber, carbon fiber and the like can be used. In addition, it is not preferable that the blending amount of the fibrous raw material is less than 2% by weight because the bending strength is low, and if it exceeds 8% by weight, it is not preferable because it is not incombustible. Moreover, when using polypropylene, vinylon, glass fiber, carbon fiber, etc., it is preferable that those compounding quantities shall be 5 weight% or less.
[0020]
Further, as the inorganic filler, for example, pearlite, wollastonite, mica, talc, calcium carbonate, dihydrate gypsum and the like can be used. In addition, it is not preferable that the blending amount of the inorganic filler is less than 5% by weight because the dimensional change rate due to water absorption increases, and if it exceeds 30% by weight, the bending strength decreases, which is not preferable.
[0021]
The feature of this invention is the following six methods as a manufacturing method of a calcium silicate board:
According to the production method of the first invention of the present invention, 5 to 30% by weight of type II anhydrous gypsum is added to the raw material slurry having the above-described composition, and 0.5 to 5 in an external ratio to type II anhydrous gypsum. The raw material slurry is laminated by a paper making method and molded by adding a weight% curing accelerator, and then the resulting molded body is primarily cured to hydrate the type II anhydrous gypsum, and then water. A calcium silicate board can be manufactured by performing a thermal reaction.
[0022]
The type II anhydrous gypsum used in the present invention preferably has a specific surface area in the range of 1000 to 9000 cm ² / g, preferably 3000 to 8000 cm ² / g. If the specific surface area of the type II anhydrous gypsum is less than 1000 cm ² / g, the initial hydration reaction is slow, the sedimentation is quick at the time of paper making, and it is not preferable because the paper making according to the blending ratio becomes difficult. Moreover, even if the specific surface area exceeds 8000 cm ³ / g, the hydration rate of type II anhydrous gypsum corresponding to the increase in the specific surface area cannot be increased, and conversely, the drainage decrease during papermaking, the papermaking film or the green sheet This is not preferable because it causes wrinkles.
[0023]
That is, the raw material slurry used in the first invention has a solid content of 17-50% by weight, a siliceous raw material 15-45% by weight, a fibrous raw material 2-8% by weight, and a type II anhydrous gypsum 5-30% by weight. In addition, 5 to 30% by weight of an inorganic filler and 0.5 to 5% by weight of a hardening accelerator in an external ratio with respect to type II anhydrous gypsum. Here, if the blending amount of type II anhydrous gypsum is less than 5% by weight, it is not preferable because the expression of the interlayer strength of the green sheet is poor, and if it exceeds 30% by weight, the amount of curing accelerator to be used is used. This increases the raw material cost and lowers the bending strength, which is not preferable. The amount of type II anhydrous gypsum is preferably 10 to 20% by weight.
[0024]
In addition, when using a type II anhydrous gypsum in a slurry state, since the hydration reaction of a type II anhydrous gypsum does not express, addition of a hardening accelerator to the raw material slurry becomes essential. Here, if the blending amount of the curing accelerator is less than 0.5% by weight relative to the type II anhydrous gypsum, the curing accelerating effect cannot be exhibited and the hydration reaction is completed easily even if the raw slurry is made. In addition, after paper making, the primary curing for hydrating the type II anhydrous gypsum in the molded product takes a very long time, so that sufficient hydration cannot be performed and the strength of the molded product is weakened. It is not preferable. Further, if the blending amount of the curing accelerator exceeds 5% by weight, hydration is completed before making the slurry, and this is not preferable because it does not contribute to the development of the interlayer strength of the green sheet. An increase in the amount of added is not preferable because it causes spots, color unevenness, metal corrosion in the hydrothermal reactor, and the like due to precipitation of the curing accelerator component on the surface of the molded body. That is, by adding 0.5 to 5% by weight of a curing accelerator to Type II anhydrous gypsum, the hydration reaction of Type II anhydrous gypsum can be completed in about 10 to 20 hours after slurry preparation. Therefore, if the production of the green sheet is completed within about 6 to 15 hours after the slurry is prepared, the effect of the present invention can be obtained.
[0025]
Next, according to the manufacturing method according to the second invention of the present invention, the first and last papermaking of the round net type papermaking machine is carried out by laminating and forming the raw material slurry having the above-described component blending by the papermaking method. At least one of the slurries in the box contains 5 to 30% by weight of type II anhydrous gypsum as a solid content and 0.5 to 5% by weight of a hardening accelerator based on the amount of type II anhydrous gypsum, A calcium silicate plate can be produced by hydrating the type II anhydrous gypsum by first curing the molded body obtained by papermaking and then performing a hydrothermal reaction.
[0026]
That is, in the second invention, a slurry having the same composition as that of the raw material slurry used in the first invention is used as a slurry for the first and / or last box making box of the round net type machine. Here, the amount of type II anhydrous gypsum in the slurry used in the first and / or last box is preferably less than 5% by weight as the solid content, because the green sheet has poor interlayer strength and is preferable. In addition, if it exceeds 30% by weight, the amount of the setting retarder used is increased, the raw material cost is increased, and the bending strength is lowered.
[0027]
In addition, when using a type II anhydrous gypsum in a slurry state, since the hydration reaction of a type II anhydrous gypsum does not express, addition of a hardening accelerator to the raw material slurry becomes essential. Here, if the blending amount of the curing accelerator is less than 0.5% by weight relative to the type II anhydrous gypsum, the curing accelerating effect cannot be exhibited and the hydration reaction is completed easily even if the raw slurry is made. In addition, after paper making, the primary curing for hydrating the type II anhydrous gypsum in the molded product takes a very long time, so that sufficient hydration cannot be performed and the strength of the molded product is weakened. It is not preferable. On the other hand, if the blending amount of the curing accelerator exceeds 5% by weight, hydration is completed before making the slurry, and this is not preferable because it does not contribute to the development of the interlayer strength of the green sheet. That is, by adding 0.5 to 5% by weight of a curing accelerator to Type II anhydrous gypsum, the hydration reaction of Type II anhydrous gypsum can be completed in about 10 to 20 hours after slurry preparation. Therefore, if the production of the green sheet is completed within about 6 to 15 hours after the slurry is prepared, the effect of the present invention can be obtained.
[0028]
According to the second invention of the present invention, a slurry obtained by further adding type II anhydrous gypsum and a curing accelerator to the raw material slurry of the basic composition is put into the first and / or the last box of the round net type paper machine. Then, it is laminated and formed by a papermaking method. The method of putting this slurry into the first and / or last paper box is not particularly limited. For example, a slurry having a blending ratio different from that of other paper boxes is prepared and sent from a dedicated chest. Alternatively, the slurry of each of the type II anhydrous gypsum and the curing accelerator may be added to other slurries between the chest and the box.
[0029]
Next, according to the manufacturing method according to the third aspect of the present invention, when the raw material slurry having the basic composition as described above is laminated and formed by the papermaking method, the papermaking between the return roll and the making roll of the papermaking machine. The ratio of 10 to 50 g / m ² as a type II anhydrous gypsum slurry containing 0.5 to 5% by weight of a type II anhydrous gypsum and a type II anhydrous gypsum on the film. in after lamination spraying while laminated to a predetermined thickness, to hydrate the type II anhydrous gypsum by primary curing the resulting formed form a paper-making, then, calcium silicate by conducting the hydrothermal reaction A board can be manufactured.
[0030]
Here, if the application amount of type II anhydrous gypsum is less than 10 g / m ^{2 in} terms of solid content, it is not preferable because the expression of interlayer strength is poor, and if the application amount of type II anhydrous gypsum exceeds 50 g / m ² It is not preferable because a layer of type II anhydrous gypsum is formed and cracks occur during drying and bending strength is lowered.
[0031]
An example of a round net-type paper machine that can be used in the third invention of the present invention is shown in FIG. According to this round net-making machine, the slurry (7) is rolled up by the round net cylinder (8) provided in the paper box (6) and transferred to the felt (3). A green sheet is obtained by repeating the number of mesh cylinders) to make a papermaking film (4), and further winding the papermaking film (4) to a predetermined thickness with a making roll (1) and then cutting. Can do. In general, delamination and puncture occur between films laminated by a making roll (1) .Therefore, a spraying device (5) is installed between the return roll (2) and the making roll (1) to provide type II anhydrous gypsum. And by spreading the slurry for spreading made of a curing accelerator, it is possible to prevent delamination and puncture by improving the adhesion (interlayer strength) between the films.
[0032]
In addition, even when the type II anhydrous gypsum is sprayed in the slurry for spraying, since the hydration reaction of the type II anhydrous gypsum does not occur, it is essential to add the curing accelerator to the raw material slurry. Here, if the blending amount of the curing accelerator is less than 0.5% by weight relative to the type II anhydrous gypsum, the curing accelerating effect cannot be exhibited and the hydration reaction is completed easily even if the raw slurry is made. In addition, after paper making, the primary curing for hydrating the type II anhydrous gypsum in the molded product takes a very long time, so that sufficient hydration cannot be performed and the strength of the molded product is weakened. It is not preferable. On the other hand, if the blending amount of the curing accelerator exceeds 5% by weight, hydration is completed before making the slurry, and this is not preferable because it does not contribute to the development of the interlayer strength of the green sheet. That is, by adding 0.5 to 5% by weight of a curing accelerator to Type II anhydrous gypsum, the hydration reaction of Type II anhydrous gypsum can be completed in about 10 to 20 hours after slurry preparation. Therefore, if the production of the green sheet is completed within about 6 to 15 hours after the slurry is prepared, the effect of the present invention can be obtained.
[0033]
Next, according to the manufacturing method according to the fourth aspect of the present invention, when the raw slurry having the basic composition as described above is laminated and formed by the papermaking method, the first and last papermaking of the round net type papermaking machine. Either one of the slurries in the box is 92 to 98% by weight of type II anhydrous gypsum as a solid content, 2 to 8% by weight of fiber raw material, and 0.5 to 5% by weight based on type II anhydrous gypsum. The thickness of the paper made by the slurry is 1 to 10%, preferably 1 to 5% of the total paper thickness that is made while the felt of the round net paper making machine goes around. The obtained shaped body is primarily cured to hydrate the type II anhydrous gypsum, and then a hydrothermal reaction can be performed to produce a calcium silicate plate.
[0034]
Here, if the papermaking thickness by the slurry is less than 1%, it is not preferable because peeling between the sheets tends to occur due to poor expression of interlayer strength. In addition, when using a slurry having a high content of type II anhydrous gypsum, such as 92 to 98% by weight, if the papermaking thickness exceeds 10%, the layer of type II anhydrous gypsum becomes thick, and after hydrothermal reaction Since bending strength falls, it is not preferable.
[0035]
Moreover, as a fiber raw material, a cellulose fiber etc. can be used. It should be noted that if the proportion of type II anhydrous gypsum exceeds 98% by weight, the proportion of fibrous raw material decreases and powder loss increases during papermaking, which is not preferable. Further, if the blending ratio of the fibrous raw material exceeds 8% by weight, it is not preferable because a fibrous raw material layer can be formed and easily peeled off.
[0036]
In addition, when using a type II anhydrous gypsum in a slurry state, since the hydration reaction of a type II anhydrous gypsum does not express, addition of a hardening accelerator to the raw material slurry becomes essential. Here, if the blending amount of the curing accelerator is less than 0.5% by weight relative to the type II anhydrous gypsum, the curing accelerating effect cannot be exhibited and the hydration reaction is completed easily even if the raw slurry is made. In addition, after paper making, the primary curing for hydrating the type II anhydrous gypsum in the molded product takes a very long time, so that sufficient hydration cannot be performed and the strength of the molded product is weakened. It is not preferable. On the other hand, if the blending amount of the curing accelerator exceeds 5% by weight, hydration is completed before making the slurry, and this is not preferable because it does not contribute to the development of the interlayer strength of the green sheet. That is, by adding 0.5 to 5% by weight of a curing accelerator to Type II anhydrous gypsum, the hydration reaction of Type II anhydrous gypsum can be completed in about 10 to 20 hours after slurry preparation. Therefore, if the production of the green sheet is completed within about 6 to 15 hours after the slurry is prepared, the effect of the present invention can be obtained.
[0037]
When using type II anhydrous gypsum in a slurry state, the concentration of this slurry is preferably the same as or lower than the concentration of the raw material slurry of other box making boxes, and the solid content concentration is preferably 1 to 10%, preferably Is preferably 3 to 7%. However, if it is necessary to lower the slurry water level in the box or change the cylinder mesh to an appropriate size in order to adjust the amount of slurry solids on the round net as much as possible. There is also.
[0038]
Next, according to the manufacturing method according to the fifth aspect of the present invention, in forming and laminating the raw material slurry having the above basic composition by the papermaking method, the first and last papermaking of the round net type papermaking machine. Either one of the slurries in the box is selected from the group consisting of type II anhydrous gypsum 30 wt% and less than 98 wt%, fibrous raw material 2 to 8 wt%, calcareous raw material and inorganic filler as solid content 68% by weight or less of seeds or two or more ingredients, and 0.5 to 5% by weight of a hardening accelerator based on type II anhydrous gypsum. Hydrating type II anhydrous gypsum by primary curing of the molded body obtained by papermaking, with 1 to 10%, preferably 1 to 5% of the total papermaking thickness made while the felt of the papermaking machine goes around. And then a hydrothermal reaction to produce a calcium silicate Um plate can be manufactured.
[0039]
If the paper making thickness by the slurry is less than 1%, the interlayer strength is poorly developed, and peeling is likely to occur, which is not preferable. In addition, when using a slurry having a relatively high content of type II anhydrous gypsum exceeding 30% by weight and less than 98% by weight, if the papermaking thickness exceeds 10%, the layer of type II anhydrous gypsum becomes thick. , Because the bending strength after hydrothermal reaction tends to decrease.
[0040]
Cellulose fibers and the like can be used as the fiber raw material. As the calcareous raw material, for example, slaked lime, quick lime and the like can be used. Furthermore, as the inorganic filler, for example, pearlite, wollastonite, mica, talc, calcium carbonate, silica sand, dihydrate gypsum and the like can be used. By blending one or more selected from the group consisting of the calcareous raw material and the inorganic filler, the raw material cost of the calcium silicate plate can be reduced while maintaining the interlayer strength. If the blending ratio of type II anhydrous gypsum exceeds 98% by weight, the blending ratio of the fiber raw material decreases and the loss of powder increases, which is not preferable, and the blending ratio of type II anhydrous gypsum is 30% by weight or less. In the case of type II anhydrous gypsum, only one of the slurry put in the first and the last box of the round net type paper machine is mixed with the type II anhydrous gypsum because the compounding effect does not appear remarkably. It is not preferable. When the blending ratio of the fibrous raw material exceeds 8% by weight, it is not preferable because a fibrous raw material layer is formed and is easily peeled off. Furthermore, when the mixing ratio of the calcareous raw material and / or the inorganic filler exceeds 68% by weight, it is not preferable because the type II anhydrous gypsum and the fibrous raw material cannot be sufficiently mixed.
[0041]
In addition, when using a type II anhydrous gypsum in a slurry state, since the hydration reaction of a type II anhydrous gypsum does not express, addition of a hardening accelerator to the raw material slurry becomes essential. Here, if the blending amount of the curing accelerator is less than 0.5% by weight relative to the type II anhydrous gypsum, the curing accelerating effect cannot be exhibited and the hydration reaction is completed easily even if the raw slurry is made. In addition, after paper making, the primary curing for hydrating the type II anhydrous gypsum in the molded product takes a very long time, so that sufficient hydration cannot be performed and the strength of the molded product is weakened. It is not preferable. On the other hand, if the blending amount of the curing accelerator exceeds 5% by weight, hydration is completed before making the slurry, and this is not preferable because it does not contribute to the development of the interlayer strength of the green sheet. That is, by adding 0.5 to 5% by weight of a curing accelerator to Type II anhydrous gypsum, the hydration reaction of Type II anhydrous gypsum can be completed in about 10 to 20 hours after slurry preparation. Therefore, if the production of the green sheet is completed within about 6 to 15 hours after the slurry is prepared, the effect of the present invention can be obtained.
[0042]
The concentration of the slurry is preferably the same as or lower than the concentration of the raw material slurry of the other paper box, and is preferably 1 to 10%, preferably 3 to 7% in terms of solid content. However, if it is necessary to lower the slurry water level in the box or change the cylinder mesh to an appropriate size in order to adjust the amount of slurry solids on the round net as much as possible. There is also.
[0043]
Next, the manufacturing method according to the sixth aspect of the present invention, the slurry having ingredients as described above is contained type II anhydrous Suiseki plaster 5-30 wt%, and the return roll and making the papermaking machine on papermaking film between the rolls, after lamination by laminating while sparging with a solid concentration of 5 to 15 wt% of the curing accelerator solution at a ratio of solids equivalent amount 1 to 5 g / m ² to a predetermined thickness, was hydrated with type II anhydrous gypsum by primary curing the resulting formed form a paper-making, then it is possible to manufacture a calcium silicate board by performing a hydrothermal reaction.
[0044]
Here, if the blending amount of type II anhydrous gypsum is less than 5% by weight, it is not preferable because the expression of the interlayer strength of the green sheet is poor, and if it exceeds 30% by weight, the amount of curing accelerator to be used is used. This increases the raw material cost and lowers the bending strength, which is not preferable. The amount of type II anhydrous gypsum is preferably 10 to 20% by weight.
[0045]
In addition, when using a type II anhydrous gypsum in a slurry state, since the hydration reaction of a type II anhydrous gypsum does not express, addition of a hardening accelerator to the raw material slurry becomes essential. The sixth invention of the present invention is characterized in that a curing accelerator is used as a solution and laminated on a papermaking film between a return roll and a making roll of the papermaking machine while being dispersed. The concentration of the curing accelerator solution for spraying is preferably in the range of 2 to 15% by weight. Here, when the concentration of the curing accelerator solution is less than 2% by weight, it is not preferable because the effect of adding the curing accelerator is small, and when the concentration exceeds 15% by weight, the amount of spraying is reduced and uniform. It is not preferable because it becomes difficult to spray. Moreover, the application quantity of a hardening accelerator solution exists in the range of 1-5 g / m < ² > in solid content conversion amount. When the application amount of the curing accelerator solution is less than 1 g / cm ² , the curing acceleration effect cannot be exhibited, and even if the raw material slurry is made, the hydration reaction is not completed easily. The primary curing for hydrating gypsum takes a very long time, and it is not preferable because sufficient hydration cannot be performed and the strength of the molded body is weakened. Further, if the application amount of the curing accelerator solution exceeds 5 g / m ² , it is not preferable because the hydration reaction is completed before the paper making process is completed and it does not contribute to the development of the interlayer strength of the green sheet. When the addition amount of the curing accelerator is increased, it is not preferable because it causes spots, color unevenness, metal corrosion in the hydrothermal reactor, etc. due to precipitation of the curing accelerator component on the surface of the molded body. That is, a hydration reaction of type II anhydrous gypsum is carried out for about 10 to 20 hours after the paper making process by spreading a 5 to 15% by weight hardening accelerator solution on the paper making film in an amount of 1 to 5 g / m ^2. Can be completed with. The sixth invention of the present invention can also be carried out by using the round net type paper machine shown in FIG.
[0046]
The curing accelerator used in the present invention is not particularly limited, and alkali metal sulfates (for example, K ₂ SO ₄ , Na ₂ SO ₄ etc.), aluminum sulfates and alums [for example, Al ₂ (SO ₄ ) ₃ , KAl (SO ₄ ) ₂ · 12H ₂ O, NaAl (SO ₄ ) ₂ · 12H ₂ O, NH ₄ Al (SO ₄ ) ₂ · 12H ₂ O, etc.] or the like may be used alone or in combination Can do.
[0047]
The molded body obtained by papermaking undergoes a hydrothermal reaction after hydration of type II anhydrous gypsum by primary curing. The conditions for the primary curing are not particularly limited, and can be carried out under conventional conditions for hydration reaction of II anhydrite, preferably at 20 to 60 ° C. for 3 hours or more.
[0048]
The molded body after the primary curing as described above can be hydrated under conventional hydrothermal reaction conditions, and can be made into a calcium silicate plate through the subsequent conventional steps. The hydrothermal reaction can be carried out in a pressure vessel under a saturated water vapor pressure at a temperature of 150 to 200 ° C., preferably 170 to 190 ° C. for 5 to 20 hours, preferably 8 to 12 hours.
[0049]
The calcium silicate plate manufactured by the manufacturing method according to the first to sixth inventions of the present invention as described above exhibits a very excellent value with a delamination strength of 3% or more of a bending strength (an absolutely dry state). It will be a thing. The bending strength is a result of testing with a No. 3 test piece in accordance with JIS A 5418, and the delamination strength test is a result of being performed at 30 × 30 mm.
[0050]
【Example】
Example 1
The raw materials were blended at the ratio shown in Table 1, and stirred and mixed with 12 times the amount of water. The gel was synthesized with 10% by weight of slaked lime and 10% by weight of diatomaceous earth (weight ratio 1: 1) at 90 ° C. for 2 hours. Further, water was added to obtain a raw material slurry having a solid content concentration of about 3% by weight, and the paper was made into a thickness of 6 mm. In this example, potassium sulfate was used as a curing accelerator.
Next, after performing primary curing at 30 ° C. for 8 hours in a humid air atmosphere, hydrothermal reaction was performed in a pressure vessel under saturated steam at 180 ° C. for 10 hours.
Table 1 shows the bulk specific gravity, bending strength and delamination strength (both in an absolutely dry state) after the hydrothermal reaction.
[0051]
[Table 1]

[0052]
Example 2
The raw materials were blended in the proportions shown in Table 2, and stirred and mixed with 12 times the water. The gel was synthesized with 10% by weight of slaked lime and 10% by weight of diatomaceous earth (weight ratio 1: 1) at 90 ° C. for 2 hours. Further, water was added to obtain a raw material slurry having a solid concentration of about 3% by weight. The first or last box was made into a slurry containing a separately prepared type II anhydrous gypsum having a solid content concentration of 10% by weight and a curing accelerator, and was made into a thickness of 6 mm. In this example, potassium sulfate was used as a curing accelerator.
Next, after performing primary curing at 30 ° C. for 8 hours in a humid air atmosphere, hydrothermal reaction was performed in a pressure vessel under saturated steam at 180 ° C. for 10 hours.
Table 2 shows the bulk specific gravity, bending strength and delamination strength (both in an absolutely dry state) after the hydrothermal reaction.
[0053]
[Table 2]

[0054]
Example 3
The raw materials were blended in the proportions shown in Table 3, and stirred and mixed with 12 times the water. The gel was synthesized with 10% by weight of slaked lime and 10% by weight of diatomaceous earth (weight ratio 1: 1) at 90 ° C. for 2 hours. Further, water was added to form a raw material slurry having a solid content concentration of about 3% by weight, and the paper was made into a thickness of 6 mm. In making paper, it was sprayed on the papermaking film between the return roll and the making roll as a slurry of type II anhydrous gypsum and a hardening accelerator shown in Table 3. The spray slurry concentration was set to a solid content concentration of 10% by weight. In this example, potassium sulfate was used as the curing accelerator.
Next, after performing primary curing at 30 ° C. for 8 hours in a humid air atmosphere, hydrothermal reaction was performed in a pressure vessel under saturated steam at 180 ° C. for 10 hours.
Table 3 shows the bulk specific gravity, bending strength and delamination strength (both in an absolutely dry state) after the hydrothermal reaction.
[0055]
[Table 3]

[0056]
Example 4
The raw materials were blended in the proportions shown in Table 4, and stirred and mixed with 12 times the water. The gel was synthesized with 10% by weight of slaked lime and 10% by weight of diatomaceous earth (weight ratio 1: 1) at 90 ° C. for 2 hours. Furthermore, water was added to obtain a raw material slurry having a solid concentration of about 3% by weight. In addition, the first box or the last box was blended and mixed in the same manner to obtain a raw material slurry having a solid content concentration of about 2% by weight, and was made into a thickness of 6 mm. In this example, potassium sulfate was used as a curing accelerator.
Next, after performing primary curing at 30 ° C. for 8 hours in a humid air atmosphere, hydrothermal reaction was performed in a pressure vessel under saturated steam at 180 ° C. for 10 hours.
Table 4 shows the bulk specific gravity, bending strength and delamination strength (both in an absolutely dry state) after the hydrothermal reaction.
[0057]
[Table 4]

[0058]
The raw materials were blended in the proportions shown in Table 5, and stirred and mixed with 12 times the water. The gel was synthesized with 10% by weight of slaked lime and 10% by weight of diatomaceous earth (weight ratio 1: 1) at 90 ° C. for 2 hours. Further, water was added to form a raw material slurry having a solid content concentration of about 3% by weight, and the paper was made into a thickness of 6 mm. At this time, a potassium sulfate solution having a solid content of 2% by weight was sprayed as a hardening accelerator solution on the felt between the return roll and the making roll of the paper machine.
Next, after performing primary curing at 30 ° C. for 8 hours in a humid air atmosphere, hydrothermal reaction was performed in a pressure vessel under saturated steam at 180 ° C. for 10 hours.
Table 5 shows the bulk specific gravity, bending strength and delamination strength (both completely dry) after hydrothermal reaction.
[0059]
[Table 5]

[0060]
【The invention's effect】
As described above, if the raw material slurry is formed by a papermaking method using the method for producing a calcium silicate plate of the present invention, the strength and interlayer strength of the molded body before the hydrothermal reaction can be improved, and thereby hydrothermal While preventing peeling and puncture of the molded body during the reaction, there are effects that the delamination strength of the obtained calcium silicate plate can be improved.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a round net-type paper machine usable in the third invention of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Making roll 2 Return roll 3 Felt 4 Papermaking film 5 Spreading device 6 Papermaking box 7 Raw material slurry 8 Round net cylinder

Claims

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. In the manufacturing method of the calcium silicate board which consists of making the molded object obtained by making it hydrothermally react in a pressure vessel, a raw material slurry is 5 to 30 weight% as a solid content of type II anhydrous gypsum, and II type anhydrous gypsum It contains 0.5 to 5% by weight of a hardening accelerator in the outer ratio, and the type II anhydrite is hydrated by first curing the molded body obtained by papermaking, and then hydrothermal reaction is performed. A method for producing a lightweight calcium silicate plate, characterized in that it is performed.

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. In the method for producing a calcium silicate plate comprising hydrothermal reaction of the molded body obtained in the pressure vessel, at least one of the slurries placed in the first and last box of the round net type paper machine is type II It contains 5 to 30% by weight of anhydrous gypsum as a solid content and 0.5 to 5% by weight of a hardening accelerator with respect to type II anhydrous gypsum. A method for producing a lightweight calcium silicate plate, characterized in that type II anhydrous gypsum is hydrated and then subjected to a hydrothermal reaction.

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. In the method for producing a calcium silicate plate comprising hydrothermal reaction of a molded product obtained in a pressure vessel, type II anhydrous gypsum and type II on a papermaking film between a return roll and a making roll of a papermaking machine Predetermined thickness is obtained by laminating slurry containing 0.5 to 5% by weight of hardening accelerator on an anhydrous basis with an amount of 10 to 50 g / m ² as a type II anhydrous gypsum. after lamination, the hydrated and type II anhydrous gypsum by primary curing the resulting formed form a paper-making, a method of manufacturing a lightweight calcium silicate board and performing hydrothermal reaction.

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. In the manufacturing method of the calcium silicate board which consists of carrying out the hydrothermal reaction of the molded object obtained in this way, either one of the slurry put into the 1st and the last box making of a round net type paper machine is It contains 92 to 98% by weight of type II anhydrous gypsum as a solid content, 2 to 8% by weight of fiber raw material, and 0.5 to 5% by mass of a curing accelerator in an external ratio with respect to type II anhydrous gypsum, The thickness of the paper made by the slurry is set to 1 to 10% of the total paper thickness made during the round of the felt of the round net-type paper machine. And then a hydrothermal reaction Method of manufacturing a lightweight calcium silicate board according to claim.

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. In the manufacturing method of the calcium silicate board which consists of carrying out the hydrothermal reaction of the molded object obtained in this way, either one of the slurry put into the 1st and the last box making of a round net type paper machine is Type II anhydrous gypsum as a solid content of more than 30% by weight and less than 98% by weight, fiber raw material 2-8% by weight, one or more components selected from the group consisting of calcareous raw materials and inorganic fillers 58% by weight It contains 0.5 to 5% by weight of a hardening accelerator in the following and with respect to type II anhydrous gypsum, and the paper making thickness by the slurry is made while the felt of the round net making machine goes around. 1 to 10 of total paper making thickness And then, to hydrate the type II anhydrous gypsum by primary curing the resulting shaped body by papermaking, then, the production method of a lightweight calcium silicate board and performing hydrothermal reaction.

A raw material slurry containing 17 to 50% by weight of a calcareous raw material, 15 to 45% by weight of a siliceous raw material, 2 to 8% by weight of a fibrous raw material, and 5 to 30% by weight of an inorganic filler as a solid content is laminated by a papermaking method. the molded body obtained Te, in the manufacturing method of a calcium silicate plate consists in hydrothermal reaction, a raw material slurry having 5-30 wt% including the type II anhydrous gypsum as solid content becomes in a pressure vessel, and papermaking On the papermaking film between the return roll and the making roll of the machine, a curing accelerator solution having a solid content concentration of 5 to 15% by weight is laminated while being sprayed at a ratio of the solid content conversion amount of 1 to 5 g / m ² . after lamination in the thickness, to hydrate the type II anhydrous gypsum by primary curing the resulting formed form a paper-making, a method of manufacturing a lightweight calcium silicate board and performing hydrothermal reaction.