JP3575150B2 - Aluminum hydroxide for resin filling and resin composition using the same - Google Patents
Aluminum hydroxide for resin filling and resin composition using the same Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は樹脂充填用水酸化アルミニウムに係わり、更に詳しくは樹脂への適用において、成型性が良好で、特にＢＭＣ（Ｂｕｌｋ Ｍｏｕｌｄｉｎｇ Ｃｏｍｐｏｕｎｄ）成型に適したコンパウンド粘度挙動を与え、硬化時の成型サイクル性に優れ、硬化後の成型体の機械的強度及び外観に優れた樹脂組成物を提供し得る樹脂充填用水酸化アルミニウムに関するものである。
【０００２】
【従来の技術】
従来、無機フィラーを樹脂に充填、硬化して得られる人工大理石は、キッチンカウンター、バスタブ等の用途に広く用いられている。これらの無機フィラーの中でも水酸化アルミニウムは透明性、化学的安定性、難燃性等の物性の他に、硬度がシリカ等に比べ低いことより、金型或いは樹脂との混合に用いる撹拌装置の磨耗が少なく、また価格面でも安価であることより人工大理石用フィラーとして非常に有用である。更に有機物質等の不純物の少ない高白色のものは成型体の着色も少なく、高級感のある人工大理石を与えるものとして、人工大理石用フィラーとして特に優れている。
【０００３】
しかし従来市販の水酸化アルミニウムをフィラーとして用いた場合、ＢＭＣ成型においては充分なコンパウンド硬さが得られない等の問題があった。それ故コンパウンド硬さを保持する（充填粘度を高くする）方法として、粒径の小さい水酸化アルミニウムを使用したり、充填量を増やしたり、増粘剤等を添加する方法等がとられてきた。しかしながら、これらの方法により樹脂充填粘度を上昇させる場合には、充分な硬さのコンパウンドは得られるものの、混合時の粘度が高いため樹脂中に水酸化アルミニウムが均一に分散できず、このため成型体の機械的強度が充分得られないとか、気泡の巻き込みやプレス時に巣ができるなど成型体の外観や機械的強度に悪影響を及ぼす等の問題が生起する。
【０００４】
【発明が解決しようとする課題】
かかる事情下に鑑み、本発明者等は多くの実験結果より、ＢＭＣ用途に適した樹脂組成物としては、プレス時（すなわち低ずり速度時）に巣が発生しない程度の充分なコンパウンド硬さを有し、しかも混合時（すなわち高ずり速度時）には水酸化アルミニウム粉末が均一に混合できる程度の低粘性が要求されるため、ある一定範囲のチクソ性が必要となること、しかして、ＢＭＣ用途に適した充填材としては、２５℃で８〜１０ポイズの粘度を有するビニルエステル樹脂１００重量部に水酸化アルミニウム２００重量部を充填した樹脂組成物を２５℃に保ち、ＤＶＵ−Ｂ型粘度計でＮｏ．７ローターを使用し５ｒｐｍ（低ずり速度時）での粘度が５００ポイズ〜２０００ポイズである場合には、プレス時に巣が発生しない程度の充分なコンパウンド硬さを呈すること、またローター回転数のみを２０ｒｐｍにして粘度測定をした値（高ずり速度時）で前記した５ｒｐｍでの測定粘度値を割った値（５ｒｐｍ粘度／２０ｒｐｍ粘度：これをチクソ性指数と称する）が１〜３の範囲にある場合には水酸化アルミニウムが樹脂中に均一に分散し、気泡がなく、外観が美麗で機械的強度にも優れた成形体が得られることを見出し、これを指標として多くの水酸化アルミニウムの粉末物性を変数として組み合わせ実験整理した結果、ある特定範囲の平均粒子径、ＢＥＴ比表面積、Ｘ線形状係数を有し、かつ高白色度を有する水酸化アルミニウムを用いる場合には上記問題点が全て解決されたＢＭＣ用途に適した樹脂充填用水酸化アルミニウムが得られること、またこれを充填材として用いる場合には優れた物性を有する成形体を提供しえる樹脂組成物が得られることを見い出し本発明を完成するに至った。
【０００５】
【課題を解決するための手段】
すなわち本発明は、平均粒子径５μｍ〜２０μｍ、ＢＥＴ比表面積０．５ｍ２ ／ｇ〜４．５ｍ２ ／ｇ、Ｘ線による形状係数４〜１０〔ギブサイト（００２）面／（１１０）面のピーク強度比〕、白色度９３以上であることを特徴とするＢＭＣ成形に用いる樹脂充填用水酸化アルミニウムを提供するにある。
【０００６】
さらに本発明は、上記の樹脂充填用水酸化アルミニウムを不飽和ポリエステル樹脂、ビニルエステル樹脂またはメタアクリレート樹脂１００重量部に対し５０〜４００重量部充填してなる樹脂組成物を提供するにある。
【０００７】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
本発明に用いる水酸化アルミニウム粉末は、一般式Ａｌ２ Ｏ３ ・ｎＨ２ Ｏ（式中ｎ＝１〜３）で示されるアルミナ水和物、一般的にはアルミナ三水和物が使用される。
【０００８】
本発明に用いる水酸化アルミニウム粉末の平均粒子径は５μｍ〜３０μｍ、好ましくは８μｍ〜２０μｍの範囲である。５μｍより小さいと、樹脂充填時の粘度が高くなりすぎ均一分散が困難になり、またゲル化時間が遅くなる等の問題があり、樹脂中への人工大理石の質感が付与し得る量の水酸化アルミニウムの充填が困難になる。逆に、３０μｍより大きいと最終的に得られる樹脂組成物成型体の表面光沢が悪くなり、また機械的強度も低下するばかりでなく、硬化条件によっては水酸化アルミニウム粉末の重力沈降等が起こり樹脂中の充填物の分散が不均一な成型体が得られる場合がある。ここで本発明に用いる平均粒子径は、レーザー回折法による粒度分布測定装置で測定した値をいう。
【０００９】
また、本発明に用いる水酸化アルミニウム粉末のＢＥＴ比表面積は０．５ｍ２ ／ｇ〜４．５ｍ２ ／ｇ、好ましくは１．５ｍ２ ／ｇ〜３．０ｍ２ ／ｇの範囲である。該粉末のＢＥＴ比表面積が０．５ｍ２ ／ｇより小さいと水酸化アルミニウム表面上の物理吸着水分が少なく、充分なコンパウンド硬さが得られずプレス成型が困難になる。逆に４．５ｍ２ ／ｇより大きいと水酸化アルミニウム粉末表面上の物理吸着水分が多くなりすぎゲル化時間（コンパウンドが硬化し成形体になるまでの時間）が遅くなり場合によっては硬化不良を起こす可能性があり、また樹脂充填粘度も高くなる。ここで本発明に用いるＢＥＴ比表面積は窒素の吸着法で測定した値をいう。
【００１０】
さらに本発明に用いる水酸化アルミニウム粉末のＸ線形状係数は２〜１０、好ましくは４〜８の範囲である。この値が２より小さいとＢＭＣ成型に必要なチクソ性、即ち混合時の粘度が低くプレス時の粘度が高いという粘度挙動が得られない。逆にこの値が１０より大きいとチクソ性は発生するものの実質混合時の粘度は高くなり、樹脂中への該粉末の均一分散が難しくなり、更にプレス成型時の粘度も高くなりすぎ成型体に巣が生じる場合がある。ここで本発明に用いるＸ線形状係数とは、水酸化アルミニウム粉末を電圧５０ｋＶ，４０ｍＡの条件で発生させたＣｕ−Ｋα線にてＸ線回折測定を行ったときのギブサイト（００２）面のピーク強度をギブサイト（１１０）面のピーク強度で割った値を指し、粉砕によりへき開面がどれだけ現れたかを示す値である。
【００１１】
本発明に用いる水酸化アルミニウム粉末の白色度は９３以上、好ましくは９５以上の範囲である。この値が９３より小さいと成型体が着色し高級感のある人工大理石の外観は得られない。ここで本発明に於ける白色度は粉末のハンター白度を指す。
これらの物性をそれぞれ独立して有する水酸化アルミニウムは従来から存在したが、本発者等はこれらの物性全てを同時に満足する場合に、ＢＭＣ成型用樹脂充填材として、優れた作業性、並びに物性を有する樹脂組成物が得られることを見出したもので、例え平均粒子径及びＢＥＴ比表面積がこの範囲内にあったとしてもＸ線形状係数がこの範囲から外れている場合にはＢＭＣ成型に適したチクソ性が得られない等の問題が生じる。
【００１２】
このような物性を有する水酸化アルミニウム粉末を得る方法としては、特に制限されないが、白色度が高く粒度分布のシャープな水酸化アルミニウム原料、例えば、平均粒子径約２０〜１２０μｍ、ＢＥＴ比表面積０．０５〜０．５ｍ２ ／ｇ、Ｄ９０％ ／Ｄ１０％ 比が３．５以下、より好ましくは３以下で、白色度が８５以上の水酸化アルミニウム粉末を原料として用い、これを振動ミル等の体積粉砕機を用いて粉砕することにより得ることができる。
【００１３】
本発明の実施に際し、水酸化アルミニウムは得られる成型体の機械的強度或いは耐煮沸性等を向上させる目的で、水酸化アルミニウム表面をシランカップリング剤等の表面処理剤で処理して用いることもできる。
【００１４】
このようなシランカップリング剤としては特に限定されないが、例えばメタクリル系シラン，アクリル系シラン，ビニル系シラン，エポシキ系シラン，アミノ系シラン等が挙げられる。またこれらシランカップリング剤はシリケート等と併用してもよく、目的に応じて使い分けることができる。
これら表面処理剤の添加量は所望とする物性並びに価格のバランスより自ずと決定されるが、通常、水酸化アルミニウム粉末１００重量部に対し約０．１〜３重量部の範囲で使用されるのが一般的である。
またこれら表面処理剤の添加方法については特に限定されるものではないが、ヘンシェルミキサー，ブレンダー等で水酸化アルミニウム粉末を撹拌しながら添加する方法が一般的であり、また粉砕機に水酸化アルミニウムと同時にこれらの表面処理剤を添加し粉砕と同時に処理を行ってもよい。
【００１５】
本発明の水酸化アルミニウムの配合対象となる樹脂としてはＢＭＣ成形に用いられる樹脂であれば特に制限されないが、人工大理石用としては、例えば不飽和ポリエステル樹脂、ビニルエステル樹脂、メチルメタアクリレート樹脂等が挙げられる。
該樹脂中への本発明の水酸化アルミニウムの添加量（充填量）は公知の範囲であればよく、例えば人工大理石用に用いる場合には樹脂１００重量部に対し約５０重量部〜約４００重量部、好ましくは約１５０重量部〜約３００重量部の範囲で使用すればよい。樹脂に対する水酸化アルミニウムの添加量が少ない場合は人工大理石の風合いをだすことが困難となり、また樹脂量が相対的に多くなることよりコストも高くなるので好ましくない。また逆に水酸化アルミニウムの充填量が多すぎる場合には樹脂中での水酸化アルミニウム粉末の分散性が悪くなり得られた成形体の機械的強度が低下する。
【００１６】
【発明の効果】
以上、詳述した如く、本発明の水酸化アルミニウム粉末は、これをかなり多量に不飽和ポリエステル樹脂、ビニルエステル或いはメタアクリレート等の樹脂に充填し人工大理石等の成形体を得る場合に於いても、混合時に樹脂中への均一分散が可能で、プレス時に充分なコンパウンド硬さを与え、かつ得られる樹脂成形体も優れた機械的強度や外観性をも有するもので、ＢＭＣ成形用樹脂充填水酸化アルミニウム粉末として極めて有効であり、その産業的価値は頗る大である。
【００１７】
【実施例】
以下、本発明を実施例により更に詳細に説明するが、本発明はかかる実施例により制限を受けるものではない。
尚、本実施例に於いて粒度分布は以下の方法により測定した。
粒度分布：０．２％ヘキサメタリン酸ナトリウム水溶液６０ｍｌ中に水酸化アルミニウム粉末０．５ｇを加え１０分間超音波分散し得られた試料液をレーザー回折式のマイクロトラック粒度分析計モデル７９９７−１０−ＳＲＡにて、それぞれ累積５０パーセント粒径，累積９０パーセント粒径及び累積１０パーセント粒径を測定し、算出した。
【００１８】
実施例１
白色度９８でＢＥＴ比表面積０．１３ｍ２ ／ｇ、平均粒子径６２．１μｍ、Ｄ９０％ ／Ｄ１０％ 比が３．２である粒度分布のシャープな水酸化アルミニウム３００ｇを内容積２リットルのアルミナ製ポット（直径８ｍｍのアルミナ製ボール２．９ｋｇを充填）に投入し振幅３ｍｍで３０分振動ミル粉砕を行った。その結果得られた水酸化アルミニウムは平均粒子径９．８μｍ、ＢＥＴ比表面積１．５８ｍ２ ／ｇ、Ｘ線形状係数４．０、白色度９７であった。
上記水酸化アルミニウム２００重量部を２５℃で８．５ポイズの粘度を有するビニルエステル樹脂（商品名ＸＰ−６７５、武田薬品工業株式会社製）１００重量部に充填し、よく混合した。この組成物の２５℃におけるＤＶＵ−Ｂ型粘度計（Ｎｏ．７ローター使用）で測定したときの５ｒｐｍでの粘度は１２００ポイズであり、そのチクソ性指数は１．５であった。
この組成物を硬化して得た成形体の外観は、透明感があり着色が少なく良好であった。
【００１９】
実施例２
実施例１に使用した粉砕原料を用い、粉砕時間を６０分に変更した他は実施例１と同条件で振動ミル粉砕を行った。
その結果得られた水酸化アルミニウムは平均粒子径７．１μｍ、ＢＥＴ比表面積２．６３ｍ２ ／ｇ、Ｘ線形状係数６．８、白色度９６であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は１６４０ポイズであり、チクソ性指数は２．０であった。
この組成物を硬化して得た成形体の外観は、透明感があり着色が少なく良好であった。
【００２０】
試験例１
粉砕原料に白色度９６でＢＥＴ比表面積０．１４ｍ２ ／ｇ、平均粒子径８８．０μｍ、Ｄ９０％ ／Ｄ１０％ 比が２．７である粒度分布のシャープな水酸化アルミニウムを使用する以外は実施例１と同条件で振動ミル粉砕を行った。 その結果得られた水酸化アルミニウムは平均粒子径１２．０μｍ、ＢＥＴ比表面積１．７０ｍ２ ／ｇ、Ｘ線形状係数２．３、白色度９６であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は８５０ポイズであり、チクソ性指数は１．３であった。
この組成物を硬化して得た成形体の外観は、透明感があり着色が少なく良好であった。
【００２１】
実施例３
試験例１に使用した粉砕原料を用い、粉砕時間を６０分に変更した他は試験例１と同条件で振動ミル粉砕を行った。
その結果得られた水酸化アルミニウムは平均粒子径９．０μｍ、ＢＥＴ比表面積２．４４ｍ２ ／ｇ、Ｘ線形状係数８．０、白色度９５であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は１８５０ポイズであり、チクソ性指数は２．３であった。
この樹脂組成物を硬化して得た成形体の外観は、透明感があり着色が少なく良好であった。
【００２２】
比較例１
粉砕原料に白色度９６でＢＥＴ比表面積０．１５ｍ２ ／ｇ、平均粒子径７４．４μｍ、Ｄ９０％ ／Ｄ１０％ 比が４．０である水酸化アルミニウムを使用した以外は実施例１と同条件で振動ミル粉砕を行った。その結果得られた水酸化アルミニウムは平均粒子径３５．２μｍ、ＢＥＴ比表面積１．２３ｍ２ ／ｇ、Ｘ線形状係数３．５、白色度９６であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は４６０ポイズであり、チクソ性指数は１．３であった。
【００２３】
比較例２
比較例１に使用した粉砕原料を用い、粉砕時間を６０分に変更した他は比較例１と同条件で振動ミル粉砕を行った。
その結果得られた水酸化アルミニウムは平均粒子径１３．９μｍ、ＢＥＴ比表面積２．４２ｍ２ ／ｇ、Ｘ線形状係数１５．３、白色度９５であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は２５００ポイズであり、チクソ性指数は３．５であった。
【００２４】
比較例３
実施例１に使用した粉砕原料を用い、粉砕時間を１０分に変更した他は実施例１と同条件で振動ミル粉砕を行った。
その結果得られた水酸化アルミニウムは平均粒子径３２．７μｍ、ＢＥＴ比表面積１．００ｍ２ ／ｇ、Ｘ線形状係数１．７、白色度９８であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は４５０ポイズであり、チクソ性指数は１．２であった。
【００２５】
比較例４
実施例１に使用した粉砕原料を用い、粉砕時間を１２０分に変更した他は実施例１と同条件で振動ミル粉砕を行った。
その結果得られた水酸化アルミニウムは平均粒子径５．３μｍ、ＢＥＴ比表面積４．８５ｍ２ ／ｇ、Ｘ線形状係数９．４、白色度９４であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は３１００ポイズであり、チクソ性指数は２．９であった。
【００２６】
比較例５
粉砕原料に白色度８３でＢＥＴ比表面積０．２１ｍ２ ／ｇ、平均粒子径６７．１μｍ、Ｄ９０％ ／Ｄ１０％ 比が３．３である水酸化アルミニウムを使用する以外は実施例１と同条件で振動ミル粉砕を行った。 その結果得られた水酸化アルミニウムは平均粒子径１１．０μｍ、ＢＥＴ比表面積１．３２ｍ２ ／ｇ、Ｘ線形状係数３．５、白色度８９であった。
このものを用い実施例１と同じ方法で樹脂組成物を作製し、粘度を測定した。
その結果５ｒｐｍでの粘度は１０３０ポイズであり、チクソ性指数は１．４であった。
この樹脂組成物を硬化して得た成形体の外観は、透明感はあるものの黄色く着色しており人工大理石の色調として好ましくなかった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aluminum hydroxide for filling a resin, and more particularly, to a resin having good moldability in application to a resin, giving a compound viscosity behavior particularly suitable for BMC (Bulk Molding Compound) molding, and improving molding cycle properties during curing. The present invention relates to an aluminum hydroxide for resin filling which can provide a resin composition which is excellent and has excellent mechanical strength and appearance of a molded article after curing.
[0002]
[Prior art]
Conventionally, artificial marble obtained by filling and curing an inorganic filler in a resin has been widely used for applications such as kitchen counters and bathtubs. Among these inorganic fillers, aluminum hydroxide is transparent, chemically stable, in addition to its physical properties such as flame retardancy, because its hardness is lower than that of silica, etc., it can be used in a stirrer used for mixing with a mold or a resin. It is very useful as a filler for artificial marble due to its low abrasion and low price. Further, a high-white one containing few impurities such as organic substances has little coloring of the molded product, and gives a high-grade artificial marble, and is particularly excellent as a filler for artificial marble.
[0003]
However, when conventional commercially available aluminum hydroxide is used as a filler, there has been a problem that sufficient compound hardness cannot be obtained in BMC molding. Therefore, as a method for maintaining the compound hardness (to increase the filling viscosity), a method of using aluminum hydroxide having a small particle size, increasing the filling amount, or adding a thickener or the like has been adopted. . However, when the resin filling viscosity is increased by these methods, a compound having sufficient hardness can be obtained, but the viscosity at the time of mixing is high, so that aluminum hydroxide cannot be uniformly dispersed in the resin. Problems such as insufficient mechanical strength of the body, entrapped air bubbles and formation of nests at the time of pressing adversely affect the appearance and mechanical strength of the molded body.
[0004]
[Problems to be solved by the invention]
In view of such circumstances, the present inventors have found from a number of experimental results that a resin composition suitable for BMC use has a sufficient compound hardness such that nests do not occur at the time of pressing (that is, at a low shear rate). And at the time of mixing (ie, at high shear rate), a low viscosity is required so that the aluminum hydroxide powder can be uniformly mixed. Therefore, a certain range of thixotropy is required. As a filler suitable for the application, a resin composition obtained by charging 200 parts by weight of aluminum hydroxide to 100 parts by weight of a vinyl ester resin having a viscosity of 8 to 10 poise at 25 ° C. is maintained at 25 ° C., and a DVU-B type viscosity is used. No. in total. When the viscosity at 5 rpm (at low shear rate) is 500 poise to 2000 poise using a 7 rotor, the compound must exhibit sufficient compound hardness to the extent that nests do not occur during pressing. The value (5 rpm viscosity / 20 rpm viscosity: this is referred to as a thixotropic index) obtained by dividing the viscosity value measured at 5 rpm by the value measured at 20 rpm (at a high shear rate) is in the range of 1-3. In this case, aluminum hydroxide was uniformly dispersed in the resin, and it was found that a molded article having no bubbles, a beautiful appearance, and excellent mechanical strength was obtained. As a result of conducting experiments by combining physical properties as variables, it was found that aluminum hydroxide having a high average brightness, a specific range of average particle diameter, a BET specific surface area, and an X-ray shape factor. In the case where a resin is used, it is possible to obtain an aluminum hydroxide for resin filling suitable for BMC applications in which all of the above problems are solved, and in the case where this is used as a filler, a molded article having excellent physical properties can be provided. It has been found that a resin composition can be obtained, and the present invention has been completed.
[0005]
[Means for Solving the Problems]
That is, the present invention has an average particle diameter of 5 m to 20 [mu] m, BET specific surface area 0.5m 2 /g~4.5m 2 / g, a shape factor 4 -10 by X-ray [gibbsite (002) plane / (110) plane of the Peak intensity ratio], and a whiteness of 93 or more.
[0006]
The present invention further provides a resin composition obtained by filling the above-mentioned aluminum hydroxide for resin filling with 50 to 400 parts by weight based on 100 parts by weight of an unsaturated polyester resin, a vinyl ester resin or a methacrylate resin.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
As the aluminum hydroxide powder used in the present invention, an alumina hydrate represented by the general formula Al 2 O 3 .nH 2 O (where n = 1 to 3), generally alumina trihydrate, is used. .
[0008]
The average particle size of the aluminum hydroxide powder used in the present invention is in the range of 5 μm to 30 μm, preferably 8 μm to 20 μm. If the particle size is less than 5 μm, the viscosity at the time of filling the resin becomes too high, making uniform dispersion difficult, and there is a problem that the gelation time is delayed, and the amount of hydroxylation that can give the texture of artificial marble to the resin is increased. Filling of aluminum becomes difficult. Conversely, if it is larger than 30 μm, not only the surface gloss of the finally obtained resin composition molded body will deteriorate, and also the mechanical strength will decrease, but also depending on the curing conditions, gravitational sedimentation of the aluminum hydroxide powder and the like will occur. In some cases, a molded product in which the dispersion of the filler therein is uneven is obtained. Here, the average particle diameter used in the present invention refers to a value measured by a particle size distribution measuring device by a laser diffraction method.
[0009]
Further, BET specific surface area of the aluminum hydroxide powder used in the present invention is in the range of 0.5m 2 /g~4.5m 2 / g, preferably 1.5m 2 /g~3.0m 2 / g. If the BET specific surface area of the powder is smaller than 0.5 m 2 / g, the amount of physically adsorbed water on the aluminum hydroxide surface is small, and sufficient compound hardness cannot be obtained, so that press molding becomes difficult. Conversely, if it is more than 4.5 m 2 / g, the amount of physically adsorbed water on the surface of the aluminum hydroxide powder becomes too large, and the gelation time (time until the compound hardens and becomes a molded product) becomes slow, and in some cases poor curing may occur. May occur, and the resin filling viscosity will increase. Here, the BET specific surface area used in the present invention refers to a value measured by a nitrogen adsorption method.
[0010]
Further, the X-ray shape factor of the aluminum hydroxide powder used in the present invention is in the range of 2 to 10, preferably 4 to 8. If this value is less than 2, the thixotropy required for BMC molding, that is, the viscosity behavior of low viscosity during mixing and high viscosity during pressing cannot be obtained. Conversely, if this value is greater than 10, thixotropic properties are generated, but the viscosity at the time of substantial mixing increases, making it difficult to uniformly disperse the powder in the resin, and further increasing the viscosity at the time of press molding becomes too high. Nests may form. Here, the X-ray shape factor used in the present invention refers to the peak of the gibbsite (002) plane when X-ray diffraction measurement is performed with Cu-Kα radiation generated from aluminum hydroxide powder at a voltage of 50 kV and 40 mA. It refers to a value obtained by dividing the intensity by the peak intensity of the gibbsite (110) plane, and is a value indicating how much cleavage surface appears due to pulverization.
[0011]
The whiteness of the aluminum hydroxide powder used in the present invention is 93 or more, preferably 95 or more. When this value is smaller than 93, the molded article is colored and a high-grade artificial marble appearance cannot be obtained. Here, the whiteness in the present invention indicates the Hunter whiteness of the powder.
Aluminum hydroxide having each of these physical properties independently existed in the past, but the present inventors, when satisfying all of these physical properties simultaneously, have excellent workability and physical properties as a resin filler for BMC molding. It has been found that a resin composition having the following formula can be obtained. Even if the average particle diameter and the BET specific surface area are within this range, if the X-ray shape factor is out of this range, it is suitable for BMC molding. In addition, problems such as inability to obtain a thixotropic property occur.
[0012]
A method for obtaining an aluminum hydroxide powder having such physical properties is not particularly limited, but an aluminum hydroxide raw material having a high whiteness and a sharp particle size distribution, for example, an average particle diameter of about 20 to 120 μm, and a BET specific surface area of 0. An aluminum hydroxide powder having a ratio of 0.05 to 0.5 m 2 / g, a D 90% / D 10% ratio of 3.5 or less, more preferably 3 or less, and a whiteness of 85 or more is used as a raw material. Can be obtained by pulverizing using a volume pulverizer.
[0013]
In the practice of the present invention, aluminum hydroxide may be used by treating the surface of aluminum hydroxide with a surface treating agent such as a silane coupling agent for the purpose of improving the mechanical strength or boiling resistance of the obtained molded article. it can.
[0014]
Such a silane coupling agent is not particularly limited, but examples include methacrylic silane, acrylic silane, vinyl silane, epoxy silane, amino silane and the like. These silane coupling agents may be used in combination with a silicate or the like, and can be used properly according to the purpose.
The amount of the surface treating agent to be added is naturally determined according to the desired balance between physical properties and price, but it is usually used in the range of about 0.1 to 3 parts by weight based on 100 parts by weight of the aluminum hydroxide powder. General.
The method of adding these surface treatment agents is not particularly limited, but a method of adding aluminum hydroxide powder while stirring with a Henschel mixer, a blender or the like is generally used. At the same time, these surface treatment agents may be added and the treatment may be performed simultaneously with the pulverization.
[0015]
The resin to be compounded with the aluminum hydroxide of the present invention is not particularly limited as long as it is a resin used for BMC molding. For artificial marble, for example, unsaturated polyester resin, vinyl ester resin, methyl methacrylate resin, etc. No.
The addition amount (filling amount) of the aluminum hydroxide of the present invention to the resin may be in a known range. For example, when used for artificial marble, about 50 parts by weight to about 400 parts by weight with respect to 100 parts by weight of the resin. Parts, preferably from about 150 parts to about 300 parts by weight. When the amount of aluminum hydroxide added to the resin is small, it is difficult to obtain the texture of artificial marble, and the cost is increased due to the relatively large amount of resin, which is not preferable. On the other hand, if the amount of the aluminum hydroxide is too large, the dispersibility of the aluminum hydroxide powder in the resin is deteriorated, and the mechanical strength of the obtained molded body is reduced.
[0016]
【The invention's effect】
As described above in detail, the aluminum hydroxide powder of the present invention can be used in a case where a considerably large amount of the aluminum hydroxide powder is filled into a resin such as an unsaturated polyester resin, vinyl ester or methacrylate to obtain a molded article such as artificial marble. It can be uniformly dispersed in the resin at the time of mixing, gives sufficient compound hardness at the time of pressing, and the obtained resin molded product also has excellent mechanical strength and appearance. It is extremely effective as an aluminum oxide powder, and its industrial value is extremely large.
[0017]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by such Examples.
In this example, the particle size distribution was measured by the following method.
Particle size distribution: 0.5 g of aluminum hydroxide powder was added to 60 ml of 0.2% sodium hexametaphosphate aqueous solution, and the mixture was ultrasonically dispersed for 10 minutes. The resulting sample solution was subjected to laser diffraction microtrack particle size analyzer model 7997-10-SRA. , The cumulative 50% particle size, the cumulative 90% particle size, and the cumulative 10% particle size were measured and calculated, respectively.
[0018]
Example 1
300 g of a sharp particle size distribution aluminum hydroxide having a BET specific surface area of 0.13 m 2 / g, an average particle diameter of 62.1 μm, a D 90% / D 10% ratio of 3.2 at a whiteness of 98, and an inner volume of 2 liters. The mixture was charged into an alumina pot (filled with 2.9 kg of alumina balls having a diameter of 8 mm) and subjected to vibration mill pulverization at an amplitude of 3 mm for 30 minutes. The resulting aluminum hydroxide had an average particle size of 9.8 μm, a BET specific surface area of 1.58 m 2 / g, an X-ray shape factor of 4.0, and a whiteness of 97.
200 parts by weight of the above aluminum hydroxide was charged into 100 parts by weight of a vinyl ester resin (trade name: XP-675, manufactured by Takeda Pharmaceutical Co., Ltd.) having a viscosity of 8.5 poise at 25 ° C. and mixed well. The viscosity at 5 rpm of this composition measured at 25 ° C with a DVU-B viscometer (using a No. 7 rotor) was 1200 poise, and its thixotropy index was 1.5.
The appearance of the molded article obtained by curing this composition was transparent, less colored and good.
[0019]
Example 2
Vibration mill pulverization was performed under the same conditions as in Example 1 except that the pulverization raw material used in Example 1 was used and the pulverization time was changed to 60 minutes.
The resulting aluminum hydroxide had an average particle size of 7.1 μm, a BET specific surface area of 2.63 m 2 / g, an X-ray shape factor of 6.8, and a whiteness of 96.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 1640 poise, and the thixotropy index was 2.0.
The appearance of the molded article obtained by curing this composition was transparent, less colored and good.
[0020]
Test example 1
Except for using sharp aluminum hydroxide having a particle size distribution with a whiteness of 96, a BET specific surface area of 0.14 m 2 / g, an average particle diameter of 88.0 μm, and a D 90% / D 10% ratio of 2.7 as the pulverized raw material. Was subjected to vibration mill pulverization under the same conditions as in Example 1. The resulting aluminum hydroxide had an average particle size of 12.0 μm, a BET specific surface area of 1.70 m 2 / g, an X-ray shape factor of 2.3, and a whiteness of 96.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 850 poise, and the thixotropy index was 1.3.
The appearance of the molded article obtained by curing this composition was transparent, less colored and good.
[0021]
Example 3
Vibration mill pulverization was performed under the same conditions as in Test Example 1 except that the pulverization raw material used in Test Example 1 was used and the pulverization time was changed to 60 minutes.
The resulting aluminum hydroxide had an average particle size of 9.0 μm, a BET specific surface area of 2.44 m 2 / g, an X-ray shape factor of 8.0, and a whiteness of 95.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 1850 poise, and the thixotropy index was 2.3.
The appearance of a molded article obtained by curing this resin composition was transparent, less colored, and good.
[0022]
Comparative Example 1
Example 1 was repeated except that aluminum hydroxide having a BET specific surface area of 0.15 m 2 / g, an average particle diameter of 74.4 μm, and a D 90% / D 10% ratio of 4.0 was used as the pulverized raw material at a whiteness of 96. Vibration mill grinding was performed under the same conditions. The resulting aluminum hydroxide had an average particle size of 35.2 μm, a BET specific surface area of 1.23 m 2 / g, an X-ray shape factor of 3.5, and a whiteness of 96.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 460 poise, and the thixotropy index was 1.3.
[0023]
Comparative Example 2
Vibration mill pulverization was performed under the same conditions as in Comparative Example 1 except that the pulverizing raw material used in Comparative Example 1 was used and the pulverizing time was changed to 60 minutes.
The resulting aluminum hydroxide had an average particle size of 13.9 μm, a BET specific surface area of 2.42 m 2 / g, an X-ray shape factor of 15.3, and a whiteness of 95.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 2500 poise, and the thixotropy index was 3.5.
[0024]
Comparative Example 3
Vibration mill pulverization was performed under the same conditions as in Example 1 except that the pulverization raw material used in Example 1 was used and the pulverization time was changed to 10 minutes.
The resulting aluminum hydroxide had an average particle size of 32.7 μm, a BET specific surface area of 1.00 m 2 / g, an X-ray shape factor of 1.7, and a whiteness of 98.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 450 poise, and the thixotropy index was 1.2.
[0025]
Comparative Example 4
Vibration mill pulverization was performed under the same conditions as in Example 1 except that the pulverization raw material used in Example 1 was used and the pulverization time was changed to 120 minutes.
The resulting aluminum hydroxide had an average particle size of 5.3 μm, a BET specific surface area of 4.85 m 2 / g, an X-ray shape factor of 9.4, and a whiteness of 94.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 3100 poise, and the thixotropy index was 2.9.
[0026]
Comparative Example 5
Example 1 was repeated except that an aluminum hydroxide having a BET specific surface area of 0.21 m 2 / g, an average particle diameter of 67.1 μm, and a D 90% / D 10% ratio of 3.3 was used as the pulverized raw material at a brightness of 83. Vibration mill grinding was performed under the same conditions. The resulting aluminum hydroxide had an average particle size of 11.0 μm, a BET specific surface area of 1.32 m 2 / g, an X-ray shape factor of 3.5, and a whiteness of 89.
Using this, a resin composition was prepared in the same manner as in Example 1, and the viscosity was measured.
As a result, the viscosity at 5 rpm was 1030 poise, and the thixotropy index was 1.4.
The appearance of the molded product obtained by curing the resin composition was yellow although it was transparent, and was not preferable as the color tone of the artificial marble.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33455495A JP3575150B2 (en) | 1995-12-22 | 1995-12-22 | Aluminum hydroxide for resin filling and resin composition using the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33455495A JP3575150B2 (en) | 1995-12-22 | 1995-12-22 | Aluminum hydroxide for resin filling and resin composition using the same |
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| Publication Number | Publication Date |
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| JPH09176367A JPH09176367A (en) | 1997-07-08 |
| JP3575150B2 true JP3575150B2 (en) | 2004-10-13 |
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| US11549190B2 (en) | 2018-07-31 | 2023-01-10 | Uacj Corporation | Aluminum member and method of manufacturing aluminum member |
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| US6887454B1 (en) | 1999-06-29 | 2005-05-03 | Albemarle Corporation | Process for the production of aluminium hydroxide |
| KR100894589B1 (en) * | 2001-06-21 | 2009-04-24 | 쇼와 덴코 가부시키가이샤 | Aluminum hydroxide and production process thereof |
| KR100894590B1 (en) * | 2001-06-21 | 2009-04-24 | 쇼와 덴코 가부시키가이샤 | Aluminum hydroxide and production process thereof |
| CN101360777B (en) * | 2005-11-30 | 2012-12-19 | 亚什兰许可和知识产权有限公司 | Prepregs and cured in place solid surfaces prepared therefrom |
| CN109810442B (en) * | 2019-01-24 | 2021-06-08 | 广州秀珀化工涂料有限公司 | MMA-vinyl blind guiding brick material and preparation method thereof |
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1995
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US11549190B2 (en) | 2018-07-31 | 2023-01-10 | Uacj Corporation | Aluminum member and method of manufacturing aluminum member |
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