JP3729234B2 - Fine particle dispersion and method for producing the same - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、表面に特定の有機高分子カップリング剤を結合させた微粒子とその製造方法、並びに該微粒子を有機溶媒に分散した微粒子分散体に関するものである。
【０００２】
【従来の技術】
一般的に、シリカ、アルミナ等の無機酸化物微粒子を有機溶媒に安定に分散等させるために、微粒子の表面を修飾することが行われている。このような表面修飾法としては、反応性モノマ−またはカップリング剤等と微粒子表面の官能基、例えばヒドロキシル基を反応させる方法が知られている。具体的には、粉末状の微粒子を有機溶媒に分散させたのちに修飾剤を添加して微粒子表面を修飾する方法、あるいは微粒子の水分散液の水を有機溶媒と置換したのちに修飾剤を添加して微粒子表面を修飾する方法などがある。
【０００３】
しかしながら、これらの方法では、微粒子の凝集を完全に抑制することができず、分散性の良い安定な有機溶媒ゾルを得ることが困難であった。また、高濃度で増粘することなく分散性の良い安定な有機溶媒ゾルを得ることが困難であった。また、ゾルを乾燥して粉体化した後再分散させて有機溶媒ゾルを得ようとしても、凝集しているために分散性の良い安定な有機溶媒ゾルを得ることが困難であった。
【０００４】
さらに、最近、水または有機溶媒に微粒子を分散させた、光彩色を呈する分散液が注目されている。例えば、特公平１−２３４１１号公報には、光彩色を呈する透明で且つ安定なシリカ質ゾルの製造方法が開示されている。この製造法によれば、０. ２〜１μｍの粒子径で、粒径が揃った無定型シリカ球を用いてチンダル散光を呈するアルコール類分散液を作り、このアルコール類分散媒を低極性溶媒で置換することにより前記シリカ質ゾルを製造するものである。更に、同公報には光彩色を呈する原理に関して、粒子が溶媒中で面心立法配列をとり、配列面の重なりの間隔が光の波長程度に小さいため、その面に対してある角度で入射した白色光は分光され、特定方向に特定の波長の光が回折する結果、特定の単色光が見られ、目の位置を変えることにより、その色が連続的に変化する旨説明されている。
【０００５】
また、特開平６−１００４３２号公報には、オパール色を呈する微粒子分散液が開示されている。平均粒径が７００ｎｍ以下の均一な有機高分子あるいは無機化合物微粒子を水またはアルコール類の他、極性有機溶媒に分散させ、脱イオン化により微粒子分散液の電気伝導度を５６０μＳ／ｃｍ以下にすることにより前記分散液を得ている。
【０００６】
上記公報では、オパール色を呈する原理に関して、前記脱イオン化により、粒子表面の電気２重層が膨張し、粒子間に相互反発力が作用する結果、微粒子の分散状態が安定化し、微粒子は沈降することなく、分散液全体において一様に規則的配列をとるようになる。この結果、微結晶の集合体に似た構造をとり、この微結晶類似構造の面により光が分光され、特定方向に特定波長の光が回折されて単色光が観察されるが、この分散液は微結晶間の粒界と同様な不連続面が存在するので、個々の微結晶類似構造面での回折光が異なり種々の色の光彩が観察される、すなわちオパールに固有の遊色と呼ばれる現象が発現すると説明されている。しかしながらこの場合、脱イオン工程に長時間を要し、振動により遊色が一時的に消滅し再び遊色を発現する迄に時間を要すること、さらに遊色が不安定であるなどの問題点も記載されている。
【０００７】
【発明が解決しようとする課題】
本発明は、高濃度においても増粘することが無く、安定性、再分散性に優れた微粒子分散体であって、微粒子を有機分散媒に分散させた液体状あるいは固体状の遊色を呈する分散体とその製造方法を提供することを目的としている。
【０００８】
【課題を解決するための手段】
本発明に係る微粒子分散体は、遊色を呈する微粒子分散体であって、無機微粒子または有機無機複合微粒子表面にシラン系有機高分子カップリング剤が結合してなることを特徴とする。
前記シラン系有機高分子カップリング剤が結合した微粒子におけるシラン系有機高分子カップリング剤の表面密度は３．０×１０-8〜５. ０×１０-6mole／ｍ2 であることが好ましい。
【０００９】
前記シラン系有機高分子カップリング剤が結合した微粒子の粒径範囲は５〜７００ｎｍであることが好ましく、前記シラン系有機高分子カップリング剤の分子量は１０００〜２００００の範囲にあることが好ましい。
【００１０】
本発明に係る遊色を呈する微粒子分散体の製造方法は、低極性有機溶媒にシラン系有機高分子カップリング剤を溶解した後、微粒子表面に３. ０×１０-6〜１. ３×１０-5mole／ｍ2 の表面密度の官能基を有する無機微粒子または有機無機複合微粒子を添加して加熱反応させて微粒子表面にカップリング剤を結合させ、該微粒子を有機液体分散媒または有機固体分散媒に分散させることを特徴とする。
前記シラン系有機高分子カップリング剤溶液における前記無機微粒子または有機無機複合微粒子の濃度は０. １〜５重量％であることが好ましい。
【００１１】
【発明の実施の形態】
本発明において原料無機微粒子または有機無機複合微粒子は、表面に官能基を有していることが必要である。この官能基はＯＨ基であることが好ましく、さらに固体酸性（イオン交換性）を有し反応性に富むことが好ましい。このような官能基であれば後述するシラン系有機高分子カップリング剤の加水分解性基と容易に反応し、本願発明の微粒子を得ることができる。
【００１２】
また、上記官能基の密度は３. ０×１０-6〜１. ３×１０-5mole／ｍ2 の範囲にあることが好ましい。３. ０×１０-6mole／ｍ2 未満では微粒子表面のシラン系有機高分子カップリング剤の量が少なくなり、本願発明の効果を発現しない場合がある。他方、１. ３×１０-5mole／ｍ2 を超えても、シラン系有機高分子カップリング剤の分子専有断面積の点から、微粒子表面のシラン系有機高分子カップリング剤の量が増加することはない。ＯＨ基の測定は加熱した際に脱離する水の量を測定しＯＨ基量に換算することによって求めることができ、あるいは分光学的な方法、化学的な方法等の公知方法によっても求めることができる。
【００１３】
原料無機微粒子または有機無機複合微粒子は、前記のような表面官能基を有していれば良く、シリカ、チタニア、アルミナ、ジルコニア等の微粒子またはこれらの２種以上の混合物あるいは複合物からなる微粒子であっても、アルコキシシランなどの有機金属化合物を加水分解して得られる有機無機複合微粒子であってもよい。
【００１４】
前記無機微粒子または有機無機複合微粒子の粒径は５〜２０００ｎｍの範囲にあることが好ましい。５ｎｍ未満では、無機微粒子または有機無機複合微粒子の大きさに対してシラン系有機高分子カップリング剤が大きすぎるため、後述するミセル様の形成が困難となり、このため無機微粒子または有機無機複合微粒子の表面を充分に疎水性とすることができないため、増粘することが無く、安定性、再分散性に優れた微粒子を分散質とする有機溶媒ゾルが得られない場合がある。他方、２０００ｎｍを超えて大きい場合は粒子が沈降しやすく安定な有機溶媒ゾルが得られにくい。
【００１５】
特に遊色を呈する微粒子分散体としては、微粒子の粒径の範囲は５〜７００ｎｍ、好ましくは１０〜５５０ｎｍの範囲である。５ｎｍ未満では明瞭な遊色が発現せず、７００ｎｍを超えて大きい場合は遊色が観察できない場合がある。
【００１６】
本発明に用いるシラン系有機高分子カップリング剤は、一端に加水分解性基を有する鎖状構造であって、低極性のものが好ましい。シラン系有機高分子カップリング剤の分子量は、ＧＰＣ法（分子排除クロマト法）によって求めることができ、好ましくは５００〜５００００の範囲、さらに好ましくは１０００〜２００００の範囲である。５００未満では修飾効果が不充分となり、２００００を超えると修飾効果の増加が無くなる。また、１０００〜２００００の範囲にない場合は遊色が不明瞭になったり、あるいは、遊色を発現しにくくなる。
【００１７】
このようなシラン系有機高分子カップリング剤は、一端に加水分解性基を有するシランカップリング剤の他端に反応性モノマーおよび／またはカルボン酸（例えば、無水マレイン酸）を重合あるいは共重合させることにより高分子疎水基を形成させるなどの公知の方法により得ることができる。
【００１８】
無機微粒子または有機無機複合微粒子表面に結合したシラン系有機高分子カップリング剤の表面密度は３．０×１０-8〜５. ０×１０-6mole／ｍ2 の範囲であることが好ましい。さらに好ましい範囲は３．０×１０-7〜２．０×１０-6mole／ｍ2 である。シラン系有機高分子カップリング剤の表面密度は、微粒子を１００℃で充分乾燥して微粒子の重量を測定した後１０００℃まで昇温して重量を測定し、この時の重量減少と前記シラン系有機高分子カップリング剤の分子量から求めることができる。表面密度が３．０×１０-8mole／ｍ2 未満では微粒子表面のシラン系有機高分子カップリング剤の量が少ないので後記する本願発明の効果（分散性、安定性、非凝集性、再分散性、遊色性）を発現しにくく、５. ０×１０-6mole／ｍ2 を超えて高くすることは、シラン系有機高分子カップリング剤の分子専有断面積の点から困難である。
【００１９】
本発明の微粒子を製造するには、予め、低極性の有機溶媒にシラン系有機高分子カップリング剤を添加して、シラン系有機高分子カップリング剤の低極性有機溶媒溶液を調製する。このとき、必要に応じて超音波照射などを行い溶解を促進させる。
【００２０】
前記低極性有機溶媒としては、シラン系有機高分子カップリング剤が可溶のものであれば特に制限はない。特に、比誘電率が２〜５０の低極性有機溶媒が好ましく、例えばアセトン、アセトニトリル、酢酸エチル、ニトロベンゼン、ジメチルフォルムアミド（ＤＭＦ）、ジメトキシエタン（ＤＭＥ）、テトラヒドロフラン（ＴＨＦ）等が挙げられる。
有機溶媒の比誘電率が２未満の低極性有機溶媒は入手が困難で、また比誘電率が５０を超えるとシラン系有機高分子カップリング剤が充分溶解しないことがあり、微粒子との反応が不充分となり本願発明の微粒子が得られにくい。
【００２１】
この時のシラン系有機高分子カップリング剤の濃度は０. １〜５. ０重量％の範囲が好ましい。０. １重量％未満では後述するミセル様を形成し難いためにシラン系有機高分子カップリング剤と無機微粒子または有機無機複合微粒子との反応が充分進行しない場合があり、さらに反応しても粒子表面上のシラン系有機高分子カップリング剤の密度が低すぎて本願発明の効果が発現しにくい。５. ０重量％を超えて高い場合は未溶解のシラン系有機高分子カップリング剤が存在したり、溶解に時間を要することがあるので好ましくない。
【００２２】
次に、上記シラン系有機高分子カップリング剤の溶液に前述した無機微粒子または有機無機複合微粒子を、溶液中の微粒子の濃度が０. １〜５重量％となるように添加する。この時微粒子は粉体のままで添加することができるが、微粒子を予めアルコールなどの有機溶媒に単分散させて用いるのが好ましい。溶液中の微粒子の濃度が０. １重量％未満の場合は処理効率が低く、５重量％を超えて高い場合は微粒子表面上のシラン系有機高分子カップリング剤の量が粒子によって異なり不均一となることがあるので好ましくない。
【００２３】
このような条件が好適である理由は明らかでないが、シラン系有機高分子カップリング剤の一端の加水分解性基が粒子表面官能基に配向して吸着しミセル様構造をとり、次の加熱による反応工程で粒子表面の官能基（ＯＨ基）と加水分解性基が脱アルコール反応等を行い、有機高分子カップリング剤が微粒子表面に結合して本願発明の微粒子が得られるものと考えられる。
【００２４】
続いて、上記微粒子分散溶液を必要に応じて加熱し、無機微粒子あるいは有機無機複合微粒子の単分散に用いたアルコールを留去して濃縮してもよく、さらに必要に応じて低極性有機溶媒を追加してもよい。その後、５０℃、好ましくは６０℃以上の温度で環流しながら反応させ、次いで冷却して有機溶媒で洗浄する。この時の有機溶媒は残留低極性溶媒および反応により副生するアルコールを除去できるものであれば特に制限はないが、先ず極性溶媒で洗浄し、次いで非極性溶媒で洗浄するのが効率的に洗浄できる点で好ましい。最後に、これを乾燥し、溶媒を除去して本願発明の微粒子を得るが、乾燥温度は得られる粒子が変質しない範囲でできるだけ低い方が好ましく、減圧乾燥が特に好ましい。
【００２５】
次に、本発明の微粒子分散体を説明する。
微粒子分散体は、上述した本発明の微粒子が有機液体分散媒または有機固体分散媒に分散してなるものである。
【００２６】
前記有機液体分散媒としては、公知の有機溶媒を用いることができ、例えばアルコール類の他、アセトン、アセトニトリル、ジメチルフォルムアミド（ＤＭＦ）、ジメトキシエタン（ＤＭＥ）、テトラヒドロフラン（ＴＨＦ）等が挙げられる。
【００２７】
特に、遊色を呈するための有機液体分散媒としては、アルコール以外の比誘電率が２〜５０の低極性有機溶媒が好ましく、アセトン、アセトニトリル、ニトロベンゼン、ＤＭＦ、ＤＭＥ等が挙げられる。遊色を呈するための有機固体分散媒としては、硬化樹脂が好ましい。この場合、微粒子分散体は樹脂モノマーに前記微粒子を分散させた後、加熱あるいは紫外線等を照射して硬化させることによって得られる。当該樹脂モノマーとしてはＮ' Ｎ−ジメチルアクリルアミド、アクリロニトリル等が好ましい。
【００２８】
本発明の微粒子分散体中の微粒子の濃度は体積分率で０. １〜５０％の範囲が好ましい。特に遊色を呈する分散体中の微粒子の濃度は体積分率で０. １〜２０％の範囲が好ましく、特に好ましい範囲は０. ５〜１０％である。０. １％未満では有色を呈する迄の時間が長くなり、５０％を超えて高い場合は均一に分散させることが困難になるとともに、得られる分散体の粘度が高くなるので好ましくない。
【００２９】
【実施例】
以下、実施例を示して本発明を具体的に説明する。
【００３０】
実施例１
［有機高分子カップリング剤の調製］
容器に無水マレイン酸６０２ｇ、乾燥スチレン６７ｇおよび乾燥テトラヒドロフラン（ＴＨＦ）１４０ｍｌを計量し、これに３−メルカプトプロピルトリメトキシシランを４０ｍｌと２, ２’−アゾビスイソブチロニトリル（ＡＩＢＮ：重合開始剤・触媒）０. ８ｇを添加し、窒素雰囲気下、７０℃で３時間環流した。ついで室温まで冷却した後、充分量のテトラヒドロフランに溶解し、その後約２００Ｌのエーテルに沈殿させ、濾過分離後に減圧乾燥してシラン系有機高分子カップリング剤（ａ）を調製した。分子量の測定結果は表１に示した。
【００３１】
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、シラン系有機高分子カップリング剤（ａ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ａ）を完全に溶解した。これにシリカ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２６Ｌ、粒子径１２０ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ａ）を調製した。有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００３２】
実施例２
［シラン系有機高分子カップリング剤の調製］
容器に無水マレイン酸６０２ｇ、乾燥スチレン６７ｇおよび乾燥テトラヒドロフラン（ＴＨＦ）１４０ｍｌを計量し、これに３−メルカプトプロピルトリメトキシシランを２００ｍｌ（実施例１の５倍量）と２, ２’−アゾビスイソブチロニトリル（ＡＩＢＮ：重合開始剤・触媒）４ｇを添加し、窒素雰囲気下、７０℃で３時間環流した。ついで室温まで冷却した後、充分量のテトラヒドロフランに溶解し、その後約２００Ｌのエーテルに沈殿させ、濾過分離後に減圧乾燥してシラン系有機高分子カップリング剤（ｂ）を調製した。分子量の測定結果は表１に示した。
【００３３】
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、シラン系有機高分子カップリング剤（ｂ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ｂ）を完全に溶解した。これにシリカ・アルミナ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２２、粒子径１０ｎｍ、ＳｉＯ2 ・Ａｌ2 Ｏ3 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｂ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００３４】
実施例３
［シラン系有機高分子カップリング剤の調製］
容器に無水マレイン酸１２００ｇ、酢酸ビニル１３４ｇおよび乾燥テトラヒドロフラン（ＴＨＦ）２８０ｍｌを計量し、これに３−メルカプトプロピルトリメトキシシランを４０ｍｌと２, ２’−アゾビスイソブチロニトリル（ＡＩＢＮ：重合開始剤・触媒）０. ８ｇを添加し、窒素雰囲気下、７０℃で３時間環流した。ついで室温まで冷却した後、充分量のテトラヒドロフランに溶解し、その後約２００Ｌのエーテルに沈殿させ、濾過分離後に減圧乾燥してシラン系有機高分子カップリング剤（ｃ）を調製した。分子量の測定結果は表１に示した。
【００３５】
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、シラン系有機高分子カップリング剤（ｃ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ｃ）を完全に溶解した。これにシリカ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２８、粒子径３００ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｃ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００３６】
実施例４
［シラン系有機高分子カップリング剤の調製］
容器に無水マレイン酸６０２ｇ、乾燥スチレン６７ｇおよび乾燥テトラヒドロフラン（ＴＨＦ）１４０ｍｌを計量し、これに３−メルカプトプロピルトリメトキシシランを６７ｍｌと２, ２’−アゾビスイソブチロニトリル（ＡＩＢＮ：重合開始剤・触媒）１. ３ｇを添加し、窒素雰囲気下、７０℃で３時間環流した。ついで室温まで冷却した後、充分量のテトラヒドロフランに溶解し、その後約２００Ｌのエーテルに沈殿させ、濾過分離後に減圧乾燥してシラン系有機高分子カップリング剤（ｄ）を調製した。分子量の測定結果は表１に示した。
【００３７】
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、実施例１のシラン系有機高分子カップリング剤（ｄ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ｄ）を完全に溶解した。これにシリカ・ジルコニア微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２４、粒子径５０ｎｍ、ＳｉＯ2・ＺｒＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。次いで９０℃に加熱して溶媒を２９Ｌ留出した後テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｄ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００３８】
実施例５
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、実施例１で調製したシラン系有機高分子カップリング剤（ａ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ａ）を完全に溶解した。これにシリカ・アルミナ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２６Ｌ、粒子径１２０ｎｍ、ＳｉＯ2 ・Ａｌ2 Ｏ3 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥して有機高分子カップリング剤修飾微粒子（Ｅ）を調製した。有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００３９】
［固体状微粒子分散体の調製］
有機液体分散媒または有機固体分散媒に分散してなる微粒子分散体。
次に、上記液体状の微粒子分散体１００ｇに９０ｇのアクリロニトリルを混合した後、乾燥して分散媒を除去し、次いで紫外線を照射して硬化して固体状微粒子分散体（Ｅ−１）を調製した。また、アクリロニトリルの代わりにＮ’Ｎ−ジメチルアクリルアミドを使用した以外は（Ｅ−１）と同様にして、固体状微粒子分散体（Ｅ−２）を調製した。
得られた固体状微粒子分散体について有色を観察したところ、上記液体状微粒子分散体と比較して鮮明ではなく部分的ではあるもの、遊色が観察された。
【００４０】
実施例６
［シラン系有機高分子カップリング剤の調製］
容器に無水マレイン酸２４００ｇ、乾燥スチレン２６８ｇおよび乾燥テトラヒドロフラン（ＴＨＦ）５６０ｍｌを計量し、これに３−メルカプトプロピルトリメトキシシランを４０ｍｌと２, ２’−アゾビスイソブチロニトリル（ＡＩＢＮ：重合開始剤・触媒）０. ８ｇを添加し、窒素雰囲気下、７０℃で３時間環流した。ついで室温まで冷却した後、充分量のテトラヒドロフランに溶解し、その後約２００Ｌのエーテルに沈殿させ、濾過分離後に減圧乾燥してシラン系有機高分子カップリング剤（ｆ）を調製した。分子量の測定結果は表１に示した。
【００４１】
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、シラン系有機高分子カップリング剤（ｆ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ｆ）を完全に溶解した。これにシリカ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−ＰＡ−７００、粒子径７００ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後、テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｆ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００４２】
実施例７
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、実施例１で調製したシラン系有機高分子カップリング剤（ａ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ａ）を完全に溶解した。これに特開平１０−４５４０３号公報に基づいて調製したビニル基を含有するシリカ微粒子をエタノールに分散させたゾル（粒子径１２０ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後、テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｇ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００４３】
実施例８
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、実施例１で調製したシラン系有機高分子カップリング剤（ａ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射してシラン系有機高分子カップリング剤（ａ）を完全に溶解した。これにテトラアルコキシシランを加水分解して調製した有機無機複合シリカ系微粒子をエタノールに分散させたゾル（粒子径２００ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後、テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｈ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００４４】
比較例１
［シランカップリング剤修飾微粒子の調製］
容器に、ビニルエトキシシラン２０ｇをとり、これをシリカ・アルミナ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−１２２６Ｌ、粒子径１２０ｎｍ、ＳｉＯ2 ・Ａｌ2 Ｏ3 濃度１７. ８重量％）２. ２Ｌに添加した。ついで８０℃に加熱して撹拌し、シランカップリング剤（ｉ）で修飾した後分離し、次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシランカップリング剤修飾微粒子（Ｉ）を調製した。シランカップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００４５】
比較例２
［シラン系有機高分子カップリング剤修飾微粒子の調製］
容器に、実施例１で調製したシラン系有機高分子カップリング剤（ａ）５００ｇをとり、これにジメトキシエタン３０Ｌとテトラヒドロフラン５Ｌを加え、超音波を照射して有機高分子カップリング剤（ａ）を完全に溶解した。これにシリカ微粒子をエタノールに分散させたゾル（触媒化成製 ＯＳＣＡＬ−ＰＡ−３０００、粒子径３０００ｎｍ、ＳｉＯ2 濃度１７. ８重量％）を２. ２Ｌ添加した。ついで９０℃に加熱して溶媒を２９Ｌ留出した後、テトラヒドロフラン３Ｌを加えて２４時間環流した。次にアセトンで遠心洗浄を４回行い、ついでエーテルで１回遠心洗浄した後、減圧乾燥してシラン系有機高分子カップリング剤修飾微粒子（Ｊ）を調製した。シラン系有機高分子カップリング剤の結合量は表１に示した。
得られた粒子を表１に示す分散媒に濃度が１０重量％となるように分散させ、分散安定性として凝集および沈降の有無を観察した。同時に有色の観察をし、結果を表１に示した。
【００４６】
【表１】
【発明の効果】
本発明に係る微粒子は、表面に特定の有機高分子カップリング剤が結合しているため、これを分散させた分散液は、高濃度においても増粘することが無く、安定性、再分散性に優れている。さらに該微粒子を有機分散媒に分散させた液体状あるいは固体状の微粒子分散体は安定的に且つ明瞭な遊色を呈する。
本発明の微粒子および微粒子分散体は塗料、絶縁被膜、フィルムフィラー、染料および顔料用添加剤、表示装置用ディスプレイ、内外装材の添加剤、化粧水・乳液その他の化粧料配合剤などに有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to fine particles having a specific organic polymer coupling agent bonded to the surface, a method for producing the fine particles, and a fine particle dispersion in which the fine particles are dispersed in an organic solvent.
[0002]
[Prior art]
Generally, in order to stably disperse inorganic oxide fine particles such as silica and alumina in an organic solvent, the surface of the fine particles is modified. As such a surface modification method, a method of reacting a reactive monomer or a coupling agent or the like with a functional group on the surface of fine particles, such as a hydroxyl group, is known. Specifically, after dispersing fine powder particles in an organic solvent, a modifier is added to modify the surface of the fine particles, or the water in the aqueous dispersion of fine particles is replaced with an organic solvent, and then the modifier is added. There is a method of modifying the surface of the fine particles by adding.
[0003]
However, these methods cannot completely suppress aggregation of fine particles, and it is difficult to obtain a stable organic solvent sol with good dispersibility. Moreover, it has been difficult to obtain a stable organic solvent sol with good dispersibility without thickening at a high concentration. Further, even if an organic solvent sol is obtained by drying and pulverizing the sol to obtain an organic solvent sol, it is difficult to obtain a stable organic solvent sol having good dispersibility due to aggregation.
[0004]
Furthermore, recently, a dispersion liquid exhibiting a bright color in which fine particles are dispersed in water or an organic solvent has attracted attention. For example, Japanese Patent Publication No. 1-23411 discloses a method for producing a transparent and stable siliceous sol exhibiting a bright color. According to this production method, an amorphous dispersion having a particle diameter of 0.2 to 1 μm and an amorphous silica sphere having a uniform particle diameter is used to produce an alcohol dispersion that exhibits Tyndall diffused light. The siliceous sol is produced by substitution. Furthermore, in this publication, regarding the principle of exhibiting a brilliant color, the particles have a face-centered arrangement in a solvent, and since the overlapping interval of the arrangement planes is as small as the wavelength of the light, it is incident on the plane at an angle. It is described that white light is dispersed and specific monochromatic light is seen as a result of diffracting light of a specific wavelength in a specific direction, and changing its position continuously changes its color.
[0005]
Japanese Laid-Open Patent Publication No. 6-10000432 discloses a fine particle dispersion exhibiting an opal color. By dispersing uniform organic polymer or inorganic compound fine particles with an average particle size of 700 nm or less in a polar organic solvent in addition to water or alcohols, and deionizing the electric conductivity of the fine particle dispersion to 560 μS / cm or less. The dispersion is obtained.
[0006]
In the above publication, regarding the principle of opal color, the electric double layer on the particle surface expands due to the deionization, and as a result of the mutual repulsive force acting between the particles, the dispersion state of the fine particles is stabilized and the fine particles settle. In other words, a uniform and regular arrangement is obtained throughout the dispersion. As a result, it takes a structure resembling an aggregate of microcrystals, and light is dispersed by the surface of this microcrystal-analogous structure, and light of a specific wavelength is diffracted in a specific direction, and monochromatic light is observed. Since there are discontinuous surfaces similar to the grain boundaries between the microcrystals, the diffracted light on the individual microcrystal-analogous structural surfaces is different, and various colors of light are observed. It is explained that the phenomenon appears. In this case, however, the deionization process takes a long time, and it takes time until the play color disappears temporarily due to vibration and the play color is developed again, and the play color is unstable. Has been described.
[0007]
[Problems to be solved by the invention]
The present invention does not thicken even at a high concentration, and has excellent stability and redispersibility.Dispersion having a liquid or solid idle color in which fine particles are dispersed in an organic dispersion mediumAnd its manufacturing method.
[0008]
[Means for Solving the Problems]
Fine particles according to the present inventionDispersionIsA fine particle dispersion exhibiting a play color,A silane-based organic polymer coupling agent is bonded to the surface of inorganic fine particles or organic-inorganic composite fine particles.
The surface density of the silane organic polymer coupling agent in the fine particles to which the silane organic polymer coupling agent is bonded is 3.0 × 10.-8~ 5.0 × 10-6mole / m2It is preferable that
[0009]
The particle size range of the fine particles to which the silane organic polymer coupling agent is bonded is preferably 5 to 700 nm, and the molecular weight of the silane organic polymer coupling agent is in the range of 1000 to 20000.It is preferable.
[0010]
According to the present inventionExhibit playful colorFine particlesDispersionIn the production method of this method, a silane organic polymer coupling agent is dissolved in a low-polarity organic solvent, and then 3.0 × 10 3 on the fine particle surface.-6~ 1.3 × 10-Fivemole / m2Add inorganic fine particles or organic-inorganic composite fine particles with functional group of surface density and heat reactionCoupling a coupling agent to the surface of the fine particles, and dispersing the fine particles in an organic liquid dispersion medium or an organic solid dispersion medium.It is characterized by that.
The concentration of the inorganic fine particles or organic / inorganic composite fine particles in the silane-based organic polymer coupling agent solution is preferably 0.1 to 5% by weight.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the raw inorganic fine particles or the organic / inorganic composite fine particles are required to have a functional group on the surface. This functional group is preferably an OH group, and preferably has a solid acidity (ion exchangeability) and is highly reactive. If it is such a functional group, it will react easily with the hydrolyzable group of the silane type organic polymer coupling agent mentioned later, and the microparticles | fine-particles of this invention can be obtained.
[0012]
The density of the functional group is 3.0 × 10-6~ 1.3 × 10-Fivemole / m2 It is preferable that it exists in the range. 3.0 × 10-6mole / m2 If it is less than this, the amount of the silane-based organic polymer coupling agent on the surface of the fine particles will be small, and the effects of the present invention may not be exhibited. On the other hand, 1.3 × 10-Fivemole / m2 The amount of the silane-based organic polymer coupling agent on the surface of the fine particles does not increase from the viewpoint of the molecular exclusive cross-sectional area of the silane-based organic polymer coupling agent. Measurement of OH groups can be obtained by measuring the amount of water desorbed when heated and converting to the amount of OH groups, or by a known method such as a spectroscopic method or a chemical method. Can do.
[0013]
The raw material inorganic fine particles or the organic / inorganic composite fine particles may be fine particles composed of fine particles of silica, titania, alumina, zirconia, etc., or a mixture or composite of two or more thereof, as long as it has the surface functional group as described above. Alternatively, organic / inorganic composite fine particles obtained by hydrolyzing an organometallic compound such as alkoxysilane may be used.
[0014]
The particle size of the inorganic fine particles or organic-inorganic composite fine particles is preferably in the range of 5 to 2000 nm. If the thickness is less than 5 nm, the silane-based organic polymer coupling agent is too large relative to the size of the inorganic fine particles or organic-inorganic composite fine particles, so that it becomes difficult to form a micelle that will be described later. Since the surface cannot be made sufficiently hydrophobic, there is a case where an organic solvent sol using fine particles having excellent stability and redispersibility as a dispersoid cannot be obtained. On the other hand, if it exceeds 2000 nm, the particles are likely to settle and it is difficult to obtain a stable organic solvent sol.
[0015]
In particular, for a fine particle dispersion exhibiting a playful color, the particle size range of the fine particles is 5 to 700 nm, preferably 10 to 550 nm. If the thickness is less than 5 nm, no clear play color appears, and if it exceeds 700 nm, the play color may not be observed.
[0016]
The silane organic polymer coupling agent used in the present invention is preferably a chain structure having a hydrolyzable group at one end and having a low polarity. The molecular weight of the silane-based organic polymer coupling agent can be determined by the GPC method (molecular exclusion chromatography method), preferably in the range of 500 to 50000, more preferably in the range of 1000 to 20000. If it is less than 500, the modification effect is insufficient, and if it exceeds 20000, the modification effect is not increased. In addition, when it is not in the range of 1000 to 20000, the play color becomes unclear or it becomes difficult to express the play color.
[0017]
Such a silane organic polymer coupling agent polymerizes or copolymerizes a reactive monomer and / or a carboxylic acid (for example, maleic anhydride) at the other end of the silane coupling agent having a hydrolyzable group at one end. Thus, it can be obtained by a known method such as forming a polymer hydrophobic group.
[0018]
The surface density of the silane organic polymer coupling agent bonded to the surface of the inorganic fine particles or the organic / inorganic composite fine particles is 3.0 × 10-8~ 5.0 × 10-6mole / m2 It is preferable that it is the range of these. A more preferable range is 3.0 × 10.-7~ 2.0 × 10-6mole / m2 It is. The surface density of the silane-based organic polymer coupling agent was determined by thoroughly drying the fine particles at 100 ° C. and measuring the weight of the fine particles, then raising the temperature to 1000 ° C. and measuring the weight. It can be determined from the molecular weight of the organic polymer coupling agent. Surface density is 3.0 × 10-8mole / m2 If it is less than 5, the amount of the silane-based organic polymer coupling agent on the surface of the fine particles is small, so that the effects of the present invention described later (dispersibility, stability, non-aggregation, redispersibility, playability) are difficult to be exhibited. 0x10-6mole / m2 It is difficult to increase the value beyond the range from the viewpoint of the molecular exclusive cross-sectional area of the silane-based organic polymer coupling agent.
[0019]
In order to produce the fine particles of the present invention, a silane organic polymer coupling agent is added in advance to a low polarity organic solvent to prepare a low polarity organic solvent solution of the silane organic polymer coupling agent. At this time, dissolution is promoted by performing ultrasonic irradiation or the like as necessary.
[0020]
The low-polar organic solvent is not particularly limited as long as the silane organic polymer coupling agent is soluble. In particular, a low polar organic solvent having a relative dielectric constant of 2 to 50 is preferable, and examples thereof include acetone, acetonitrile, ethyl acetate, nitrobenzene, dimethylformamide (DMF), dimethoxyethane (DME), and tetrahydrofuran (THF).
It is difficult to obtain a low polar organic solvent having a relative dielectric constant of less than 2, and when the relative dielectric constant exceeds 50, the silane organic polymer coupling agent may not be sufficiently dissolved, and the reaction with fine particles may not occur. It becomes insufficient and it is difficult to obtain the fine particles of the present invention.
[0021]
At this time, the concentration of the silane organic polymer coupling agent is preferably in the range of 0.1 to 5.0% by weight. If the amount is less than 0.1% by weight, it is difficult to form the micelle-like state described later, so that the reaction between the silane organic polymer coupling agent and the inorganic fine particles or organic-inorganic composite fine particles may not proceed sufficiently. The density of the silane-based organic polymer coupling agent on the surface is too low, and the effect of the present invention is hardly exhibited. If it exceeds 5.0% by weight, it is not preferable because an undissolved silane-based organic polymer coupling agent may be present or dissolution may take time.
[0022]
Next, the above-mentioned inorganic fine particles or organic-inorganic composite fine particles are added to the silane-based organic polymer coupling agent solution so that the concentration of the fine particles in the solution is 0.1 to 5% by weight. At this time, the fine particles can be added in the form of powder, but it is preferable to use the fine particles monodispersed in advance in an organic solvent such as alcohol. When the concentration of the fine particles in the solution is less than 0.1% by weight, the treatment efficiency is low. When the concentration is higher than 5% by weight, the amount of the silane organic polymer coupling agent on the fine particle surface varies depending on the particles and is not uniform. This is not preferable.
[0023]
The reason why such conditions are suitable is not clear, but the hydrolyzable group at one end of the silane-based organic polymer coupling agent is oriented and adsorbed on the particle surface functional group to form a micelle-like structure. It is considered that the functional group (OH group) and the hydrolyzable group on the particle surface undergo a dealcoholization reaction or the like in the reaction step, and the organic polymer coupling agent binds to the surface of the fine particle to obtain the fine particle of the present invention.
[0024]
Subsequently, the fine particle dispersion may be heated as necessary, and the alcohol used for monodispersing the inorganic fine particles or the organic / inorganic composite fine particles may be distilled off and concentrated, and if necessary, a low-polar organic solvent may be added. May be added. Then, it is made to react at reflux at a temperature of 50 ° C., preferably 60 ° C. or higher, and then cooled and washed with an organic solvent. The organic solvent at this time is not particularly limited as long as it can remove residual low-polar solvent and alcohol by-produced by the reaction, but it is efficient to wash first with a polar solvent and then with a non-polar solvent. It is preferable in that it can be performed. Finally, this is dried and the solvent is removed to obtain the fine particles of the present invention. The drying temperature is preferably as low as possible within the range in which the obtained particles are not altered, and vacuum drying is particularly preferred.
[0025]
Next, the fine particle dispersion of the present invention will be described.
The fine particle dispersion is obtained by dispersing the above-described fine particles of the present invention in an organic liquid dispersion medium or an organic solid dispersion medium.
[0026]
As the organic liquid dispersion medium, known organic solvents can be used, and examples include alcohols, acetone, acetonitrile, dimethylformamide (DMF), dimethoxyethane (DME), tetrahydrofuran (THF), and the like.
[0027]
In particular, as the organic liquid dispersion medium for exhibiting playful color, a low polarity organic solvent having a relative dielectric constant of 2 to 50 other than alcohol is preferable, and examples thereof include acetone, acetonitrile, nitrobenzene, DMF, DME and the like. A cured resin is preferable as the organic solid dispersion medium for exhibiting play color. In this case, the fine particle dispersion is obtained by dispersing the fine particles in a resin monomer and then curing by heating or irradiating with ultraviolet rays or the like. As the resin monomer, N ′ N-dimethylacrylamide, acrylonitrile and the like are preferable.
[0028]
The concentration of fine particles in the fine particle dispersion of the present invention is preferably in the range of 0.1 to 50% in terms of volume fraction. In particular, the concentration of the fine particles in the dispersion exhibiting playful color is preferably in the range of 0.1 to 20% in terms of volume fraction, and particularly preferably in the range of 0.5 to 10%. If it is less than 0.1%, it takes a long time to give a color, and if it exceeds 50%, it is difficult to disperse uniformly and the viscosity of the resulting dispersion becomes high, which is not preferable.
[0029]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
[0030]
Example 1
[Preparation of organic polymer coupling agent]
In a container, 602 g of maleic anhydride, 67 g of dry styrene and 140 ml of dry tetrahydrofuran (THF) are weighed, and 40 ml of 3-mercaptopropyltrimethoxysilane and 2,2′-azobisisobutyronitrile (AIBN: polymerization initiator). -Catalyst) 0.8 g was added and refluxed at 70 ° C for 3 hours under a nitrogen atmosphere. Then, after cooling to room temperature, it was dissolved in a sufficient amount of tetrahydrofuran, then precipitated in about 200 L of ether, filtered and dried under reduced pressure to prepare a silane organic polymer coupling agent (a). The measurement results of molecular weight are shown in Table 1.
[0031]
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane organic polymer coupling agent (a) was taken, 30 L of dimethoxyethane and 5 L of tetrahydrofuran were added thereto, and ultrasonic waves were applied to completely dissolve the organic polymer coupling agent (a). This is a sol in which silica fine particles are dispersed in ethanol (catalytic conversion OSCAL-1226L, particle diameter 120 nm, SiO 22 2.2 L of 17.8% by weight) was added. Then, the mixture was heated to 90 ° C. to distill 29 L of the solvent, and then 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (A). The binding amount of the organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0032]
Example 2
[Preparation of Silane Organic Polymer Coupling Agent]
In a container, weigh 602 g of maleic anhydride, 67 g of dry styrene and 140 ml of dry tetrahydrofuran (THF). To this, 200 ml of 3-mercaptopropyltrimethoxysilane (5 times the amount of Example 1) and 2,2′-azobisiso 4 g of butyronitrile (AIBN: polymerization initiator / catalyst) was added and refluxed at 70 ° C. for 3 hours in a nitrogen atmosphere. Next, after cooling to room temperature, it was dissolved in a sufficient amount of tetrahydrofuran, then precipitated in about 200 L of ether, filtered and dried under reduced pressure to prepare a silane organic polymer coupling agent (b). The measurement results of molecular weight are shown in Table 1.
[0033]
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of a silane organic polymer coupling agent (b) was taken, 30 L of dimethoxyethane and 5 L of tetrahydrofuran were added thereto, and ultrasonic waves were applied to completely dissolve the organic polymer coupling agent (b). A sol in which silica / alumina fine particles are dispersed in ethanol (catalytic conversion OSCAL-1222, particle diameter 10 nm, SiO 22 ・ Al2 OThree 2.2 L of 17.8% by weight) was added. Subsequently, the mixture was heated to 90 ° C. to distill 29 L of the solvent, and then 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (B). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0034]
Example 3
[Preparation of Silane Organic Polymer Coupling Agent]
In a container, 1200 g of maleic anhydride, 134 g of vinyl acetate and 280 ml of dry tetrahydrofuran (THF) were weighed, 40 ml of 3-mercaptopropyltrimethoxysilane and 2,2′-azobisisobutyronitrile (AIBN: polymerization initiator) -Catalyst) 0.8 g was added and refluxed at 70 ° C for 3 hours under a nitrogen atmosphere. Next, after cooling to room temperature, it was dissolved in a sufficient amount of tetrahydrofuran, then precipitated in about 200 L of ether, filtered and dried under reduced pressure to prepare a silane organic polymer coupling agent (c). The measurement results of molecular weight are shown in Table 1.
[0035]
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of a silane organic polymer coupling agent (c) was added, 30 L of dimethoxyethane and 5 L of tetrahydrofuran were added thereto, and ultrasonic waves were applied to completely dissolve the organic polymer coupling agent (c). This is a sol in which silica fine particles are dispersed in ethanol (catalytic conversion OSCAL-1228, particle diameter 300 nm, SiO 22 2.2 L of 17.8% by weight) was added. Then, the mixture was heated to 90 ° C. to distill 29 L of the solvent, and then 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (C). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0036]
Example 4
[Preparation of Silane Organic Polymer Coupling Agent]
In a container, 602 g of maleic anhydride, 67 g of dry styrene and 140 ml of dry tetrahydrofuran (THF) are weighed, and 67 ml of 3-mercaptopropyltrimethoxysilane and 2,2′-azobisisobutyronitrile (AIBN: polymerization initiator) Catalyst) 1.3 g was added and refluxed at 70 ° C. for 3 hours under a nitrogen atmosphere. Next, after cooling to room temperature, it was dissolved in a sufficient amount of tetrahydrofuran, then precipitated in about 200 L of ether, filtered and dried under reduced pressure to prepare a silane organic polymer coupling agent (d). The measurement results of molecular weight are shown in Table 1.
[0037]
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, take 500 g of the silane organic polymer coupling agent (d) of Example 1, add 30 L of dimethoxyethane and 5 L of tetrahydrofuran, and irradiate ultrasonic waves to completely remove the organic polymer coupling agent (d). Dissolved in. This is a sol in which silica / zirconia fine particles are dispersed in ethanol (catalytic conversion OSCAL-1224, particle size 50 nm, SiO 22・ ZrO2 2.2 L of 17.8% by weight) was added. Next, the mixture was heated to 90 ° C., 29 L of the solvent was distilled off, 3 L of tetrahydrofuran was added, and the mixture was refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (D). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0038]
Example 5
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane organic polymer coupling agent (a) prepared in Example 1 is added, 30 L of dimethoxyethane and 5 L of tetrahydrofuran are added thereto, and ultrasonic waves are applied to the organic polymer coupling agent (a). Was completely dissolved. This is a sol in which silica / alumina fine particles are dispersed in ethanol (catalytic conversion OSCAL-1226L, particle diameter 120 nm, SiO 22 ・ Al2 OThree 2.2 L of 17.8% by weight) was added. Then, the mixture was heated to 90 ° C. to distill 29 L of the solvent, and then 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed 4 times, followed by centrifugal washing with ether once, and then drying under reduced pressure to prepare organic polymer coupling agent-modified fine particles (E). The binding amount of the organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0039]
[Preparation of solid fine particle dispersion]
A fine particle dispersion dispersed in an organic liquid dispersion medium or an organic solid dispersion medium.
Next, after mixing 90 g of acrylonitrile with 100 g of the above liquid fine particle dispersion, drying is performed to remove the dispersion medium, followed by curing by irradiation with ultraviolet rays to prepare a solid fine particle dispersion (E-1). did. Further, a solid fine particle dispersion (E-2) was prepared in the same manner as (E-1) except that N′N-dimethylacrylamide was used instead of acrylonitrile.
As a result of observing the color of the obtained solid fine particle dispersion, it was not clear but partial compared with the liquid fine particle dispersion, and a loose color was observed.
[0040]
Example 6
[Preparation of Silane Organic Polymer Coupling Agent]
In a container, weigh 2400 g of maleic anhydride, 268 g of dry styrene and 560 ml of dry tetrahydrofuran (THF), and add 40 ml of 3-mercaptopropyltrimethoxysilane and 2,2′-azobisisobutyronitrile (AIBN: polymerization initiator). -Catalyst) 0.8 g was added and refluxed at 70 ° C for 3 hours under a nitrogen atmosphere. Next, after cooling to room temperature, it was dissolved in a sufficient amount of tetrahydrofuran, then precipitated in about 200 L of ether, filtered and dried under reduced pressure to prepare a silane organic polymer coupling agent (f). The measurement results of molecular weight are shown in Table 1.
[0041]
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane organic polymer coupling agent (f) was taken, 30 L of dimethoxyethane and 5 L of tetrahydrofuran were added thereto, and ultrasonic waves were applied to completely dissolve the organic polymer coupling agent (f). A sol in which silica fine particles are dispersed in ethanol (catalytic conversion OSCAL-PA-700, particle diameter 700 nm, SiO 22 2.2 L of 17.8% by weight) was added. Subsequently, after heating to 90 ° C. and distilling 29 L of the solvent, 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (F). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0042]
Example 7
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane organic polymer coupling agent (a) prepared in Example 1 is added, 30 L of dimethoxyethane and 5 L of tetrahydrofuran are added thereto, and ultrasonic waves are applied to the organic polymer coupling agent (a). Was completely dissolved. To this, a sol (particle diameter 120 nm, SiO 2) in which silica fine particles containing vinyl groups prepared based on JP-A-10-45403 are dispersed in ethanol.2 2.2 L of 17.8% by weight) was added. Subsequently, after heating to 90 ° C. and distilling 29 L of the solvent, 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (G). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0043]
Example 8
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane-based organic polymer coupling agent (a) prepared in Example 1 is added, 30 L of dimethoxyethane and 5 L of tetrahydrofuran are added thereto, and ultrasonic waves are applied to silane-based organic polymer coupling agent ( a) was completely dissolved. A sol (particle diameter 200 nm, SiO 2) in which organic-inorganic composite silica-based fine particles prepared by hydrolyzing tetraalkoxysilane are dispersed in ethanol.2 2.2 L of 17.8% by weight) was added. Subsequently, after heating to 90 ° C. and distilling 29 L of the solvent, 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (H). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0044]
Comparative Example 1
[Preparation of fine particles modified with silane coupling agent]
In a container, 20 g of vinylethoxysilane was taken, and this was a sol (catalytic conversion OSCAL-1226L, particle diameter 120 nm, SiO 22 ・ Al2 OThree (Concentration 17.8 wt%) was added to 2.2 L. Subsequently, the mixture is heated to 80 ° C. and stirred, separated after being modified with the silane coupling agent (i), then centrifuged four times with acetone, then once with ether, and then dried under reduced pressure. Coupling agent-modified fine particles (I) were prepared. The binding amount of the silane coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0045]
Comparative Example 2
[Preparation of fine particles modified with silane organic polymer coupling agent]
In a container, 500 g of the silane organic polymer coupling agent (a) prepared in Example 1 is added, 30 L of dimethoxyethane and 5 L of tetrahydrofuran are added thereto, and ultrasonic waves are applied to the organic polymer coupling agent (a). Was completely dissolved. This is a sol in which silica fine particles are dispersed in ethanol (catalytic conversion OSCAL-PA-3000, particle diameter 3000 nm, SiO 22 2.2 L of 17.8% by weight) was added. Subsequently, after heating to 90 ° C. and distilling 29 L of the solvent, 3 L of tetrahydrofuran was added and refluxed for 24 hours. Next, centrifugal washing with acetone was performed four times, and then centrifugal washing with ether was performed once, followed by drying under reduced pressure to prepare silane-based organic polymer coupling agent-modified fine particles (J). The binding amount of the silane organic polymer coupling agent is shown in Table 1.
The obtained particles were dispersed in a dispersion medium shown in Table 1 so as to have a concentration of 10% by weight, and the presence or absence of aggregation and sedimentation was observed as dispersion stability. At the same time, colored observations were made, and the results are shown in Table 1.
[0046]
[Table 1]
【The invention's effect】
Since the fine particles according to the present invention have a specific organic polymer coupling agent bonded to the surface, the dispersion in which the fine particles are dispersed does not thicken even at high concentrations, and is stable and redispersible. Is excellent. Further, a liquid or solid fine particle dispersion in which the fine particles are dispersed in an organic dispersion medium exhibits a stable and clear play color.
The fine particles and fine particle dispersions of the present invention are useful for paints, insulating coatings, film fillers, additives for dyes and pigments, displays for display devices, additives for interior and exterior materials, lotions, emulsions and other cosmetic ingredients. is there.
Claims (4)
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|---|---|---|---|---|
| DE102005039435A1 (en) * | 2005-08-18 | 2007-03-01 | Clariant International Limited | Process for the preparation of silane-surface-modified nanocorundum |
| JP5121169B2 (en) * | 2006-06-14 | 2013-01-16 | 株式会社日本触媒 | Organic solvent dispersion of inorganic-containing particles and inorganic-containing particles used in the dispersion |
-
1998
- 1998-04-27 JP JP11697198A patent/JP3729234B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008100894A (en) * | 2006-10-23 | 2008-05-01 | Kyushu Institute Of Technology | Polymer-grafted colloidal silica, polymer-grafted colloidal silica dispersion and its manufacturing method |
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| Publication number | Publication date |
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| JPH11310733A (en) | 1999-11-09 |
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