JP3744188B2

JP3744188B2 - Heat ray shielding film forming coating solution and heat ray shielding film

Info

Publication number: JP3744188B2
Application number: JP06490398A
Authority: JP
Inventors: 裕子久野; 広充武田; 健治足立
Original assignee: Sumitomo Metal Mining Co Ltd
Current assignee: Sumitomo Metal Mining Co Ltd
Priority date: 1998-03-16
Filing date: 1998-03-16
Publication date: 2006-02-08
Anticipated expiration: 2018-03-16
Also published as: JPH11263639A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両、ビル、事務所、一般住宅などの窓、電話ボックス、ショーウインドー、照明用ランプなど、ガラス、プラスチックスその他の各種熱線遮蔽機能を必要とする透明もしくは半透明基材に塗布して熱線遮蔽膜とするための塗布液、及び、これにより得られる熱線遮蔽膜に関する。
【０００２】
【従来の技術】
従来、太陽光や電球などの外部光源から熱成分を除去・減少する方法として、ガラス表面に可視・赤外域の波長を反射する材料を利用して熱線反射ガラスとすることが行なわれていた。そして、熱線反射のための材料には、ＦｅＯ_X，ＣｏＯ_X，ＣｒＯ_X，ＴｉＯ_X等の金属酸化物や、Ａｇ、Ａｕ、Ｃｕ、Ｎｉ、Ａｌなどの自由電子を多量にもつ金属材料が選択されてきた。
【０００３】
しかし、これらの材料では熱効果に大きく寄与する近赤外線以外に、可視光領域の光も同時に反射もしくは吸収する性質があり、可視光透過率が低下してしまう欠点があった。建材、乗り物、電話ボックスなどに用いられる透明基材では、可視光領域の高い透過率が必要とされ、これらの材料を利用する場合は可視光透過率を高くするため膜厚を非常に薄くしなければならず、従ってスプレー焼き付けやＣＶＤ法、或いはスパッタ法や真空蒸着法などの物理成膜法を用いて１０ｎｍ厚レベルの極めて薄い膜に成膜して用いられることが通常行なわれてきた。
【０００４】
これらの成膜方法は大がかりな装置や真空設備を必要とし、生産性、大面積化に問題があり、また膜の製造コストが高かった。
【０００５】
また、これらの膜では膜厚を薄くして透過率を高くすると熱線遮蔽特性が低下し、逆に膜厚を厚くして熱線遮蔽特性を高くすると膜が暗くなってしまう。さらに、これらの材料は熱線遮蔽特性を高くしようとすると可視光領域の反射率も同時に高くなってしまう傾向があり、鏡のようなギラギラした外観を与えて美観を損ねてしまった。
【０００６】
さらに、これらの材料では膜の導電性が高くなるものが多く、膜の導電性が高いと携帯電話やＴＶ、ラジオなどの電波を反射して受信不能になったり、周辺地域に電波障害を引き起こすなどの欠点があった。
【０００７】
上記従来の欠点を改善するためには、膜の物理特性として、可視光領域の光の反射率が低く、近赤外領域の光の反射率が高く、かつ、膜の導電性が概ね１０⁶Ω／□以上に制御可能な膜を形成する必要があった。しかしながら従来このような膜、或いはこのような膜を形成する材料は知られていなかった。
【０００８】
可視光透過率が高く、かつ熱線遮蔽機能をもつ材料としては、アンチモン含有酸化錫（ＡＴＯ）や、錫含有酸化インジウム（ＩＴＯ）が知られている。これらの材料は可視光反射率が比較的低く、ギラギラした外観を与えることはないが、プラズマ波長が近赤外域の比較的長波長側にあり、可視光に近い近赤外域におけるこれらの膜の反射・吸収効果は十分ではなかった。また、物理成膜法でこれらの膜を形成した場合には、膜の導電性が上がって電波を反射してしまう欠点があった。
【０００９】
【発明が解決しようとする課題】
本発明は、上記従来の問題を解決し、可視光領域の光の透過率が高くて反射率が低く、近赤外領域の光の透過率が低くて反射率が高く、膜の導電性が概ね１０⁶Ω／□以上に制御可能な膜を、高コストの物理成膜法を用いずに簡便な塗布法で成膜できる塗布液と、これを用いた熱線遮蔽膜とを提供することを目的とする。
【００１０】
【課題を解決するための手段】
上記目的を達成するために、本発明者らは、材料そのものの特性として自由電子を多量に保有する窒化物に着目し、種々検討の結果、これを超微粒子化し、かつ高度に分散された膜を得ることにより、可視光領域に透過率の極大をもつとともに、可視光領域に近い近赤外域に強いプラズマ反射を発現して透過率の極小をもつようになるという事実を見出し、本発明を完成した。
【００１１】
すなわち、本発明の熱線遮蔽膜形成用塗布液は、波長４００〜７００ｎｍに透過率の極大値を、波長７００〜１８００ｎｍに透過率の極小値をもち、かつ、極大値と極小値との差が百分率で１５ポイント以上である熱線遮蔽膜を得るための熱線遮蔽膜形成用塗布液であって、平均粒径１００ｎｍ以下の窒化チタン微粒子、平均粒径１００ｎｍ以下の窒化ジルコニウム微粒子、平均粒径１００ｎｍ以下の窒化ハフニウム微粒子、平均粒径１００ｎｍ以下の窒化バナジウム微粒子、平均粒径１００ｎｍ以下の窒化ニオブ微粒子、および、平均粒径１００ｎｍ以下の窒化タンタル微粒子から選択される少なくとも１種が分散されたことを特徴とする。
【００１２】
また、本発明の他の熱線遮蔽膜形成用塗布液は、波長４００〜７００ｎｍに透過率の極大値を、波長７００〜１８００ｎｍに透過率の極小値をもち、かつ、極大値と極小値との差が百分率で１５ポイント以上である熱線遮蔽膜を得るための熱線遮蔽膜形成用塗布液であって、平均粒径１００ｎｍ以下の窒化チタン微粒子、平均粒径１００ｎｍ以下の窒化ジルコニウム微粒子、平均粒径１００ｎｍ以下の窒化ハフニウム微粒子、平均粒径１００ｎｍ以下の窒化バナジウム微粒子、平均粒径１００ｎｍ以下の窒化ニオブ微粒子、および、平均粒径１００ｎｍ以下の窒化タンタル微粒子から選択される少なくとも１種と、平均粒径１００ｎｍ以下の酸化ルテニウム微粒子、および、平均粒径１００ｎｍ以下の酸化イリジウム微粒子から選択される少なくとも１種とが分散されたことを特徴とする。
【００１３】
また、本発明の他の熱線遮蔽膜形成用塗布液は、上記いずれかの構成で更に、珪素、ジルコニウム、チタン、もしくは、アルミニウムの金属アルコキシド、金属アルコキシドの部分加水分解重合物、以下に述べるオルガノシラザン溶液、常温硬化型シリケート液から選択される無機系バインダー成分を含有することを特徴とする。
【００１４】
上記いずれかの構成の熱線遮蔽膜形成用塗布液は、樹脂バインダーを含有していてもよい。
【００１５】
また、本発明の熱線遮蔽膜は、上記いずれかの熱線遮蔽膜形成用塗布液を基材に塗布後加熱して得た波長４００〜７００ｎｍに透過率の極大値を、波長７００〜１８００ｎｍに透過率の極小値をもち、かつ、極大値と極小値との差が百分率で１５ポイント以上である微粒子分散膜であって、熱線遮蔽特性を示す主成分が、窒化チタン、窒化ジルコニウム、窒化ハフニウム、窒化バナジウム、窒化ニオブ、窒化タンタルから選択される少なくとも１種の微粒子であり、または、窒化チタン、窒化ジルコニウム、窒化ハフニウム、窒化バナジウム、窒化ニオブ、窒化タンタルから選択される少なくとも１種の微粒子と、酸化ルテニウム、酸化イリジウムから選択される少なくとも１種の微粒子であり、該微粒子成分が、上記無機系バインダーまたは樹脂バインダー中に分散されたことを特徴とする。
【００１６】
また、上記熱線遮蔽膜上に更に、珪素、ジルコニウム、チタン、および、アルミニウムのいずれかの金属酸化物のうちの少なくとも１種を含有する酸化物膜を被膜して、もしくは、上記熱線遮蔽膜上に更に、樹脂膜を被膜して多層熱線遮蔽膜としてもよい。
【００１７】
上記いずれかの熱線遮蔽膜は、透過率が、波長４００〜７００ｎｍに極大値を、波長７００〜１８００ｎｍに極小値をもち、かつ、極大値と極小値との差が百分率で１５ポイント以上である特性を有することを特徴とし、また、表面抵抗値が１０⁶Ω／□以上であることを特徴とする。
【００１８】
【発明の実施の形態】
本発明に使用される窒化物微粒子としては、窒化チタン（ＴｉＮ）、窒化ジルコニウム（ＺｒＮ）、窒化ハフニウム（ＨｆＮ）、窒化バナジウム（ＶＮ）、窒化ニオブ（ＮｂＮ）、窒化タンタル（ＴａＮ）などがその代表的なものとして挙げられる。また、本発明に使用される窒化物微粒子は、一部または全量がオキシ窒化物で代替されたものであっても良い。またこれらの窒化物微粒子は、その表面が酸化していないことが好ましいが、通常は僅かに酸化していることが多く、また微粒子の分散工程で表面の酸化が起こることはある程度避けられない。しかしその場合でも熱線遮蔽効果を発現する有効性に変わりはない。またこれらの窒化物微粒子は、結晶としての完全性が高いほど大きい熱線遮蔽効果が得られるが、結晶性が低くＸ線回折で極めてブロードな回折ピークを生じるようなものであっても、微粒子内部の基本的な結合が各金属と窒素の結合から成り立っているものであるならば熱線遮蔽効果を発現する。
【００１９】
また、本発明に使用される酸化ルテニウムまたは酸化イリジウムの微粒子としては、二酸化ルテニウム（ＲｕＯ₂）、二酸化イリジウム（ＩｒＯ₂）などの微粒子がその代表的な例として挙げられる。これらの微粒子は酸化物として安定であり、また多量の自由電子を保持しており極めて有効な熱線遮蔽機能をもっている。
【００２０】
これらの窒化物微粒子、酸化ルテニウム微粒子、酸化イリジウム微粒子は、灰黒色、茶黒色、緑黒色などに着色した粉末であるが、粒径が可視光波長に比べて十分小さく、薄膜中に分散された状態においては膜に可視光透過性が生じる。しかし、赤外光遮蔽能は十分強く保持できる。この理由は詳細には理解されていないが、これら微粒子中の自由電子の量が多く、微粒子内部及び表面の自由電子プラズモンによるプラズマ周波数がちょうど、可視〜近赤外の付近にあるために、この波長領域の熱線が選択的に反射・吸収されると考えられる。実験によれば、これら微粒子を十分細かく、かつ、均一に分散された膜では、透過率が波長４００〜７００ｎｍに極大値をもち、かつ、波長７００〜１８００ｎｍに極小値をもち、さらに透過率の極大値と極小値の差が百分率で１５ポイント以上であることが観察される。可視光波長が３８０〜７８０ｎｍであり、視感度が５５０ｎｍ付近をピークとする釣鐘型であることを考慮すると、このような膜では可視光を有効に透過し,それ以外の熱線を有効に反射・吸収することが理解できる。
【００２１】
本発明において、塗布液中の窒化物微粒子、酸化ルテニウム微粒子、酸化イリジウム微粒子の平均粒径は、１００ｎｍ以下が好ましい。粒子径が１００ｎｍよりも大きくなると、上に述べたような特有の透過率プロファイル、すなわち透過率が波長４００〜７００ｎｍに極大値をもち、かつ、波長７００〜１８００ｎｍに極小値をもち、さらに極大値と極小値との差が百分率で１５ポイント以上であるようなプロファイルが得られず、単調に透過率が減少した灰色っぽい膜になる。また粒子径が１００ｎｍよりも大きい場合には、分散液中の微粒子同士の凝集傾向が強くなり、微粒子の沈降原因となる。また１００ｎｍ以上の微粒子もしくはそれらの凝集した粗大粒子は光散乱源となって膜に曇り（ヘイズ）を生じたり、可視光透過率が減少する原因となる。従って、上記無機微粒子の平均粒径は１００ｎｍ以下とする必要がある。なお、経済的に入手可能な最低の粒径は２ｎｍ程度であるが下限をこれに限定するものではない。
【００２２】
塗布液中の微粒子の分散媒は特に限定されるものではなく、塗布条件や塗布環境、塗布液中のアルコキシド、合成樹脂バインダーなどに合わせて選択可能であり、例えば、水や、アルコール、エーテル、エステル、ケトンなどの有機溶媒の各種が使用可能である。また、必要に応じて酸やアルカリを添加してｐＨを調整しても良い。更に塗布液中微粒子の分散安定性を一層向上させるために、各種の界面活性剤、カップリング剤などを添加することも可能である。そのときのそれぞれの添加量は、無機微粒子に対して３０重量％以下、好ましくは５重量％以下である。
【００２３】
この塗布液を用いて膜としたときの膜の導電性は、微粒子の接触箇所を経由した導電パスに沿って行われるため、例えば界面活性剤やカップリング剤の量を加減することで導電パスを部分的に切断することができ、１０⁶Ω／□以上の表面抵抗値へ膜の導電性を低下させることは容易に可能である。また、珪素、ジルコニウム、チタン、アルミニウムの金属アルコキシド、もしくはこれら金属の部分加水分解重合物、または合成樹脂バインダーの含有量を加減することによっても導電性の制御が可能である。
【００２４】
上記微粒子の分散方法は、微粒子が均一に溶液中に分散する方法であれば任意に選択できるが、例としては、ビーズミル、ボールミル、サンドミル、超音波分散などの方法を挙げることができる。
【００２５】
本発明における熱線遮蔽膜は、基材上に上記微粒子が高密度に堆積し膜を形成するものであり、塗布液中に含まれる珪素、ジルコニウム、チタン、アルミニウムの金属アルコキシド、もしくはこれら金属の部分加水分解重合物、または合成樹脂バインダーは、塗布、硬化後、微粒子の基材への結着性を向上させ、更に膜の硬度を向上させる効果がある。またこのようにして得られた膜上に、更に珪素、ジルコニウム、チタン、アルミニウムなどの金属アルコキシドもしくはこれら金属アルコキシドの加水分解重合物、または、合成樹脂を含有する被膜を第２層として被膜することで、微粒子を主成分とする膜の基材への結着力や、膜の硬度及び耐候性を一層向上させることも可能となる。
【００２６】
塗布液中に珪素、ジルコニウム、チタン、アルミニウムの金属アルコキシド、もしくはこれら金属の加水分解重合物、または合成樹脂バインダーを含まない場合、この塗布液を基材に塗布後に得られる膜は、基材上に上記微粒子のみが堆積した膜構造になる。このままでも熱線遮蔽効果を示すが、この膜に上記と同様に、更に珪素、ジルコニウム、チタン、アルミニウムの金属アルコキシド、もしくはこれら金属の加水分解重合物、または合成樹脂バインダーを含む塗布液を塗布して被膜を形成して多層膜とすることにより、塗布液成分が第１層の微粒子の堆積した間隙を埋めて成膜されるため、膜のヘイズが低減し可視光透過率が向上し、また微粒子の基材への結着性が向上する。
【００２７】
上記微粒子を主成分とする膜を、珪素、ジルコニウム、チタン、もしくは、アルミニウムの金属アルコキシド、または、これら金属の加水分解重合物からなる被膜で結着する方法としては、スパッタ法や蒸着法も可能であるが、成膜工程の容易さやコストが低いなどの利点から塗布法が有効である。この被膜用塗布液は、水やアルコール中に珪素、ジルコニウム、チタン、もしくは、アルミニウムの金属アルコキシド、または、これら金属の加水分解重合物を１種以上含むものであり、その含有液は加熱後に得られる酸化物換算で全溶液中の４０重量％以下が好ましい。また必要に応じて酸やアルカリを添加してｐＨを調整することも可能である。このような液を上記微粒子を主成分とする膜上に更に第２層として塗布し加熱することで、珪素、ジルコニウム、チタン、アルミニウムなどの酸化物被膜を容易に作製することが可能である。
【００２８】
塗布液及び被膜用の塗布液の塗布方法は特に限定されるものではなく、スピンコート法、スプレーコート法、ディップコート法、スクリーン印刷法、ロールコート法、流し塗りなど、処理液を平坦かつ薄く均一に塗布できる方法であれば如何なる方法でも適宜採用することができる。
【００２９】
上記金属アルコキシド及びその加水分解重合物を含む塗布液の塗布後の基材加熱温度は、１００℃未満では塗膜中に含まれるアルコキシドまたはその加水分解重合物の重合反応が未完結で残る場合が多く、また水や有機溶媒が膜中に残留し、加熱後の膜の可視光透過率の低減の原因となるので、１００℃以上が好ましく、更に好ましくは塗布液中の溶媒の沸点以上で加熱を実施することができる。
【００３０】
また合成樹脂バインダーを使用した場合は、それぞれの硬化方法に従って硬化させれば良く、例えば紫外線硬化樹脂であれば紫外線を適宜照射すれば良く、また常温硬化樹脂であれば塗布後そのまま放置しておけばよいため、既存の窓ガラスなどへの現場での塗布が可能であり、汎用性が広がる。
【００３１】
本発明の塗布液に使用するバインダー成分として、或いはオーバーコート用の塗布液としては、オルガノシラザン溶液を用いても良い。オルガノシザラン溶液としては、側鎖基の修正や酸化触媒の添加で重合硬化温度が１００℃以下のものも市販されており、これらを用いることによって成膜温度をかなり低くできる。常温硬化性バインダーとしては、市販のシリケート系のものを用いることも可能である。どちらも硬化後はＳｉＯ₂の無機膜を形成し、耐候性や膜強度において樹脂膜よりも優れている。
【００３２】
本発明の膜では上記超微粒子の分散された膜であるために、物理成膜法により製造された酸化物薄膜のように結晶が緻密に膜内を埋めた鏡面状表面をもつ膜に比べると、可視光領域での反射が少なく、ギラギラした外観を呈することが回避できる。その一方で、上記のように、可視〜近赤外域にプラズマ周波数をもつために、これに伴うプラズマ反射が近赤外域で大きくなる、という非常に好ましい特性をもっている。また可視光領域の反射をさらに抑制したい場合は、本微粒子分散膜の上に、ＳｉＯ₂やＭｇＦのような低屈折率の膜を成膜することにより、容易に視感反射率１％以下の多層膜が製造可能である。
【００３３】
本発明の塗布液には、透過率を向上させるために、更に、ＡＴＯやＩＴＯやアルミニウム添加酸化亜鉛などの超微粒子を混合することも可能である。これらの透明超微粒子は添加量を増すと可視光に近い近赤外線領域での吸収が増加するため、可視光透過率の高い熱線遮蔽膜とすることが可能である。また逆に、ＡＴＯやＩＴＯやアルミニウム添加酸化亜鉛などの超微粒子が分散された液に本発明の塗布液を添加して、膜に着色すると同時にその熱線遮蔽効果を補助することも可能である。この場合、主体となるＩＴＯなどに対してほんの僅かの添加量で熱線遮蔽効果を補助できるため、ＩＴＯの必要量の大幅な減少が可能となり、液のコストを下げられるという利点がある。
【００３４】
また、本発明の塗布液には、膜になったときの赤外線の遮蔽能と同時に、人体に有害な紫外線の遮蔽機能を向上させるために、無機系の酸化チタンや酸化亜鉛、酸化セリウムなどの微粒子や、有機系のベンゾフェノンやベンゾトリアゾールなどの１種もしくは２種以上を添加することも可能である。
【００３５】
本発明による塗布液は、上記無機微粒子が分散されたものであり、焼成時の熱による塗布成分の分解或いは化学反応を利用して目的の熱線遮蔽膜を形成するものではないため、特性の安定した均一な膜厚の透過膜を形成することができる。
【００３６】
本発明における微粒子分散膜は、基材上に微粒子が高密度に堆積し膜を形成するものであり、塗布液中に含まれる珪素、ジルコニウム、チタン、もしくはアルミニウムの金属アルコキシド、またはこれらの加水分解重合物、または合成樹脂バインダーは、塗膜の硬化後、微粒子の基材上への結着性を向上させ、さらに膜の強度を向上させる効果がある。
【００３７】
このように本発明によれば、上記無機微粒子の材料を適当に混合することで熱線遮蔽効果を有する膜の製造が可能であるが、これらの微粒子材料は無機材料であるので、有機材料と比べて耐候性は非常に高く、例えば太陽光線（紫外線）の当たる部位に使用しても、色や諸機能の劣化はほとんど生じない。
【００３８】
【実施例】
以下本発明の実施例を比較例と共に説明する。
【００３９】
（実施例１）平均粒径４０ｎｍのＴｉＮ微粒子８ｇ、ジアセトンアルコール（ＤＡＡ）８０ｇ、水及び分散剤適量を混合し、直径４ｍｍのジルコニアボールを用いて１００時間ボールミル混合して、ＴｉＮ分散液１００ｇを作製した。これをＡ液とする。次に、平均重合度で４〜５量体である多摩化学工業株式会社製エチルシリケート４０を６ｇ、エタノール３１ｇ、５％塩酸水溶液８ｇ、水５ｇで調製したエチルシリケート溶液５０ｇと、水８００ｇ、及びエタノール３００ｇを良く混合・攪拌して、エチルシリケート混合液１１５０ｇを調製した。これをＢ液とする。
【００４０】
Ａ液とＢ液とを、ＴｉＮ濃度が１．０％、ＴｉＮ／ＳｉＯ₂比が４：１となるような割合で混合・攪拌し、塗布液を作製した。これをＣ液とする。このＣ液１５ｇを、１４５ｒｐｍで回転する２００×２００×３ｍｍのソーダライム板ガラス基板上にビーカから滴下し、そのまま３分間振り切った後、回転を止めた。これを１８０℃の電気炉に入れて３０分間加熱し目的とする膜を得た。
【００４１】
形成された膜の分光特性は、日立製作所製の分光光度計を用いて測定した。ＴｉＮ微粒子を用いた本実施例の膜の透過プロファイル及び反射プロファイルを図１及び図２に示す。透過率の極大値が４２５ｎｍ、極小値が７４５ｎｍ、反射率の極大値が１０００ｎｍ付近にあり、透過率の極大値と極小値の差が百分率で２２ポイントあって、可視光波長で透過率が高く近赤外波長で透過率が小さいプロファイルになっており、ＪＩＳ−Ｒ−３１０６に基づいて可視光透過率４４％、日射透過率４２％が得られた。
【００４２】
この膜付きガラスを１００×１００×６０ｍｍの塩化ビニル製の升型小ボックスの上面にセットして晴れた日の日射下に１ｈｒ放置し、ボックス内の温度変化を測定した。この膜付きガラスを配置した場合には４５℃で一定になったが、市販の熱線吸収ブロンズガラス（可視光透過率６４％）を配置した場合には５５℃、透明なクリアガラスを配置した場合には６１℃となり、日射による熱線の明らかな遮蔽効果が観察された。このように可視光に透過率の極大があり、近赤外に透過率の極小があり、さらに近赤外に反射率の極大をもつような本実施例による膜では、優れた熱線遮蔽効果をもつことが確認された。
【００４３】
本実施例による膜の透過色は美しい深青色であった。また日射反射率１８％と高い一方で、可視光反射率は１２％と低く、市販の熱線反射ガラスのような膜面のギラツキ感は感じられなかった。
【００４４】
更にこの膜の表面抵抗値を、三菱化学製の表面抵抗計を用いて測定したところ８×１０⁸Ω／□が得られ、膜抵抗値が十分高いために電波透過性には全く問題がないことが分かった。
【００４５】
（比較例１）塗布法に比べて高コストの物理成膜法により作製された市販の熱線反射ブロンズガラスについて、３４０〜１８００ｎｍの分光透過率を測定し、ＪＩＳ−Ｒ−３１０６に従って可視光透過率、日射透過率を求めたところ、それぞれ４５％、５１％となり、上記実施例１の膜よりも日射透過率がやや高い値が得られた。また日射反射率は２３％と良い値であるが、可視光反射率は３０％と非常に高く、外観もギラギラしたミラー状の外観を呈していた。また膜面の表面抵抗値は８３Ω／□と低く、電波透過性及び反射性には問題があることが明らかである。
【００４６】
（実施例２）実施例１で作製したＣ液を板ガラスの１層目としてスピンコートした後、そのまま３分間回転を続け、続いてＢ液をＳｉＯ₂固形分換算で０．９％になるようにエタノールで希釈したシリケート液１５ｇを板ガラス上にビーカから滴下してさらに回転を３分間続けた後、回転を止めた。このようにして塗布した２層膜のガラス基板を１８０℃の電気炉に入れ、３０分間加熱して目的とする２層膜を得た。
【００４７】
形成された膜の分光特性を実施例１と同様にして評価した。可視光透過率は５１．８％と上昇した反面、可視光反射率は４．６％となって反射光が非常に抑えられた。さらに裏面に黒テープを貼って裏面からの反射を無くして測定すると可視光反射率は１．５％となり、無反射ガラスに近い外観になった。この膜の透過率の極大・極小値の位置は、実施例１での単層膜とほぼ同じであり、同様の熱線遮蔽効果をもつことは明らかである。
【００４８】
以下の実施例３〜１６において成膜された膜の可視光透過率と透過率の極大・極小値、及び表面抵抗値は、実施例１に述べたと同様な方法で評価し、実施例１、２の結果も含めてまとめて表１に示した。
【００４９】
（実施例３）平均粒径４０ｎｍのＴｉＮ微粒子８ｇ、イソホロン８０ｇ、水及び分散剤適量を混合し、ジルコニアボールを用いて１００時間ボールミル混合して、ＴｉＮイソホロン分散液１００ｇを作製した。これをＤ液とする。バインダーとして、エポキシ樹脂５０重量％をイソホロンに溶解して、エポキシ樹脂バインダー溶液を作製した。これをＥ液とする。Ｄ液とＥ液とエタノールを強力に混合・攪拌して、ＴｉＮとエポキシ樹脂の固形分が全体の１．４重量％、ＴｉＮとエポキシ樹脂の重量比が７０：３０となるようにして塗布液を作製し、実施例１と同様にして塗布液を作製し、成膜・加熱して膜を得た。
【００５０】
（実施例４）バインダーとして、信越シリコーン製常温硬化型シリケート液Ｘ−４０−９７４０をＢ液の代わりに用いて、実施例１と同様にして塗布液を作製し、成膜して膜を得た。ただし加熱はせずに、２５℃の室温内２日間放置で乾燥膜となったものを評価した。
【００５１】
（実施例５）バインダーとして、ＮＥケムキャット（株）製低温硬化型ポリペルヒドロシラザン溶液をＥ液の代わりに用いて、実施例３に示したＴｉＮイソホロン分散液（Ｄ液）及びキシレンを混合・攪拌して、ＴｉＮ濃度が１．０％、ＴｉＮ／ＳｉＯ₂比が４：１となるようにして、これを塗布液とした。これを用いて実施例１と同様にして成膜し、８０℃の電気炉で加熱して膜を得た。
【００５２】
（実施例６）Ａ液調製において、ＴｉＮの代わりに平均粒径３５ｎｍのＺｒＮ微粒子を用いた他は、実施例１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の膜を得た。
【００５３】
（実施例７）Ａ液調製において、ＴｉＮの代わりに平均粒径４７ｎｍのＨｆＮ微粒子を用いた他は、実施例１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の膜を得た。
【００５４】
（実施例８）Ａ液調製において、ＴｉＮの代わりに平均粒径６４ｎｍのＶＮ微粒子を用いた他は、実施例１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の膜を得た。
【００５５】
（実施例９）Ａ液調製において、ＴｉＮの代わりに平均粒径５５ｎｍのＮｂＮ微粒子を用いた他は、実施例１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の膜を得た。
【００５６】
（実施例１０）Ａ液調製において、ＴｉＮの代わりに平均粒径４３ｎｍのＴａＮ微粒子を用いた他は、実施例１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の膜を得た。
【００５７】
（実施例１１）平均粒径３０ｎｍの酸化ルテニウム（ＲｕＯ₂）微粒子１５ｇ、Ｎ−メチル−２−ピロリドン（ＮＭＰ）２３ｇ、ジアセトンアルコール（ＤＡＡ）５７ｇ、水及び分散剤適量を混合し、直径４ｍｍのジルコニアボールを用いて１００時間ボールミル混合して、ＲｕＯ₂分散液１００ｇを作製した。このＲｕＯ₂分散液に、ＲｕＯ₂濃度が１％、ＲｕＯ₂：ＳｉＯ₂＝４：１となるようにＢ液のシリケート液を混合・攪拌してＲｕＯ₂分散シリケート液とした。これをＦ液とする。Ｆ液に、ＲｕＯ₂：ＴｉＮ＝１．０：０．０１の重量比になるようにＡ液を混合して十分攪拌し、塗布液を調製した。この塗布液を用いて、実施例１と全く同様にして成膜・加熱して目的の膜を得た。
【００５８】
（実施例１２）Ｆ液とＡ液の混合時に、ＲｕＯ₂：ＴｉＮの重量比を１．０：０．２５とした以外は、実施例１１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の塗膜を得た。
【００５９】
（実施例１３）Ｆ液とＡ液の混合時に、ＲｕＯ₂：ＴｉＮの重量比を１．０：０．５とした以外は、実施例１１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の塗膜を得た。
【００６０】
（実施例１４）Ｆ液とＡ液の混合時に、ＲｕＯ₂：ＴｉＮの重量比を１．０：１．０とした以外は、実施例１１と全く同様にして塗布液を調製し、これを成膜・加熱して目的の塗膜を得た。
【００６１】
（実施例１５）平均粒径２８ｎｍのＩｒＯ₂微粒子を用いた他は、実施例１１と全く同様にして、ＩｒＯ₂：ＴｉＮ混合分散シリケート塗布液を作製し、これを成膜・加熱して目的の膜を得た。
【００６２】
（実施例１６）平均粒径２８ｎｍのＩｒＯ₂微粒子を用いた他は、実施例１２と全く同様にして、ＩｒＯ₂：ＴｉＮ混合分散シリケート塗布液を作製し、これを成膜・加熱して目的の膜を得た。
【００６３】
以上の実施例１〜１６では全ての膜について、透過率の極大が波長４００〜７００ｎｍの間にあり、極小値が波長７００〜１８００ｎｍの間にあってかつ極大値と極小値の差が１５ポイント以上であることが観測され、これらの膜が熱線遮蔽膜として有用であることが確認された。また実施例の全ての膜は可視光領域での反射率が１４％以下であってミラー状のギラツキが無く、さらに表面抵抗値が全ての膜で１０⁷Ω／□以上であって電波透過性において問題のないことが確かめられた。
【００６４】
（比較例２）平均粒径１２０ｎｍのＴｉＮを用いた他は、実施例１と全く同様にして、ＴｉＮ分散シリケート塗布液を作製し、これを成膜・加熱して目的の膜を得た。しかしこの膜は曇りが大きくて（ヘイズ値１４％）透明性に欠き、また青みがかった灰色となり、熱線遮蔽膜として実用に供することは困難と判断された。
【００６５】
（比較例３）平均粒径２２ｎｍのＩＴＯ超微粒子を用いた他は、実施例１と全く同様にして、ＩＴＯ分散シリケート塗布液を作製し、これを成膜・加熱して目的の膜を得た。しかしこの膜は透過率が、可視光域から１５００ｎｍの赤外域に至るまで９０％以上であり、近赤外線を遮蔽するという目的にはこの濃度では使用できないことが分かった。
【００６６】
【表１】

【００６７】
【発明の効果】
以上の実施例に示されるように、本発明によれば、可視光領域の光の透過率が高くて反射率が低く、近赤外領域の光の透過率が低くて反射率が高く、膜の導電性が概ね１０⁶Ω／□以上に制御可能な膜を、高コストの物理成膜法を用いずに簡便な塗布法で成膜できる塗布液と、これを用いた熱線遮蔽膜とが提供できた。本発明の膜は、従来膜に比べて表面のギラツキ感が無く、また電波透過性にも優れた熱線遮蔽膜である。また、本発明の塗布液を用いることにより、コスト面や大面積膜の面から工業的有用性が高い。
【図面の簡単な説明】
【図１】本発明の実施例１、１１、１２、１３、１４の透過率を示すグラフである。
【図２】本発明の実施例１、１１、１２、１３、１４の反射率を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to transparent or translucent substrates that require glass, plastics, and other various heat ray shielding functions, such as windows for vehicles, buildings, offices, ordinary houses, telephone boxes, show windows, and lighting lamps. The present invention relates to a coating solution for making a heat ray shielding film and a heat ray shielding film obtained thereby.
[0002]
[Prior art]
Conventionally, as a method of removing or reducing a heat component from an external light source such as sunlight or a light bulb, a heat ray reflecting glass has been performed by using a material that reflects visible and infrared wavelengths on the glass surface. The material for heat ray reflection includes FeO _X , CoO _X , CrO _X , TiO _X A metal material having a large amount of free electrons such as Ag, Au, Cu, Ni, and Al has been selected.
[0003]
However, these materials have the property of reflecting or absorbing light in the visible light region at the same time, in addition to the near-infrared light that greatly contributes to the thermal effect, and have the drawback of reducing the visible light transmittance. Transparent substrates used for building materials, vehicles, telephone boxes, etc. require high transmittance in the visible light region. When these materials are used, the film thickness is made very thin in order to increase the visible light transmittance. Therefore, it has been generally used to form a very thin film having a thickness of 10 nm by using a physical film forming method such as spray baking, CVD method, sputtering method or vacuum deposition method.
[0004]
These film formation methods require large-scale equipment and vacuum equipment, have problems in productivity and area increase, and the film production cost is high.
[0005]
Further, in these films, when the film thickness is reduced and the transmittance is increased, the heat ray shielding characteristics are lowered. Conversely, when the film thickness is increased and the heat ray shielding characteristics are increased, the film becomes dark. Further, these materials tend to increase the reflectivity in the visible light region at the same time when the heat ray shielding property is increased, and this gives a glaring appearance like a mirror and impairs the beauty.
[0006]
In addition, many of these materials have high film conductivity. When the film conductivity is high, radio waves from mobile phones, TVs, radios, etc. are reflected and cannot be received, or radio interference is caused in the surrounding area. There were drawbacks.
[0007]
In order to improve the conventional defects, the physical properties of the film are such that the light reflectance in the visible light region is low, the light reflectance in the near infrared region is high, and the conductivity of the film is approximately 10%. ⁶ It was necessary to form a film that could be controlled to Ω / □ or more. However, such a film or a material for forming such a film has not been known.
[0008]
Antimony-containing tin oxide (ATO) and tin-containing indium oxide (ITO) are known as materials having a high visible light transmittance and a heat ray shielding function. These materials have a relatively low visible light reflectivity and do not give a glaring appearance, but the plasma wavelength is on the relatively long wavelength side of the near infrared region, and these films in the near infrared region close to visible light. The reflection / absorption effect was not sufficient. Further, when these films are formed by a physical film forming method, there is a drawback that the conductivity of the film is increased and the radio waves are reflected.
[0009]
[Problems to be solved by the invention]
The present invention solves the above-described conventional problems, and has high light transmittance and low reflectance in the visible light region, low light transmittance and high reflectance in the near infrared region, and film conductivity. Approximately 10 ⁶ An object of the present invention is to provide a coating solution capable of forming a film that can be controlled to Ω / □ or more by a simple coating method without using a high-cost physical film forming method, and a heat ray shielding film using the same. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have focused on nitrides that possess a large amount of free electrons as a characteristic of the material itself, and as a result of various studies, they have been made into ultrafine particles and highly dispersed films. To obtain the fact that it has a maximum of transmittance in the visible light region and a strong plasma reflection in the near infrared region close to the visible light region and has a minimum of transmittance. completed.
[0011]
That is, the heat ray shielding film of the present invention Formation The coating solution for To obtain a heat ray shielding film having a maximum value of transmittance at a wavelength of 400 to 700 nm, a minimum value of transmittance at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value being 15 points or more in percentage A coating solution for forming a heat ray shielding film, Titanium nitride fine particles having an average particle size of 100 nm or less, zirconium nitride fine particles having an average particle size of 100 nm or less, hafnium nitride fine particles having an average particle size of 100 nm or less, vanadium nitride fine particles having an average particle size of 100 nm or less, niobium nitride fine particles having an average particle size of 100 nm or less, And tantalum nitride fine particles having an average particle size of 100 nm or less Selected from At least one kind is dispersed.
[0012]
Moreover, the other coating solution for forming a heat ray shielding film of the present invention is: To obtain a heat ray shielding film having a maximum value of transmittance at a wavelength of 400 to 700 nm, a minimum value of transmittance at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value being 15 points or more in percentage A coating solution for forming a heat ray shielding film, Titanium nitride fine particles having an average particle size of 100 nm or less, zirconium nitride fine particles having an average particle size of 100 nm or less, hafnium nitride fine particles having an average particle size of 100 nm or less, vanadium nitride fine particles having an average particle size of 100 nm or less, niobium nitride fine particles having an average particle size of 100 nm or less, And at least one selected from tantalum nitride fine particles having an average particle size of 100 nm or less, and an average particle size of 100 nm or less Ruthenium oxide fine particles And an average particle size of 100 nm or less Iridium oxide fine particles And at least one selected from the group consisting of dispersed.
[0013]
In addition, another heat ray shielding film-forming coating solution of the present invention has any of the above-described configurations, and further includes a metal alkoxide of silicon, zirconium, titanium, or aluminum, a partially hydrolyzed polymer of metal alkoxide, Inorganic binder components selected from organosilazane solutions and room temperature curable silicate solutions described below It is characterized by containing.
[0014]
The coating solution for forming a heat ray shielding film having any one of the above-described structures may contain a resin binder.
[0015]
Moreover, the heat ray shielding film of the present invention was obtained by applying the heat-shielding film forming coating solution described above to a substrate and then heating it. The maximum value of the transmittance is at a wavelength of 400 to 700 nm, the minimum value of the transmittance is at a wavelength of 700 to 1800 nm, and the difference between the maximum value and the minimum value is 15 points or more in percentage. The fine particle dispersion film, the main component showing the heat ray shielding property is at least one fine particle selected from titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, tantalum nitride, or titanium nitride, At least one fine particle selected from zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, and tantalum nitride, and at least one fine particle selected from ruthenium oxide and iridium oxide, and the fine particle component is the above-mentioned inorganic type Dispersed in a binder or resin binder.
[0016]
Further, an oxide film containing at least one of metal oxides of silicon, zirconium, titanium, and aluminum is further coated on the heat ray shielding film, or on the heat ray shielding film. Further, a resin film may be coated to form a multilayer heat ray shielding film.
[0017]
Any one of the heat ray shielding films described above has a maximum value at a wavelength of 400 to 700 nm, a minimum value at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value is 15 points or more in percentage. And a surface resistance value of 10 ⁶ It is characterized by being Ω / □ or more.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the nitride fine particles used in the present invention include titanium nitride (TiN), zirconium nitride (ZrN), hafnium nitride (HfN), vanadium nitride (VN), niobium nitride (NbN), and tantalum nitride (TaN). A typical example. The nitride fine particles used in the present invention may be partially or wholly replaced with oxynitride. These nitride fine particles are preferably not oxidized on the surface, but are usually slightly oxidized, and it is inevitable that oxidation of the surface occurs in the fine particle dispersion process to some extent. However, even in that case, the effectiveness of developing the heat ray shielding effect remains unchanged. Further, these nitride fine particles have a higher heat ray shielding effect as the crystal completeness is higher. However, even if the crystallinity is low and X-ray diffraction produces a very broad diffraction peak, If the basic bond is composed of a bond between each metal and nitrogen, a heat ray shielding effect is exhibited.
[0019]
Also used in the present invention Ruthenium oxide or iridium oxide As the fine particles, ruthenium dioxide (RuO) ₂ ), Iridium dioxide (IrO ₂ ) And the like are typical examples. These fine particles are stable as oxides, hold a large amount of free electrons, and have a very effective heat ray shielding function.
[0020]
These nitride fine particles, ruthenium oxide fine particles, and iridium oxide fine particles are powders colored in gray-black, brown-black, green-black, etc., but the particle size is sufficiently smaller than the visible light wavelength and dispersed in the thin film. In the state, the membrane has visible light permeability. However, the infrared light shielding ability can be kept sufficiently strong. The reason for this is not understood in detail, but because the amount of free electrons in these particles is large and the plasma frequency due to free electron plasmons inside and on the surface of the particles is just around the visible to near infrared, It is considered that heat rays in the wavelength region are selectively reflected and absorbed. According to experiments, in a film in which these fine particles are sufficiently finely and uniformly dispersed, the transmittance has a maximum value at a wavelength of 400 to 700 nm, a minimum value at a wavelength of 700 to 1800 nm, and a transmittance of It is observed that the difference between the local maximum and the local minimum is 15 points or more as a percentage. Considering that the visible light wavelength is 380 to 780 nm and the visibility is a bell-shaped peak with a peak near 550 nm, such a film effectively transmits visible light and effectively reflects other heat rays. It can be understood that it absorbs.
[0021]
In the present invention, nitride fine particles in the coating solution, Ruthenium oxide Fine particles, Iridium oxide The average particle diameter of the fine particles is preferably 100 nm or less. When the particle diameter is larger than 100 nm, the characteristic transmittance profile as described above, that is, the transmittance has a maximum value at a wavelength of 400 to 700 nm, a minimum value at a wavelength of 700 to 1800 nm, and a maximum value. A profile in which the difference between the minimum value and the minimum value is 15 points or more cannot be obtained, and a grayish film with a monotonously reduced transmittance is obtained. On the other hand, when the particle diameter is larger than 100 nm, the tendency of aggregation of fine particles in the dispersion becomes strong, which causes sedimentation of the fine particles. Further, fine particles of 100 nm or more or coarse particles formed by agglomeration thereof serve as a light scattering source and cause clouding (haze) in the film or cause a decrease in visible light transmittance. Therefore, the average particle size of the inorganic fine particles needs to be 100 nm or less. The minimum particle size that is economically available is about 2 nm, but the lower limit is not limited to this.
[0022]
The dispersion medium of the fine particles in the coating liquid is not particularly limited and can be selected according to the coating conditions and coating environment, the alkoxide in the coating liquid, the synthetic resin binder, etc., for example, water, alcohol, ether, Various organic solvents such as esters and ketones can be used. Moreover, you may adjust pH by adding an acid and an alkali as needed. Furthermore, in order to further improve the dispersion stability of the fine particles in the coating solution, various surfactants, coupling agents and the like can be added. The amount of each added at that time is 30% by weight or less, preferably 5% by weight or less based on the inorganic fine particles.
[0023]
The conductivity of the film when it is made into a film using this coating solution is performed along the conductive path that passes through the contact point of the fine particles. Therefore, for example, by adjusting the amount of the surfactant and the coupling agent, the conductive path Can be partially cut ⁶ It is easy to reduce the conductivity of the film to a surface resistance value of Ω / □ or more. The conductivity can also be controlled by adjusting the content of silicon, zirconium, titanium, aluminum metal alkoxide, or a partially hydrolyzed polymer of these metals, or a synthetic resin binder.
[0024]
The fine particle dispersion method can be arbitrarily selected as long as the fine particles are uniformly dispersed in the solution. Examples of the fine particle dispersion method include a bead mill, a ball mill, a sand mill, and an ultrasonic dispersion method.
[0025]
The heat ray shielding film in the present invention is a film in which the fine particles are deposited at a high density on a substrate to form a film. The metal alkoxide of silicon, zirconium, titanium, aluminum contained in the coating solution, or a part of these metals The hydrolyzed polymer or the synthetic resin binder has an effect of improving the binding property of the fine particles to the substrate after coating and curing, and further improving the hardness of the film. Further, a film containing a metal alkoxide such as silicon, zirconium, titanium, aluminum or the like, a hydrolysis polymer of these metal alkoxides, or a synthetic resin is coated as a second layer on the film thus obtained. Thus, it is possible to further improve the binding force of the film containing fine particles as a main component to the base material, the hardness and weather resistance of the film.
[0026]
If the coating solution does not contain metal alkoxides of silicon, zirconium, titanium, aluminum, hydrolyzed polymers of these metals, or synthetic resin binders, the film obtained after applying this coating solution to the substrate Thus, a film structure in which only the fine particles are deposited is obtained. Although the heat ray shielding effect is exhibited as it is, a coating liquid containing a metal alkoxide of silicon, zirconium, titanium, aluminum, a hydrolysis polymer of these metals, or a synthetic resin binder is further applied to this film in the same manner as described above. By forming a film to form a multilayer film, the coating liquid component fills the gap in which the fine particles of the first layer are deposited, so that the haze of the film is reduced and the visible light transmittance is improved. The binding property to the base material is improved.
[0027]
Sputtering and vapor deposition can also be used as a method of binding the film containing the fine particles as a main component with a film made of a metal alkoxide of silicon, zirconium, titanium, or aluminum, or a hydrolysis polymer of these metals. However, the coating method is effective because of the advantages such as the ease of the film forming process and low cost. This coating solution for coating contains one or more metal alkoxides of silicon, zirconium, titanium, or aluminum in water or alcohol, or a hydrolyzed polymer of these metals. It is preferably 40% by weight or less in the total solution in terms of oxide. Moreover, it is also possible to adjust pH by adding an acid and an alkali as needed. By applying such a liquid as a second layer on the film containing the fine particles as a main component and heating, an oxide film of silicon, zirconium, titanium, aluminum, or the like can be easily produced.
[0028]
The coating method of the coating solution and the coating solution for coating is not particularly limited, and the processing solution is flat and thin, such as spin coating method, spray coating method, dip coating method, screen printing method, roll coating method, and flow coating method. Any method can be appropriately employed as long as it can be applied uniformly.
[0029]
When the base material heating temperature after coating the coating liquid containing the metal alkoxide and its hydrolysis polymer is less than 100 ° C., the polymerization reaction of the alkoxide or its hydrolysis polymer contained in the coating film may remain incomplete. In addition, since water and organic solvents remain in the film and cause reduction in the visible light transmittance of the film after heating, the temperature is preferably 100 ° C. or higher, more preferably heated above the boiling point of the solvent in the coating solution. Can be implemented.
[0030]
If a synthetic resin binder is used, it may be cured according to the respective curing method. For example, if it is an ultraviolet curable resin, it may be appropriately irradiated with ultraviolet rays, and if it is a room temperature curable resin, it may be left as it is after being applied. Therefore, it can be applied to existing window glass in the field, expanding versatility.
[0031]
An organosilazane solution may be used as a binder component used in the coating solution of the present invention or as a coating solution for overcoat. As organosizaran solutions, those having a polymerization curing temperature of 100 ° C. or lower are also commercially available by correcting the side chain groups or adding an oxidation catalyst. By using these solutions, the film forming temperature can be considerably lowered. As the room temperature curable binder, a commercially available silicate-based binder can also be used. Both are SiO after curing ₂ The inorganic film is formed and is superior to the resin film in terms of weather resistance and film strength.
[0032]
Since the film of the present invention is a film in which the above ultrafine particles are dispersed, compared to a film having a mirror-like surface in which crystals are densely filled, such as an oxide thin film manufactured by a physical film forming method. The reflection in the visible light region is small, and it is possible to avoid a glaring appearance. On the other hand, as described above, since it has a plasma frequency in the visible to near-infrared region, it has a very favorable characteristic that plasma reflection associated therewith increases in the near-infrared region. In addition, when it is desired to further suppress the reflection in the visible light region, SiO 2 is formed on the fine particle dispersion film. ₂ By forming a low refractive index film such as MgF, a multilayer film having a luminous reflectance of 1% or less can be easily produced.
[0033]
In order to improve the transmittance, the coating liquid of the present invention can further be mixed with ultrafine particles such as ATO, ITO, and aluminum-added zinc oxide. These transparent ultrafine particles increase absorption in the near-infrared region close to visible light as the amount added is increased, so that a heat ray shielding film having high visible light transmittance can be obtained. Conversely, it is also possible to add the coating liquid of the present invention to a liquid in which ultrafine particles such as ATO, ITO, and aluminum-added zinc oxide are dispersed to color the film and at the same time assist the heat ray shielding effect. In this case, since the heat ray shielding effect can be assisted with only a slight addition amount to the main ITO or the like, there is an advantage that the required amount of ITO can be greatly reduced and the cost of the liquid can be reduced.
[0034]
In addition, the coating liquid of the present invention includes an inorganic titanium oxide, zinc oxide, cerium oxide, etc. in order to improve the shielding function of ultraviolet rays harmful to the human body simultaneously with the shielding ability of infrared rays when it becomes a film. It is also possible to add one kind or two or more kinds such as fine particles, organic benzophenone and benzotriazole.
[0035]
The coating liquid according to the present invention is a dispersion of the above-mentioned inorganic fine particles, and does not form a target heat ray shielding film by utilizing decomposition or chemical reaction of the coating component due to heat during firing, so that the characteristics are stable. A permeable membrane having a uniform film thickness can be formed.
[0036]
The fine particle-dispersed film in the present invention is a film in which fine particles are deposited at a high density on a substrate to form a film, and a metal alkoxide of silicon, zirconium, titanium, or aluminum contained in a coating solution, or a hydrolysis thereof. The polymer or the synthetic resin binder has an effect of improving the binding property of the fine particles on the substrate after the coating film is cured, and further improving the strength of the film.
[0037]
As described above, according to the present invention, it is possible to manufacture a film having a heat ray shielding effect by appropriately mixing the inorganic fine particle materials. However, since these fine particle materials are inorganic materials, they are compared with organic materials. The weather resistance is very high. For example, even if it is used in a part exposed to sunlight (ultraviolet rays), the color and various functions hardly deteriorate.
[0038]
【Example】
Examples of the present invention will be described below together with comparative examples.
[0039]
(Example 1) 8 g of TiN fine particles having an average particle diameter of 40 nm, 80 g of diacetone alcohol (DAA), water and a suitable amount of a dispersant are mixed and ball mill mixed for 100 hours using a zirconia ball having a diameter of 4 mm to obtain 100 g of a TiN dispersion. Was made. This is A liquid. Next, 6 g of ethyl silicate 40 manufactured by Tama Chemical Industry Co., Ltd. having an average degree of polymerization of 4 to 5 mer, 31 g of ethanol, 8 g of 5% hydrochloric acid aqueous solution and 5 g of water, 50 g of ethyl silicate solution, 800 g of water, and Ethanol 300 g was mixed and stirred well to prepare 1150 g of ethyl silicate mixed solution. This is B liquid.
[0040]
A liquid and B liquid are mixed with a TiN concentration of 1.0%, TiN / SiO ₂ The mixture was mixed and stirred at a ratio such that the ratio was 4: 1 to prepare a coating solution. This is liquid C. 15 g of this liquid C was dropped from a beaker onto a 200 × 200 × 3 mm soda lime plate glass substrate rotating at 145 rpm, and after shaking for 3 minutes, the rotation was stopped. This was put in an electric furnace at 180 ° C. and heated for 30 minutes to obtain the intended film.
[0041]
The spectral characteristics of the formed film were measured using a spectrophotometer manufactured by Hitachi. The transmission profile and reflection profile of the film of this example using TiN fine particles are shown in FIGS. The maximum value of the transmittance is 425 nm, the minimum value is 745 nm, the maximum value of the reflectance is around 1000 nm, the difference between the maximum value and the minimum value of the transmittance is 22 points, and the transmittance is high at the visible light wavelength. The profile has a low transmittance at near infrared wavelengths, and a visible light transmittance of 44% and a solar radiation transmittance of 42% were obtained based on JIS-R-3106.
[0042]
This film-coated glass was set on the top surface of a 100 × 100 × 60 mm vinyl chloride small box and left for 1 hr under sunny sunlight to measure the temperature change in the box. When this glass with a film was placed, it became constant at 45 ° C, but when a commercially available heat ray absorbing bronze glass (visible light transmittance of 64%) was placed, 55 ° C, when a transparent clear glass was placed The temperature was 61 ° C., and a clear shielding effect of heat rays by solar radiation was observed. In this way, the film according to this example having a maximum transmittance in visible light, a minimum transmittance in the near infrared, and a maximum reflectance in the near infrared has an excellent heat ray shielding effect. It was confirmed to have.
[0043]
The transmitted color of the membrane according to this example was a beautiful deep blue color. Further, while the solar reflectance was as high as 18%, the visible light reflectance was as low as 12%, and the glare of the film surface as in a commercially available heat ray reflective glass was not felt.
[0044]
Furthermore, when the surface resistance value of this film was measured using a surface resistance meter manufactured by Mitsubishi Chemical, 8 × 10 ⁸ Ω / □ was obtained, and the film resistance value was sufficiently high, and it was found that there was no problem with radio wave transmission.
[0045]
(Comparative example 1) About the commercially available heat ray reflective bronze glass produced by the high cost physical film-forming method compared with the apply | coating method, the spectral transmittance of 340-1800nm is measured, and visible light transmittance | permeability according to JIS-R-3106 The solar transmittance was determined to be 45% and 51%, respectively, and the solar transmittance was slightly higher than that of the film of Example 1 above. The solar reflectance was a good value of 23%, but the visible light reflectance was as high as 30%, and the appearance was glaring and mirror-like. Also, the surface resistance value of the film surface is as low as 83Ω / □, and it is clear that there are problems with radio wave transmission and reflection.
[0046]
(Example 2) After spin-coating the liquid C produced in Example 1 as the first layer of the plate glass, the rotation was continued for 3 minutes, and then the liquid B was added to SiO 2 ₂ 15 g of a silicate solution diluted with ethanol so as to be 0.9% in terms of solid content was dropped from a beaker onto a plate glass and further rotated for 3 minutes, and then the rotation was stopped. The two-layer glass substrate coated in this manner was placed in an electric furnace at 180 ° C. and heated for 30 minutes to obtain the desired two-layer film.
[0047]
The spectral characteristics of the formed film were evaluated in the same manner as in Example 1. While the visible light transmittance increased to 51.8%, the visible light reflectance was 4.6%, and the reflected light was greatly suppressed. Furthermore, when a black tape was applied to the back surface and the reflection from the back surface was eliminated, the visible light reflectance was 1.5%, which was an appearance close to non-reflective glass. The position of the maximum / minimum value of the transmittance of this film is almost the same as that of the single-layer film in Example 1, and it is clear that it has the same heat ray shielding effect.
[0048]
In the following Examples 3 to 16, the visible light transmittance and the maximum / minimum values of the transmittance and the surface resistance value of the films formed were evaluated by the same method as described in Example 1, and Example 1, The results of 2 are shown together in Table 1.
[0049]
(Example 3) 8 g of TiN fine particles having an average particle diameter of 40 nm, 80 g of isophorone, water and an appropriate amount of a dispersant were mixed and ball mill mixed for 100 hours using zirconia balls to prepare 100 g of a TiN isophorone dispersion. This is D liquid. As a binder, 50% by weight of an epoxy resin was dissolved in isophorone to prepare an epoxy resin binder solution. This is E liquid. D liquid, E liquid and ethanol are mixed and stirred vigorously so that the solid content of TiN and epoxy resin is 1.4% by weight of the whole, and the weight ratio of TiN and epoxy resin is 70:30. A coating solution was prepared in the same manner as in Example 1, and a film was obtained by film formation and heating.
[0050]
(Example 4) Using Shin-Etsu Silicone room temperature curable silicate liquid X-40-9740 as a binder instead of Liquid B, a coating liquid was prepared in the same manner as in Example 1, and a film was obtained by film formation. It was. However, without heating, a film which was allowed to stand at room temperature for 2 days at 25 ° C. to form a dry film was evaluated.
[0051]
(Example 5) As a binder, the TiN isophorone dispersion liquid (D liquid) and xylene shown in Example 3 were mixed using a low-temperature curing polyperhydrosilazane solution manufactured by NE Chemcat Co., Ltd. instead of the liquid E. When stirred, the TiN concentration is 1.0%, TiN / SiO ₂ This was used as a coating solution so that the ratio was 4: 1. Using this, a film was formed in the same manner as in Example 1, and heated in an electric furnace at 80 ° C. to obtain a film.
[0052]
(Example 6) In the preparation of liquid A, a coating liquid was prepared in the same manner as in Example 1 except that ZrN fine particles having an average particle diameter of 35 nm were used instead of TiN. Film was obtained.
[0053]
(Example 7) In the preparation of liquid A, a coating liquid was prepared in the same manner as in Example 1 except that HfN fine particles having an average particle diameter of 47 nm were used instead of TiN. Film was obtained.
[0054]
(Example 8) In the preparation of liquid A, a coating liquid was prepared in the same manner as in Example 1 except that VN fine particles having an average particle diameter of 64 nm were used instead of TiN. Film was obtained.
[0055]
(Example 9) In preparing the liquid A, a coating liquid was prepared in the same manner as in Example 1 except that NbN fine particles having an average particle diameter of 55 nm were used instead of TiN. Film was obtained.
[0056]
(Example 10) In the preparation of liquid A, a coating liquid was prepared in the same manner as in Example 1 except that TaN fine particles having an average particle diameter of 43 nm were used instead of TiN. Film was obtained.
[0057]
(Example 11) Ruthenium oxide (RuO) having an average particle diameter of 30 nm ₂ ) 15 g of fine particles, 23 g of N-methyl-2-pyrrolidone (NMP), 57 g of diacetone alcohol (DAA), an appropriate amount of water and a dispersing agent were mixed, and ball mill mixing was performed for 100 hours using zirconia balls having a diameter of 4 mm. ₂ 100 g of a dispersion was produced. This RuO ₂ In the dispersion, RuO ₂ Concentration is 1%, RuO ₂ : SiO ₂ = Mixing and stirring the silicate solution of B so as to be 4: 1, RuO ₂ A dispersed silicate solution was obtained. This is designated F solution. RuO in F liquid ₂ : A liquid A was mixed so that it might become a weight ratio of TiN = 1.0: 0.01, and it stirred sufficiently, and prepared the coating liquid. Using this coating solution, the target film was obtained by film formation and heating in exactly the same manner as in Example 1.
[0058]
(Example 12) At the time of mixing F liquid and A liquid, RuO ₂ A coating solution was prepared in the same manner as in Example 11 except that the weight ratio of TiN was changed to 1.0: 0.25, and this was formed into a film and heated to obtain the desired coating film.
[0059]
(Example 13) At the time of mixing F liquid and A liquid, RuO ₂ A coating solution was prepared in the same manner as in Example 11 except that the weight ratio of TiN was changed to 1.0: 0.5, and this was formed into a film and heated to obtain the desired coating film.
[0060]
(Example 14) At the time of mixing F liquid and A liquid, RuO ₂ A coating solution was prepared in the same manner as in Example 11 except that the weight ratio of TiN was changed to 1.0: 1.0, and this was formed into a film and heated to obtain the desired coating film.
[0061]
(Example 15) IrO having an average particle diameter of 28 nm ₂ Except for using fine particles, IrO was exactly the same as Example 11. ₂ : A TiN mixed-dispersed silicate coating solution was prepared, and this was formed and heated to obtain the desired film.
[0062]
Example 16 IrO with an average particle size of 28 nm ₂ Except for using fine particles, IrO was exactly the same as Example 12. ₂ : A TiN mixed-dispersed silicate coating solution was prepared, and this was formed and heated to obtain the desired film.
[0063]
In the above Examples 1 to 16, the transmittance maximum is in the wavelength range of 400 to 700 nm, the minimum value is in the wavelength range of 700 to 1800 nm, and the difference between the maximum value and the minimum value is 15 points or more. It was observed that these films were useful as heat ray shielding films. Further, all the films of the examples have a reflectance in the visible light region of 14% or less, no mirror-like glare, and a surface resistance value of 10 for all films. ⁷ It was confirmed that there was no problem in radio wave transmission because it was Ω / □ or more.
[0064]
Comparative Example 2 A TiN-dispersed silicate coating solution was prepared in the same manner as in Example 1 except that TiN having an average particle size of 120 nm was used, and this was formed and heated to obtain a target film. However, this film was cloudy (haze value 14%), lacked transparency, and turned bluish gray, and it was judged difficult to put it to practical use as a heat ray shielding film.
[0065]
Comparative Example 3 An ITO dispersed silicate coating solution was prepared in the same manner as in Example 1 except that ITO ultrafine particles having an average particle diameter of 22 nm were used, and this was formed and heated to obtain the target film. It was. However, this film has a transmittance of 90% or more from the visible light region to the 1500 nm infrared region, and it was found that this film cannot be used at this concentration for the purpose of shielding near infrared light.
[0066]
[Table 1]

[0067]
【The invention's effect】
As shown in the above embodiments, according to the present invention, the light transmittance in the visible light region is high and the reflectance is low, the light transmittance in the near infrared region is low and the reflectance is high, and the film The conductivity of the ⁶ It was possible to provide a coating solution capable of forming a film that can be controlled to Ω / □ or more by a simple coating method without using a high-cost physical film forming method, and a heat ray shielding film using the same. The film of the present invention is a heat ray shielding film that has no surface glare compared to conventional films and is excellent in radio wave transmission. Moreover, by using the coating liquid of this invention, industrial usefulness is high from the surface of a cost or a large area film | membrane.
[Brief description of the drawings]
FIG. 1 is a graph showing the transmittance of Examples 1, 11, 12, 13, and 14 of the present invention.
FIG. 2 is a graph showing the reflectance of Examples 1, 11, 12, 13, and 14 of the present invention.

Claims

To obtain a heat ray shielding film having a maximum value of transmittance at a wavelength of 400 to 700 nm, a minimum value of transmittance at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value being 15 points or more in percentage A coating solution for forming a heat ray shielding film, comprising titanium nitride fine particles having an average particle size of 100 nm or less, zirconium nitride fine particles having an average particle size of 100 nm or less, hafnium nitride fine particles having an average particle size of 100 nm or less, and vanadium nitride fine particles having an average particle size of 100 nm or less A coating solution for forming a heat ray shielding film, wherein at least one selected from niobium nitride fine particles having an average particle size of 100 nm or less and tantalum nitride fine particles having an average particle size of 100 nm or less is dispersed.

To obtain a heat ray shielding film having a maximum value of transmittance at a wavelength of 400 to 700 nm, a minimum value of transmittance at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value being 15 points or more in percentage A coating solution for forming a heat ray shielding film, comprising titanium nitride fine particles having an average particle size of 100 nm or less, zirconium nitride fine particles having an average particle size of 100 nm or less, hafnium nitride fine particles having an average particle size of 100 nm or less, and vanadium nitride fine particles having an average particle size of 100 nm or less At least one selected from niobium nitride fine particles having an average particle size of 100 nm or less, tantalum nitride fine particles having an average particle size of 100 nm or less, ruthenium oxide fine particles having an average particle size of 100 nm or less, and oxidation having an average particle size of 100 nm or less heat and at least one is equal to or dispersed is selected from iridium microparticles Shielding film-forming coating solution.

The coating solution for forming a heat ray shielding film according to claim 1 or 2, further comprising a metal alkoxide of silicon, zirconium, titanium, or aluminum, a partially hydrolyzed polymer of metal alkoxide, an organosilazane solution, A coating solution for forming a heat ray shielding film, which contains an inorganic binder component selected from a curable silicate solution.

A heat-ray shielding film forming coating liquid according to claim 1 or claim 2, further heat-ray shielding film forming coating solution characterized by containing a resin binder component.

The maximum value of the transmittance is obtained at a wavelength of 400 to 700 nm obtained by applying the coating solution for forming a heat ray shielding film according to claim 1 to a substrate and then heated, and the transmittance is obtained at a wavelength of 700 to 1800 nm. A fine particle dispersion film having a local minimum value and having a difference between the local maximum value and the local minimum value of 15 points or more, and the main component exhibiting heat ray shielding characteristics is titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride Or at least one fine particle selected from niobium nitride and tantalum nitride, or at least one fine particle selected from titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride and tantalum nitride, and ruthenium oxide. , At least one kind of fine particles selected from iridium oxide, and the fine particle component contains the inorganic binder or the resin binder. Heat-ray shielding film, which has been dispersed in Nda.

The maximum value of the transmittance is obtained at a wavelength of 400 to 700 nm obtained by applying the coating solution for forming a heat ray shielding film according to claim 1 to a substrate and then heated, and the transmittance is obtained at a wavelength of 700 to 1800 nm. On the heat ray shielding film having the minimum value and the difference between the maximum value and the minimum value being 15 points or more in percentage , further, among metal oxides of any of silicon, zirconium, titanium, and aluminum A multilayer heat ray shielding film, wherein an oxide film containing at least one kind is coated.

The maximum value of the transmittance is obtained at a wavelength of 400 to 700 nm obtained by applying the coating solution for forming a heat ray shielding film according to claim 1 to a substrate and then heated, and the transmittance is obtained at a wavelength of 700 to 1800 nm. A multilayer heat ray shielding film characterized in that a resin film is further coated on a heat ray shielding film having a minimum value and having a difference between the maximum value and the minimum value of 15 points or more as a percentage .

Heat-ray shielding film as set forth in any one claims 5 to 7, the surface resistance value is equal to or is 10 ⁶ Ω / □ or more.