JP3797469B2 - Modified resin-containing stain-resistant coating composition, coating finishing method and coated article - Google Patents

Description

【０００９】
（式中のＲ^５およびＲ^６はそれぞれ水素原子または炭素数1〜４のアルキル基であり、ｙは１〜１０の整数である。）で表される有機基を有する耐汚染性塗料組成物を提供するものである。
また、本発明は、上記耐汚染性塗料組成物において、（Ａ）成分の変性樹脂のアクリル樹脂構造部分に、一般式（３）
【００１０】
【化４】

【００１１】
（式中のＲ^５およびＲ^６はそれぞれ水素原子または炭素数1〜４のアルキル基であり、ｙは１〜１０の整数である。）で表される有機基を有する耐汚染性塗料組成物を提供するものである。
また、本発明は、上記の耐汚染性塗料組成物の（Ａ）成分、（Ｂ）成分及び（Ｃ）成分の全不揮発成分１００質量部あたり、顔料を０〜２００質量部含有する上塗り塗料を被塗装体に塗装することを特徴とする塗装仕上げ方法を提供するものである。
また、本発明は、基材上に着色フィルム形成性組成物を塗布してベースコートを形成し、次いで該ベースコートにクリヤーフィルム形成性組成物を塗布して透明トップコートを形成することから成る被塗装体に複合被膜を塗装する方法において、該トップコートクリヤーフィルム形成性組成物のみが、あるいは該トップコートクリヤーフィルム形成性組成物および着色フィルム形成性組成物のいずれもが、請求項１〜９に記載の耐汚染性塗料組成物のいずれかを含有することを特徴とする塗装仕上げ方法を提供するものである。
【００１２】
また、本発明は、基材上に着色ベースコート塗料を塗装し、未架橋の状態でアンダークリヤー塗料を塗布し、これを焼き付けた後、さらにオーバーコートクリヤー塗料を塗布して焼き付ける塗装方法において、該アンダークリヤー塗料がアクリル樹脂／アミノプラスト樹脂系塗料、アクリル樹脂／ウレタン樹脂硬化剤系塗料またはアクリル樹脂／アミノプラスト樹脂／ウレタン樹脂硬化剤系塗料のいずれかから選ばれるものであり、かつ当該オーバーコートクリヤー塗料が上記の耐汚染性塗料組成物のいずれかを含有することを特徴とする塗装仕上げ方法を提供するものである。
また、本発明は、上記塗装仕上げ方法において、基材上に着色ベースコート塗料を塗装し、未架橋の状態でアンダークリヤー塗料を塗布し、これを焼き付けた後、さらにオーバーコートクリヤー塗料を塗布して焼き付ける塗装方法において、該アンダークリヤー塗料が（ａ）水酸基とエポキシ基の両方を有するアクリル樹脂４０〜８０質量％、（ｂ）アミノプラスト樹脂０〜６０質量％、（ｃ）ウレタン樹脂硬化剤０〜６０質量％から構成される樹脂混合物を主成分とすることを特徴とする塗料組成物である塗装仕上げ方法を提供するものである。
また、本発明は、上記塗装仕上げ方法により塗装されたこと特徴とする塗装物品を提供するものである。
【００１３】
【発明の実施の形態】
本発明の耐汚染性塗料組成物（以下、単に塗料組成物と略すこともある。）において（Ａ）成分として用いられる変性樹脂は、塗膜を親水化させるのに必要であるオルガノシリケート及び／又はその縮合物を塗膜中に均一に分散させ、親水性の発現と耐水性の向上の両立を果たすために用いられる。かかる変性樹脂としては、一般式(１)
（Ｒ^１）_ｍ−Ｓｉ−（ＯＲ^２）_４−ｍ （１）
（式中のＲ^１およびＲ^２はそれぞれ水素原子または炭素数１〜１０のアルキル基またはアリール基であり、ｍは０又は１である。）で表されるオルガノシリケート及び／又はその縮合物の存在下で、水酸基を有するラジカル重合性単量体とその他のラジカル重合性単量体を有機溶媒中で通常のラジカル共重合するか、もしくは水酸基を有するラジカル重合性単量体と、エポキシ基を有するラジカル重合性単量体と、その他のラジカル重合性単量体を有機溶媒中で通常のラジカル共重合することにより得られる。
【００１４】
一般式(１)で表されるオルガノシリケートの好ましい具体例としては、例えばテトラヒドロキシシラン、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン、テトラフェノキシシラン、ジメトキシジエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、フェニルトリメトキシシラン、フェニルトリエトキシシラン、ブチルトリメトキシシラン、ヘキシルトリメトキシシラン、デシルトリメトキシシラン、エトキシトリメトキシシラン、プロポキシトリメトキシシラン、ブトキシトリメトキシシランなどが挙げられる。
またオルガノシリケートの縮合物としては、前記一般式（１）で表されるオルガノシリケートの１種又は２種以上の分岐状もしくは直鎖状の縮合物であって、重量平均分子量が２００〜２０００の範囲にあるものが好ましく、３００〜１５００の範囲内にあるものが特に好ましい。オルガノシリケートの縮合物の市販品としては、ＭＫＣシリケートＭＳ５１、ＭＳ５６、ＭＳ５７、ＭＳ５６Ｓ、ＭＳ５６ＳＢ５、ＥＳ４０、ＥＭＳ３１、ＢＴＳ（いずれも商品名、三菱化学（株）製）、メチルシリケート５１、エチルシリケート４０、エチルシリケート４０Ｔ、エチルシリケート４８（いずれも商品名、コルコート（株）製）、エチルシリケート４０、４５（いずれも商品名多摩化学工業（株）製）などが挙げられる。
【００１５】
水酸基を有するラジカル重合性単量体の具体例としては、例えば、アクリル酸-２-ヒドロキシエチル、アクリル酸-２-ヒドロキシプロピル、アクリル酸-３-ヒドロキシプロピル、アクリル酸-４-ヒドロキシブチル、メタクリル酸-２-ヒドロキシエチル、メタクリル酸-２-ヒドロキシプロピル、メタクリル酸-３-ヒドロキシプロピル、メタクリル酸-４-ヒドロキシブチル、アリルアルコール、アクリル酸とバーサチック酸グリシジルエステルの付加物、メタクリル酸とバーサチック酸グリシジルエステルの付加物；アクリル酸-２-ヒドロキシエチル、アクリル酸-２-ヒドロキシプロピル、アクリル酸-３-ヒドロキシプロピル、アクリル酸-４-ヒドロキシブチル、メタクリル酸-２-ヒドロキシエチル、メタクリル酸-２-ヒドロキシプロピル、メタクリル酸-３-ヒドロキシプロピル、メタクリル酸-４-ヒドロキシブチルのε−カプロラクトン付加物；アクリル酸-２-ヒドロキシエチル、アクリル酸-２-ヒドロキシプロピル、アクリル酸-３-ヒドロキシプロピル、アクリル酸-４-ヒドロキシブチル、メタクリル酸-２-ヒドロキシエチル、メタクリル酸-２-ヒドロキシプロピル、メタクリル酸-３-ヒドロキシプロピル、メタクリル酸-４-ヒドロキシブチルのエチレンオキサイド及び／又はプロピレンオキサイド付加物などが挙げられ、1種又は2種以上の混合物として用いられる。
【００１６】
また、エポキシ基を有するラジカル重合性単量体の具体例としては、例えば、アクリル酸グリシジル、メタクリル酸グリシジル、アクリル酸３,４-エポキシシクロヘキシルメチル、メタクリル酸３,４-エポキシシクロヘキシルメチルなどが挙げられ、１種又は２種以上の混合物として用いられる。
ここで水酸基を有するラジカル重合性単量体は、(Ａ)成分の変性樹脂のアクリル樹脂構造部分を構成する全単量体中１〜３０質量％の範囲内で用いられることが望ましく、１〜１５質量％がより望ましく、２〜７質量％が特に望ましい。該ラジカル重合性単量体が１質量％未満の場合、最終的に得られる硬化塗膜の耐水性が低下するため好ましくなく、また３０質量％を越える場合は変性反応の際にゲル化しやすくなるため好ましくない。
また、エポキシ基を有するラジカル重合性単量体は、(Ａ)成分の変性樹脂のアクリル樹脂構造部分を構成する全単量体中０〜７０質量％の範囲内で用いられることが望ましく、５〜６０質量％がより望ましく、１０〜５０質量％が特に望ましい。該ラジカル重合性単量体が７０質量％を越える場合は、硬化塗膜の耐クラック性が低下するため好ましくない。
【００１７】
その他のラジカル重合性単量体の具体例としては、例えば、アクリル酸メチル、アクリル酸エチル、アクリル酸n-プロピル、アクリル酸イソプロピル、アクリル酸n-ブチル、アクリル酸イソブチル、アクリル酸ｓｅｃ-ブチル、アクリル酸ヘキシル、アクリル酸シクロヘキシル、アクリル酸２-エチルヘキシル、アクリル酸オクチル、アクリル酸ラウリル、アクリル酸ステアリル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸n-プロピル、メタクリル酸イソプロピル、メタクリル酸n-ブチル、メタクリル酸イソブチル、メタクリル酸ｓｅｃ-ブチル、メタクリル酸ヘキシル、メタクリル酸シクロヘキシル、メタクリル酸２-エチルヘキシル、メタクリル酸オクチル、メタクリル酸ラウリル、メタクリル酸ステアリル、スチレン、アクリロニトリル、メタクリロニトリル、アクリルアミド、メタクリルアミド、アクリル酸、メタクリル酸、イタコン酸、メサコン酸、マレイン酸、フマル酸などが挙げられ、１種又は２種以上の混合物として用いられる。
ただし、(Ａ)成分の変性樹脂のアクリル樹脂構造部分を構成する単量体にエポキシ基を有するラジカル重合性単量体が用いられる場合は、アクリル酸、メタクリル酸、イタコン酸、メサコン酸、マレイン酸、フマル酸などのカルボキシル基を有するラジカル重合性単量体は、合成反応中のゲル化を避けるため用いない方が良い。
また、(Ａ)成分の変性樹脂のアクリル樹脂構造部分を構成する単量体は、一般式（３）で示される有機基を含有するラジカル重合性単量体を用いることもできる。
【００１８】
【化５】

【００１９】
（式中のＲ^５及びＲ^６はそれぞれ水素原子又は炭素数1〜４のアルキル基であり、
ｙは１〜１０の整数である。）
かかるラジカル重合性単量体の具体例としては、例えば、アクリル酸-２-メトキシプロピル、アクリル酸-２-メトキシエチル、アクリル酸-２-エトキシプロピル、アクリル酸-２-エトキシエチル、メタクリル酸-２-メトキシプロピル、メタクリル酸-２-メトキシエチル、メタクリル酸-２-エトキシプロピル、メタクリル酸-２-エトキシエチル、ブレンマーＰＭＥ−１００、−２００、−４００、ブレンマーＰＥ−９０、−２００、−３５０、ブレンマーＰＰ−１０００、−５００（いずれも商品名、日本油脂（株）製）などが挙げられ、１種又は２種以上の混合物として得られる。（３）式で示される有機基を含有するラジカル重合性単量体は、（Ｃ）成分が少量でも有効に塗膜表面に配向させ目的の親水性を発現させるのに有用であり、(Ａ)成分の変性樹脂のアクリル樹脂構造部分を構成する全単量体中１〜４０質量％の範囲内で用いられることが望ましく、１〜３０質量％がより望ましく、２〜２５質量％が特に望ましい。ここで該ラジカル重合性単量体が１質量％未満の場合、（Ｃ）成分の表面配向度が減少し親水性が十分でないため好ましくなく、４０質量％を越える場合は、塗膜の極性が高すぎ平滑性、耐水性が低下するため好ましくない。
【００２０】
この際、(Ａ)成分の変性樹脂は、アクリル樹脂構造部分を合成後に一般式（１）で表されるオルガノシリケート及び／又はその縮合物を反応させる方法も考えられるが、この場合オルガノシリケート及び／又はその縮合物が遊離して残り、塗膜中で島状となり、外観性を損ねることがあるため、好ましくない。
一般式（１）で表されるオルガノシリケート及び／又はその縮合物は（Ａ）成分の変性樹脂中１〜７０質量％の範囲内で用いられることが望ましく、３〜５０質量％がより望ましく、５〜４０質量％が特に望ましい。該オルガノシリケート及び／又はその縮合物が１質量％未満の場合、最終的に得られる硬化塗膜の耐汚染性が不十分となるため好ましくなく、７０質量％を越える場合は硬化塗膜の耐水性が低下するため好ましくない。
また、本発明の耐汚染性塗料組成物において、（Ａ）成分の変性樹脂は（Ａ）〜（Ｃ）成分の全不揮発分総量に対して３〜８０質量％の範囲内で用いられることが望ましく、１０〜８０質量％がより望ましく、２０〜８０質量％が特に望ましい。ここで（Ａ）成分が３質量％未満の場合、最終的に得られる硬化塗膜の耐汚染性が不十分となるため好ましくなく、８０質量％を越える場合は硬化塗膜の耐水性が低下するため好ましくない。
【００２１】
本発明の耐汚染性塗料組成物に用いられる（Ｂ）成分は、（Ａ）成分と熱硬化反応する化合物であり、一分子中にカルボキシル基、カルボン酸無水物基及びアルキルビニルエーテル化合物でブロック化されたカルボキシル基の官能基から選ばれる少なくとも１種を有する化合物（以下、単に硬化剤と略す場合もある）である。かかる硬化剤の具体例としては、一分子中にカルボキシル基を有する化合物では、例えばコハク酸、マロン酸、グルタル酸、アジピン酸、アゼライン酸、セバシン酸、デカメチレンジカルボン酸、ダイマー酸、フタル酸、マレイン酸、トリメリット酸、ピロメリット酸、テトラヒドロフタル酸、ヘキサヒドロフタル酸、メチルヘキサヒドロフタル酸などが挙げられる。また、その他の一分子中にカルボキシル基を有する化合物としては、▲１▼一分子当たり水酸基を１個以上、好ましくは２〜５０個有するポリオールとカルボン酸無水物をハーフエステルさせる、▲２▼一分子当たりイソシアネート基を１個以上、好ましくは２〜５０個有するポリイソシアネート化合物とヒドロキシカルボン酸又はアミノ酸とを付加させる、▲３▼カルボキシル基含有ラジカル重合性単量体を単独重合又は他のラジカル重合性単量体と共重合させる、▲４▼カルボキシル基末端のポリエステル樹脂を合成するなどの方法によって得られる化合物などが挙げられる。また、一分子中にカルボン酸無水物基を有する化合物としては、例えば、無水コハク酸、無水フタル酸、無水ヘキサヒドロフタル酸、メチル化無水ヘキサヒドロフタル酸、無水テトラヒドロフタル酸などの一分子中にカルボン酸無水物基を1個有する化合物の他に、酸無水物基を有するラジカル重合性単量体、例えば無水マレイン酸、無水イタコン酸などと他のラジカル重合性単量体との共重合体が挙げられる。
【００２２】
さらに、アルキルビニルエーテル化合物でブロックされたカルボキシル基を有する化合物としては、上記のカルボキシル基を有する化合物のカルボキシル基をアルキルビニルエーテル化合物でブロックすることによって得られる化合物などが挙げられる。かかるアルキルビニルエーテル化合物としては、エチルビニルエーテル、n-プロピルビニルエーテル、イソプロピルビニルエーテル、n-ブチルビニルエーテル、イソブチルビニルエーテル、t-ブチルビニルエーテル、ペンチルビニルエーテル、ヘキシルビニルエーテル、イソヘキシルビニルエーテル、シクロヘキシルビニルエーテル、２,３-ジヒドロフラン、３,４-ジヒドロフラン、３,４-ジヒドロ-２Ｈ-ピラン、３,４-ジヒドロ-２-メトキシ-２Ｈ-ピラン、３,４-ジヒドロ-４,４-ジメチル-２Ｈ-ピラン-２-オン、３,４-ジヒドロ-２-エトキシ-２Ｈ−ピランなどが挙げられる。
本発明の耐汚染性塗料組成物において、（Ｂ）成分の硬化剤の含有量は、（Ａ）〜（Ｃ）成分の全不揮発分総量に対して３〜８０質量％が好ましく、５〜７０質量％がより好ましく、１０〜５０質量％が特に好ましい。（Ｂ）成分が３質量％未満の場合、最終的に得られる硬化塗膜の耐溶剤性が不十分となるため好ましくなく、８０質量％を越える場合は硬化塗膜の耐クラック性が低下するため好ましくない。
本発明の耐汚染性塗料組成物に用いられる（Ｃ）成分は、塗膜表面に浮上し濃縮層を形成することで、塗膜硬化後に短時間で高度な耐汚染性を発現するために必要であり、一般式（２）で表されるオルガノシリケート及び／又はその縮合物が用いられる。一般式（２）で表されるオルガノシリケート及び／又はその縮合物の好ましい具体例としては、例えばテトラヒドロキシシラン、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン、テトラフェノキシシラン、ジメトキシジエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、フェニルトリメトキシシラン、フェニルトリエトキシシラン、ブチルトリメトキシシラン、ヘキシルトリメトキシシラン、デシルトリメトキシシラン、エトキシトリメトキシシラン、プロポキシトリメトキシシラン、ブトキシトリメトキシシランなどが挙げられる。
【００２３】
またオルガノシリケートの縮合物としては、前記一般式（２）で表されるオルガノシリケートの１種又は２種以上の分岐状もしくは直鎖状の縮合物であって、重量平均分子量が５００〜１００００の範囲にあるものが好ましく、５００〜５０００の範囲内にあるものが特に好ましい。オルガノシリケートの縮合物の市販品としては、ＭＫＣシリケートＭＳ５１、ＭＳ５６、ＭＳ５７、ＭＳ５６Ｓ、ＭＳ５６ＳＢ５、ＥＳ４０、ＥＭＳ３１、ＢＴＳ（いずれも商品名、三菱化学（株）製）、メチルシリケート５１、エチルシリケート４０、エチルシリケート４０Ｔ、エチルシリケート４８（いずれも商品名、コルコート（株）製）、エチルシリケート４０、４５（いずれも商品名多摩化学工業（株）製）などが挙げられ、上記オルガノシリケートの縮合物の市販品を微量の水存在下でさらに縮合を進めたものも用いることができる。
本発明の耐汚染性塗料組成物において、（Ｃ）成分のオルガノシリケート及び／又はその縮合物の含有量は、（Ａ）〜（Ｃ）成分の全不揮発分総量に対して０．１〜３０質量％が好ましく、０．２〜２５質量％がより好ましく、０．５〜２０質量％が特に好ましい。（Ｃ）成分が０．１質量％未満の場合、硬化塗膜を形成した飽和水接触角が目的の耐汚染性能を満たすまで低下しないため好ましくなく、３０質量％を越える場合は硬化塗膜の耐水性が低下するため好ましくない。
【００２４】
さらに、本発明の耐汚染性塗料組成物において、硬化塗膜の形成後直ちに耐汚染性を発現させたい場合には、加水分解反応促進触媒を含有することもできる。該加水分解反応促進触媒（以下単に加水分解触媒と略すこともある。）は、（Ｃ）成分のオルガノシリケート及び／又はその縮合物のアルコキシ基を加水分解することで早期に耐汚染性能を発現することができる。かかる加水分解触媒としては、例えば、ジブチル錫ジアセテート、ジブチル錫ジラウレート、ジブチル錫ジマレエート、オクチル酸錫、ジブチル錫ジオキサイドなどの有機金属化合物、パラトルエンスルホン酸、ドデシルベンゼンスルホン酸、ジノニルナフタレンスルホン酸、ジノニルナフタレンジスルホン酸、メタンスルホン酸などのスルホン酸化合物、リン酸エチル、リン酸ブチル、リン酸オクチルなどの有機リン酸化合物、トリエチルアミン、ジメチルベンジルアミン、ジメチルエタノールアミン、ジメチルラウリルアミン、ジブチルアミン、ジ−２−エチルヘキシルアミン、テトラメチルブタンジアミン、ピリジン、トリエタノールアミンなどの塩基化合物が挙げられる。
本発明の耐汚染性塗料組成物の硬化に要する温度及び時間については、特に制限されるものではないが、通常５０〜３００℃の範囲の温度で、１０秒〜２４時間程度加熱することにより硬化が完了する。
【００２５】
本発明の耐汚染性塗料組成物は、そのままで、あるいは必要に応じ、着色顔料、光輝顔料、フィラー、溶剤、紫外線吸収剤、ラジカル捕捉剤、酸化防止剤、ワキ防止剤、表面調整剤、タレ止め剤、流動性調整剤、硬化触媒、界面活性剤帯電防止剤、香料、脱水剤などを加えることもできる。
本発明の耐汚染性塗料組成物を塗布して形成される塗膜の膜厚は何ら制限させるものではなく、例えば１〜１００μm、通常は１０〜６０μmの範囲内になるよう、選定すればよい。また、塗膜が２層以上である場合は、各層の厚みが前記の範囲なるように、選定すればよい。塗装方法としては、エアスプレー、エアレススプレー、静電エアスプレー、静電回転式霧化塗装、浸漬塗装、ロール塗装などの慣用の塗装機を用いて塗装される方法が挙げられる。
塗料を塗布する基材としては、特に限定されるものではなく、種種の基材を用いることができ、例えば、木、ガラス、金属、布、プラスチック、発泡体、弾性体、紙、セラミック、コンクリート、石膏ボード等の有機素材及び無機素材などが挙げられる。
【００２６】
本発明の耐汚染性塗料組成物は、単層上塗り塗料又は着色ベースコートとクリヤートップコートとから成る複数層の塗膜（複合塗膜）を有する物品を調整する方法に使用する塗料などとして用いることができ、例えば自動車その他の道路車両用塗料などに用いることができる。これらの塗料に用いる際、（Ａ）〜（Ｃ）成分の全不揮発成分１００質量部あたり、顔料を０〜２００質量部配合させることができるが、顔料を配合する場合には、少なくとも０．１質量部配合させることが好ましい。顔料は有機顔料、無機顔料、金属顔料、その他プラスチックピグメント等、通常の塗料に使用されるものを何ら制限なく用いることが可能である。複合塗膜の例としては、例えば基材上に着色フィルム形成性組成物を塗布してベースコート膜を形成させ、次いで該ベースコート膜上に本発明の耐汚染性塗料組成物であるクリヤーフィルム形成性組成物を塗布する方法がある。この際着色フィルム形成性組成物は、溶剤系もしくは水系のいずれの形態でも構わない。さらに着色フィルム形成性組成物を塗布後は、加熱硬化してから本発明の耐汚染性塗料組成物であるクリヤーフィルム形成性組成物を塗布することもできるし、また着色フィルム形成性組成物を塗布後、硬化させずに続けて本発明の耐汚染性塗料組成物であるクリヤーフィルム形成性組成物を塗布し２層同時に硬化させることもできる。
【００２７】
上記複合塗膜の塗装仕上げ方法は、ベースコートの着色フィルム形成性組成物を、必要に応じて加温したり、有機溶媒又は反応性希釈剤を添加することにより所望の粘度に調整した後、乾燥後の塗膜が、５〜３００μｍになるように塗布し、通常５０〜３００℃の温度で５秒〜２４時間加熱硬化させ、又は２コート１ベーク方式の塗装を行う場合には、着色フィルム形成性組成物を例えば有機溶剤等の適当な希釈剤にて所望の粘度に希釈した後、上記方法を用いて乾燥後の膜厚が通常５〜４０μｍ、好ましくは７〜３５μｍになるように塗布し、室温〜１００℃の温度で１〜２０分間放置し、次いでクリヤーコート膜のクリヤーフィルム形成性組成物を、上記方法を用いて乾燥後の膜厚が１０〜１００μｍ、好ましくは１０〜６０μｍになるように塗布し、５０〜３００℃の温度で５秒〜２４時間熱硬化させる方法などが挙げられる。
【００２８】
さらに本発明の耐汚染性塗料組成物は、すでに上塗り塗装まで完成された塗膜の上にオーバーコートクリヤー塗料として用いることもできる。この際該上塗り塗膜としては、前記の溶剤系もしくは水系の着色フィルム形成性組成物を塗装し、未架橋の状態の上にアクリル樹脂／アミノプラスト樹脂系塗料、アクリル樹脂／ウレタン樹脂硬化剤系塗料又はアクリル樹脂／アミノプラスト樹脂／ウレタン樹脂硬化剤系塗料のいずれかから選ばれるクリヤー塗料（以下アンダークリヤー塗料と略すこともある。）を塗装し、２層同時に硬化させることにより形成されるものであることが好ましい。この際該アンダークリヤー塗料は、（ａ）水酸基とエポキシ基の両方を有するアクリル樹脂４０〜８０質量％、好ましくは４５〜７５質量％、（ｂ）アミノプラスト樹脂０〜６０質量％、好ましくは１０〜５０質量％、（ｃ）ウレタン樹脂硬化剤０〜６０質量％、好ましくは１〜３０質量％から構成される樹脂樹脂混合物を主成分とすることを特徴とする塗料組成物であることがオーバーコートクリヤー塗料との密着性の観点からより望ましい。
【００２９】
（ａ）成分の水酸基とエポキシ基の両方を有するアクリル樹脂は、前記の水酸基を有するラジカル重合性単量体及びエポキシ基を有するラジカル重合性単量体と、その他のラジカル重合性単量体を有機溶媒中で通常のラジカル共重合することにより得られる。ここで（ａ）成分が４０質量％未満の場合、オーバーコートクリヤー塗料との密着性が低下するため好ましくなく、８０質量％を越える場合は硬化塗膜の耐ガソリン性が低下するため好ましくない。（ｂ）成分のアミノプラスト樹脂は例えば、メラミン樹脂、尿素樹脂、グアナミン樹脂、グリコルリル樹脂などを用いることができ、中でもメラミン樹脂が耐候性の観点から特に好ましい。ここで（ｂ）成分が６０質量％を越えると硬化塗膜の耐クラック性が低下するため好ましくない。（ｃ）成分のウレタン樹脂硬化剤は、ポリオールなどと化学反応してウレタン結合を形成できる官能基を有する化合物であり、例えば、ポリイソシアネート化合物、ブロック化ポリイソシアネート化合物、ポリカーバメート化合物などを用いることができ、中でもブロック化ポリイソシアネート化合物が好ましい。さらにより好ましくは脂肪族系のブロック化ポリイソシアネート化合物が硬化塗膜の耐黄変性の点で好適である。ここで（ｃ）成分が６０質量％を越えると硬化塗膜の耐クラック性が低下するため好ましくない。また該アンダークリヤー塗料は、必要に応じ、アクリル樹脂、ポリエステル樹脂、着色顔料、光輝顔料、フィラー、溶剤、紫外線吸収剤、ラジカル捕捉剤、酸化防止剤、ワキ防止剤、表面調整剤、タレ止め剤、流動性調整剤、硬化触媒、界面活性剤帯電防止剤、香料などを加えることもできる。
【００３０】
アンダークリヤー塗料及びオーバーコートクリヤー塗料の塗装方法としては、着色ベースコート塗料を例えば必要に応じて加温したり、有機溶媒又は反応性希釈剤を添加することにより所望の粘度に調整した後、乾燥後の塗膜が、５〜３００μｍになるように塗布し、室温〜１００℃の温度で１〜２０分間放置し、次いでアンダークリヤー塗料を、上記方法を用いて乾燥後の膜厚が１０〜１００μｍ、好ましくは１０〜６０μｍになるように塗布し、５０〜３００℃の温度で５秒〜２４時間熱硬化させ、次いで、オーバークリヤーコート塗料を上記方法を用いて乾燥後の膜厚が１０〜１００μｍ、好ましくは１０〜６０μｍになるように塗布し、５０〜３００℃の温度で５秒〜２４時間熱硬化させる方法などが挙げられる。
また該アンダークリヤー硬化塗膜の上に本発明の耐汚染性塗料組成物をオーバーコート塗装する際、必要に応じて、透明プライマーを塗装してから、オーバーコート塗装することもできる。
本発明の塗料組成物を塗布して得られる塗装物品としては、例えば、構造物、木製品、金属製品、プラスチック製品、ゴム製品、加工紙、セラミック製品、ガラス製品などが挙げられる。より具体的には、自動車、鋼鈑等の金属板、二輪車、船舶、鉄道車両、航空機、家具、楽器、家電製品、建築材料、容器、事務用品、スポーツ用品、玩具などが挙げられる。
【００３１】
【実施例】
次に、本発明を実施例によりさらに具体的に説明するが、本発明はこれらの実施例によって何ら制限されるものではない。なお、本発明の耐汚染性塗料組成物により得られる塗膜の性能は次ぎのようにして求めた。
(１)仕上がり外観性
目視観察により、次ぎの基準に従い評価した。
○：塗膜に蛍光灯を映すと、蛍光灯が鮮明に映る。
△：塗膜に蛍光灯を映すと、蛍光灯の周囲（輪郭）がややぼやける。
×：塗膜に蛍光灯を映すと、蛍光灯の周囲（輪郭）が著しくぼやける。
(２)水の接触角
得られた試験板をＪＩＳ Ｋ−５４００（１９９０）９．９耐候性に準じて屋外で７〜３０日間曝露した。その後試験板を洗浄後２０℃で塗膜表面に０．８μｌの脱イオン水の液滴を注射器を用いて乗せ、（株）エルマ製、エルマゴニオメータ式・接触角測定器Ｇ−Ｉ型を用いて測定した。液滴当り３０、６０、９０秒毎に接触角を測定し、時間と接触角の直線回帰式から０秒へ接触角を外挿し、これを試験板の接触角とした。
【００３２】
(３)耐屋外曝露汚染性
ＪＩＳ Ｋ−５４００（１９９０）９．９耐候性に準じて屋外にて３ヶ月曝露後、塗膜の未洗浄面の色（ＪＩＳ Ｋ−５４００（１９９０）７.４．２系速報）を測定し、曝露後のＬ値から未曝露時のＬ値を引くことにより△Ｌ値を算出し、塗膜の汚染性を判定した。
(４)耐候性
サンシャインカーボンアーク灯式促進耐候性試験機（ＪＩＳ Ｋ−５４００（１９９０）９．８.１）を用いて３０００時間曝露後、塗膜の状態を目視判定した。
(５)耐水性
試験片を４０℃の温水に２４０時間浸漬し塗膜の状態を目視判定した。
(６)耐酸性
４０質量％硫酸０．２ｍｌを試験片上にスポット状に乗せ、６０℃で３０分加熱後、塗膜の異常を目視にて判定した。
【００３３】
（Ａ）成分の変性樹脂の製造例
＜製造例１、２＞
温度計、還流冷却器、攪拌機、滴下ロートを備えた4つ口フラスコに、表１の組成のキシレンおよびオルガノシリケート混合物（初期仕込み）を仕込み、攪拌下で加熱し１４０℃を保った。次に１４０℃の温度で表１の組成の単量体および重合開始剤混合物（滴下成分）を２時間かけて滴下ロートより等速滴下した。滴下終了後１４０℃の温度を１時間保った後、反応温度を１１０℃に下げた。、その後表１の組成の重合開始剤溶液（追加触媒）を添加し、さらに１１０℃の温度を２時間保ったところで反応を終了し、表１記載の不揮発分を有する変性樹脂溶液Ａ−１およびＡ−２を得た。
【００３４】
【表１】

表中の添字の物質は、以下に示すものである。
1)オルガノシリケートの縮合物（商品名、コルコート（株）製）
【００３５】
（Ｂ）成分の硬化剤の製造例
＜製造例３＞
温度計、還流冷却器、攪拌機、滴下ロートを備えた４つ口フラスコにトリメチロールプロパン１３４質量部およびメチルイソブチルケトン４２５．３質量部を仕込み攪拌下で１２０℃に加熱した。次いで、１２０℃の温度を保ちながらメチルヘキサヒドロフタル酸無水物５０４質量部を２時間かけて滴下し、混合物の酸価（ピリジン／水＝９／１（重量比）混合液で約５０重量倍に希釈し、９０℃で３０分間加熱処理した溶液を水酸化カリウム標準溶液で滴定）が、１６０以下になるまで加熱攪拌を継続することで不揮発分６０質量％、溶液としてのカルボン酸当量３５５の硬化剤溶液Ｂ−１を得た。
【００３６】
＜製造例４＞
温度計、還流冷却器、攪拌機、滴下ロートを備えた４つ口フラスコに、メチルアミルケトン８４質量部を仕込み、攪拌下で加熱し１４０℃を保った.。次に１４０℃の温度で下記の組成の単量体および重合開始剤混合物（滴下成分）を２時間かけて滴下ロートより等速滴下した。

滴下終了後１４０℃の温度を１時間保った後、反応温度を１１０℃に下げた。その後ｔ−ブチルパーオキシ−２−エチルヘキサノエート１質量部およびメチルアミルケトン１０質量部を添加し、さらに１１０℃の温度を２時間保ったところで反応を終了し、ガードナー粘度（２５℃）Ｒ〜Ｓ、不揮発分５０．４％、溶液としてのカルボン酸当量８６０の硬化剤溶液Ｂ−２を得た。
【００３７】
（実施例１〜４）
(1)クリヤー塗料の製造
表２の組成の原料を混合し、クリヤー塗料を作成した。
【００３８】
【表２】

【００３９】
表中の添字の物質は、以下のものを示す。
１）：製造例１の変性樹脂溶液Ａ−１
２）：製造例２の変性樹脂溶液Ａ−２
３）：製造例３の硬化剤溶液Ｂ−１
４）：製造例４の硬化剤溶液Ｂ−２
５）：ＭＫＣシリケートＭＳ５６ＳＢ５（商品名、三菱化学（株）製、Ｍｗ１５００）
６）：エチルシリケート４０（商品名、多摩化学工業（株）製、Ｍｗ７５０）
７）：ジブチル錫ジラウレートの１０質量％キシレン溶液
８）：テトラブチルアンモニウムブロマイドの１０質量％酢酸イソブチル溶液
９）：チヌビン９００（商品名、チバスペシャルティケミカルス社製）の２０質量％キシレン溶液
１０）：チヌビン２９２（商品名、チバスペシャルティケミカルス社製）の２０質量％キシレン溶液
１１）：ＢＹＫ−３００（商品名、ビックケミー社製）の１０質量％キシレン溶液
１２）：商品名、エッソ社製、芳香族石油ナフサ
【００４０】
（２）試験片の作成及び塗膜性能の検討
リン酸亜鉛処理軟鋼板にカチオン電着塗料アクアＮｏ．４２００（商品名、日本油脂（株）製）を乾燥膜厚２０μｍとなるよう電着塗装して１７５℃で２５分間焼き付け、さらに中塗り塗料ＨＳ−Ｈ３００（商品名、日本油脂（株）製）を乾燥膜厚３０μｍとなるようエアスプレー塗装し、１４０℃で３０分間焼き付けた。次いで、ベルコートＮｏ．６０００溶剤系ブラックベースコート塗料（商品名、日本油脂（株）製）をエアスプレーにて乾燥膜厚１５μｍとなるよう塗装し、２０℃で３分間セットした。さらに前記（１）の塗料をシンナー（ソルベッソ１００／酢酸ブチル＝９／１（重量比））で塗装粘度（フォードカップＮｏ．４、２０℃で２５秒）に希釈したものをウェット・オン・ウェット方式でエアスプレーにて乾燥膜厚４０μｍとなるよう塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。ただし実施例１〜４のいずれの場合も耐屋外曝露汚染性の試験板のみは、ベルコートＮｏ．６０００溶剤系ブラックベースコートに代えて、ベルコートＮｏ.６０００溶剤系ホワイトベースコート塗料（商品名、日本油脂（株）製）を用いた。塗膜性能を表３に示すが、いずれの場合も均一でツヤのある塗膜が得られ、優れた塗膜外観性、親水性、耐屋外曝露汚染性、耐候性、耐水性、耐酸性を示した。
【００４１】
（実施例５、６）
リン酸亜鉛処理軟鋼板にカチオン電着塗料アクアＮｏ．４２００（商品名、日本油脂（株）製）を乾燥膜厚２０μｍとなるよう電着塗装して１７５℃で２５分間焼き付け、さらに中塗り塗料ＨＳ−Ｈ３００（商品名、日本油脂（株）製）を乾燥膜厚３０μｍとなるようエアスプレー塗装し、１４０℃で３０分間焼き付けた。次いで、ベルコートＮｏ．６０００溶剤系ブラックベースコート塗料（商品名、日本油脂（株）製）をエアスプレーにて乾燥膜厚１５μｍとなるよう塗装し、２０℃で３分間セット後、下記に示すアンダークリヤー塗料をウェット・オン・ウェット方式でエアスプレーにて乾燥膜厚４０μｍとなるよう塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。さらに、実施例５では実施例１で作成したクリヤー塗料を、実施例６では実施例２で作成したクリヤー塗料をエアスプレーにて前記の方法で作成した試験片に乾燥膜厚４０μｍとなるようオーバーコート塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。ただし実施例５、６ともに耐屋外曝露汚染性の試験板のみは、ベルコートＮｏ.６０００溶剤系ブラックベースコートに代えて、ベルコートＮｏ.６０００溶剤系ホワイトベースコート塗料（商品名、日本油脂（株）製）を用いた。塗膜性能を表３に示すが、いずれの場合も均一でツヤのある塗膜が得られ、優れた塗膜外観性、親水性、耐屋外曝露汚染性、耐候性、耐水性、耐酸性を示した。
【００４２】
＜アンダークリヤー塗料の製造＞
温度計、還流冷却器、攪拌機、滴下ロートを備えた４つ口フラスコに、キシレン６０質量部を仕込み、攪拌下で加熱し１４０℃を保った.。次に１４０℃の温度でメタクリル酸グリシジル８質量部、メタクリル酸ブチル７７質量部、メタクリル酸−２−ヒドロキシエチル１５質量部およびｔ−ブチルパーオキシ−２−エチルヘキサノエート２質量部の混合物を２時間かけて滴下ロートより等速滴下した。滴下終了後１４０℃の温度を1時間保った後、反応温度を１１０℃に下げた。、その後ｔ−ブチルパーオキシ−２−エチルヘキサノエート０．２質量部およびキシレン４．５質量部の混合物を添加し、さらに１１０℃の温度を２時間保ったところで反応を終了し、６０．９％の不揮発分を有するアンダークリヤー用アクリル樹脂溶液Ｕ−１を得た。
【００４３】
次いで上記のアクリル樹脂溶液を用いて以下の原料を混合しアンダークリヤー塗料を作成した。

上記のアンダークリヤー塗料をシンナー（ソルベッソ１００／ｎ−ブタノール＝９／１（重量比））で塗装粘度（フォードカップＮｏ．４、２０℃で２５秒）に希釈した。
【００４４】
（実施例７、８）
リン酸亜鉛処理軟鋼板にカチオン電着塗料アクアＮｏ．４２００（商品名、日本油脂（株）製）を乾燥膜厚２０μｍとなるよう電着塗装して１７５℃で２５分間焼き付け、さらに中塗り塗料ＨＳ−Ｈ３００（商品名、日本油脂（株）製）を乾燥膜厚３０μｍとなるようエアスプレー塗装し、１４０℃で３０分間焼き付けた。次いで、アクアＢＣ−３水系ブラックベースコート塗料（商品名、日本油脂（株）製）をエアスプレーにて乾燥膜厚１５μｍとなるよう塗装し、２０℃で３分間セット後８０℃で１０分間乾燥した。さらに試験片を室温まで放冷後、実施例５、６に記載のアンダークリヤー塗料をエアスプレーにて乾燥膜厚４０μｍとなるよう塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。さらに、実施例７では実施例３で作成したクリヤー塗料を、実施例８では実施例４で作成したクリヤー塗料をエアスプレーにて前記の方法で作成した試験片に乾燥膜厚４０μｍとなるようオーバーコート塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。ただし実施例７、８共に耐屋外曝露汚染性の試験板のみは、アクアＢＣ−３水系ブラックベースコート塗料（商品名、日本油脂（株）製）ベースコートに代えて、アクアＢＣ−３水系ホワイトベースコート塗料（商品名、日本油脂（株）製）を用いた。塗膜性能を表３に示すが、いずれの場合も均一でツヤのある塗膜が得られ、優れた塗膜外観性、親水性、耐屋外曝露汚染性、耐候性、耐水性、耐酸性を示した。
【００４５】
【表３】

表中の添字は、以下のものを示す。
１）不揮発分の配合割合
２）２Ｃ１Ｂ：２コート１ベイク塗膜
３） ＯＢ：２コート１ベイク塗膜の上にオーバーコートクリヤー塗料を塗装
【００４６】
比較例１
(1)エポキシ基を含有するアクリル樹脂の製造
温度計、還流冷却器、攪拌機、滴下ロートを備えた４つ口フラスコに、キシレン６３質量部を仕込み、攪拌下で加熱し１００℃を保った。次に１４０℃の温度で下記の組成の単量体および重合開始剤混合物（滴下成分）を２時間かけて滴下ロートより等速滴下した。

【００４７】
滴下終了後１４０℃の温度を１時間保った後、反応温度を１１０℃に下げた。その後ｔ−ブチルパーオキシ−２−エチルヘキサノエート０．５質量部およびキシレン２質量部を添加し、さらに１１０℃の温度を２時間保ったところで反応を終了し、ガードナー粘度（２５℃）Ｕ〜Ｖ、不揮発分５９．４％、溶液としてのエポキシ当量６８０のアクリル樹脂溶液Ｄ−１を得た。
（２）クリヤー塗料の製造
表４の組成の原料を混合し、クリヤー塗料を作成した。
【００４８】
【表４】

表中の添字は、以下のものを示す。
注１）〜注３）前出と同じ。
注４）上記により製造したエポキシ基を含有するアクリル樹脂溶液Ｄ−１
注５）〜注１０）前出と同じ。
【００４９】
（３）試験片の作成及び塗膜性能の検討
リン酸亜鉛処理軟鋼板にカチオン電着塗料アクアＮｏ．４２００（商品名、日本油脂（株）製）を乾燥膜厚２０μｍとなるよう電着塗装して１７５℃で２５分間焼き付け、さらに中塗り塗料ＨＳ−Ｈ３００（商品名、日本油脂（株）製）を乾燥膜厚３０μｍとなるようエアスプレー塗装し、１４０℃で３０分間焼き付けた。次いで、ベルコートＮｏ．６０００ブラックベースコート塗料（商品名、日本油脂（株）製）をエアスプレーにて乾燥膜厚１５μｍとなるよう塗装し、２０℃で３分間セットした。さらに前記（１）の塗料をシンナー（ソルベッソ１００／酢酸ブチル＝９／１（重量比））で塗装粘度（フォードカップＮｏ．４、２０℃で２５秒）に希釈したものをウェット・オン・ウェット方式でエアスプレーにて乾燥膜厚４０μｍとなるよう塗装し、１４０℃で３０分間の硬化条件で焼き付けて試験片を作成した。ただし、耐屋外曝露汚染性の試験板のみはベルコートＮｏ.６０００ブラックベースコートに代えてベルコートＮｏ.６０００ホワイトベースコート（商品名、日本油脂（株）製）を用いた。塗膜性能を表５に示すが、比較例１では（Ａ）成分の変性樹脂を含まないため、耐候性および耐水性が劣った。
【００５０】
【表５】

【００５１】
【発明の効果】
本発明の耐汚染性塗料組成物は、塗膜形成直後から高度な親水性に基づく耐汚染性能を有し、さらに良好な長期耐候性、耐水性、耐化学性能を有する硬化物を与えることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel coating composition, a paint finishing method, and a coated article. More specifically, the present invention relates to a coating composition, a coating finishing method, and a coated article capable of providing a coating film excellent in stain resistance, decontamination resistance, weather resistance, water resistance, chemical resistance and appearance, particularly in the field of automobile coating. is there.
[0002]
[Prior art]
Currently, automobile users want to maintain the beautiful appearance of the new car, and in order to remove dirt, which is an impediment to it, washing with water using a detergent, wiping off moisture, and removing dirt with glossy water repellent wax Is going.
However, this work is labor consuming several hours and is a heavy load on the user. In particular, since wax is mainly water-repellent, it has a large adhesion work when it rains, whether it is hydrophilic or hydrophobic, and the dirt does not come off. The maintenance of the user's corner may be wasted in a day. Users want products that reduce this maintenance burden.
In addition, due to the recent increase in environmental protection awareness, there is concern about water pollution due to river runoff of detergents and petroleum waxes, and in some countries, home car washing is prohibited in Europe. From these backgrounds, research on paints and post-treatment agents that can remove dirt by rain to reduce the frequency of car wash by users and remove dirt without using detergent. For this purpose, it has been proposed that the adhesion work of dirt in water is reduced, that is, the surface energy of the coating film is increased and hydrophilicity is good (Paint Engineering Vol.31 No.7, pages 260-320). (1996).
As a specific method for hydrophilizing the coating film, for example, International Publication No. WO94 / 06870 includes a coating composition obtained by blending a specific organosilicate and / or a condensate thereof with a specific organic coating composition. It is disclosed that a coating film having a water contact angle of 70 degrees or less after acid treatment is obtained. Further, International Publication No. WO97 / 23572 discloses that high hydrophilicity can be imparted by applying a photocatalytic coating to the surface of a substrate.
[0003]
[Problems to be solved by the invention]
However, in the method of International Publication No. WO94 / 06870, it takes a long time to make the coating hydrophilic after forming a coating film. Unlike a structure, the vehicle is required to express its function immediately after purchase. Absent. In addition, since the silicate exists as a large island inside the coating film, it has a tendency to whiten due to the difference in refractive index from the binder, or when it touches water, the island-like silicate tends to absorb water and cause whitening. It is fatal for automobile paints that require durability and durability. In addition, the water contact angle of the acid-treated film is 56 °, which is the lowest in the examples, and the hydrophilicity is not sufficient, and the contact of 30 ° or less that can remove hydrophobic dirt such as carbon only by a spray car wash. In the sense of a maintenance-easy coating with corners, it was far from sufficient.
[0004]
In addition, in the method of International Publication No. WO97 / 23572, when irradiated with light, the coating film can be made highly hydrophilic, but vertical surfaces such as doors cannot receive enough light, and can be used at night or in garage storage. If the light irradiation is cut off, the effect may be reduced or disappear. Therefore, the effect is uneven and not sufficient. Further, hydroxy radicals and superoxide ions generated by the photocatalytic reaction deteriorate the lower organic coating film, and therefore cannot be said to be suitable for automobiles that require long-term weather resistance. Although there is a countermeasure by performing repainting maintenance periodically, the maintenance cost of the user may be the same as that of the conventional maintenance, or rather, it may be increased, which is not desirable in terms of cost.
The object of the present invention is not only self-cleaning due to rain, but also develops a high hydrophilicity that has the function of removing dirt only by spray car washing even if it gets dirty, and also has weather resistance comparable to that of conventional automobile coating, Provided is a coating composition capable of forming a coating film having water resistance and chemical resistance, and a coating finishing method capable of providing a more excellent finished appearance, and a coated article obtained by the method. There is.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to develop a coating composition having the above-mentioned preferable properties, the present inventors have (A) radical polymerization having a hydroxyl group in the presence of a specific organosilicate and / or its condensate. By polymerizing a polymerizable monomer mixture for synthesizing an acrylic resin containing a monomer or containing both a radical polymerizable monomer having a hydroxyl group and a radical polymerizable monomer having an epoxy group Preferably, (B) a compound having at least one selected from a carboxyl group, a carboxylic acid anhydride group and a functional group of a carboxyl group blocked with an alkyl vinyl ether compound in one molecule, and (B) C) The object can be achieved by a stain-resistant coating composition comprising a specific organosilicate and / or a condensate thereof. The heading which resulted in the completion of the present invention ..
That is, the present invention provides (A) the general formula (1)
(R ¹ ) _m -Si- (OR ² ) _4-m (1)
(R in the formula ¹ And R ² Are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and m is 0 or 1. Modified resin obtained by polymerizing a polymerizable monomer mixture for acrylic resin synthesis containing a radical polymerizable monomer having a hydroxyl group in the presence of an organosilicate represented by It is intended to provide a stain-resistant coating composition characterized by containing.
[0006]
Further, the present invention provides the above stain-resistant coating composition, wherein (A) the general formula (1)
(R ¹ ) _m -Si- (OR ² ) _4-m (1)
(R in the formula ¹ And R ² Are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and m is 0 or 1. In the presence of an organosilicate and / or a condensate thereof represented by) for polymerization of an acrylic resin containing both a radical polymerizable monomer having a hydroxyl group and a radical polymerizable monomer having an epoxy group. The present invention provides a stain-resistant coating composition comprising a modified resin obtained by polymerizing a monomer mixture.
Further, the present invention provides the antifouling coating composition, wherein (B) at least one selected from a carboxyl group, a carboxylic acid anhydride group and a carboxyl group functional group blocked with an alkyl vinyl ether compound in one molecule. The present invention provides a stain-resistant coating composition containing a compound having the same.
[0007]
Further, the present invention provides the above stain-resistant coating composition, wherein (C) the general formula (2)
(R ³ ) _n -Si- (OR ⁴ ) _4-n (2)
(R in the formula ³ And R ⁴ Are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and n is 0 or 1. The anti-fouling coating composition containing the organosilicate represented by the above and / or its condensate is provided.
Further, the present invention provides the above stain-resistant coating composition, wherein (C) the general formula (2)
(R ³ ) _n -Si- (OR ⁴ ) _4-n (2)
(R in the formula ³ And R ⁴ Are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and n is 0 or 1. The anti-fouling coating composition containing the organosilicate represented by the above and / or its condensate is provided.
Moreover, this invention is 3-80 mass% of (A) component in the said stain | pollution resistant coating composition, 3-80 mass% of (B) component, 0.1-30 mass% of (C) component. The present invention provides a stain-resistant coating composition that is contained in a proportion.
Further, the present invention provides the above stain-resistant coating composition, wherein the acrylic resin structure portion of the modified resin of the component (A) has the general formula (3)
[0008]
[Chemical 3]

[0009]
(R in the formula ⁵ And R ⁶ Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and y is an integer of 1 to 10. A stain-resistant coating composition having an organic group represented by
Further, the present invention provides the above stain-resistant coating composition, wherein the acrylic resin structure portion of the modified resin of the component (A) has the general formula (3)
[0010]
[Formula 4]

[0011]
(R in the formula ⁵ And R ⁶ Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and y is an integer of 1 to 10. A stain-resistant coating composition having an organic group represented by
Further, the present invention provides a top coating composition containing 0 to 200 parts by mass of pigment per 100 parts by mass of all the non-volatile components of the (A) component, the (B) component and the (C) component of the stain resistant coating composition. The present invention provides a paint finishing method characterized by painting on an object to be coated.
The present invention also relates to a coating method comprising: applying a colored film-forming composition on a substrate to form a base coat; and then applying a clear film-forming composition to the base coat to form a transparent top coat. In the method of applying a composite coating on the body, only the topcoat clear film-forming composition or both the topcoat clear film-forming composition and the colored film-forming composition are claimed in claims 1 to 9. The present invention provides a paint finishing method comprising any one of the stain-resistant coating compositions described.
[0012]
Further, the present invention provides a coating method in which a colored base coat paint is applied onto a substrate, an under-clear paint is applied in an uncrosslinked state, and after baking, an overcoat clear paint is further applied and baked. The under clear paint is selected from acrylic resin / aminoplast resin-based paint, acrylic resin / urethane resin hardener-based paint or acrylic resin / aminoplast resin / urethane resin hardener-based paint, and the overcoat The present invention provides a paint finishing method characterized in that the clear paint contains any of the above stain-resistant paint compositions.
Further, the present invention is the above paint finishing method, wherein a colored base coat paint is applied on a substrate, an under-clear paint is applied in an uncrosslinked state, and after baking, an overcoat clear paint is further applied. In the coating method for baking, the under clear coating is (a) 40-80% by mass of acrylic resin having both hydroxyl group and epoxy group, (b) 0-60% by mass of aminoplast resin, (c) urethane resin curing agent 0 A coating composition comprising a resin mixture composed of 60% by mass as a main component Paint finish method Is to provide.
In addition, the present invention provides a coated article characterized by being coated by the above-described coating finishing method.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The modified resin used as component (A) in the stain-resistant coating composition of the present invention (hereinafter sometimes simply referred to as “coating composition”) is an organosilicate and / or an organosilicate necessary for hydrophilizing the coating film. Alternatively, the condensate thereof is uniformly dispersed in the coating film, and used to achieve both hydrophilic expression and improved water resistance. As such a modified resin, the general formula (1)
(R ¹ ) _m -Si- (OR ² ) _4-m (1)
(R in the formula ¹ And R ² Are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and m is 0 or 1. In the presence of an organosilicate and / or a condensate thereof represented by the following formula): a radical-polymerizable monomer having a hydroxyl group and another radical-polymerizable monomer in an organic solvent, or It can be obtained by carrying out normal radical copolymerization of a radical polymerizable monomer having a hydroxyl group, a radical polymerizable monomer having an epoxy group, and another radical polymerizable monomer in an organic solvent.
[0014]
Preferable specific examples of the organosilicate represented by the general formula (1) include, for example, tetrahydroxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, dimethoxydiethoxysilane, methyltri Methoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, ethoxytrimethoxysilane, propoxytrimethoxysilane, butoxytrimethoxysilane, etc. It is done.
The organosilicate condensate is one or two or more branched or linear condensates of the organosilicate represented by the general formula (1) having a weight average molecular weight of 200 to 2,000. Those within the range are preferred, and those within the range of 300-1500 are particularly preferred. Commercially available products of organosilicate condensates include MKC silicate MS51, MS56, MS57, MS56S, MS56SB5, ES40, EMS31, BTS (all trade names, manufactured by Mitsubishi Chemical Corporation), methylsilicate 51, ethylsilicate 40, Examples thereof include ethyl silicate 40T, ethyl silicate 48 (both trade names, manufactured by Colcoat Co., Ltd.), ethyl silicates 40, 45 (both trade names manufactured by Tama Chemical Co., Ltd.), and the like.
[0015]
Specific examples of the radical polymerizable monomer having a hydroxyl group include, for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, methacryl Acid-2-hydroxyethyl, methacrylic acid-2-hydroxypropyl, methacrylic acid-3-hydroxypropyl, methacrylic acid-4-hydroxybutyl, allyl alcohol, adduct of acrylic acid and versic acid glycidyl ester, methacrylic acid and versatic acid Glycidyl ester adducts: 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, -2-hydroxyethyl methacrylate, methacrylic acid-2 -Hydroxypropyl, methacrylic acid- Ε-caprolactone adduct of 4-hydroxypropyl methacrylate-4-hydroxybutyl; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, Ethylene oxide and / or propylene oxide adducts of methacrylic acid-2-hydroxyethyl, methacrylic acid-2-hydroxypropyl, methacrylic acid-3-hydroxypropyl, and methacrylic acid-4-hydroxybutyl are listed. Used as a mixture of seeds or more.
[0016]
Specific examples of the radical polymerizable monomer having an epoxy group include glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and the like. And used as a mixture of one or more.
Here, the radically polymerizable monomer having a hydroxyl group is preferably used in the range of 1 to 30% by mass in the total monomers constituting the acrylic resin structure portion of the modified resin of the component (A). 15 mass% is more desirable, and 2-7 mass% is particularly desirable. When the radically polymerizable monomer is less than 1% by mass, the water resistance of the finally obtained cured coating film is unfavorable, and when it exceeds 30% by mass, gelation tends to occur during the modification reaction. Therefore, it is not preferable.
The radical polymerizable monomer having an epoxy group is desirably used in the range of 0 to 70% by mass in the total monomers constituting the acrylic resin structure portion of the modified resin of the component (A). -60 mass% is more desirable, and 10-50 mass% is especially desirable. When the radical polymerizable monomer exceeds 70% by mass, the crack resistance of the cured coating film is lowered, which is not preferable.
[0017]
Specific examples of other radical polymerizable monomers include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, Hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, sec-butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, styrene, acrylo Tolyl, methacrylonitrile, acrylamide, methacrylamide, acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, maleic acid, fumaric acid and the like, whether employed alone or in combination of two or more thereof.
However, when a radical polymerizable monomer having an epoxy group is used as the monomer constituting the acrylic resin structure part of the modified resin (A), acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, maleic Radical polymerizable monomers having a carboxyl group such as acid and fumaric acid should not be used in order to avoid gelation during the synthesis reaction.
Moreover, the monomer which comprises the acrylic resin structure part of the modified resin of (A) component can also use the radically polymerizable monomer containing the organic group shown by General formula (3).
[0018]
[Chemical formula 5]

[0019]
(R in the formula ⁵ And R ⁶ Are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
y is an integer of 1-10. )
Specific examples of such radically polymerizable monomers include, for example, 2-methoxypropyl acrylate, 2-methoxyethyl acrylate, 2-ethoxypropyl acrylate, 2-ethoxyethyl acrylate, methacrylic acid- 2-methoxypropyl, 2-methoxyethyl methacrylate, 2-ethoxypropyl methacrylate, 2-ethoxyethyl methacrylate, Blemmer PME-100, -200, -400, Blemmer PE-90, -200, -350 , BLEMMER PP-1000, -500 (both trade names, manufactured by Nippon Oil & Fats Co., Ltd.) and the like are obtained as a mixture of one or more. The radically polymerizable monomer containing the organic group represented by the formula (3) is useful for effectively orienting the surface of the coating film and expressing the desired hydrophilicity even when the component (C) is small. ) It is desirable to be used within the range of 1 to 40% by mass in the total monomer constituting the acrylic resin structural part of the modified resin of the component, more preferably 1 to 30% by mass, and particularly preferably 2 to 25% by mass. . Here, when the radical polymerizable monomer is less than 1% by mass, the degree of surface orientation of the component (C) is decreased and the hydrophilicity is not sufficient, which is not preferable. When it exceeds 40% by mass, the polarity of the coating film is Since it is too high and smoothness and water resistance are lowered, it is not preferable.
[0020]
At this time, the modified resin of the component (A) may be a method of reacting the organosilicate represented by the general formula (1) and / or its condensate after synthesizing the acrylic resin structure part. This is not preferable because the condensate thereof is liberated and remains and becomes an island shape in the coating film, which may impair the appearance.
The organosilicate represented by the general formula (1) and / or the condensate thereof is preferably used in the range of 1 to 70% by mass in the modified resin of the component (A), more preferably 3 to 50% by mass, 5-40 mass% is especially desirable. When the organosilicate and / or the condensate thereof is less than 1% by mass, the finally obtained cured coating film is unsatisfactory because the stain resistance is insufficient, and when it exceeds 70% by mass, the cured coating film has water resistance. This is not preferable because the properties are lowered.
Moreover, in the stain-resistant coating composition of the present invention, the modified resin of the component (A) is used within a range of 3 to 80% by mass with respect to the total non-volatile content of the components (A) to (C). Desirably, 10 to 80% by mass is more desirable, and 20 to 80% by mass is particularly desirable. Here, when the component (A) is less than 3% by mass, the cured coating film finally obtained is unsatisfactory because the stain resistance is insufficient, and when it exceeds 80% by mass, the water resistance of the cured coating film decreases. Therefore, it is not preferable.
[0021]
The component (B) used in the stain-resistant coating composition of the present invention is a compound that undergoes a thermosetting reaction with the component (A) and is blocked with a carboxyl group, a carboxylic acid anhydride group, and an alkyl vinyl ether compound in one molecule. And a compound having at least one selected from functional groups of the carboxyl group (hereinafter sometimes simply referred to as a curing agent). Specific examples of such curing agents include compounds having a carboxyl group in one molecule, such as succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decamethylene dicarboxylic acid, dimer acid, phthalic acid, Examples include maleic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and methylhexahydrophthalic acid. Other compounds having a carboxyl group in one molecule are: (1) half-esterifying a carboxylic acid anhydride with a polyol having 1 or more, preferably 2 to 50, hydroxyl groups per molecule; A polyisocyanate compound having one or more, preferably 2 to 50, isocyanate groups per molecule and a hydroxycarboxylic acid or amino acid are added. (3) A homopolymerization or other radical polymerization of a carboxyl group-containing radical polymerizable monomer And (4) a compound obtained by a method of synthesizing a polyester resin terminated with a carboxyl group. Examples of the compound having a carboxylic acid anhydride group in one molecule include, for example, succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride, methylated hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and the like in one molecule. In addition to a compound having one carboxylic acid anhydride group, a radical polymerizable monomer having an acid anhydride group, such as maleic anhydride, itaconic anhydride, and other radical polymerizable monomers Coalescence is mentioned.
[0022]
Furthermore, examples of the compound having a carboxyl group blocked with an alkyl vinyl ether compound include compounds obtained by blocking the carboxyl group of the compound having a carboxyl group with an alkyl vinyl ether compound. Such alkyl vinyl ether compounds include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, isohexyl vinyl ether, cyclohexyl vinyl ether, and 2,3-dihydrofuran. 3,4-dihydrofuran, 3,4-dihydro-2H-pyran, 3,4-dihydro-2-methoxy-2H-pyran, 3,4-dihydro-4,4-dimethyl-2H-pyran-2- ON, 3,4-dihydro-2-ethoxy-2H-pyran and the like.
In the stain-resistant coating composition of the present invention, the content of the curing agent as the component (B) is preferably 3 to 80% by mass with respect to the total nonvolatile content of the components (A) to (C). The mass% is more preferable, and 10 to 50 mass% is particularly preferable. When the component (B) is less than 3% by mass, the finally obtained cured coating film is insufficient in solvent resistance, and when it exceeds 80% by mass, the crack resistance of the cured coating film is lowered. Therefore, it is not preferable.
The component (C) used in the stain-resistant coating composition of the present invention is necessary to express high stain resistance in a short time after the coating is cured by floating on the coating surface and forming a concentrated layer. An organosilicate represented by the general formula (2) and / or a condensate thereof is used. Preferable specific examples of the organosilicate represented by the general formula (2) and / or the condensate thereof include, for example, tetrahydroxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, and dimethoxy. Diethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, ethoxytrimethoxysilane, propoxytrimethoxysilane, butoxy Examples include trimethoxysilane.
[0023]
The organosilicate condensate is one or two or more branched or linear condensates of the organosilicate represented by the general formula (2) having a weight average molecular weight of 500 to 10,000. Those within the range are preferred, and those within the range of 500 to 5000 are particularly preferred. Commercially available products of organosilicate condensates include MKC silicate MS51, MS56, MS57, MS56S, MS56SB5, ES40, EMS31, BTS (all trade names, manufactured by Mitsubishi Chemical Corporation), methylsilicate 51, ethylsilicate 40, Examples include ethyl silicate 40T, ethyl silicate 48 (both trade names, manufactured by Colcoat Co., Ltd.), ethyl silicates 40, 45 (both trade names, manufactured by Tama Chemical Co., Ltd.), and the like. A commercially available product obtained by further condensing in the presence of a small amount of water can also be used.
In the stain-resistant coating composition of the present invention, the content of the organosilicate of component (C) and / or the condensate thereof is 0.1 to 30 with respect to the total non-volatile content of components (A) to (C). % By mass is preferable, 0.2 to 25% by mass is more preferable, and 0.5 to 20% by mass is particularly preferable. When the component (C) is less than 0.1% by mass, the saturated water contact angle that forms the cured coating does not decrease until the desired antifouling performance is satisfied. Since water resistance falls, it is not preferable.
[0024]
Furthermore, in the stain-resistant coating composition of the present invention, a hydrolysis reaction promoting catalyst can also be contained when it is desired to develop stain resistance immediately after the cured coating film is formed. The hydrolysis reaction accelerating catalyst (hereinafter sometimes simply referred to as a hydrolysis catalyst) expresses antifouling performance at an early stage by hydrolyzing the organosilicate of component (C) and / or the alkoxy group of its condensate. can do. Examples of the hydrolysis catalyst include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dimaleate, tin octylate, dibutyltin dioxide, and the like, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfone. Acids, sulfonic acid compounds such as dinonylnaphthalenedisulfonic acid, methanesulfonic acid, organic phosphate compounds such as ethyl phosphate, butyl phosphate, octyl phosphate, triethylamine, dimethylbenzylamine, dimethylethanolamine, dimethyllaurylamine, di Examples include basic compounds such as butylamine, di-2-ethylhexylamine, tetramethylbutanediamine, pyridine, and triethanolamine.
The temperature and time required for curing the stain-resistant coating composition of the present invention are not particularly limited, but are usually cured by heating for about 10 seconds to 24 hours at a temperature in the range of 50 to 300 ° C. Is completed.
[0025]
The stain-resistant coating composition of the present invention can be used as it is, or as necessary, as a color pigment, a bright pigment, a filler, a solvent, an ultraviolet absorber, a radical scavenger, an antioxidant, an anti-waxing agent, a surface conditioner, a sagging agent. A stopper, a fluidity modifier, a curing catalyst, a surfactant, an antistatic agent, a fragrance, a dehydrating agent, and the like can be added.
The film thickness of the coating film formed by applying the stain-resistant coating composition of the present invention is not limited at all, and may be selected, for example, in the range of 1 to 100 μm, usually 10 to 60 μm. . Moreover, what is necessary is just to select so that the thickness of each layer may become the said range when a coating film is two or more layers. Examples of the coating method include a method of coating using a conventional coating machine such as air spray, airless spray, electrostatic air spray, electrostatic rotary atomization coating, immersion coating, roll coating, and the like.
The substrate on which the paint is applied is not particularly limited, and various types of substrates can be used. For example, wood, glass, metal, cloth, plastic, foam, elastic body, paper, ceramic, concrete And organic materials such as gypsum board and inorganic materials.
[0026]
The stain-resistant paint composition of the present invention is used as a paint for use in a method for preparing an article having a multi-layer coating film (composite coating film) composed of a single-layer top coating or a colored base coat and a clear top coat. For example, it can be used for paints for automobiles and other road vehicles. When used in these paints, 0 to 200 parts by mass of the pigment can be blended per 100 parts by mass of all the non-volatile components of the components (A) to (C). It is preferable to mix part by mass. As the pigment, organic pigments, inorganic pigments, metal pigments, and other plastic pigments that are used in ordinary paints can be used without any limitation. As an example of a composite coating film, for example, a base film is formed by applying a colored film-forming composition on a substrate, and then the clear film-forming property of the stain-resistant coating composition of the present invention is formed on the base coating film. There is a method of applying the composition. In this case, the colored film-forming composition may be in a solvent-based or water-based form. Furthermore, after applying the colored film-forming composition, the clear film-forming composition, which is the stain-resistant coating composition of the present invention, can be applied after heat-curing, or the colored film-forming composition can be applied. After application, the clear film-forming composition, which is the stain-resistant coating composition of the present invention, can be applied without being cured, and two layers can be simultaneously cured.
[0027]
The above-mentioned composite coating coating finish method is a method of heating the base coat colored film-forming composition as necessary, adjusting it to a desired viscosity by adding an organic solvent or a reactive diluent, and then drying. When the subsequent coating is applied so as to have a thickness of 5 to 300 μm and usually cured by heating at a temperature of 50 to 300 ° C. for 5 seconds to 24 hours, or when a 2-coat 1-bake method is applied, a colored film is formed. The composition is diluted to a desired viscosity with an appropriate diluent such as an organic solvent, and then applied using the above method so that the film thickness after drying is usually 5 to 40 μm, preferably 7 to 35 μm. The film is allowed to stand at room temperature to 100 ° C. for 1 to 20 minutes, and then the clear film-forming composition of the clear coat film is dried to a thickness of 10 to 100 μm, preferably 10 to 60 μm using the above method. Like And a method of heat curing at a temperature of 50 to 300 ° C. for 5 seconds to 24 hours.
[0028]
Furthermore, the stain-resistant coating composition of the present invention can be used as an overcoat clear coating on a coating that has already been completed up to the top coating. In this case, as the top coat film, the above-mentioned solvent-based or water-based colored film-forming composition is applied, and an acrylic resin / aminoplast resin-based paint or acrylic resin / urethane resin curing agent system is applied on the uncrosslinked state. Formed by applying a clear paint (hereinafter also abbreviated as "under clear paint") selected from either paint or acrylic resin / aminoplast resin / urethane resin hardener-based paint, and simultaneously curing two layers. It is preferable that In this case, the under-clear coating is composed of (a) acrylic resin having both a hydroxyl group and an epoxy group of 40 to 80% by mass, preferably 45 to 75% by mass, and (b) aminoplast resin 0 to 60% by mass, preferably 10%. Over 50% by weight, (c) 0 to 60% by weight of urethane resin curing agent, preferably 1 to 30% by weight. It is more desirable from the viewpoint of adhesion to the coat clear paint.
[0029]
The acrylic resin having both a hydroxyl group and an epoxy group as the component (a) includes the above-mentioned radical polymerizable monomer having a hydroxyl group, a radical polymerizable monomer having an epoxy group, and other radical polymerizable monomers. It can be obtained by ordinary radical copolymerization in an organic solvent. Here, when the component (a) is less than 40% by mass, the adhesion to the overcoat clear paint is lowered, which is not preferable. When it exceeds 80% by mass, the gasoline resistance of the cured coating film is decreased, which is not preferable. For example, a melamine resin, a urea resin, a guanamine resin, a glycoluril resin, or the like can be used as the component (b) aminoplast resin, and among them, the melamine resin is particularly preferable from the viewpoint of weather resistance. Here, when the component (b) exceeds 60% by mass, the crack resistance of the cured coating film is lowered, which is not preferable. The urethane resin curing agent of component (c) is a compound having a functional group that can form a urethane bond by chemically reacting with a polyol or the like. For example, a polyisocyanate compound, a blocked polyisocyanate compound, a polycarbamate compound, or the like is used. Of these, blocked polyisocyanate compounds are preferred. Even more preferably, an aliphatic blocked polyisocyanate compound is suitable from the viewpoint of yellowing resistance of the cured coating film. Here, when the component (c) exceeds 60% by mass, the crack resistance of the cured coating film is lowered, which is not preferable. In addition, the under-clear coating is made of an acrylic resin, a polyester resin, a colored pigment, a bright pigment, a filler, a solvent, an ultraviolet absorber, a radical scavenger, an antioxidant, an anti-waxing agent, a surface conditioner, an anti-sagging agent. Further, a fluidity adjusting agent, a curing catalyst, a surfactant, an antistatic agent, a fragrance and the like can be added.
[0030]
The under clear paint and overcoat clear paint can be applied by heating the colored base coat paint as necessary, for example, by adjusting it to a desired viscosity by adding an organic solvent or a reactive diluent, and after drying. The coating film of 5 to 300 μm was applied, left at room temperature to 100 ° C. for 1 to 20 minutes, and then the under-clear coating was dried to a thickness of 10 to 100 μm using the above method. Preferably, it is applied so as to have a thickness of 10 to 60 μm, thermally cured at a temperature of 50 to 300 ° C. for 5 seconds to 24 hours, and then the over-clear coat coating is dried to a thickness of 10 to 100 μm using the above method, Preferably, a method of applying to 10 to 60 μm and thermally curing at a temperature of 50 to 300 ° C. for 5 seconds to 24 hours may be used.
In addition, when overcoating the stain-resistant coating composition of the present invention on the cured undercoat film, it is possible to apply an overcoat after applying a transparent primer, if necessary.
Examples of coated articles obtained by applying the coating composition of the present invention include structures, wooden products, metal products, plastic products, rubber products, processed paper, ceramic products, glass products, and the like. More specifically, examples thereof include metal plates such as automobiles and steel plates, motorcycles, ships, railway vehicles, aircraft, furniture, musical instruments, home appliances, building materials, containers, office supplies, sports equipment, toys and the like.
[0031]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited at all by these Examples. In addition, the performance of the coating film obtained with the stain-resistant coating composition of the present invention was determined as follows.
(1) Finished appearance
Evaluation was made according to the following criteria by visual observation.
○: When a fluorescent lamp is projected on the coating film, the fluorescent lamp is clearly reflected.
(Triangle | delta): When a fluorescent lamp is projected on a coating film, the circumference | surroundings (outline) of a fluorescent lamp will be blurred a little.
X: When a fluorescent lamp is projected on the coating film, the periphery (outline) of the fluorescent lamp is significantly blurred.
(2) Contact angle of water
The obtained test plate was exposed outdoors for 7 to 30 days in accordance with JIS K-5400 (1990) 9.9 weather resistance. Then, after washing the test plate, 0.8 μl of deionized water droplets were placed on the surface of the coating film at 20 ° C. using a syringe, and an Elmagoniometer type contact angle measuring device GI type manufactured by Elma Co., Ltd. was used. Measured. The contact angle was measured every 30, 60, and 90 seconds per droplet, and the contact angle was extrapolated from the linear regression equation of time and contact angle to 0 seconds, which was used as the contact angle of the test plate.
[0032]
(3) Resistance to outdoor exposure contamination
According to JIS K-5400 (1990) 9.9 weather resistance, the color of the unwashed surface of the coating (JIS K-5400 (1990) 7.4.2 system bulletin) was measured after exposure for 3 months outdoors. The ΔL value was calculated by subtracting the L value at the time of non-exposure from the L value after exposure, and the contamination of the coating film was determined.
(4) Weather resistance
After exposure for 3000 hours using a sunshine carbon arc lamp type accelerated weathering tester (JIS K-5400 (1990) 9.8.1), the state of the coating film was visually determined.
(5) Water resistance
The test piece was immersed in warm water at 40 ° C. for 240 hours to visually determine the state of the coating film.
(6) Acid resistance
0.2 ml of 40% by mass sulfuric acid was placed in a spot shape on the test piece, and after heating at 60 ° C. for 30 minutes, the abnormality of the coating film was visually determined.
[0033]
Example of production of component (A) modified resin
<Production Examples 1 and 2>
A four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was charged with a mixture of xylene and organosilicate (initial charge) having the composition shown in Table 1 and heated at 140 ° C. with stirring. Next, the monomer and polymerization initiator mixture (dropping component) having the composition shown in Table 1 were dropped at a constant temperature from a dropping funnel over 2 hours at a temperature of 140 ° C. After the completion of dropping, the temperature of 140 ° C. was maintained for 1 hour, and then the reaction temperature was lowered to 110 ° C. Then, a polymerization initiator solution (additional catalyst) having the composition shown in Table 1 was added, and the reaction was terminated when the temperature of 110 ° C. was maintained for 2 hours, and the modified resin solution A-1 having a nonvolatile content shown in Table 1 and A-2 was obtained.
[0034]
[Table 1]

The subscript substances in the table are shown below.
1) Condensate of organosilicate (trade name, manufactured by Colcoat Co., Ltd.)
[0035]
(B) Production Example of Component Curing Agent
<Production Example 3>
A four-necked flask equipped with a thermometer, reflux condenser, stirrer, and dropping funnel was charged with 134 parts by mass of trimethylolpropane and 425.3 parts by mass of methyl isobutyl ketone and heated to 120 ° C. with stirring. Next, 504 parts by mass of methylhexahydrophthalic anhydride was added dropwise over 2 hours while maintaining the temperature at 120 ° C., and the acid value of the mixture (pyridine / water = 9/1 (weight ratio)) was about 50 times by weight. The solution was heated to 90 ° C. for 30 minutes and titrated with a potassium hydroxide standard solution). A curing agent solution B-1 was obtained.
[0036]
<Production Example 4>
A four-necked flask equipped with a thermometer, reflux condenser, stirrer, and dropping funnel was charged with 84 parts by mass of methyl amyl ketone, and heated under stirring to maintain 140 ° C. Next, at a temperature of 140 ° C., a monomer and a polymerization initiator mixture (dropping component) having the following composition were dropped at a constant rate from a dropping funnel over 2 hours.

After the completion of dropping, the temperature of 140 ° C. was maintained for 1 hour, and then the reaction temperature was lowered to 110 ° C. Thereafter, 1 part by mass of t-butylperoxy-2-ethylhexanoate and 10 parts by mass of methyl amyl ketone were added, and the reaction was terminated when the temperature of 110 ° C. was maintained for 2 hours. Gardner viscosity (25 ° C.) R A curing agent solution B-2 having ˜S, a nonvolatile content of 50.4%, and a carboxylic acid equivalent of 860 as a solution was obtained.
[0037]
(Examples 1-4)
(1) Manufacture of clear paint
Raw materials having the composition shown in Table 2 were mixed to prepare a clear paint.
[0038]
[Table 2]

[0039]
The subscript substances in the table indicate the following.
1): Modified resin solution A-1 of Production Example 1
2): Modified resin solution A-2 of Production Example 2
3): Hardener solution B-1 of Production Example 3
4): Hardener solution B-2 of Production Example 4
5): MKC silicate MS56SB5 (trade name, manufactured by Mitsubishi Chemical Corporation, Mw1500)
6): Ethyl silicate 40 (trade name, manufactured by Tama Chemical Industry Co., Ltd., Mw750)
7): 10% by weight xylene solution of dibutyltin dilaurate
8): 10% by mass isobutyl acetate solution of tetrabutylammonium bromide
9): 20% by mass xylene solution of Tinuvin 900 (trade name, manufactured by Ciba Specialty Chemicals)
10): 20% by mass xylene solution of Tinuvin 292 (trade name, manufactured by Ciba Specialty Chemicals)
11): 10% by mass xylene solution of BYK-300 (trade name, manufactured by Big Chemie)
12): Trade name, manufactured by Esso, aromatic petroleum naphtha
[0040]
(2) Preparation of test piece and examination of coating film performance
Cation electrodeposition paint Aqua No. 4200 (trade name, manufactured by NOF Corporation) was electrodeposited to a dry film thickness of 20 μm, baked at 175 ° C. for 25 minutes, and then an intermediate coating HS-H300 (trade name, manufactured by NOF Corporation) Was sprayed with air to a dry film thickness of 30 μm and baked at 140 ° C. for 30 minutes. Then, Bell Coat No. A 6000 solvent-based black base coat paint (trade name, manufactured by Nippon Oil & Fats Co., Ltd.) was applied by air spray to a dry film thickness of 15 μm, and set at 20 ° C. for 3 minutes. Further, a paint obtained by diluting the paint (1) with a thinner (Solvesso 100 / butyl acetate = 9/1 (weight ratio)) to a coating viscosity (Ford Cup No. 4, 25 seconds at 20 ° C.) is wet-on-wet. The test piece was prepared by coating with an air spray so as to have a dry film thickness of 40 μm and baking at 140 ° C. under curing conditions for 30 minutes. However, in all cases of Examples 1 to 4, only the test panel for resistance to outdoor exposure contamination was Bell Coat No. Instead of the 6000 solvent-based black base coat, Bellcoat No. 6000 solvent-based white base coat paint (trade name, manufactured by NOF Corporation) was used. The coating performance is shown in Table 3. In each case, a uniform and glossy coating can be obtained, and excellent coating appearance, hydrophilicity, resistance to outdoor exposure, weather resistance, water resistance, and acid resistance. Indicated.
[0041]
(Examples 5 and 6)
Cation electrodeposition paint Aqua No. 4200 (trade name, manufactured by NOF Corporation) was electrodeposited to a dry film thickness of 20 μm, baked at 175 ° C. for 25 minutes, and then an intermediate coating HS-H300 (trade name, manufactured by NOF Corporation) Was sprayed with air to a dry film thickness of 30 μm and baked at 140 ° C. for 30 minutes. Then, Bell Coat No. 6000 solvent-based black base coat paint (trade name, manufactured by Nippon Oil & Fats Co., Ltd.) was applied by air spray to a dry film thickness of 15 μm, set at 20 ° C. for 3 minutes, and then the following under clear paint was wet-on A test piece was prepared by applying a wet film with an air spray to a dry film thickness of 40 μm and baking at 140 ° C. for 30 minutes under curing conditions. Further, in Example 5, the clear coating material prepared in Example 1 was applied, and in Example 6, the clear coating material prepared in Example 2 was applied to the test piece prepared by the above method by air spray so that the dry film thickness was 40 μm. The coating was applied and baked at 140 ° C. for 30 minutes under a curing condition to prepare a test piece. However, in both Examples 5 and 6, only the test panel for resistance to outdoor exposure contamination was replaced with Bell Coat No. 6000 solvent-based black base coat instead of Bell Coat No. 6000 solvent-based black base coat (trade name, Nippon Oil & Fats Co., Ltd.). Made). The coating performance is shown in Table 3. In each case, a uniform and glossy coating can be obtained, and excellent coating appearance, hydrophilicity, resistance to outdoor exposure, weather resistance, water resistance, and acid resistance. Indicated.
[0042]
<Manufacture of under clear paint>
A four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was charged with 60 parts by mass of xylene, and heated at 140 ° C. with stirring. Next, a mixture of 8 parts by mass of glycidyl methacrylate, 77 parts by mass of butyl methacrylate, 15 parts by mass of 2-hydroxyethyl methacrylate and 2 parts by mass of t-butylperoxy-2-ethylhexanoate at a temperature of 140 ° C. It dropped at a constant speed from the dropping funnel over 2 hours. After the completion of dropping, the temperature of 140 ° C. was maintained for 1 hour, and then the reaction temperature was lowered to 110 ° C. Then, a mixture of 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate and 4.5 parts by mass of xylene was added, and the reaction was terminated when the temperature of 110 ° C. was maintained for 2 hours. An acrylic resin solution U-1 for underclear having 9% non-volatile content was obtained.
[0043]
Next, using the above acrylic resin solution, the following raw materials were mixed to prepare an underclear paint.

The above-mentioned under clear paint was diluted with a thinner (Solvesso 100 / n-butanol = 9/1 (weight ratio)) to a coating viscosity (Ford Cup No. 4, at 20 ° C. for 25 seconds).
[0044]
(Examples 7 and 8)
Cation electrodeposition paint Aqua No. 4200 (trade name, manufactured by NOF Corporation) was electrodeposited to a dry film thickness of 20 μm, baked at 175 ° C. for 25 minutes, and then an intermediate coating HS-H300 (trade name, manufactured by NOF Corporation) Was sprayed with air to a dry film thickness of 30 μm and baked at 140 ° C. for 30 minutes. Next, Aqua BC-3 water-based black base coat paint (trade name, manufactured by Nippon Oil & Fats Co., Ltd.) was applied by air spray to a dry film thickness of 15 μm, set at 20 ° C. for 3 minutes, and then dried at 80 ° C. for 10 minutes. . Further, after allowing the test piece to cool to room temperature, the under-clear paint described in Examples 5 and 6 was applied by air spray to a dry film thickness of 40 μm, and baked at 140 ° C. for 30 minutes under curing conditions. Created. Further, in Example 7, the clear coating material prepared in Example 3 was applied, and in Example 8, the clear coating material prepared in Example 4 was applied to the test piece prepared by the above-described method by air spray so that the dry film thickness was 40 μm. The coat was applied and baked at 140 ° C. for 30 minutes under a curing condition to prepare a test piece. However, in Examples 7 and 8, only the test panel for resistance to outdoor exposure contamination was replaced with Aqua BC-3 aqueous black base coat paint (trade name, manufactured by Nippon Oil & Fats Co., Ltd.) base coat, and Aqua BC-3 aqueous white base coat paint. (Trade name, manufactured by NOF Corporation) was used. The coating performance is shown in Table 3. In each case, a uniform and glossy coating can be obtained, and excellent coating appearance, hydrophilicity, resistance to outdoor exposure, weather resistance, water resistance, and acid resistance. Indicated.
[0045]
[Table 3]

The subscripts in the table indicate the following.
1) Mixing ratio of non-volatile content
2) 2C1B: 2 coats 1 bake coating
3) OB: 2 coat 1 bake paint on overcoat clear paint
[0046]
Comparative Example 1
(1) Manufacture of acrylic resin containing epoxy group
A four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was charged with 63 parts by mass of xylene and heated under stirring to maintain 100 ° C. Next, at a temperature of 140 ° C., a monomer and a polymerization initiator mixture (dropping component) having the following composition were dropped at a constant rate from a dropping funnel over 2 hours.

[0047]
After the completion of dropping, the temperature of 140 ° C. was maintained for 1 hour, and then the reaction temperature was lowered to 110 ° C. Thereafter, 0.5 parts by mass of t-butylperoxy-2-ethylhexanoate and 2 parts by mass of xylene were added, and the reaction was terminated when the temperature of 110 ° C. was maintained for 2 hours, and the Gardner viscosity (25 ° C.) U An acrylic resin solution D-1 having ~ V, a nonvolatile content of 59.4%, and an epoxy equivalent of 680 as a solution was obtained.
(2) Manufacture of clear paint
Raw materials having the composition shown in Table 4 were mixed to prepare a clear paint.
[0048]
[Table 4]

The subscripts in the table indicate the following.
Note 1) to Note 3) Same as above.
Note 4) Acrylic resin solution D-1 containing epoxy group produced as described above
Note 5) to Note 10) Same as above.
[0049]
(3) Preparation of test piece and examination of coating film performance
Cation electrodeposition paint Aqua No. 4200 (trade name, manufactured by NOF Corporation) was electrodeposited to a dry film thickness of 20 μm, baked at 175 ° C. for 25 minutes, and then an intermediate coating HS-H300 (trade name, manufactured by NOF Corporation) Was sprayed with air to a dry film thickness of 30 μm and baked at 140 ° C. for 30 minutes. Then, Bell Coat No. A 6000 black base coat paint (trade name, manufactured by NOF Corporation) was applied by air spray to a dry film thickness of 15 μm and set at 20 ° C. for 3 minutes. Further, a paint obtained by diluting the paint (1) with a thinner (Solvesso 100 / butyl acetate = 9/1 (weight ratio)) to a coating viscosity (Ford Cup No. 4, 25 seconds at 20 ° C.) is wet-on-wet. The test piece was prepared by coating with an air spray so as to have a dry film thickness of 40 μm and baking at 140 ° C. under curing conditions for 30 minutes. However, Bellcoat No. 6000 white base coat (trade name, manufactured by Nippon Oil & Fats Co., Ltd.) was used instead of Bellcoat No. 6000 black base coat only for the outdoor exposure stain resistance test plate. Although the coating film performance is shown in Table 5, in Comparative Example 1, since the modified resin (A) was not included, the weather resistance and water resistance were inferior.
[0050]
[Table 5]

[0051]
【The invention's effect】
The stain resistant coating composition of the present invention has a stain resistance performance based on a high degree of hydrophilicity immediately after the formation of the coating film, and can give a cured product having a good long-term weather resistance, water resistance and chemical resistance performance. it can.

Claims (14)

(A) General formula (1)
_{^{(R 1) m -Si- (OR}} 2) 4-m (1)
(Wherein R ¹ and R ² are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, and m is 0 or 1), and / or a condensate thereof. Contamination-resistant coating composition comprising a modified resin obtained by polymerizing a polymerizable monomer mixture for synthesizing an acrylic resin containing a radically polymerizable monomer having a hydroxyl group in the presence . (A) General formula (1)
_{^{(R 1) m -Si- (OR}} 2) 4-m (1)
(Wherein R ¹ and R ² are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, and m is 0 or 1), and / or a condensate thereof. A modified resin obtained by polymerizing a polymerizable monomer mixture for acrylic resin synthesis containing both a radical polymerizable monomer having a hydroxyl group and a radical polymerizable monomer having an epoxy group in the presence of Contamination-resistant paint composition characterized by containing. In the stain resistant paint composition,
(B) The antifouling paint according to claim 1, comprising a compound having at least one selected from a carboxyl group, a carboxylic acid anhydride group and a functional group of a carboxyl group blocked with an alkyl vinyl ether compound in one molecule. Composition. In the stain resistant paint composition,
(B) The antifouling paint according to claim 2, comprising a compound having at least one selected from a carboxyl group, a carboxylic acid anhydride group and a carboxyl group functional group blocked with an alkyl vinyl ether compound in one molecule. Composition. In the stain resistant paint composition,
(C) General formula (2)
_{^{(R 3) n -Si- (OR}} 4) 4-n (2)
(Wherein R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, and n is 0 or 1), and / or a condensate thereof. The stain-resistant coating composition according to claim 3, which is contained. In the stain resistant paint composition,
(C) General formula (2)
_{^{(R 3) n -Si- (OR}} 4) 4-n (2)
(Wherein R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, and n is 0 or 1), and / or a condensate thereof. The stain-resistant coating composition according to claim 4, which is contained. Contamination resistance according to claim 5 or 6, comprising 3 to 80% by mass of component (A), 3 to 80% by mass of component (B), and 0.1 to 30% by mass of component (C). Paint composition. In the acrylic resin structure part of the modified resin (A), the general formula (3)

(Wherein R ⁵ and R ⁶ are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and y is an integer of 1 to 10). The stain resistant coating composition according to any one of 5 and 7. In the acrylic resin structure part of the modified resin (A), the general formula (3)

(Wherein R ⁵ and R ⁶ are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and y is an integer of 1 to 10). The stain-resistant coating composition according to any one of 6 and 7. The pigment is contained in an amount of 0 to 200 parts by mass per 100 parts by mass of all the non-volatile components of the component (A), the component (B) and the component (C) of the stain-resistant coating composition according to claim 1. A painting finishing method characterized in that a top coating is applied to an object. Applying a colored film-forming composition on a substrate to form a base coat, and then applying a clear film-forming composition to the base coat to form a transparent top coat to coat a composite film The stain-resistant paint according to claim 1, wherein only the topcoat clear film-forming composition or both the topcoat clear film-forming composition and the colored film-forming composition are used. A paint finishing method comprising any one of the compositions. In a coating method in which a colored base coat paint is applied onto a base material, an under-clear paint is applied in an uncrosslinked state, baked, and then further over-coated clear paint is applied and baked, the under-clear paint is an acrylic resin / Aminoplast resin-based paint, acrylic resin / urethane resin hardener-based paint, or acrylic resin / aminoplast resin / urethane resin hardener-based paint, and the overcoat clear paint A paint finishing method comprising any one of the stain-resistant coating compositions according to -9. 13. The coating method according to claim 12, wherein a colored base coat paint is applied onto a substrate, an under-clear paint is applied in an uncrosslinked state, baked, and then further coated with an over-coat clear paint. Resin composed of (a) acrylic resin 40-80% by mass having both hydroxyl group and epoxy group, (b) aminoplast resin 0-60% by mass, (c) urethane resin curing agent 0-60% by mass A paint finishing method , which is a coating composition comprising a mixture as a main component. A coated article, which is coated by the coating finishing method according to claim 10.