JP2004010748A - Surface treating agent for transparent resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treating agent for a transparent resin molded product, exhibiting excellent durability and stain-resistant properties without affecting the transparency originally possessed by the transparent resin molded product. <P>SOLUTION: The surface treating agent for the transparent resin molded product comprises (A) a primer composition and (B) a coating composition. The primer composition (A) comprises at least a solvent-soluble type fluororesin for a coating material, an adhesion-imparting agent, and an organosilicate represented by the general formula and/or an organosilicate compound comprising a partial hydrolyzate thereof, and forms a transparent primer layer by being coated on the surface of the transparent resin molded product. The coating composition (B) comprises a hydrolyzate of the organosilicate obtained by hydrolyzing the organosilicate represented by the same general formula and/or the organosilicate compound comprising the partial hydrolyzate in the presence of a hydrolysis catalyst. <P>COPYRIGHT: (C)2004,JPO

Description

【００１２】
（但し、式中、Ｒ^１〜Ｒ^４は、炭素数１〜１０のアルキル基又はアリル基若しくは炭素数６〜２４のアリール基であり、互いに同じであっても異なっていてもよく、また、ｎは１以上の整数である）で表わされるオルガノシリケート及び／又はその部分加水分解物からなるオルガノシリケート化合物とを含み、透明樹脂成形品の表面に塗布されて透明プライマー層を形成するプライマー組成物と、（Ｂ）上記一般式（１）と同じ一般式で表されるオルガノシリケート及び／又はその部分加水分解物からなるオルガノシリケート化合物を加水分解触媒の存在下に加水分解して得られたオルガノシリケートの加水分解物を含み、上記プライマー層の上に塗布されて透明表面防汚層を形成するコーティング組成物とからなる透明樹脂成形品用表面処理剤である。
【００１３】
本発明において、プライマー組成物を構成する溶剤可溶型塗料用フッ素樹脂としては、従来この種の溶剤可溶型塗料用フッ素樹脂として用いられているものであれば特に制限はないが、好ましくは、繰返し単位中にフルオロオレフィン構造単位と、構造単位内に水酸基、カルボキシル基、エステル基、及びエーテル基から選ばれた１種又は２種以上の官能基を有するビニル構造単位から選ばれた１種又は２種以上を含むフッ素樹脂であり、より好ましくは、繰返し単位中にクロロトリフルオロエチレン構造単位と、アルキルビニルエステル構造単位、アルキルビニルエーテル構造単位、ヒドロキシアルキルビニルエーテル構造単位、フルオロアルキルビニルエーテル構造単位、クロトン酸又はそのヒドロキシアルキルエステル構造単位、アルケニルカルボン酸構造単位、トリアルコキシビニルシラン構造単位無水コハク酸との反応により導入される構造単位等から選ばれた１種又は２種以上のビニル構造単位とを有するフッ素樹脂である。
【００１４】
この種の溶剤可溶型塗料用フッ素樹脂として、具体的には、特公昭６０−２１，６８６号、特公平１−３４，４６０号、特公平４−４０，３６５号、特開昭６２−７，７６７号、特開平３−２３１，９０６号等の各公報に記載のものを挙げることができ、より具体的にはセフラルコート（セントラル硝子社製商品名）、ルミフロン（旭硝子社製商品名）、フルオネート（大日本インキ化学工業社製商品名）、ザフロン（東亞合成社製商品名）、ゼッフル（ダイキン工業社製商品名）等を挙げることができる。
【００１５】
また、上記溶剤可溶型塗料用フッ素樹脂と共に用いられてプライマー組成物を構成するオルガノシリケート化合物は、上記一般式（１）で表されるオルガノシリケート及び／又はその部分加水分解物であって、このプライマー組成物により透明樹脂成形品の表面に形成される透明プライマー層とこの透明プライマー層の上に形成される表面防汚層との間の密着性を発現せしめるものである。このオルガノシリケート化合物としては、具体的には、置換基Ｒ^１〜Ｒ^４が、例えば、メチル基、エチル基、ｎ−プロピル基、ｉｓｏ−プロピル基、ｎ−ブチル基、ｉｓｏ−ブチル基、ｔｅｒｔ−ブチル基、ｎ−ペンチル基、ｉｓｏ−ペンチル基、ネオペンチル基、ｎ−ヘキシル基、ｉｓｏ−ヘキシル基、ビニル基、フェニル基、トルイル基、キシリル基、ナフチル基、１，５−ジメチルナフチル基等から選ばれた１種又は２種以上アルキル基及び／又はアリール基を有する化合物を挙げることができる。
【００１６】
これらのオルガノシリケート化合物として、好ましくはその置換基Ｒ^１〜Ｒ^４が炭素数１〜４のアルキル基であるものがよく、具体的には、テトラメトキシシラン、テトラエトキシシラン、テトライソプロポキシシラン、テトラ−ｎ−プロポキシシラン、テトラ−ｎ−ブトキシシラン、テトラ−２−メトキシエトキシシラン、テトラ−２−エチルヘキシロキシラン等や、これらのオルガノシリケートに水、酸及び溶剤を加えて部分的に加水分解縮合させて得られる部分加水分解物を挙げることができる。この部分加水分解物については縮合度、構造、アルコキシ基の異なる各種のものが市販されており、具体的には、有効シリカ分を２８〜５６重量％の範囲で含有するエチルシリケート４０、エチルシリケート４５、エチルシリケート４８、メチルシリケート５１、及びメチルシリケート５６や、テトラエトキシシランをエタノールやイソプロピルアルコールに溶解し加水分解して得られたＨＡＳ−６、及びＨＡＳ−１０（いずれもコルコート社製商品名）等が挙げられる。また、これらの部分加水分解縮合物のオリゴマーどうしを反応させて得られる化合物も使用することができる。
【００１７】
また、本発明のプライマー組成物中に添加される密着付与剤は、透明樹脂成形品の成形品表面とこのプライマー組成物により透明樹脂成形品の表面に形成される透明プライマー層との間の密着性を付与する機能又は作用を発揮するものであって、使用する溶剤可溶型塗料用フッ素樹脂との相溶性が必要であり、好ましくは分子内に水酸基を有する溶剤可溶型樹脂であり、より好ましくはこの水酸基とカルボキシル基、エステル基及びエーテル基から選ばれた１種又は２種以上の官能基とを有する溶剤可溶型樹脂であるのがよい。そして、この密着付与剤としての溶剤可溶型樹脂については、樹脂ベースで水酸基価（ソリッド）が２０〜２００ｍｇＫＯＨ／ｇ、好ましくは２０〜１００ｍｇＫＯＨ／ｇであり、また、酸価（ワニス）が０〜１０ｍｇＫＯＨ／ｇ、好ましくは０〜５ｍｇＫＯＨ／ｇである。このような密着付与剤としては、具体的には、アクリル樹脂、フッ素樹脂等を挙げることができ、特に好ましくはアクリル樹脂である。
【００１８】
本発明のプライマー組成物を構成する上記溶剤可溶型塗料用フッ素樹脂、オルガノシリケート化合物及び密着付与剤の配合割合は、溶剤可溶型塗料用フッ素樹脂１００重量部当り、オルガノシリケート化合物が０．５〜６０重量部、好ましくは１〜４０重量部であり、また、密着付与剤が０．５〜５０重量部、好ましくは５〜３０重量部である。この際に、オルガノシリケート化合物の配合割合が０．５重量部より少ないとコーティング組成物によって形成される表面防汚層との間の密着性が不充分になり、６０重量部を超えると、樹脂の相溶性の低下という問題が生じ、また、密着付与剤の配合割合が０．５重量部より少ないと透明樹脂成形品の成形品表面に対する密着性が不充分になり、５０重量部を超えると、耐久性が大幅に低下する。
【００１９】
このプライマー組成物については、上記溶剤可溶型塗料用フッ素樹脂、オルガノシリケート化合物及び密着付与剤に加えて、プライマー組成物の透明性が確保されることを前提に、通常の塗料の場合と同様に、着色剤、紫外線吸収剤、光安定剤、硬化剤、ベリング剤、硬化触媒、溶剤、艶消し剤、断熱フィラー等を必要に応じて適宜選択して添加することができる。
【００２０】
この目的で添加される紫外線吸収剤としては、有機系及び無機系のいずれであってもよいが、使用する溶剤可溶型塗料用フッ素樹脂との相溶性に優れていることが好ましく、透明性を確保するために、有機系の紫外線吸収剤を使用するのがより好ましく、中でもベンゾフェノン系、ベンゾトリアゾール系、アクリル系等の紫外線吸収剤が好適に用いられる。この紫外線吸収剤の添加量は、溶剤可溶型塗料用フッ素樹脂１００重量部に対して、通常０．５〜２０重量部、好ましくは２〜１５重量部の範囲であり、０．５重量部より少ないとこの紫外線吸収剤を添加した添加効果が発揮されず、反対に、２０重量部より多くなると、相溶性の確保が難しくなるほか、使用後に徐々に滲み出してかえって外観を損ねることがある。
【００２１】
また、光安定剤としては、例えば、ヒンダードアミン系、ベンゾエート系、ベンゾトリアゾール系等のものが挙げられ、好ましくはヒンダードアミン系のものであり、その添加量は、溶剤可溶型塗料用フッ素樹脂１００重量部に対して、通常０．１〜５重量部、好ましくは０．１〜３重量部の範囲である。この添加量が０．１重量部より少ないとこの光安定剤を添加した添加効果が発揮されず、反対に、５重量部より多くなると、相溶性の確保が難しくなるほか、使用後に徐々に染み出して外観を損ねるという問題がある。
【００２２】
更に、硬化剤については、使用する溶剤可溶型塗料用フッ素樹脂の種類によって異なるが、アミノ樹脂、ポリイソシアネート化合物、及びブロック化ポリイソシアネート化合物等の如く、水酸基に対して反応性を有する各種の硬化剤を使用することができる。
【００２３】
ここで、上記アミノ樹脂としては、塗料用として用いられるものであればいずれも使用することができるが、特に代表的なものとしては、例えば、メラミン、尿素、アセトグアナミン、ベンゾグアナミン、ステログアナミン、及びスピログアナミンの如きアミノ基含有化合物とホルムアルデヒド、パラホルムアルデヒド、アセチルアルデヒド、及びグリオキザール等の如きアルデヒド化合物とを反応させて得られる縮合生成物や、これら各種の縮合生成物を１価アルコール類でエーテル化して得られる変性物等を挙げることができる。
【００２４】
また、ポリイソシアネート化合物として特に代表的なものを例示すれば、例えば、テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、トリメチルヘキサメチレンジイソシアネート等の如き脂肪族ジイソシアネート類や、イソホロンジイソシアネート、メチルシクロヘキサン−２，４−ジイソシアネート、メチルシクロヘキサン−２，６−ジイソシアネート、４，４−メチレンビス（シクロヘキシルイソシアネート）、１，３−ジ（イソシアネートメチル）シクロヘキサン等の如き脂環式ジイソシアネート類や、これら各ジイソシアネート類と多価アルコール類若しくは低分子量の水酸基含有重合体類等との付加物（アダクト体）や、上記各ジイソシアネート類と水又は三級アルコール類等の如きビュレット化剤との反応物（ビュレット体）や、上記各ジイソシアネート類の三量体（イソシアヌレート）等を挙げることができる。
【００２５】
更に、上記ブロック化ポリイソシアネート化合物としては、特に代表的なものとして、例えば、上記各種のポリイソシアネート化合物を公知のブロック化剤でブロック化せしめたもの等を挙げることができる。そして、この目的で用いられるブロック化剤としては、特に代表的なものを例示すれば、例えば、メチルエチルケトオキシム、メチルイソブチルケトンオキシム等の如きオキシム化合物や、ε−カプロラクタムの如きラクタム化合物や、アセトアニリド、オクチル酸アニリドの如きアミド化合物や、イソプロピルアルコール、ｎ−ブチルアルコールの如きアルコール等の、いわゆる活性水素原子を有する各種の化合物を始めとして、アセチルアセトンやアセト酢酸エチル等の互換異性等により活性水素原子を生成する化合物等を挙げることができる。
【００２６】
そして、以上のような各種のポリイソシアネート化合物を用いて硬化させる際には、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、ジブチル錫ジオクテート等の公知の触媒を添加して硬化を促進させることもできる。また、ナフテン酸コバルト、ナフテン酸亜鉛等の各種の有機金属化合物や、トリエチレンジアミン、１，８−ジアザビシクロ−（５，４，０）−ウンデセン−７（ＤＢＵ）等の各種の塩基性化合物類も触媒として使用することができる。更に、これらの硬化触媒は、その１種のみを単独で用いることができるほか、２種以上を併用してもよい。
【００２７】
また、上記の硬化剤の添加量については、例えばポリイソシアネート類の場合には、溶剤可溶型フッ素樹脂中の水酸基（ＯＨ）と硬化剤中のイソシアネート基（ＮＣＯ）のモル比（ＯＨ／ＮＣＯ）が０．２〜３．０、好ましくは０．５〜２．０の範囲になるように添加するのがよい。このモル比（ＯＨ／ＮＣＯ）が０．２より低いと、残存するイソシアネート基が多くなり過ぎて耐候性が低下し、反対に、３．０より高くなると、フリーの水酸基が多くなり過ぎて塗膜の硬化性、耐汚染性が劣って好ましくない。このモル比（ＯＨ／ＮＣＯ）が０．５〜２．０の範囲、特に１．０付近であると、塗膜の硬化性、耐候性、耐汚染性等の点で最も良好な塗料となる。
【００２８】
本発明のプライマー組成物に用いられる溶剤としては、種々のものを使用することができるが、このプライマー組成物が塗布される成形品の樹脂の種類に応じて選択するのがよく、例えば、成形品の樹脂がアクリル樹脂やポリエステル樹脂のように比較的耐薬品性に優れている場合には、トルエン、キシレン等の芳香族系化合物が主体の、いわゆるウレタン塗料用シンナーなどが使用可能であり、また、成形品の樹脂がポリカーボネート等の比較的耐薬品性に劣る場合には、特定の溶剤を選択して用いることが必要であり、例えば、酢酸エチル、酢酸ブチル等の脂肪族エステル類を挙げることができる。更に、塗料化時や塗装時に用いる希釈溶剤としては、アセトン、メチルエチルケトン、ジイソブチルケトン等の脂肪族ケトン類や、エチルアルコール、イソプロピルアルコール、ｎ−（ｉ−，　ｔ−）ブチルアルコール等のアルコール類や、エチレンオキシド、テトラヒドロフラン、ジオキサン等の環状エーテル類等を挙げることができる。
【００２９】
また、本発明において、コーティング組成物を構成するオルガノシリケートの加水分解物は、上記一般式（１）と同じ一般式を有するオルガノシリケート及び／又はその部分加水分解物からなるオルガノシリケート化合物を加水分解媒の存在下に加水分解して得られるものである。ここで、コーティング組成物のオルガノシリケート加水分解物を得るためのオルガノシリケート化合物は、上記プライマー組成物を構成するオルガノシリケート化合物と同じであっても、また、異なっていてもよい。
【００３０】
そして、このオルガノシリケート化合物の加水分解反応については、結果的にオルガノシリケート化合物を略完全に加水分解できればよいが、好ましくは、加水分解触媒の存在下に、オルガノシリケート中Ｓｉ原子のＳｉＯ_２換算１００重量部に対して６０重量部以上６００重量部以下、好ましくは１２０重量部以上４００重量部以下の加水分解水分量の水で加水分解し、次いで得られた加水分解反応物に水含有希釈剤を添加して調整後水分量がオルガノシリケート中のＳｉ原子のＳｉＯ_２換算１００重量部に対して６００重量部以上４０００重量部以下、好ましくは１０００重量部以上３５００重量部以下となるように水分調整するのがよい。加水分解水分量が６０重量部より少ないと加水分解が十分に進まず、所望の親水性が得られず初期からの防汚性が得られず、反対に、６００重量部より多くなると加水分解物がゲル化し易くなる。また、調整後水分量が６００重量部より少ないと最終的にアルコキシ基が残留して所望の親水性が得られない場合があり、反対に、４０００重量部より多くなると貯蔵安定性が低下して製品ライフが短くなるという問題が生じる。
【００３１】
なお、上記の加水分解水分量とは、オルガノシリケートを加水分解する際にその反応系に存在して加水分解反応に関与する全水分の量をいい、加水分解反応系に反応剤として添加される水に限らず、この加水分解反応系に酸触媒と共に、あるいは反応溶剤と共に導入される水を含む全ての水分量をいう。また、オルガノシリケートの加水分解物の水分量を調整するのに用いられる水含有希釈剤としては、分散性や溶解性を考慮して好ましくは所定量の水を含むエチルアルコール、イソプロピルアルコール、ｎ−（ｉ−，　ｔ−）ブチルアルコール等のアルコール類が望ましい。
【００３２】
また、この加水分解反応に用いられる加水分解触媒としては、特に制限はないが、好ましくは硝酸、硫酸、塩酸等の鉱酸類や、蟻酸、酢酸等の有機酸類等が挙げられる。この加水分解触媒の使用量は、反応系中に通常０．０１重量％以上５重量％以下、好ましくは０．０５重量％以上２重量％以下の範囲で存在せしめるのがよく、０．０１重量％未満では、加水分解速度が遅くなり、アルコキシ基が残存して所望の親水性が得られず、反対に、５重量％を超えると、合成時にゲル化し易くなる。
【００３３】
本発明の表面処理剤が適用される透明樹脂成形品については、それがどのような種類の樹脂によりどのような形状に成形されたものであるかは特に制限はないが、本発明のプライマー組成物を構成する溶剤可溶型塗料用フッ素樹脂との密着性に優れたものであるのがよく、例えば、アクリル樹脂、ポリエステル樹脂、ポリカーボネート樹脂、ポリスチレン樹脂等を挙げることができ、また、その形状についても、シート状、フィルム状、プレート状、パイプ状、その他の成形品固有の形状等を挙げることができる。
【００３４】
このような透明樹脂成形品の表面に本発明の表面処理剤を適用する方法については、先ず透明樹脂成形品の表面にプライマー組成物を塗布し、乾燥させてプライマー層を形成し、次いでこのプライマー層の上にコーティング剤を塗布し、乾燥させて表面防汚層を形成せしめればよく、プライマー組成物やコーティング組成物の塗布方法については特に制限はなく、例えば、エアースプレー、エアレススプレー、カーテンフローコーター、ロールコーター、グラビアコート、リバースコート等の一般的な塗布方法を採用できるほか、刷毛塗り等の手塗りも可能であり、また、乾燥方法については、常温乾燥でも加熱乾燥でもよいが、加熱乾燥の方が短時間で乾燥皮膜を得ることができる。
【００３５】
本発明の表面処理剤を用いて形成される表面処理透明樹脂成形品は、透明樹脂成形品の成形品表面に、（ａ）少なくとも溶剤可溶型塗料用フッ素樹脂と、密着付与剤と、一般式（１）で表わされるオルガノシリケート及び／又はその部分加水分解物からなるオルガノシリケート化合物とを含むプライマー組成物を上記成形品表面に塗布して形成された透明プライマー層と、（ｂ）上記一般式（１）と同じ一般式で表されるオルガノシリケート及び／又はその部分加水分解物からなるオルガノシリケート化合物を加水分解触媒の存在下に加水分解して得られたオルガノシリケートの加水分解物を含むコーティング組成物を上記透明プライマー層の上に塗布して形成された透明表面防汚層とを有するものである。
【００３６】
そして、本発明の表面処理剤によって透明樹脂成形品の表面に形成されるプライマー層及び表面防汚層の膜厚については、プライマー層が通常５〜４０μｍ、好ましくは１０〜３０μｍであり、また、表面防汚層が通常０．０１〜３μｍ、好ましくは０．０５〜１μｍである。プライマー層の膜厚が５μｍより薄いと劣化の主原因である紫外線の遮断が十分でなく、剥離、黄変等の問題が起こり易く、反対に、４０μｍより厚くなると不経済であるばかりでなく、硬化に時間がかかって好ましくない。また、表面防汚層の膜厚が０．０１μｍより薄いと塗装直後からの防汚性の付与が難しくなり、反対に、３μｍより厚くなると溶剤が飛散した後に細かなひび割れが入る虞がある。
【００３７】
【発明の実施の形態】
以下、実施例及び比較例に基づいて、本発明の好適な実施の形態を具体的に説明する。
【００３８】
〔プライマー組成物の配合例Ａ〜Ｇの調製〕
溶剤可溶型塗料用フッ素樹脂としてセフラルコートＡ２０２Ｂ（セントラル硝子社製商品名；固形分濃度：５０重量％、水酸基価（ソリッド）：５６ｍｇＫＯＨ／ｇ、酸価（ワニス）：４ｍｇＫＯＨ／ｇ、溶剤：酢酸ブチル）及びセフラルコートＡ４０２Ｂ（セントラル硝子社製商品名；固形分濃度：５５重量％、水酸基価（ソリッド）：４５ｍｇＫＯＨ／ｇ、酸価（ワニス）：４ｍｇＫＯＨ／ｇ、溶剤：酢酸ブチル）を、オルガノシリケート化合物としてエチルシリケートの低縮合物（多摩化学工業社製商品名：ＥＳ−４８）を、密着付与剤としてアクリディクＡ−８１１（大日本インキ化学社製商品名；固形分濃度：５０重量％、水酸基価（ソリッド）：３４ｍｇＫＯＨ／ｇ、酸価（ワニス）：４ｍｇＫＯＨ／ｇ、溶剤：酢酸ブチル／キシレン）又はＡＲ８０２８−３（特殊色料工業社製商品名；固形分濃度：４５重量％、水酸基価（ソリッド）：６５ｍｇＫＯＨ／ｇ、酸価（ワニス）：３ｍｇＫＯＨ／ｇ、溶剤：酢酸エチル／トルエン）を、紫外線吸収剤としてベンゾトリアゾール系紫外線吸収剤（共同薬品社製商品名：バイオソーブ５９１又はチバガイギー社製商品名：チヌビン９００）を、光安定剤としてヒンダートアミン系光安定剤（三共社製商品名：サノールＬＳ２９２）を、硬化剤としてイソシアネート系硬化剤〔日本ポリウレタン社製商品名：コロネートＨＸ（固形分濃度：１００重量％、ＮＣＯ割合：２１．３％）又は住友バイエルウレタン社製商品名：ディスモジュールＢＬ３１７５（固形分濃度：７５重量％、ＮＣＯ割合：１１．１％、溶剤：ソルベントナフサ）〕をそれぞれ用い、表１に示す固形分濃度となるように配合してプライマー組成物の配合例Ａ〜Ｇを調製した。
【００３９】
【表１】

【００４０】
〔コーティング組成物の調製〕
調製例Ａ
容量１５００ｍｌの三口フラスコに、エチルシリケートの平均重合度４〜５のオリゴマー体（多摩化学工業（株）製商品名：ＥＳ−４０）４０ｇとエタノール８８ｇとを仕込み、均一に混合した後、純水２１．６ｇと触媒として６ｗｔ％−硝酸水溶液２８ｇとを添加し、加熱還流下に４時間反応させた後、冷却して加水分解反応物を得た。次いで、得られた加水分解反応物中に、イソプロピルアルコール１９０ｇと純水４３２ｇとを十分に混合して得られた水含有希釈剤を添加し、攪拌下に十分に混合して調製例Ａのコーティング組成物を調製した。
なお、この調製例Ａにおける加水分解水分量と水含有希釈剤由来の水分量の合計水分量は、オルガノシリケート中Ｓｉ原子のＳｉＯ_２換算１００重量部に対して３０００重量部である。
【００４１】
調製例Ｂ
エチルシリケートの平均重合度４〜５のオリゴマー体に代えてメチルシリケートの平均重合度３〜４のオリゴマー体（多摩化学工業（株）製商品名：ＭＳ−５１）３１．４ｇを用いた以外は、上記調製例Ａと同様にして調製例Ｂのコーティング組成物を調製した。
なお、この調製例Ｂにおける加水分解水分量と水含有希釈剤由来の水分量の合計水分量は、オルガノシリケート中Ｓｉ原子のＳｉＯ_２換算１００重量部に対して３０００重量部である。
【００４２】
調製例Ｃ
調製例Ａで用いた水含有希釈剤に代えてイソプロピルアルコール１９０ｇを希釈剤として用いた以外は、上記調製例Ａと同様にして調製例Ｃのコーティング組成物を調製した。
なお、この調製例Ｃにおける加水分解水分量と水含有希釈剤由来の水分量の合計水分量は、オルガノシリケート中Ｓｉ原子のＳｉＯ_２換算１００重量部に対して３００重量部である。
【００４３】
実施例１〜８及び比較例１〜５
透明樹脂成形品として縦３０ｃｍ×横２０ｃｍ×厚さ５ｍｍの大きさの透明なアクリル樹脂板（住友化学工業社製）又はポリカーボネート板（日本ポリエステル社製）を用い、その表裏両面に、上記配合例Ａ〜Ｇのプライマー組成物１００重量部にジイソブチルケトン３０重量部を添加して得られた溶液を、エアースプレーにて乾燥後膜厚が２０μｍとなるように吹き付け、室温にて５分間セッティングし、次いでオーブン中でアクリル樹脂板の場合は８０℃、３０分間、また、ポリカーボネート板の場合は１２０℃、３０分間の条件で硬化させ、表面に膜厚２０μｍのプライマー層を形成せしめた。
【００４４】
次に、各実施例１〜８及び比較例１、４の場合には、上記アクリル樹脂板又はポリカーボネート板のプライマー層の上に、上記調製例Ａ〜Ｃで得られたコーティング組成物をエアースプレーにて吹付け量３０ｇ／ｍ^２の割合で吹き付け、５０℃、３０分の条件で乾燥し、乾燥後膜厚０．６μｍの透明な表面防汚層を形成せしめて透明試験板を調製し、また、比較例２、３及び５の場合には、上記プライマー層を有するアクリル樹脂板又はポリカーボネート板をそのまま透明試験板とした。
【００４５】
得られた各透明試験板を縦方向に２分割し、得られた一方の試験片を用いて、密着性（碁盤目粘着テープ試験；ＪＩＳ　Ｋ５４００）、全光線透過率（ＪＩＳ　Ｋ７１０５）、ヘイズ（ＪＩＳ　Ｋ７１０５）、黄色度（ＪＩＳ　Ｋ７１０５）、及び水接触角についての初期物性を調べると共に、４ｃｍ×４ｃｍにカットして超促進耐候性試験機（ダイプラウインテイス社製アイスーパーＵＶテスター）にセットし、９６時間、２８８時間、及び４８０時間経過後の外観を観察すると共に、黄色度及び水接触角の測定を行った（超促進耐候性試験）。
なお、水接触角については、各透明試験板の表面に０．０２ｃｃの脱イオン水を滴下し、接触角測定装置（協和化学社製：ＣＯＮＴＡＣＴ−ＡＮＧＬＥＭＥＴＥＲ　ＣＡ−Ａ）を使用し、２０℃での水滴の接触角を測定した。接触角の値が小さいと親水性が高いことを示す。
【００４６】
また、得られた他方の試験片を用い、図１に示すように縦方向の中心部を境に４５度だけ折り曲げ、垂直に設置した屋外暴露架台にセットし、１ヶ月後、３ヶ月後、６ヶ月後、及び１２ヶ月後にそれぞれ垂直部の雨筋発生状態を目視で観察し、◎：雨筋が全く認められない、○：痕跡程度の雨筋が認められる、△：雨筋が僅かに認められる、及び×：雨筋がはっきりと認められる、の４段階で評価した（屋外暴露試験）。
結果を表２及び表３に示す。
【００４７】
実施例９
透明成形品として縦３０ｃｍ×横２０ｃｍ×厚さ１５０μｍの大きさの透明なＰＥＴフィルムを用い、上記各実施例と同様にしてＰＥＴフィルム上にプライマー組成物を塗布し、５分間セッティングした後に１４０℃、２０分の条件で硬化させてプライマー層を積層した。また、このプライマー層の上に、上記各実施例と同様にしてコーティング組成物を塗布し、表面防汚層を積層し、透明試験フィルムを得た。
得られた透明試験フィルムについて、上記各実施例と同様にして初期物性、超促進耐候性試験、及び屋外暴露試験を行った。
結果を表２に示す。
【００４８】
【表２】

【００４９】
【表３】

【００５０】
【発明の効果】
本発明の透明樹脂成形品用表面処理剤によれば、透明樹脂成形品の表面に、当該透明樹脂成形品本来の透明性に悪影響を及ぼすことがなく、優れた耐久性や防汚性を発揮せしめることができる。
【図面の簡単な説明】
【図１】図１は、屋外暴露試験で用いられた試験片の形状を示す説明図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface treatment agent for a transparent resin molded article which can impart excellent durability and antifouling property to the surface of the transparent resin molded article without impairing its transparency.
[0002]
[Prior art]
In recent years, roofs such as carports and terraces of detached houses, noise barriers on highways, greenhouses for agricultural and horticultural use, curved mirrors, display boards for advertisements, etc. Accordingly, transparent resin molded products formed into a plate shape, a sheet shape, a film shape, and other various unique shapes with an acrylic resin, a polycarbonate resin, a polyester resin, and the like are frequently used. This is a comparatively low cost in addition to the properties that synthetic resin originally has, such as relatively light weight, easy to process and hard to corrode, and the advantages such as appearance and daylighting of the transparent resin were evaluated. It is a result, and this trend is expected to continue in the future.
[0003]
However, when this type of resin molded product is used in an outdoor environment where light, oxygen, water, earth and sand are involved in a complex manner, physical properties such as gloss, strength, elongation and the like are deteriorated in a relatively short time, and coloring is performed. Defect phenomena such as cracks, peeling, and reduced transparency occur. In particular, in the case of a transparent resin molded product, in addition to these physical property deteriorations and defect phenomena, surface contamination becomes remarkable, and cleaning is difficult. It is not unusual to have an unsightly appearance.
[0004]
Therefore, in such a transparent resin molded article, a method of adding a durability improver such as an ultraviolet absorber or a stabilizer to the resin itself, a method of coating and protecting a certain transparent resin on the surface of the molded article, Further, the endurance has been improved by, for example, a method of coloring in a range where the transparency is not impaired and making the state of deterioration less visible.
[0005]
However, in the method of adding a durability improver to a resin, there is a limit in compatibility between the resin and an ultraviolet absorber or a stabilizer of the durability improver. There are naturally limits to improving durability.
[0006]
Further, a method of coating the surface of a molded article with a transparent resin is also often performed. For example, an acrylic resin, a polyester resin, or a silicone resin to which an ultraviolet absorber or a light stabilizer is added is coated on the surface of the molded article by about 5 to 50 μm. It is actually practiced to protect the molded product by coating it with a thickness or attaching a film, but even in such a method, acrylic resin, polyester resin or silicone resin has the durability of the resin itself. Although it is not necessarily good in properties and can be expected to have a slight improvement in durability as compared with a non-coated one, it is in fact not a decisive factor.
[0007]
Further, recently, a combination of a titanium oxide having a photocatalytic function and a silicone resin-based material is used, and when oily dirt is attached, the oily dirt is easily decomposed by sunlight including ultraviolet rays and is easily adapted to water, or There has been proposed a coating material having a photocatalytic function that can be changed to a substance that is easily dissolved and can wash away dirt together with the rainwater when the water is hit by the rainwater. However, when this type of coating material is used by being applied to the surface of a transparent resin molded product, although it can impart hydrophilicity to the surface of the transparent resin molded product and exhibit antifouling properties, Due to the properties of titanium oxide having a photocatalytic function, the transparent resin molded product itself is easily attacked and deteriorated, causing defects such as coloring, cracking, peeling, and reduced transparency, and is required for resin molded products requiring transparency. Is not applicable.
[0008]
[Problems to be solved by the invention]
Accordingly, the present inventors have conducted intensive studies on a surface treatment agent for a transparent resin molded product that does not adversely affect the transparency of the transparent resin molded product itself and exhibit excellent durability and antifouling properties. Primer composition containing, on the surface of a resin molded product, a specific paint resin, that is, a solvent-soluble paint fluororesin, an adhesion-imparting agent, and an organosilicate and / or a partial hydrolyzate thereof (organosilicate compound) To form a primer layer, and found that the object can be achieved by a coating composition containing a hydrolyzate of an organosilicate on the primer layer, thereby completing the present invention.
[0009]
Accordingly, an object of the present invention is to provide a surface treatment agent for a transparent resin molded product that exhibits excellent durability and antifouling properties without adversely affecting the original transparency of the transparent resin molded product.
[0010]
[Means for Solving the Problems]
That is, the present invention provides (A) at least a fluorine resin for a solvent-soluble paint, an adhesion-imparting agent,
[0011]
Embedded image

[0012]
(Wherein, R ^{1 to} R ⁴ are an alkyl group having 1 to 10 carbon atoms or an allyl group or an aryl group having 6 to 24 carbon atoms, and may be the same or different from each other; and n is an integer of 1 or more), and an organosilicate compound consisting of an organosilicate and / or a partial hydrolyzate thereof, which is applied to the surface of a transparent resin molded article to form a transparent primer layer. And (B) an organosilicate obtained by hydrolyzing an organosilicate compound represented by the same general formula as the above general formula (1) and / or a partial hydrolyzate thereof in the presence of a hydrolysis catalyst. A surface for a transparent resin molded article comprising a silicate hydrolyzate and a coating composition applied to the primer layer to form a transparent surface antifouling layer It is a management agent.
[0013]
In the present invention, the fluororesin for the solvent-soluble paint constituting the primer composition is not particularly limited as long as it is conventionally used as this kind of fluororesin for the solvent-soluble paint, but is preferably used. One of a fluoroolefin structural unit in a repeating unit and a vinyl structural unit having one or more functional groups selected from a hydroxyl group, a carboxyl group, an ester group, and an ether group in the structural unit Or a fluororesin containing two or more, more preferably a chlorotrifluoroethylene structural unit in the repeating unit, an alkyl vinyl ester structural unit, an alkyl vinyl ether structural unit, a hydroxyalkyl vinyl ether structural unit, a fluoroalkyl vinyl ether structural unit, Crotonic acid or its hydroxyalkyl ester structural unit, al Nirukarubon acid structural unit, a fluorine resin having a one or more vinyl structural units selected from structural units or the like which is introduced by reaction with trialkoxy vinyl silane structural units succinic anhydride.
[0014]
Specific examples of this type of fluororesin for solvent-soluble paints include JP-B-60-21686, JP-B1-34,460, JP-B4-40,365, and JP-A-62-267. 7,767 and JP-A-3-231906, and more specifically, Sefral Coat (trade name of Central Glass Co., Ltd.) and Lumiflon (trade name of Asahi Glass Co., Ltd.) Fluoronate (trade name, manufactured by Dainippon Ink and Chemicals), Zafflon (trade name, manufactured by Toagosei Co., Ltd.), Zeffle (trade name, manufactured by Daikin Industries, Ltd.), and the like.
[0015]
Further, the organosilicate compound used in combination with the fluorine-containing resin for a solvent-soluble paint to constitute a primer composition is an organosilicate represented by the general formula (1) and / or a partial hydrolyzate thereof, With this primer composition, the adhesion between the transparent primer layer formed on the surface of the transparent resin molded article and the surface antifouling layer formed on the transparent primer layer is developed. As the organosilicate compound, specifically, when the substituents R ^{1 to} R ⁴ are, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert group -Butyl group, n-pentyl group, iso-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, vinyl group, phenyl group, toluyl group, xylyl group, naphthyl group, 1,5-dimethylnaphthyl group, etc. Compounds having one or more alkyl groups and / or aryl groups selected from
[0016]
As these organosilicate compounds, those whose substituents R ^{1 to} R ⁴ are preferably an alkyl group having 1 to ⁴ carbon atoms are preferable, and specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, Tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-2-methoxyethoxysilane, tetra-2-ethylhexyloxysilane, and the like, and water, an acid and a solvent are added to these organosilicates to partially hydrolyze them. A partial hydrolyzate obtained by decomposition and condensation can be exemplified. As this partial hydrolyzate, various products having different degrees of condensation, structures and alkoxy groups are commercially available. Specifically, ethyl silicate 40, ethyl silicate 40 containing an effective silica content in the range of 28 to 56% by weight HAS-6, HAS-10 obtained by dissolving and hydrolyzing 45, ethyl silicate 48, methyl silicate 51, methyl silicate 56, and tetraethoxysilane in ethanol and isopropyl alcohol (all trade names of Colcoat Co., Ltd.) ) And the like. Further, compounds obtained by reacting oligomers of these partially hydrolyzed condensates can also be used.
[0017]
Further, the adhesion-imparting agent added to the primer composition of the present invention is an adhesion between the surface of the transparent resin molded article and the transparent primer layer formed on the surface of the transparent resin molded article by the primer composition. It is a solvent-soluble resin having a function or action of imparting the property, and is required to be compatible with the fluororesin for the solvent-soluble paint to be used, and is preferably a solvent-soluble resin having a hydroxyl group in a molecule. More preferably, it is a solvent-soluble resin having the hydroxyl group and one or more functional groups selected from a carboxyl group, an ester group and an ether group. And about this solvent-soluble resin as an adhesion | attachment imparting agent, a hydroxyl value (solid) is 20-200 mgKOH / g, preferably 20-100 mgKOH / g, and an acid value (varnish) is 0 based on resin. It is 10 mgKOH / g, preferably 0-5 mgKOH / g. Specific examples of such an adhesion-imparting agent include an acrylic resin and a fluorine resin, and an acrylic resin is particularly preferable.
[0018]
The mixing ratio of the fluororesin for the solvent-soluble paint, the organosilicate compound and the adhesion-imparting agent constituting the primer composition of the present invention is such that the organosilicate compound is 0.1 part per 100 parts by weight of the fluororesin for the solvent-soluble paint. The amount is 5 to 60 parts by weight, preferably 1 to 40 parts by weight, and the adhesion promoter is 0.5 to 50 parts by weight, preferably 5 to 30 parts by weight. At this time, if the compounding ratio of the organosilicate compound is less than 0.5 parts by weight, the adhesion between the surface antifouling layer formed by the coating composition becomes insufficient, and if it exceeds 60 parts by weight, the resin When the mixing ratio of the adhesion promoter is less than 0.5 part by weight, the adhesion of the transparent resin molded article to the surface of the molded article becomes insufficient, and when it exceeds 50 parts by weight. , The durability is greatly reduced.
[0019]
About this primer composition, in addition to the above-mentioned fluorine resin for solvent-soluble paint, an organosilicate compound, and an adhesion promoter, on the assumption that transparency of the primer composition is ensured, the same as in the case of ordinary paints Coloring agents, ultraviolet absorbers, light stabilizers, curing agents, belling agents, curing catalysts, solvents, matting agents, heat-insulating fillers, and the like can be appropriately selected and added as needed.
[0020]
The UV absorber added for this purpose may be any of an organic type and an inorganic type, but preferably has excellent compatibility with the fluororesin for the solvent-soluble paint used, and has high transparency. It is more preferable to use an organic ultraviolet absorber in order to ensure the above, and among them, a benzophenone-based, benzotriazole-based, acrylic-based ultraviolet absorber and the like are suitably used. The amount of the ultraviolet absorber added is usually in the range of 0.5 to 20 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the fluorine resin for solvent-soluble paint, and 0.5 parts by weight. If the amount is less than the above, the effect of adding the ultraviolet absorber is not exhibited. Conversely, if the amount is more than 20 parts by weight, it becomes difficult to ensure compatibility, and it may gradually exude after use to deteriorate the appearance. .
[0021]
Examples of the light stabilizer include hindered amine-based, benzoate-based, and benzotriazole-based light stabilizers, and are preferably hindered amine-based light stabilizers. The amount is usually in the range of 0.1 to 5 parts by weight, preferably 0.1 to 3 parts by weight based on parts. When the amount is less than 0.1 part by weight, the effect of adding the light stabilizer is not exhibited. On the other hand, when the amount is more than 5 parts by weight, it is difficult to ensure compatibility, and the stain gradually disappears after use. There is a problem that the appearance is deteriorated.
[0022]
Further, the curing agent varies depending on the type of the fluorine resin for the solvent-soluble coating used, but various types having reactivity to hydroxyl groups, such as amino resins, polyisocyanate compounds, and blocked polyisocyanate compounds. Curing agents can be used.
[0023]
Here, as the amino resin, any one can be used as long as it is used for paints, and particularly typical examples include, for example, melamine, urea, acetoguanamine, benzoguanamine, sterguanamine, and Condensation products obtained by reacting an amino group-containing compound such as spiroganamin with an aldehyde compound such as formaldehyde, paraformaldehyde, acetylaldehyde and glyoxal, and etherification of these various condensation products with monohydric alcohols. And the like.
[0024]
Particularly typical examples of the polyisocyanate compound include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate, isophorone diisocyanate, and methylcyclohexane-2,4-diisocyanate. Alicyclic diisocyanates such as methylcyclohexane-2,6-diisocyanate, 4,4-methylenebis (cyclohexylisocyanate), and 1,3-di (isocyanatomethyl) cyclohexane, and these diisocyanates and polyhydric alcohols or Adducts (adducts) with low molecular weight hydroxyl group-containing polymers and the like, and reaction products of the above diisocyanates with a burette agent such as water or tertiary alcohols Biuret) or trimers of the above diisocyanates (isocyanurates), and the like.
[0025]
Further, as the above-mentioned blocked polyisocyanate compound, particularly typical ones include, for example, those obtained by blocking the above-mentioned various polyisocyanate compounds with a known blocking agent. Examples of the blocking agent used for this purpose include, for example, oxime compounds such as methyl ethyl ketoxime and methyl isobutyl ketone oxime, and lactam compounds such as ε-caprolactam, acetanilide, and the like. Active compounds such as amide compounds such as octylic acid anilide and various compounds having so-called active hydrogen atoms such as alcohols such as isopropyl alcohol and n-butyl alcohol, as well as active hydrogen atoms by compatible isomerism such as acetylacetone and ethyl acetoacetate. The resulting compound can be exemplified.
[0026]
When curing using various polyisocyanate compounds as described above, a known catalyst such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctate, or the like can be added to accelerate the curing. In addition, various organic metal compounds such as cobalt naphthenate and zinc naphthenate, and various basic compounds such as triethylenediamine and 1,8-diazabicyclo- (5,4,0) -undecene-7 (DBU) are also included. It can be used as a catalyst. Furthermore, these curing catalysts can be used alone or in combination of two or more.
[0027]
For the amount of the curing agent added, for example, in the case of polyisocyanates, the molar ratio (OH / NCO) of the hydroxyl group (OH) in the solvent-soluble fluororesin to the isocyanate group (NCO) in the curing agent is used. ) Is in the range of 0.2 to 3.0, preferably 0.5 to 2.0. If the molar ratio (OH / NCO) is lower than 0.2, the remaining isocyanate groups become too large and the weather resistance is lowered. On the other hand, if the molar ratio (OH / NCO) is higher than 3.0, the free hydroxyl groups become too large and the coating is stopped. The curability and stain resistance of the film are poor, which is not preferable. When the molar ratio (OH / NCO) is in the range of 0.5 to 2.0, particularly around 1.0, the coating film becomes the most favorable in terms of curability, weather resistance, stain resistance and the like. .
[0028]
As the solvent used in the primer composition of the present invention, various solvents can be used, and it is preferable to select the solvent according to the type of resin of a molded article to which the primer composition is applied. When the resin of the product is relatively excellent in chemical resistance like acrylic resin or polyester resin, it is possible to use a so-called urethane paint thinner mainly composed of an aromatic compound such as toluene and xylene. Further, when the resin of the molded article is relatively poor in chemical resistance such as polycarbonate, it is necessary to select and use a specific solvent, and examples thereof include aliphatic esters such as ethyl acetate and butyl acetate. be able to. Further, as a diluting solvent used at the time of coating or coating, aliphatic ketones such as acetone, methyl ethyl ketone and diisobutyl ketone, alcohols such as ethyl alcohol, isopropyl alcohol and n- (i-, t-) butyl alcohol, And cyclic ethers such as ethylene oxide, tetrahydrofuran and dioxane.
[0029]
In the present invention, the hydrolyzate of the organosilicate constituting the coating composition is obtained by hydrolyzing an organosilicate having the same general formula as the above general formula (1) and / or an organosilicate compound composed of a partial hydrolyzate thereof. It is obtained by hydrolysis in the presence of a medium. Here, the organosilicate compound for obtaining the organosilicate hydrolyzate of the coating composition may be the same as or different from the organosilicate compound constituting the primer composition.
[0030]
As for the hydrolysis reaction of the organosilicate compound, it suffices that the organosilicate compound be consequently substantially completely hydrolyzed. Preferably, in the presence of a hydrolysis catalyst, the Si atoms in the organosilicate are converted to 100 equivalent to SiO _2. 60 parts by weight or more and 600 parts by weight or less, preferably 120 parts by weight or more and 400 parts by weight or less with water having a hydrolyzed water content of not more than 120 parts by weight, and then a water-containing diluent is added to the obtained hydrolysis reaction product. After the addition and adjustment, the water content is adjusted so that the water content is 600 to 4000 parts by weight, preferably 1,000 to 3,500 parts by weight, based on 100 parts by weight of Si atoms in the organosilicate in terms of SiO _2. Is good. When the hydrolysis water content is less than 60 parts by weight, the hydrolysis does not proceed sufficiently, the desired hydrophilicity cannot be obtained, and the antifouling property cannot be obtained from the initial stage. Easily gels. If the water content after the adjustment is less than 600 parts by weight, the alkoxy group may ultimately remain and the desired hydrophilicity may not be obtained. Conversely, if the amount is more than 4000 parts by weight, the storage stability may decrease. There is a problem that the product life is shortened.
[0031]
The above-mentioned amount of hydrolyzed water refers to the amount of all water present in the reaction system and involved in the hydrolysis reaction when hydrolyzing the organosilicate, and is added as a reactant to the hydrolysis reaction system. It refers not only to water but also to the total amount of water including water introduced into the hydrolysis reaction system together with the acid catalyst or with the reaction solvent. As the water-containing diluent used for adjusting the water content of the hydrolyzate of the organosilicate, ethyl alcohol, isopropyl alcohol, n-isopropyl alcohol preferably containing a predetermined amount of water in consideration of dispersibility and solubility. Alcohols such as (i-, t-) butyl alcohol are desirable.
[0032]
The hydrolysis catalyst used in the hydrolysis reaction is not particularly limited, but preferably includes mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid, and organic acids such as formic acid and acetic acid. The amount of the hydrolysis catalyst to be used is usually 0.01 to 5% by weight, preferably 0.05 to 2% by weight in the reaction system. If the amount is less than 5% by weight, the hydrolysis rate will be low, and the desired hydrophilicity cannot be obtained due to the remaining alkoxy group. Conversely, if the amount exceeds 5% by weight, gelation tends to occur during synthesis.
[0033]
Regarding the transparent resin molded article to which the surface treatment agent of the present invention is applied, there is no particular limitation on what kind of resin it is molded into and in what shape, but the primer composition of the present invention It is preferable to have excellent adhesiveness with the solvent-soluble paint fluororesin constituting the product, for example, an acrylic resin, a polyester resin, a polycarbonate resin, a polystyrene resin, and the like. Examples of the shape include a sheet shape, a film shape, a plate shape, a pipe shape, and other shapes specific to molded articles.
[0034]
Regarding the method of applying the surface treatment agent of the present invention to the surface of such a transparent resin molded product, first, a primer composition is applied to the surface of the transparent resin molded product, dried to form a primer layer, and then the primer layer is formed. It is only necessary to apply a coating agent on the layer and dry it to form a surface antifouling layer, and there is no particular limitation on the method of applying the primer composition or the coating composition, for example, air spray, airless spray, curtain In addition to a general coating method such as a flow coater, a roll coater, a gravure coat, and a reverse coat, hand coating such as brush coating is also possible, and a drying method may be room temperature drying or heat drying. Heat drying can provide a dried film in a shorter time.
[0035]
The surface-treated transparent resin molded article formed by using the surface treatment agent of the present invention comprises (a) at least a fluorine resin for a solvent-soluble paint, an adhesion promoter, A transparent primer layer formed by applying a primer composition comprising an organosilicate represented by the formula (1) and / or an organosilicate compound comprising a partial hydrolyzate thereof to the surface of the molded article; Including a hydrolyzate of an organosilicate obtained by hydrolyzing an organosilicate compound represented by the same general formula as the formula (1) and / or a partial hydrolyzate thereof in the presence of a hydrolysis catalyst. A transparent surface antifouling layer formed by applying the coating composition on the transparent primer layer.
[0036]
And about the film thickness of the primer layer and the surface antifouling layer formed on the surface of the transparent resin molded article by the surface treatment agent of the present invention, the primer layer is usually 5 to 40 μm, preferably 10 to 30 μm, The surface antifouling layer has a thickness of usually 0.01 to 3 μm, preferably 0.05 to 1 μm. If the thickness of the primer layer is thinner than 5 μm, the blocking of ultraviolet light, which is the main cause of deterioration, is not sufficient, and peeling, problems such as yellowing are likely to occur, and if it is thicker than 40 μm, it is not only uneconomical, It takes a long time to cure, which is not preferable. On the other hand, if the thickness of the surface antifouling layer is less than 0.01 μm, it becomes difficult to impart antifouling properties immediately after coating, and if it is more than 3 μm, fine cracks may occur after the solvent is scattered.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described based on examples and comparative examples.
[0038]
[Preparation of Formulation Examples A to G of Primer Composition]
Sefural coat A202B (trade name, manufactured by Central Glass Co .; solid content concentration: 50% by weight, hydroxyl value (solid): 56 mg KOH / g, acid value (varnish): 4 mg KOH / g, solvent: acetic acid) as a fluorine resin for solvent-soluble paint Butyl) and Sefral coat A402B (trade name, manufactured by Central Glass Co .; solid content concentration: 55% by weight, hydroxyl value (solid): 45 mg KOH / g, acid value (varnish): 4 mg KOH / g, solvent: butyl acetate) A low-condensation product of ethyl silicate (trade name: ES-48, manufactured by Tama Chemical Industry Co., Ltd.) as a compound, and Acrydik A-811 (trade name, manufactured by Dainippon Ink and Chemicals, Inc .; solids concentration: 50% by weight, hydroxyl group) Value (solid): 34 mg KOH / g, acid value (varnish): 4 mg KOH / g, solvent: butyl acetate / key Len) or AR8028-3 (trade name, manufactured by Tokusekisho Kogyo KK; solid content concentration: 45% by weight; hydroxyl value (solid): 65 mg KOH / g; acid value (varnish): 3 mg KOH / g; solvent: ethyl acetate / toluene) ) As a UV absorber and a benzotriazole UV absorber (trade name: Biosorb 591 manufactured by Kyodo Yakuhin Co., Ltd. or trade name: Tinuvin 900 manufactured by Ciba Geigy) and a hindered amine light stabilizer (manufactured by Sankyo) as a light stabilizer. Trade name: SANOL LS292) as a curing agent, isocyanate-based curing agent [trade name: Coronate HX (solid content: 100% by weight, NCO ratio: 21.3%) manufactured by Nippon Polyurethane Co., Ltd.] or trade name manufactured by Sumitomo Bayer Urethane Co., Ltd. : Dismodule BL3175 (solid content: 75% by weight, NCO ratio: 11.1%, solvent: solvent) Using Fusa)], respectively, the formulation examples A~G of primer compositions were prepared by blending such that the solid concentration shown in Table 1.
[0039]
[Table 1]

[0040]
(Preparation of coating composition)
Preparation Example A
A three-necked flask having a capacity of 1500 ml was charged with 40 g of an oligomer of ethyl silicate having an average degree of polymerization of 4 to 5 (trade name: ES-40, manufactured by Tama Chemical Industry Co., Ltd.) and 88 g of ethanol. 21.6 g and 28 g of a 6 wt% -nitric acid aqueous solution as a catalyst were added, reacted under heating and reflux for 4 hours, and then cooled to obtain a hydrolysis reaction product. Then, a water-containing diluent obtained by sufficiently mixing 190 g of isopropyl alcohol and 432 g of pure water was added to the obtained hydrolysis reaction product, and mixed well with stirring to obtain a coating of Preparation Example A. A composition was prepared.
The total water content of the hydrolyzed water content and the water content derived from the water-containing diluent in Preparation Example A is 3000 parts by weight based on 100 parts by weight of Si atoms in the organosilicate in terms of SiO ₂ .
[0041]
Preparation Example B
Except that 31.4 g of an oligomer having an average polymerization degree of 3 to 4 of methyl silicate (trade name: MS-51, manufactured by Tama Chemical Industry Co., Ltd.) was used instead of the oligomer having an average polymerization degree of 4 to 5 of ethyl silicate. The coating composition of Preparation Example B was prepared in the same manner as in Preparation Example A.
The total water content of the hydrolysis water content and the water content derived from the water-containing diluent in Preparation Example B is 3000 parts by weight based on 100 parts by weight of Si atoms in the organosilicate in terms of SiO ₂ .
[0042]
Preparation Example C
A coating composition of Preparation Example C was prepared in the same manner as in Preparation Example A, except that 190 g of isopropyl alcohol was used as a diluent instead of the water-containing diluent used in Preparation Example A.
The total water content of the hydrolyzed water content and the water content derived from the water-containing diluent in Preparation Example C is 300 parts by weight based on 100 parts by weight of Si atoms in the organosilicate in terms of SiO ₂ .
[0043]
Examples 1 to 8 and Comparative Examples 1 to 5
A transparent acrylic resin plate (manufactured by Sumitomo Chemical Co., Ltd.) or a polycarbonate plate (manufactured by Nippon Polyester) measuring 30 cm long × 20 cm wide × 5 mm thick is used as a transparent resin molded product. A solution obtained by adding 30 parts by weight of diisobutyl ketone to 100 parts by weight of the primer compositions A to G is sprayed with an air spray so that the film thickness becomes 20 μm after drying, and set at room temperature for 5 minutes, Next, the resin was cured in an oven at 80 ° C. for 30 minutes for an acrylic resin plate and at 120 ° C. for 30 minutes for a polycarbonate plate, thereby forming a 20 μm-thick primer layer on the surface.
[0044]
Next, in the case of each of Examples 1 to 8 and Comparative Examples 1 and 4, the coating composition obtained in Preparation Examples A to C was air-sprayed on the primer layer of the acrylic resin plate or the polycarbonate plate. Spraying at a spraying rate of 30 g / m ² at 50 ° C. and drying for 30 minutes. After drying, a transparent surface antifouling layer having a thickness of 0.6 μm was formed to prepare a transparent test plate. In the case of Comparative Examples 2, 3 and 5, an acrylic resin plate or a polycarbonate plate having the primer layer was used as a transparent test plate.
[0045]
Each of the obtained transparent test plates was divided into two in the longitudinal direction, and one of the obtained test pieces was used to determine the adhesiveness (cross-cut adhesive tape test; JIS K5400), total light transmittance (JIS K7105), haze ( The initial physical properties of JIS K7105), yellowness (JIS K7105), and water contact angle were examined, and cut into 4 cm x 4 cm, and set on a super-accelerated weather resistance tester (Eye Super UV tester manufactured by Diplowince Inc.). , 96 hours, 288 hours, and 480 hours, and the yellowness and the water contact angle were measured (super-accelerated weather resistance test).
For the water contact angle, 0.02 cc of deionized water was dropped on the surface of each transparent test plate, and the contact angle was measured at 20 ° C. using a contact angle measuring device (manufactured by Kyowa Chemical Co., Ltd .: CONTACT-ANGLEMETER CA-A). The contact angle of a water drop was measured. When the value of the contact angle is small, it indicates that the hydrophilicity is high.
[0046]
In addition, using the other obtained test piece, as shown in FIG. 1, bent at 45 degrees around the center in the vertical direction, and set it on an outdoor exposure stand installed vertically, and after one month and three months, After 6 months and 12 months, the appearance of the rain streaks in the vertical portions was visually observed. そ れ ぞ れ: No rain streaks were observed at all, ○: Traces of rain streaks were observed, Δ: Slight rain streaks Recognized, and ×: Rain streak was clearly recognized, and evaluated in four stages (outdoor exposure test).
The results are shown in Tables 2 and 3.
[0047]
Example 9
Using a transparent PET film having a size of 30 cm (length) × 20 cm (width) × 150 μm (thickness) as a transparent molded product, the primer composition was applied on the PET film in the same manner as in each of the above Examples, and set for 5 minutes. After curing for 20 minutes, a primer layer was laminated. Further, on this primer layer, a coating composition was applied in the same manner as in each of the above Examples, and a surface antifouling layer was laminated to obtain a transparent test film.
The obtained transparent test film was subjected to initial physical properties, a super-accelerated weather resistance test, and an outdoor exposure test in the same manner as in each of the above Examples.
Table 2 shows the results.
[0048]
[Table 2]

[0049]
[Table 3]

[0050]
【The invention's effect】
According to the surface treatment agent for a transparent resin molded product of the present invention, the surface of the transparent resin molded product does not adversely affect the original transparency of the transparent resin molded product, and exhibits excellent durability and antifouling properties. I can do it.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing the shape of a test piece used in an outdoor exposure test.

Claims (7)

(A) At least a fluorine resin for a solvent-soluble paint, an adhesion-imparting agent, and the following general formula (1)

(Wherein, R ^{1 to} R ⁴ are an alkyl group having 1 to 10 carbon atoms or an allyl group or an aryl group having 6 to 24 carbon atoms, and may be the same or different from each other; n is an integer of 1 or more), and an organosilicate compound consisting of an organosilicate and / or a partial hydrolyzate thereof, which is applied to the surface of a transparent resin molded article to form a transparent primer layer. When,
(B) an organosilicate obtained by hydrolyzing an organosilicate compound represented by the same general formula as the above general formula (1) and / or a partial hydrolyzate thereof in the presence of a hydrolysis catalyst; A coating composition comprising a hydrolyzate and being applied on the primer layer to form a transparent surface antifouling layer. The surface treating agent for a transparent resin molded product according to claim 1, wherein the fluororesin for a solvent-soluble coating material constituting the primer composition has a hydroxyl group in a molecule. The transparent resin according to claim 2, wherein the fluorine resin for a solvent-soluble coating material constituting the primer composition has one or more functional groups selected from a carboxyl group, an ester group and an ether group in a molecule. Surface treatment agent for molded products. The surface treating agent for a transparent resin molded product according to any one of claims 1 to 3, wherein the adhesion imparting agent added to the primer composition is an acrylic resin having a hydroxyl group and / or a carboxyl group in a molecule. The surface treatment agent for a transparent resin molded product according to any one of claims 1 to 4, wherein the primer composition contains one or more additives selected from an ultraviolet absorber, a light stabilizer, and a curing agent. The hydrolyzate of the organosilicate constituting the coating composition is obtained by converting the organosilicate compound to a hydrolyzed water content of 60 to 600 parts by weight with respect to 100 parts by weight of Si atoms in the organosilicate in terms of SiO _{2 in} the presence of an acid catalyst. After hydrolyzing with water, and then adding a water-containing diluent to the resulting hydrolysis reaction product, the water content is adjusted to 600 to 4000 parts by weight based on 100 parts by weight of Si atoms in the organosilicate in terms of SiO _2. The surface treating agent for a transparent resin molded product according to any one of claims 1 to 5, which is obtained by adjusting the water content as described above. The surface treating agent for a transparent resin molded product according to any one of claims 1 to 6, wherein the transparent resin molded product is an acrylic resin, a polycarbonate resin, or a polyester resin.

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