JPWO2003006565A1 - Fluorine-containing paint compositions, coatings and painted products - Google Patents

Abstract

An object of the present invention is to form an arbitrary fluororesin on a surface by a one-coat method with a thickness comparable to that of a two-coat method, and to expand a combination range of two layers limited by a conventional surface tension. Coating compositions that can be applied to a wide range of applications, and that can provide a coating film having high adhesion to an object to be coated, corrosion resistance, abrasion resistance, heat resistance, non-adhesion and transparency. Provide painted objects.
A fluorine-containing coating composition obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm.

Description

（式中、Ｘ^１及びＸ^２は同一又は異なって、水素原子又はフッ素原子であり、Ｒｆ^１は炭素数１〜４０の二価のアルキレン基又は炭素数１〜４０のエーテル結合を有する二価の含フッ素アルキレン基であり、Ｙはメチロール基、カルボキシル基、塩を形成しているカルボキシル基、アルコキシカルボニル基又はエポキシ基であり、上記メチロール基は炭素原子に結合する水素原子の１個又は２個が−ＣＦ_３により置換されていてもよい）で表される含フッ素エチレン性単量体であることが好ましい。
このような官能基含有含フッ素エチレン性単量体（ａ）としては特に限定されず、例えば、下記式

で表される化合物等が例示される。
上記官能基含有含フッ素エチレン性単量体（ａ）としては、官能基の安定性及び種々の被塗装物との接着性の点から、上記一般式（１）におけるＹがメチロール基であるものがより好ましい。
上記官能基含有含フッ素エチレン性単量体（ａ）としては、１種又は２種以上を用いることができ、上記官能基が同一である上記官能基含有含フッ素エチレン性単量体（ａ）を１種又は２種以上用いてもよいし、用いる２種以上の上記官能基含有含フッ素エチレン性単量体（ａ）が含有する上記官能基がそれぞれ異なっていてもよい。
上記官能基非含有含フッ素エチレン性単量体（ｂ）は、上記官能基含有含フッ素エチレン性単量体（ａ）が含有する上記官能基を有しないものであり、炭素原子に直接結合するフッ素原子を有するビニル基含有単量体である。
上記官能基非含有含フッ素エチレン性単量体（ｂ）としては、このようなものであれば特に限定されないが、例えば、テトラフルオロエチレン、下記一般式（２）

（式中、Ｒｆ^２は−ＣＦ_３又は−ＯＲｆ^３である。Ｒｆ^３は炭素数１〜５のパーフルオロアルキル基である。）で表される化合物等のパーフルオロオレフィン又はパーフルオロ（アルキルビニルエーテル）；クロロトリフルオロエチレン等のフッ素及びフッ素以外のハロゲンを有するパーハロオレフィン；
ビニリデンフルオライド、フッ化ビニル、ヘキサフルオロイソブテン、下記一般式

（式中、Ｘ^３は水素原子、フッ素原子又は塩素原子であり、ｎは１〜５の整数である。）で表される化合物、下記一般式

（式中、Ｘ^３は水素原子、フッ素原子又は塩素原子であり、ｍは１〜５の整数である。）で表される化合物等の水素を有するハロゲン化オレフィン等が挙げられる。
上記官能基非含有含フッ素エチレン性単量体（ｂ）としては、１種又は２種以上を用いることができる。
上記官能基非含有含フッ素エチレン性単量体（ｂ）としては、得られる塗膜と被塗装物との接着性が優れる点から、テトラフルオロエチレン、上記一般式（２）で表されるパーフルオロオレフィン、及び、パーフルオロ（プロピルビニルエーテル）等の上記一般式（２）で表されるパーフルオロ（アルキルビニルエーテル）が好ましい。
上記官能基非含有含フッ素エチレン性単量体（ｂ）としては、得られる塗膜と被塗装物との接着性が特に優れる点から、テトラフルオロエチレンと、上記一般式（２）で表されるパーフルオロオレフィン又は上記一般式（２）で表されるパーフルオロ（アルキルビニルエーテル）とを組み合わせることがより好ましい。この場合、上記テトラフルオロエチレンのモル数が、上記テトラフルオロエチレンのモル数及び上記一般式（２）で表されるパーフルオロオレフィン又はパーフルオロ（アルキルビニルエーテル）のモル数の合計の８５〜９９．７％であることが好ましい。
上記官能基含有含フッ素エチレン性単量体（ａ）のモル数は、上記官能基含有含フッ素エチレン性単量体（ａ）のモル数及び上記官能基非含有含フッ素エチレン性単量体（ｂ）のモル数の合計の０．０５〜３０％であることが好ましい。上記官能基含有含フッ素エチレン性単量体（ａ）のモル数が０．０５％未満であると、得られる塗膜と被塗装物との密着力が低下しやすく、３０％を超えると、本発明の含フッ素塗料組成物の塗布後における焼成時に発泡が激しくなり、塗膜欠陥が出やすい。より好ましい上限は１０％、更に好ましい上限は５％である。
上記含フッ素高分子は、上記官能基含有含フッ素エチレン性単量体（ａ）と上記官能基非含有含フッ素エチレン性単量体（ｂ）に加えて、耐熱性を低下させない範囲内で、フッ素原子を有さないエチレン性単量体を共重合してもよい。この場合、フッ素原子を有さないエチレン性単量体は、耐熱性を低下させないために炭素数５以下のエチレン性単量体から選ばれることが好ましく、具体的にはエチレン、プロピレン、１−ブテン、２−ブテン等が挙げられる。
上記含フッ素高分子の粒子は、コア／シェル形の構造をとっているものであってもよい。上記コア／シェル形の構造としては、コア部分が上記官能基非含有含フッ素エチレン性単量体（ｂ）を重合させて得られる高分子鎖からなり、シェル部分が上記官能基含有含フッ素エチレン性単量体（ａ）と上記官能基非含有含フッ素エチレン性単量体（ｂ）とを共重合させて得られる高分子鎖からなる粒子であってもよい。コア部分の単量体成分は上記官能基含有含フッ素エチレン性単量体（ａ）を含有しないことが好ましい。このように官能基をシェル部分のみに導入することにより、用いる上記官能基含有含フッ素エチレン性単量体（ａ）を少量化することができ、経済的である。このようなコア／シェル形の構造は、例えば特開平４−１５４８４２号公報、特開平５−２７９５７９号公報等に記載されているような公知の方法を用いてシード重合すること等により、得ることができる。
上記含フッ素高分子としては、官能基含有フッ素樹脂であってもよい。上記官能基含有フッ素樹脂は、単量体成分として、上記含フッ素ビニル単量体の１種又は２種以上、及び、側鎖末端にヒドロキシル基、カルボニル基等の官能基を有する単量体を含み、共重合することにより得られるものである。上記含フッ素高分子は、上記官能基含有フッ素樹脂であると、上記側鎖末端の官能基が反応するので、架橋による硬化や、被塗装物との化学的結合を生じることによる接着性向上を可能にすることができる。
上記含フッ素高分子としては、少なくとも２００℃において耐熱性を有するものであることが好ましい。２００℃未満の温度で耐熱性を有しないものである場合、耐熱性、高温における柔軟性や耐久性が求められる用途に本発明の含フッ素塗料組成物を好適に用いることが困難となる。上記含フッ素高分子は、本発明の含フッ素塗料組成物の塗布後の焼成温度、塗膜形成後の使用温度に鑑み、通常、２００〜３５０℃で耐熱性を有するものであればよい。
上記含フッ素高分子は、このように耐熱性に優れたものであることにより、非フッ素系の官能基含有単量体を共重合して得られる共重合体と異なり、上述のように官能基を含有していても、本発明の含フッ素塗料組成物を塗布した後に例えば２００〜３５０℃等の高温で焼成する際であっても、熱分解性が低い。
本発明の含フッ素塗料組成物は、このように熱分解性が低いので、上記官能基を有する耐熱性の含フッ素高分子により、被塗装物との接着力が高く、着色、発泡、ピンホール、レベリング不良等のない塗膜を得ることができる。また、得られる塗装物を高温下で使用する場合であっても、塗膜は被塗装物との接着性を維持し、着色、白化、発泡、ピンホール等の塗膜欠陥を生じにくい。
上記含フッ素高分子としては、上述のように広範な材料を用いることができるので、本発明の含フッ素塗料組成物は応用範囲の広いものである。
上記含フッ素高分子は、上述のように、平均粒子径が０．００５〜０．５μｍである。上記含フッ素高分子としては、上記塗膜の下層部の充填性を高め、被塗装物との接着性を向上させることができる点から、平均粒子径が０．００５〜０．３μｍであって、被塗装物と化学的に結合することができる官能基を有するものが好ましい。この場合、上記官能基としては、ヒドロキシル基、カルボキシル基、塩を形成しているカルボキシル基、アルコキシカルボニル基及び／又はエポキシ基が好ましく、これらの官能基は、これらの官能基を有する上記官能基含有含フッ素エチレン性単量体（ａ）を単量体成分として共重合することにより導入したものであることがより好ましい。
上記含フッ素高分子の平均粒子径が０．００５〜０．３μｍである場合、本発明の含フッ素塗料組成物において、上記含フッ素高分子が被塗装物と化学的に結合することができる官能基を有するものであり、上記溶融性フッ素樹脂の平均粒子径が１〜１０００μｍであることが好ましい。この場合、上記含フッ素高分子の平均粒子径としては、より好ましい下限は０．０１μｍであり、より好ましい上限は０．１５μｍである。
上記溶融性フッ素樹脂及び上記含フッ素高分子は、液状媒体に分散したものであることが好ましい。上記液状媒体としては、通常、溶剤として用いられているものを用いる。本発明の含フッ素塗料組成物は、上記溶剤としては、通常、水又は水溶性溶剤を含むものが、環境問題等で好ましい。上記水溶性溶剤は、水溶性の有機溶剤である。上記溶剤としては、水及び水溶性溶剤の混合物、並びに、水がより好ましい。
上記水溶性溶剤は、上記溶融性フッ素樹脂を濡らす働きを有する。上記水溶性溶剤は、高沸点のものである場合、上記溶融性フッ素樹脂を濡らすことに加え、本発明の含フッ素塗料組成物を塗布した後乾燥する際に上記溶融性フッ素樹脂相互間、上記含フッ素高分子相互間、及び／又は、上記溶融性フッ素樹脂と上記含フッ素高分子との間をつなぎ、クラックの発生を防止するための乾燥遅延剤としても作用する。上記水溶性溶剤が高沸点であっても、配合量が適当であれば、本発明の含フッ素塗料組成物の塗布後における焼成の温度において充分に揮発するので、得られる塗膜の耐熱性、非粘着性等の特性を低下させることはない。
上記水溶性溶剤としては特に限定されず、例えば、沸点が１００℃未満である低沸点有機溶剤としてメタノール、エタノール、イソプロパノール、ｓｅｃ−ブタノール、ｔ−ブタノール、アセトン、メチルエチルケトン等；沸点が１００〜１５０℃である中沸点有機溶剤としてトルエン、キシレン、メチルセロソルブ、エチルセロソルブ、メチルイソブチルケトン、ｎ−ブタノール等；沸点が１５０℃を超える高沸点有機溶剤としてＮ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、ケトシン、エチレングリコール、プロピレングリコール、グリセリン、ジメチルカルビトール、ブチルジカルビトール、ブチルセロソルブ、シクロヘキサノール、ジイソブチルケトン、１，４−ブタンジオール、トリエチレングリコール、テトラエチレングリコール等が挙げられる。上記高沸点有機溶剤としては、上記溶融性フッ素樹脂との濡れ性が良好であり、取扱いが容易である点から、アルコール系溶剤が好ましい。
これらの水溶性溶剤は、１種又は２種以上を用いることができる。上記水溶性溶剤は、塗膜の下層部の充填性を高め、下層部と上層部との層分離を促進し得る点から、上記高沸点有機溶剤を、上記低沸点有機溶剤及び／又は上記中沸点有機溶剤と混合して用いることが好ましい。
上記水溶性溶剤の配合量は、本発明の含フッ素塗料組成物における液状媒体の０．５〜５０％であることが好ましい。低沸点有機溶剤の場合、配合量が少なすぎると泡の抱き込みが起こりやすくなり、配合量が多すぎると本発明の含フッ素塗料組成物が全体として引火性となって水性分散組成物の利点が損なわれることがある。中沸点有機溶剤の場合、配合量が少なすぎると本発明の含フッ素塗料組成物を塗布した後の乾燥時に溶融性フッ素樹脂が粉末に戻り、造膜性がなくなることがあり、配合量が多すぎると焼成後の塗膜に残留して塗膜物性が低下することがある。高沸点有機溶剤の場合、配合量が多すぎると焼成後の塗膜に残留して塗膜物性が低下することがある。より好ましい下限は１％であり、より好ましい上限は４５％である。
上記水溶性溶剤の配合量に関し、本発明の含フッ素塗料組成物における液状媒体の量は、例えば上記含フッ素高分子を水性分散体として調製する場合における分散媒を含むものである。
本発明の含フッ素塗料組成物としては、上記塗膜の下層部を充分に充填することができ、被塗装物との接着性を高めることができる点から、平均粒子径が１〜１０００μｍである溶融性フッ素樹脂及び平均粒子径が０．００５〜０．３μｍである含フッ素高分子を液状媒体に分散してなる含フッ素塗料組成物であって、上記含フッ素高分子は、官能基含有含フッ素エチレン性単量体（ａ）及び官能基非含有含フッ素エチレン性単量体（ｂ）を共重合することにより得られるものであって、上記官能基含有含フッ素エチレン性単量体（ａ）は、官能基を有するものであり、上記官能基は、ヒドロキシル基、カルボキシル基、塩を形成しているカルボキシル基、アルコキシカルボニル基又はエポキシ基であり、上記官能基非含有含フッ素エチレン性単量体（ｂ）は、上記官能基を含有しないものであることが好ましい。
本発明の含フッ素塗料組成物としては、また、上記塗膜の下層部を充分に充填し、下層部と上層部との層分離を促進することができ、被塗装物との接着性を高めることができる点から、平均粒子径が１〜１０００μｍである溶融性フッ素樹脂及び平均粒子径が０．００５〜０．３μｍである含フッ素高分子を配合して得られるものであり、上記含フッ素高分子が被塗装物と化学的に結合することができる官能基を有するものであり、上記溶融性フッ素樹脂の固形分重量は、上記溶融性フッ素樹脂の固形分重量及び上記含フッ素高分子の固形分重量の合計の７０〜９９．９％であるものが好ましい。この場合、上記官能基としては、ヒドロキシル基、カルボキシル基、塩を形成しているカルボキシル基、アルコキシカルボニル基及び／又はエポキシ基が好ましく、これらの官能基は、これらの官能基を含有する上記官能基含有含フッ素エチレン性単量体（ａ）を単量体成分として共重合することにより導入したものであることがより好ましい。
上記平均粒子径の場合、上記溶融性フッ素樹脂の配合量が９９．９重量％を超えると、上記含フッ素高分子の配合量が少なすぎ、被塗装物との接着に寄与する官能基が全体として少なくなるので接着性が不充分となり、上記溶融性フッ素樹脂の配合量が７０重量％未満であると、上記含フッ素高分子の配合量が過剰になり、含フッ素高分子の粒子が被塗装物との接触面を充填し、更に積層することにより、被塗装物面上の粒子の官能基が、積層した粒子の官能基と反応して被塗装物との接着に寄与しないので、却って被塗装物との接着性が不充分となる。より好ましい下限は８０重量％であり、より好ましい上限は９８重量％である。
本発明の含フッ素塗料組成物は、上記溶融性フッ素樹脂及び上記含フッ素高分子と併用して、用途や必要に応じ、顔料、充填剤、粘度調整剤、増粘剤、造膜材、安定剤、分解促進剤、防錆剤、消泡剤等の種々の添加剤を配合することができる。これらの添加剤は、透明性の高い塗膜を得る点から、必要最小限の配合量にとどめることが好ましい。
本発明の含フッ素塗料組成物を調製する方法としては特に限定されず、例えば、従来公知の方法を用いることができ、例えば、上記溶融性フッ素樹脂、上記顔料、上記含フッ素高分子等を必要に応じて次のように前処理を施し、上記溶融性フッ素樹脂と上記含フッ素高分子が上述の容量比又は固形分重量比となるように適切な割合で混合して調製する。
本発明の含フッ素塗料組成物は、水溶性溶剤及び界面活性剤の存在下に、水に溶融性フッ素樹脂及び含フッ素高分子を均一に分散させることによって調製することができる。
上記溶融性フッ素樹脂としては、例えば特開昭６３−２７０７４０号公報記載の方法等により粉末を製造し、通常、適宜分散剤を用いて溶媒に分散させる。上記分散剤の用い方としては、例えば、上記溶融性フッ素樹脂を低級アルコール、ケトン、芳香族炭化水素等の溶剤で濡らした後、ノニオン系界面活性剤、アニオン系界面活性剤等の分散剤で分散させる方法等を用いることができる。
上記溶融性フッ素樹脂の配合量は、本発明の含フッ素塗料組成物の全体重量の１５〜８０％である。１５％未満であると、本発明の含フッ素塗料組成物の粘度が低くなって被塗装物に塗装してもタレを生じやすく、塗膜の膜厚が不充分となることがあり、８０％を超えると、本発明の含フッ素塗料組成物が流動しにくくなり、塗装が不可能となることがある。好ましい下限は２０％であり、好ましい上限は７５％である。上記溶融性フッ素樹脂の配合量は、塗装法や膜厚の調整等を考慮して上記範囲内で適宜選択すればよいが、スプレー塗装やディップ塗装等の場合は比較的低濃度とし、押しつけ塗装等の場合はペースト状となる５０％以上とすることが好ましい。
上記顔料は、通常、上記溶剤、上記含フッ素高分子、上記界面活性剤等をバスケットミル、ダイナモミル、ボールミル等の粉砕分散機で粉砕分散してから使用する。
上記含フッ素高分子は、平均粒子径が０．００５〜０．５μｍと小さいので、そのまま分散することができ、通常、乳化重合等で合成され、界面活性剤を用いて濃縮したものが用いられる。
本発明の含フッ素塗料組成物に用いることができる上記界面活性剤としては上記含フッ素塗料組成物中に本発明の含フッ素塗料組成物の全体重量の１５〜８０％の溶融性フッ素樹脂の粉末を均一に分散させ得るものであれば特に限定されず、アニオン性界面活性剤、カチオン性界面活性剤、非イオン性界面活性剤、両性界面活性剤の何れをも使用することができる。
上記界面活性剤としては、例えば、ナトリウムアルキルサルフェート、ナトリウムアルキルエーテルサルフェート、トリエタノールアミンアルキルサルフェート、トリエタノールアミンアルキルエーテルサルフェート、アンモニウムアルキルサルフェート、アンモニウムアルキルエーテルサルフェート、アルキルエーテルリン酸ナトリウム、フルオロアルキルカルボン酸ナトリウム等のアニオン性界面活性剤；アルキルアンモニウム塩、アルキルベンジルアンモニウム塩等のカチオン性界面活性剤；ポリオキシエチレンアルキルエーテル、ポリオキシエチレンフェニルエーテル、ポリオキシエチレンアルキルエステル、プロピレングリコール−プロピレンオキシド共重合体、パーフルオロアルキルエチレンオキシド付加物、２−エチルヘキサノールエチレンオキシド付加物等の非イオン性界面活性剤；アルキルアミノ酢酸ベタイン、アルキルアミド酢酸ベタイン、イミダゾリウムベタイン等の両性界面活性剤等が挙げられる。なかでも、アニオン性界面活性剤及び非イオン性界面活性剤が好ましく、熱分解残量の少ないオキシエチレン鎖を有する非イオン性界面活性剤がより好ましい。
上記界面活性剤の配合量は、通常、溶融性フッ素樹脂の０．０１〜５０％である。０．０１％未満であると、上記溶融性フッ素樹脂の粉末が均一に分散せず、一部浮上することがあり、５０％を超えると、得られる塗膜に上記界面活性剤の分解残渣が多く残留して着色したり、耐熱性、非粘着性等の塗膜物性が低下することがある。好ましい下限は０．１％、より好ましい下限は０．２％であり、好ましい上限は３０％、より好ましい上限は２０％である。
本発明の含フッ素塗料組成物は、必要に応じ、適宜溶媒で希釈し、粘度調整剤等を用いて塗装しやすい粘度に調整して塗料化し、塗装してもよい。
上記含フッ素塗料組成物は、被塗装物上に塗装するために用いられるものであって、上記被塗装物は、金属、高分子化合物成形体、ガラス又は陶器からなるものであることが好ましい。
本明細書において、上記「高分子化合物成形体」とは、高分子化合物を成形することにより得られるものを意味する。上記高分子化合物としては特に限定されず、例えば、樹脂、ゴム等が挙げられるが、本発明の含フッ素塗料組成物の塗布後における焼成の温度と、得られる塗膜の使用温度に耐え得る点から、ポリイミド樹脂等の耐熱性樹脂及びシリコーンゴム等の耐熱性ゴムが好ましい。
本発明の含フッ素塗料組成物は、アルミニウム、ステンレス鋼（ＳＵＳ）、鉄、耐熱樹脂、耐熱ゴム等の被塗装物に対し、必要に応じて脱脂、粗面化等の表面処理を行った後、スプレー等の方法を用いて塗装し、得られる塗布膜を乾燥後、上記溶融性フッ素樹脂の融点以上で焼成することにより、傾斜塗膜を形成させることができる。
本発明の含フッ素塗料組成物から得られる上記傾斜塗膜としては、上記溶融性フッ素樹脂の配合量によるが、表面層として３〜１５μｍの厚さを有する塗膜を得ることができる。このような傾斜塗膜は、従来の２コート法を用いて得られる皮膜に匹敵する厚さを有するものである。従って、本発明の含フッ素塗料組成物は、現在２コート法を用いて加工されている分野であっても、１コート法により好適に用いることができる。
本発明の含フッ素塗料組成物から得られる上記傾斜塗膜としては、例えば１００μｍ程度の厚さにすることができる。
本発明の含フッ素塗料組成物から得られる上記傾斜塗膜には、必要に応じ、トップコート等の上塗り塗装を施してもよい。
本発明の含フッ素塗料組成物は、上述のように、相互に異なる平均粒子径、即ち、平均粒子径が１〜１０００μｍである溶融性フッ素樹脂及び平均粒子径が０．００５〜０．５μｍである含フッ素高分子の２つの成分を、上記特定の範囲内の容量比又は固形分重量比で配合して得られるものであるので、被塗装物に塗布することにより、１コート法により２コート法に匹敵する厚さでクラックを発生させることなく上記フッ素樹脂層を形成することができる。
本発明の含フッ素塗料組成物により厚膜化が可能となる機構としては明確ではないが、得られる傾斜塗膜において上層部に配置することとなる溶融性フッ素樹脂が上記範囲内のように比較的大きい平均粒子径を有することによるものと考えられる。なお、従来の一般的塗料では、フッ素樹脂の平均粒子径が比較的小さかったので、ある程度以上の膜厚にするとクラックを生じ、クラックは重ね塗りをしても抑制することができず、厚膜化ができなかったものと考えられる。
本発明の含フッ素塗料組成物は、このように、従来よりも厚い上記フッ素樹脂層を形成することができるので、上記溶融性フッ素樹脂の耐熱性、耐久性、耐摩耗性、耐食性、非粘着性等の優れた性質を充分に発揮させることができる。
本発明の含フッ素高分子は、また、上記含フッ素高分子の平均粒子径と上記溶融性フッ素樹脂の平均粒子径を調整することにより、上記含フッ素高分子が上記溶融性フッ素樹脂の臨界表面張力より高い臨界表面張力を有するものであっても、上記フッ素樹脂層の下、上の何れにも上記含フッ素高分子層を形成してなる塗膜を得ることができるものである。従って、本発明の含フッ素塗料組成物によると、得られる塗膜のうち上層部をなす成分の種類と、下層部をなす成分の種類とを任意に選択することができ、塗膜設計の幅や材料選択の余地を広げることができる。
このように、本発明の含フッ素塗料組成物は、従来２コート法又は２コート以上の塗布が必要とされていた用途であっても、１コート法により好適に用いることができる。本発明の含フッ素塗料組成物は、更に、上記含フッ素高分子として幅広い物質群から適宜選択することができ、これらを適切に選択することにより、用途に好適であるように適用し、使用に供することができる。
本発明の含フッ素塗料組成物は、また、１コート法により、被塗装物との接着性を良好にすることができるので、プライマーを塗装する必要がない。被塗装物がガラス、陶器等であっても、接着性を向上させることができるので、従来と異なり、例えば、ガラス基材表面をシランカップリング剤等で処理したり、シリコーン樹脂を塗料組成物中に添加する必要がない。
本発明の含フッ素塗料組成物は、更に、上述のように溶融性フッ素樹脂及び含フッ素高分子を配合して得られるものであり、クロム酸等の無機酸、又は、ポリアミドイミド、ポリイミド、ポリエーテルサルホン等の耐熱性樹脂を配合する必要がないことから、透明性の高い塗膜を得ることができるので、例えば、被塗装物の質感や意匠性を重視する用途においても好適に用いることができる。
本発明の含フッ素塗料組成物は、更に、ガラス、陶器等を被塗装物とする場合、衝撃時の飛散を効果的に防止することができる。
従って、本発明の含フッ素塗料組成物は、金属、高分子化合物成形体、ガラス、陶器等からなる様々な基材からなる物品に適用することにより、耐食性、耐摩耗性、耐熱性、非粘着性等を付与することができるとともに、塗膜の透明性、基材そのものの質感、意匠性等が求められる用途に使用することができる。
本発明の含フッ素塗料組成物を好適に適用することができるものとしては、例えば、得られる傾斜塗膜が表裏の性質が異なること等を利用して、例えば電気部品等が挙げられる。
本発明の含フッ素塗料組成物は、また、家電・厨房関係として、炊飯釜、ポット、ジャーポット、ホットプレート、アイロン、フライパン、ホームベーカリー等に用いることができ、工業用として、オフィスオートメーション〔ＯＡ〕機器用ロール、ＯＡ機器用ベルト、製紙ロール、フィルム製造用カレンダーロール、インジェクション金型等の離型用途；攪拌翼、タンク内面、ベッセル、塔、遠心分離器等の耐蝕用途等に、幅広く応用される。
本発明の含フッ素塗料組成物は、ガラスの飛散防止用途として、例えば、電球等の照明器具；ＣＲＴや液晶表示装置等の表示装置；ガラス窓等の建材；ガラス製食器、その他のガラス容器等の食器；ガラス製実験器具等の実験器具；防火ガラス、安全ガラス等の機能的ガラス等の各種ガラス製品、及び、これらの各種ガラス製品の材料に用いることができ、これらの場合、ガラスの透明性を維持することができる。
本発明の含フッ素塗料組成物は、上記溶融性フッ素樹脂により、非粘着性、摺動性等が得られ、上記フッ素樹脂層が厚いことから耐久性に優れるとともに、上記含フッ素高分子として上記弾性体としての含フッ素高分子を用いること等により、硬すぎないように柔軟性を向上することができるので、特に、ＯＡ機器ロール又はＯＡ機器用ベルトに好適に用いることができる。
上記含フッ素高分子は、特に上記フッ素ゴムである場合、耐久性と柔軟性とを特に向上することができ、例えば、従来の方法では耐久性や柔軟性が充分に発揮されなかったＯＡ機器用ロール、ＯＡ機器用ベルト等について用いる場合、耐久性が飛躍的に向上するとともに、従来よりも優れた柔軟性を発揮することができる。ＯＡ機器用ロール、ＯＡ機器用ベルト等は、従来、通常シリコーンゴムロール上にＰＦＡが塗装され、良好な耐摩耗性が要求されるので、この点からも本発明の含フッ素塗料組成物は好適に用いることができる。
また、本発明の含フッ素塗料組成物は、上記含フッ素高分子として官能基含有フッ素樹脂を用いる場合、金属、シリコーンゴム、ポリイミドなどの基材に高い接着性を示すので、これらの基材に塗装することにより、ＯＡ機器用ロールやＯＡ機器用ベルトとして好適に用いることができる。
近年、ＯＡ機器にはますます省エネルギー化が求められているが、高い熱効率でＯＡ機器用ベルトを加熱する方法の一つとして、基材に金属製ベルトを用いた ＩＨ（誘導加熱）方式が提案されている。ＩＨ方式とは、交番磁場中に置いた磁性金属に、電磁誘導により渦電流が流れ、発熱することを利用したものである。この方法では、まず基材として磁性金属製のベルトを用いた場合、このベルトが発熱し、その後、熱伝導によりベルトの表層部が昇温してトナーを溶融させるに至る。このベルトの表層部は一般にフッ素樹脂層である。ここで、トナーを充分に溶融させて高画質の画像を得るために、基材とフッ素樹脂層等の表層部との間に、中間層としてシリコーンゴム層が設けられることがある。
一方で、ＯＡ機器には、起動時間の短縮が期待されており、ベルトの表層部がより短時間で発熱することが求められている。ここで、中間層としてシリコーンゴム層が設けられた構成では、ベルト基材の発熱とベルト表層の加熱に幾らかのタイムラグが生じるという課題がある。また、金属製ベルトは屈曲性に劣り、耐久性の点で不充分であった。
これらの課題は、中間層の少なくとも一部に磁性材料を配合したシリコーンゴム層を設け、表層として本発明の含フッ素塗料組成物からなる皮膜を設けることにより、解決することができる。すなわち、基材ではなく中間層が発熱するので、熱伝導によるタイムラグを抑えることが可能となる。
中間層に磁性材料を配合した場合には、中間層から基材側への熱伝導を防ぐために、熱伝導性の低いポリイミド等を基材とするベルトを用いることが望ましい。ポリイミドは剛性の点でも優れた性質を有しており、金属製ベルトに比較して耐久性が改善され、高速化に対応することも可能となる。
上記含フッ素塗料組成物を塗装することにより得られることを特徴とする塗膜もまた、本発明の一つである。
上記塗膜を有することを特徴とする塗装物もまた、本発明の一つである。
上記塗装物は、上記塗膜が被塗装物上に形成されたものであり、上記被塗装物は、金属、高分子化合物成形体、ガラス又は陶器からなるものであることが好ましい。
上記塗装物は、電球の材料であることが好ましい。
上記塗装物は、防火ガラスの材料又は安全ガラスの材料であることが好ましい。
上記塗装物は、ガラス製食器の材料又はガラス製実験器具の材料であることが好ましい。
上記塗装物は、ＯＡ機器用ロール又はＯＡ機器用ベルトであることが好ましい。
発明を実施するための最良の形態
以下に実施例を掲げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
実施例１
粉砕で得られた平均粒子径１２μｍのＰＦＡ粉末７０ｇ、パーフルオロオクタニック酸のアンモニウム塩５ｇ、イオン交換水１００ｇをＳＵＳ製容器に入れ、攪拌機を用いてＰＦＡ粉末の表面をよく濡らして分散し、ＰＦＡ分散体を得た。この分散体に、平均粒子径０．３５μｍのＰＴＦＥ乳化重合６０質量％分散体５０ｇ、界面活性剤としてノニオンＨＳ２１０（日本油脂社製）濃縮品、増粘剤としてソディムラウリルサルフェート０．５ｇを添加し、よく分散を行い、塗料を得た。
この塗料をアルミニウム板（１５０ｍｍ×２００ｍｍ×２ｍｍ）にスプレー塗装を行い、８０℃で３０分間乾燥後、３８０℃で２０分間焼成し、塗膜の厚みが３０μｍである塗装物を得た。この塗膜を剥がし、ミクロトーム（（独）ライカ社製）を用いて断面を薄く切断し、偏向顕微鏡でフィルターを調製し、境界が確認できるように調製しながら１０００倍に拡大し、表面層（ＰＦＡ層）の厚みを測定した。結果を表１に示す。
実施例２
ＰＴＦＥの代わりに、テトラフルオロエチレン９９．９５質量部とパーフルオロ（プロピルビニルエーテル）０．０５質量部とを乳化重合して得た平均粒子径０．２５μｍの変性ＰＴＦＥ６０質量％濃縮品を用いること以外は、実施例１と同様にして塗料を調製して塗膜を得、塗膜と表面層の厚みを測定した。結果を表１に示す。
実施例３〜６
溶融性フッ素樹脂の種類と平均粒子径及び変性ＰＴＦＥの粒子径並びに配合比を表１に示すものにすること以外は実施例２と同様にして塗料を調製して塗膜を得、塗膜と表面層の厚みを作成した。結果を表１に示す。
実施例７
上記含フッ素高分子として、平均粒子径０．２〜０．３μｍのフッ化ビニリデン系フッ素ゴム（ダイエルラテックスＧＬ２５２ＣＲ−Ａ、ダイキン工業社製）と受酸剤配合塗料（濃度５０質量％、ダイキン工業社製）１００ｇと、実施例１で用いたＰＦＡ分散体１２０ｇ（ＰＦＡ：フッ素ゴムの配合比７０：３０）とを分散させ、ＰＦＡ入リフッ素ゴム塗料を得た。この塗料１００質量部に対し、硬化剤（ダイエルラテックスＧＬ２００−Ｂ液、ダイキン工業社製）３質量部を配合して分散し、アルミニウム箔（厚さ１００μｍ）の上に塗布し、室温で３０分間乾燥後、８０℃で３０分間、３２０℃で６０分間焼成を行い、塗膜を得た。
このアルミニウム箔付き塗膜をミクロトーム（（独）ライカ社製）を用いて断面を薄く切断し、偏向顕微鏡でフィルターを調製し、境界が確認できるように調整しながら１０００倍に拡大し、表面層（ＰＦＡ層）の厚みを測定した。結果を表１に示す。
実施例８
ＰＦＡ分散体に代えて実施例４で用いたＦＥＰ分散体を用いること以外は、実施例７と同様にして塗料を調製して塗膜を得、塗膜と表面層の厚みを測定した。結果を表１に示す。
実施例９
上記含フッ素高分子として、平均粒子径０．０６μｍの柔軟性ＰＦＡ（テトラフルオロエチレン：パーフルオロ（プロピルビニルエーテル）の質量比は５３：４７）の乳化重合物を用いること以外は実施例１と同様にして塗料を調製し、塗布、乾燥を行い、３２０℃で６０分間焼成を行って塗膜を得、塗膜と表面層の厚みを測定した。結果を表１に示す。
実施例１０
上記含フッ素高分子として、単量体成分として側鎖にＯＨ基を有する単量体を単量体成分全量の２質量％で用いて乳化重合することにより得た平均粒子径０．０７μｍのＰＦＡ（官能基含有ＰＦＡ）を用いること以外は実施例１と同様にして塗料を調製し、塗布、乾燥し、３３０℃で６０分間焼成すること以外は実施例１と同様にして塗膜を得た。得られた塗装物はアルミニウムと強固に接着していたため、基材を厚さ１００μｍのアルミ箔に変え、同様な方法にて塗膜を作成しなおし、実施例７と同様な方法にて塗膜と表面層の厚みを測定した。結果を表１に示す。
比較例１〜比較例４
上記溶融性フッ素樹脂の種類と平均粒子径、上記含フッ素高分子の種類と平均粒子径、及び、配合比を表１に示すものにすること以外は実施例１と同様にして塗料を調製して塗膜を得、塗膜と表面層の厚みを作成した。結果を表１に示す。

なお、用いた配合成分の各比重は、ＰＴＦＥ、ＰＦＡ及びＦＥＰが２．２、フッ素ゴムが１．７５であった。
表１から、平均粒子径が１〜３０μｍの範囲内であるＰＦＡ又はＦＥＰと、平均粒子径が０．００５〜０．５μｍの範囲内である上記含フッ素高分子とを、容量比が３５：６５〜９５：５となるように配合して塗料を得、得られた実施例１〜１０の塗膜は、表面層の厚みが２〜１５μｍであるのに対し、ＰＦＡ又はＦＥＰの平均粒子径が１μｍ未満である比較例１〜４では、表面層は形成が確認できないか又は厚みが１〜２μｍであることがわかった。
製造例１ 官能基を有する含フッ素高分子の製造
攪拌機、バルブ、圧力ゲージ、温度計を備えた３リットルガラスライニング製オートクレーブに純水１５００ｍｌ、パーフルオロオクタン酸アンモニウム９．０ｇを入れ、窒素ガスで充分置換したのち、真空にし、エタンガス２０ｍｌを仕込んだ。次いで、下記式（３）

で表されるパーフルオロー（１，１，９，９−テトラハイドロ−２，５−ビストリフルオロメチル−３，６−ジオキサ−８−ノネノール）３．８ｇ、パーフルオロ（プロピルビニルエーテル）〔ＰＰＶＥ〕１８ｇを窒素ガスを用いて圧入し、系内の温度を７０℃に保った。
攪拌を行いながらテトラフルオロエチレン〔ＴＦＥ〕ガスを内圧が８．５ｋｇｆ／ｃｍ２Ｇとなるように圧入した。
次いで、過硫酸アンモニウム０．１５ｇを水５．０ｇに溶かした溶液を窒素を用いて圧入して反応を開始した。
重合反応の進行に伴って圧力が低下するので、７．５ｋｇｆ／ｃｍ^２Ｇまで低下した時点でテトラフルオロエチレンガスで８．５ｋｇｆ／ｃｍ^２まで再加圧し、降圧、昇圧を繰り返した。
テトラフルオロエチレンの供給を続けながら、重合開始からテトラフルオロエチレンガスが約４０ｇ消費されるごとに、上記式（３）で表されるヒドロキシル基を有する含フッ素エチレン性単量体の１．９ｇを計３回（計５．７ｇ）圧入して重合を継続し、重合開始よりテトラフルオロエチレンが約１６０ｇ消費された時点で供給を止めオートクレーブを冷却し、未反応モノマーを放出し、青みがかった半透明の水性分散体１７０２ｇを得た。
得られた水性分散体中のポリマーの濃度は１０．９％、動的光散乱法で測定した粒子径は７０．７ｎｍであった。
また、得られた水性分散体の一部をとり凍結凝析を行い、析出したポリマーを洗浄、乾燥し白色固体を単離した。得られた共重合体のモル比組成は、１９Ｆ−ＮＭＲ分析、ＩＲ分析により、ＴＦＥ／ＰＰＶＥ／（式（３）で示されるヒドロキシル基を有する含フッ素エチレン性単量体）＝９７．７：１．２：１．１モル％であった。
また赤外スペクトルは３６２０〜３４００ｃｍ^−１に−ＯＨの特性吸収が観測された。
ＤＳＣ分析により、Ｔｍ＝３１０℃、ＤＴＧＡ分析により１％熱分解温度Ｔｄ＝３６８℃であった。高化式フローテスターを用いて２ｍｍ、長さ８ｍｍのノズルを用い、３７２℃で予熱５分間、荷重７ｋｇｆ／ｃｍ^２でメルトフローレートを測定したところ１２．０ｇ／１０分であった。
調製例１ 含フッ素塗料組成物Ａの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子１２重量部、ＰＦＡ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ａとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９５：５であった。
調製例２ 含フッ素塗料組成物Ｂの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子４２重量部、ＰＦＡ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｂとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は８５：１５であった。
調製例３ 含フッ素塗料組成物Ｃの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子０．２重量部、ＰＦＡ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｃとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９９．９２：０．０８であった。
調製例４ 含フッ素塗料組成物Ｄの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、官能基を有する含フッ素高分子１１０重量部、ＰＦＡ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｄとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は６８：３２であった。
調製例５ 含フッ素塗料組成物Ｅの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子１２重量部、ＦＥＰ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｅとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９５：５であった。
調製例６ 含フッ素塗料組成物Ｆの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子４２重量部、ＦＥＰ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｆとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は８５：１５であった。
調製例７ 含フッ素塗料組成物Ｇの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、純水２０重量部、官能基を有する含フッ素高分子０．２重量部、ＦＥＰ樹脂粉末（平均粒子径２５μｍ、見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｇとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９９．９２：０．０８であった。
調製例８ 含フッ素塗料組成物Ｈの調製
イソプロピルアルコール４重量部、非イオン性界面活性剤（商品名：ＤＳ−４０１、ダイキン工業社製）８重量部、トリエチレングリコール６重量部、エチレングリコール４重量部、官能基を有する含フッ素高分子１１０重量部、ＦＥＰ樹脂粉末（平均粒子径２５μｍ 見掛密度０．８ｇ／ｍｌ）２６重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｈとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は６８：３２であった。
調製例９ 含フッ素塗料組成物Ｉの調製
ＰＦＡディスパージョン（平均粒子径０．３μｍ、固形分濃度５０重量％、商品名：ＡＤ−２ＣＲ、ダイキン工業社製）５０重量部、官能基を有する含フッ素高分子１２重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｉとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９５：５であった。
調製例１０ 含フッ素塗料組成物Ｊの調製
ＦＥＰディスパージョン（平均粒子径０．２μｍ、固形分濃度５０重量％、商品名：ＮＤ−１、ダイキン工業社製）５０重量部、官能基を有する含フッ素高分子１２重量部を混合、分散して均一な分散組成物を調製した。これを含フッ素塗料組成物Ｊとした。含フッ素溶融樹脂と官能基を有する含フッ素高分子の重量配合比は９５：５であった。
実施例１１
アルミニウム板（Ａ−１０５０）に含フッ素塗料組成物Ａをスプレー塗装し、８０〜１００℃で３０分間乾燥した後に３４０℃で３０分間焼成して、約７０μｍの塗膜を有するフッ素樹脂被覆塗板を得た。
アルミニウム板に対する塗膜の接着性について、得られた塗膜に１ｃｍ間隔で短冊状の切込みを入れ、短冊の一端をアルミニウム板から剥離させ、次いで塗膜面が真上を向くように、治具を用いてテンシロン万能試験機（商品名、オリエンテック社製）にフッ素樹脂被覆塗板を固定し、アルミニウム板から剥離させた短冊の一端を塗膜上方に位置するチャックに取り付け、このチャックをクロスヘッドスピード５０ｍｍ／分で上方に移動させることにより、短冊はアルミニウム板からほぼ９０°方向に剥離させられるが、このときの剥離強度を測定することにより、評価した。結果を表２に示す。
実施例１２
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｂを用いた以外は、実施例１１の手順を繰り返した。
実施例１３
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｃを用いた以外は、実施例１１の手順を繰り返した。
実施例１４
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｄを用いた以外は、実施例１１の手順を繰り返した。
実施例１５
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｅを用いた以外は、実施例１１の手順を繰り返した。
実施例１６
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｆを用いた以外は、実施例１１の手順を繰り返した。
実施例１７
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｇを用いた以外は、実施例１１の手順を繰り返した。
実施例１８
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｈを用いた以外は、実施例１１の手順を繰り返した。
比較例５
アルミニウム板（Ａ−１０５０）の表面に含フッ素塗料組成物１をスプレー塗装し、８０〜１００℃で３０分間乾燥した後に３４０℃で３０分間焼成したが、クラックの発生により３０μｍ以上の皮膜を得ることはできなかった。
比較例６
アルミニウム板（Ａ−１０５０）の表面に含フッ素塗料組成物Ｊをスプレー塗装し、８０〜１００℃で３０分間乾燥した後に３４０℃で３０分間焼成したが、クラックの発生により３０μｍ以上の皮膜を得ることはできなかった。

表２より、溶融性フッ素樹脂の平均粒子径が１〜１０００μｍの範囲内にない比較例５〜６では、クラックが発生して厚膜が得られないが、溶融性フッ素樹脂の平均粒子径が１〜１０００μｍの範囲内にある実施例１１〜１８では、剥離強度が比較的大きく、溶融性フッ素樹脂と含フッ素高分子との固形分重量比が７０：３０〜９９．９：０．１の範囲内にある実施例１１〜１２及び実施例１５〜１６では、剥離強度がより大きいことがわかった。
実施例１９
シリコーンゴムロールに含フッ素塗料組成物Ａをスプレー塗装し、８０〜１００℃で３０分間乾燥した後に３４０℃で３０分間焼成して、約３０μｍの塗膜を有するフッ素樹脂被覆ロールを得た。
得られた塗膜の耐摩耗性について、２００℃に加熱したフッ素樹脂被覆ロール表面に荷重１ｋｇでコピー用紙（商品名：再生ＰＰＣ用紙、富士ゼロックス社製）を押し当て、回転速度３００ｒｐｍでロールを回転させることによりロール表面を摩耗させ、次いで濡れ指数標準液（３１ｄｙｎｅ／ｃｍ）を滴下してゴニオメーターによる接触角が２０°以下になるまでの時間、又は、塗膜がシリコーンゴムロール基材から剥離するまでの時間を耐久性の尺度として、評価した。結果を表３に示す。
実施例２０
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｂを用いた以外は、実施例１９の手順を繰り返した。
実施例２１
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｃを用いた以外は、実施例１９の手順を繰り返した。
実施例２２
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｄを用いた以外は、実施例１９の手順を繰り返した。

表３より、実施例１９〜２２では、耐摩耗性が比較的良好であり、溶融性フッ素樹脂と含フッ素高分子との固形分重量比が７０：３０〜９９．９：０．１の範囲内にある実施例１９〜２０では、耐摩耗性がより良好であることがわかった。実施例２３
厚さ１．５ｍｍのガラス板に含フッ素塗料組成物Ａをスプレー塗装し、８０〜１００℃で３０分間乾燥した後に３４０℃で３０分間焼成して、約７０μｍの塗膜を有するフッ素樹脂被覆ガラス板を得た。
得られたフッ素樹脂被覆ガラス板の耐衝撃性について、ＪＩＳ Ｋ ５６００−５−３に記載されたデュポン式衝撃変形試験器を用い、水平に支持した試験器に半径６．３５ｍｍの撃ち型と受け台を取り付け、この撃ち型と受け台の間にフッ素樹脂被覆ガラス板を挟み、３００ｇのおもりを１００ｍｍの高さより撃ち型の上に落としてフッ素樹脂被覆ガラス板の破壊の様子を観察し、ガラスが飛散することによる重量損失を、下記式
重量損失（％）＝飛散物の重量（ｇ）／試験前の重量（ｇ）×１００
により求めることにより、評価した。結果を表４に示す。
また、フッ素樹脂被覆ガラス板の可視光線透過性について、Ｕ−３３１０形分光光度計（商品名、日立製作所社製）を用い、４００〜７００ｎｍの代表的な可視線領域の光線透過率を測定することにより、評価した。結果を表５に示す。
実施例２４
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｂを用いた以外は、実施例２３の手順を繰り返した。
実施例２５
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｃを用いた以外は、実施例２３の手順を繰り返した。
実施例２６
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｄを用いた以外は、実施例２３の手順を繰り返した。
実施例２７
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｅを用いた以外は、実施例２３の手順を繰り返した。
実施例２８
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｆを用いた以外は、実施例２３の手順を繰り返した。
実施例２９
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｇを用いた以外は、実施例２３の手順を繰り返した。
実施例３０
含フッ素塗料組成物Ａに代えて、含フッ素塗料組成物Ｈを用いた以外は、実施例２３の手順を繰り返した。
比較例７
厚さ１．５ｍｍのガラス板にプライマーとしてγ−アミノプロピルトリエトキシシラン（商品名：Ａ−１１００、日本ユニカー社製）をスプレー塗装し、８０〜１００℃で３０分間乾燥した後に、ＰＦＡ粉体塗料（平均粒子径２０μｍ、見掛密度０．８８ｇ／ｍｌ、商品名：ＭＰ−１０３、三井・デュポンフロロケミカル社製）を静電塗装し、３４０℃で３０分間焼成して、約７０μｍの塗膜を有するフッ素樹脂被覆ガラス板を得た。塗膜の耐衝撃性を実施例２３に記載の手順に従って評価した。
比較例８
厚さ１．５ｍｍの無垢のガラス板の耐衝撃性を実施例２３に記載の手順に従って評価した。

表４から、実施例２３〜３０は、プライマーを塗装した比較例７と同等又はほぼ匹敵する程度に衝撃時の重量損失を抑制することができ、溶融性フッ素樹脂と含フッ素高分子との固形分重量比が７０：３０〜９９．９：０．１の範囲内にある実施例２３〜２４及び実施例２７〜２８では重量損失がより少ないことがわかった。

表５から、実施例２３〜３０は、プライマーを塗装した比較例７よりも可視線領域の光線透過率を高くすることができ、溶融性フッ素樹脂がＰＦＡである場合、溶融性フッ素樹脂の固形分重量が、溶融性フッ素樹脂の固形分重量及び含フッ素高分子の固形分重量の合計の７０％以上である実施例２３〜２５で光線透過率がより高く、溶融性フッ素樹脂がＦＥＰである場合、５００ｎｍ以上では上記溶融性フッ素樹脂が７０重量％である実施例２７〜２９で光線透過率がより高いことがわかった。
産業上の利用可能性
本発明の含フッ素塗料組成物は、上述の構成を有するので、１コート法により２コート法に匹敵する厚さで溶融性フッ素樹脂を主として含有する層を形成することができ、耐食性、耐摩耗性、耐熱性、非粘着性等が良好であり、かつ、臨界表面張力の比較的低い溶融性フッ素樹脂を主として含有する層の上に、臨界表面張力のより高い材料を主として含有する層を形成すること、及び、これら両層の上下を逆にして形成することの何れをも可能にすることができる。本発明の含フッ素塗料組成物は、更に、ガラス等を含む被塗装物への高い接着性と、透明性とを有する塗膜を得ることができる。Technical field
TECHNICAL FIELD The present invention relates to a fluorine-containing gradient coating composition which can form a fluorine-containing polymer layer and a fluorine resin layer thicker than before by a single coat, regardless of whether the coating is up or down. According to the present invention, a coating film having a sufficient thickness and transparency can be formed in one coat by firmly adhering to an object to be coated such as a metal, a molded article of a polymer compound, glass, and ceramics. The present invention relates to a fluorine-containing gradient paint composition, and to a painted product obtained by painting these paint compositions.
Background art
Fluororesin has excellent properties such as corrosion resistance, heat resistance, abrasion resistance, non-adhesion, etc., so it is prepared as a paint, for example, lining of chemical equipment where corrosion resistance is required, heat resistance is required It is used for various applications such as a light bulb, a sliding member such as a cookware or a roll for OA equipment and a belt for OA equipment which require abrasion resistance and non-adhesiveness.
A coating made of a fluororesin, for example, is applied to various objects to be coated such as a metal, a polymer compound molded body, glass, and pottery to obtain a coating film, dried if necessary, and baked to obtain a fluorine film. It forms a coating film made of resin.
In general, the excellent properties of the fluororesin are easily exhibited when the coating film made of the fluororesin is thicker, and the durability is easily maintained because the film has durability. For the purpose of increasing the thickness of a coating film, WO 94/05729 discloses an aqueous dispersion composition containing a specific amount of a fluorine-containing molten resin having an average particle diameter of 10 to 1000 μm.
Since the fluororesin has excellent non-adhesiveness, the coating film made of a fluororesin tends to have poor adhesion to an object to be coated. In particular, the adhesion to a painted surface made of glass, pottery, or the like is weak. Therefore, various measures have been taken for the purpose of enhancing the adhesion between the coating film and the object to be coated.
In order to enhance the adhesion between the coating film and the object to be coated, a fluororesin made of a copolymer containing a hydrocarbon monomer having a functional group such as a hydroxyl group or a carboxyl group and having no fluorine as a comonomer was used. Paints have been considered. However, since this paint has poor heat resistance, it may be decomposed during baking at the time of painting or use as a heated light bulb or the like, and there is a problem that abrasion resistance, non-adhesion, and the like are insufficient. .
Japanese Patent Application Laid-Open No. 9-157578 discloses copolymerization of a functional group-containing fluorinated ethylenic monomer and a functional group-free fluorinated ethylenic monomer in order to enhance the adhesion between the coating film and the object to be coated. A coating composition comprising the obtained fluororesin has been proposed. However, this coating composition has a problem that the thickness of the formed coating film is about 5 μm, and the corrosion resistance and abrasion resistance are not sufficient.
Conventionally, in order to obtain a coating film having not only adhesiveness to the object to be coated but also corrosion resistance, abrasion resistance and the like, a two-coat method in which a primer is applied to the object in advance and then a coating made of a fluororesin is applied. Had been done. However, in the two-coat method, a step of applying a primer to an object to be coated and forming a primer film by drying, heating, or the like is required. Therefore, a coating method capable of simplifying the steps and saving energy is desired. Was.
For the purpose of simplifying the process, saving energy, and the like, there is a one-coat method in which one paint made of a fluororesin and a binder resin is applied once. In this method, a primer film and a coating film made of a fluororesin obtained by a conventional two-coat method are formed by applying one paint.
The coating film obtained by the one-coat method is formed such that the binder resin is mainly disposed on the object to be coated and the fluorine resin is mainly disposed on the surface of the coating far from the object to be coated. Have a concentration gradient from the object side to the surface side. A paint capable of obtaining a coating film having such a concentration gradient is sometimes referred to as a gradient paint.
Since the inclined type paint made of the fluororesin can form a coating film in which the binder resin and the fluororesin are arranged in an inclined manner, it is possible to provide the binder resin with the adhesive property with the object to be coated. It has been used in a wide range of fields, taking advantage of the non-adhesiveness of fluororesins.
However, paints using heat-resistant resins such as polyamideimide, polyimide and polyethersulfone as binder resins, and paints using inorganic acids such as chromic acid, etc. Since the surface is damaged or the coating film is colored, there has been a problem that it is not suitable for applications requiring texture and design of the object to be coated.
Japanese Patent Application Publication No. 3-80741 and Japanese Patent Application Laid-Open No. 5-177768 disclose a method of adding a silicone resin to a coating material made of a fluororesin used for a glass substrate or the like. A method of treating with an agent has been proposed. However, the resulting coating film has poor adhesiveness to an object to be coated, and has a problem that it is not suitable for use in, for example, electric bulbs because the heat resistance and the translucency are reduced.
As described above, the conventional one-coat method may not be suitable for applications that require not only the adhesiveness to the base material and the heat resistance, but also the design of the object to be coated, such as texture and colorless transparency. there were. The problem of poor design cannot be solved even by using a conventional two-coat method and increasing the thickness of a coating film made of a fluororesin.
It is also desirable to take measures to prevent scattering of glass substrates and the like upon impact. For the purpose of preventing scattering, WO 98/52748 discloses that a fluorine-containing monomer having a functional group and a fluorine-containing monomer having no functional group are copolymerized in a specific molar ratio. A heat resistant polymer is disclosed.
The conventional one-coat method is to apply a gradient paint in which fluororesin particles having an average particle diameter of about 0.5 μm or less are dispersed in a dispersion medium containing a binder resin, and heat the resulting coating film. Utilizing that the critical surface tension of the fluororesin is lower than that of the dispersion medium, the fluororesin floats on the surface by buoyancy.
However, in the conventional one-coat method, the layer on the surface of the coating film made of the fluororesin is superposed due to the fact that a surfactant is used to disperse the binder resin and the fluororesin in the dispersion medium. If the coating was not too thin, cracks occurred and a sufficient film thickness could not be obtained. For this reason, there has been a problem that not only excellent characteristics such as corrosion resistance and non-adhesion inherent to the fluororesin are not sufficiently exhibited, but also the durability is poor.
In the conventional one-coat method, a concentration gradient of the contained resin is caused by utilizing a difference in surface tension, and a component having a lower surface tension floats on the surface side of the coating film. There is a problem that a material having a higher critical surface tension cannot be formed on a material having a lower surface tension, which limits the applicable range.
Japanese Patent No. 2814911 discloses a fluororesin coating composition containing fluororesin particles, a surfactant and a liquid medium, a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer having an average particle diameter of 5 to 50 μm [PFA The use of PFA particles comprising 20 to 80% by weight of particles and 80 to 20% by weight of PFA particles having an average particle diameter of 0.1 to 1 μm is disclosed, and the redispersibility of the PFA particles is improved. There is a description. However, in this publication, there is no description or suggestion that the types of fluororesin particles used are the same, and that a gradient coating film can be obtained due to the difference in particle diameter.
Summary of the Invention
SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to form an arbitrary fluororesin on a surface by a one-coat method with a thickness comparable to that of a two-coat method, and to form a two-layer film limited by a conventional surface tension. An object of the present invention is to provide a coating composition that can be widely applied by expanding the range of combinations of the above. An object of the present invention is to provide a coating composition having such a coating composition, which further has high adhesion to an object to be coated, corrosion resistance, abrasion resistance, heat resistance, non-tackiness and transparency. It is an object of the present invention to provide a product which can be used for various purposes and to provide various kinds of painted products obtained by painting.
The present invention provides a fluorine-containing coating composition obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm. Things.
The present invention is a fluorine-containing coating composition obtained by blending a fusible fluororesin having an average particle diameter of 1 to 30 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm, The fluorine-containing coating composition is characterized in that the volume of the meltable fluororesin is 35 to 95% of the total of the volume of the meltable fluororesin and the volume of the fluoropolymer.
The present invention provides a fluorine-containing coating composition obtained by dispersing a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.3 μm in a liquid medium. The fluorine-containing polymer is obtained by copolymerizing a functional group-containing fluorinated ethylenic monomer (a) and a functional group-free fluorinated ethylenic monomer (b), The functional group-containing fluorine-containing ethylenic monomer (a) has a functional group, and the functional group includes a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, or an epoxy group. Wherein the functional group-free fluorine-containing ethylenic monomer (b) does not have the functional group.
The present invention is a coating film obtained by applying the above-mentioned fluorine-containing coating composition.
The present invention is a coated article having the above-mentioned coating film.
Hereinafter, the present invention will be described in detail.
Detailed Disclosure of the Invention
The fluorine-containing coating composition of the present invention is obtained by blending a fluorine-containing polymer and a meltable fluorine resin. The fluoropolymer is conceptually different from the fusible fluororesin in that it has a different average particle diameter as described later.
The fluorine-containing coating composition of the present invention can be applied to an object to be coated such as a base material, and after heating and drying the obtained coating film as required, a coating film can be formed by firing. It is.
When the fluorine-containing coating composition of the present invention is applied to an object to be coated, the average particle diameter of the two components consisting of the fluorine-containing polymer and the meltable fluororesin is relatively small in the obtained coating film. Lamination is performed so that particles of a component that is as large as possible constitute the upper layer portion in the coating film. Particles of a component having a relatively small average particle diameter among the two components penetrate between the particles to be laminated, and are further arranged as a lower layer below the upper layer. The particles of the two components form a filled structure almost or completely filled in the coating film.
In the present specification, in a coating film obtained by applying a coating composition or a coating material on an object to be coated, a layer located on the side of the object to be coated is referred to as a lower layer, and a side far from the object to be coated, that is, What is located on the surface side of the coating film may be referred to as an upper layer portion.
The component having a relatively small average particle size may be any component that allows the particles to enter between the particles to be laminated. Therefore, assuming that these particles are spherical, the average particle diameter of the component having a relatively small average particle diameter is 15% or less of the average particle diameter of the component having a relatively large average particle diameter. It is necessary.
The average particle diameter of the component having a relatively small average particle diameter is such that the space between particles of the component having a relatively large average particle diameter can be sufficiently secured. Is preferably 0.05 to 1%. If it is less than 0.05%, it is difficult to fill the contact surface with the object to be coated, which is the lower layer in the coating film, and the adhesive strength with the object to be coated may be insufficient. . If it exceeds 1%, depending on the shape and uniformity of the particles, the particles having the relatively large average particle diameter may enter the voids between the particles and sufficiently fill the contact surface with the object to be coated. And the adhesive strength to the object to be coated may be insufficient.
The average particle diameter of the component having a relatively small average particle diameter is 0.5 μm or less in consideration of the arrangement of particles in the packing structure and the like. If it exceeds 0.5 μm, it is difficult to obtain a polymer having such an average particle diameter, since a fluorine-containing polymer which is a component having a relatively small average particle diameter is usually synthesized by emulsion polymerization as described later. It is. Preferably, it is 0.3 μm or less. The average particle diameter of the component having a relatively small average particle diameter is preferably 0.005 μm or more in consideration of film forming properties and the like. A more preferred lower limit is 0.01 μm, and a more preferred upper limit is 0.15 μm.
As the average particle diameter of the component having a relatively large average particle diameter, the average particle diameter of the component having a relatively small average particle diameter and the ratio to the average particle diameter, the dispersion stability of the coating composition, the coating In consideration of uniformity, film forming property, thickening of the obtained coating film, and the like, the average particle diameter is preferably 1 to 1000 μm.
The fluorine-containing coating composition of the present invention is formed in the upper layer portion of the coating film using the fusible fluororesin as the component having a relatively large average particle diameter, and the component having a relatively small average particle diameter. The above-mentioned fluorine-containing polymer is used to form the above-mentioned fluorine-containing polymer in a lower layer portion in the above-mentioned coating film.
Therefore, the fluorine-containing coating composition of the present invention is obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm. It is characterized by being performed. By blending the fusible fluororesin and the fluorinated polymer, each having an average particle size within the above range, as described above, the filling structure can be appropriately formed, and excellent film forming properties can be obtained. Can be obtained.
The fluorinated coating composition of the present invention has an average particle size of 1 to 30 μm as the fusible fluororesin, and an average particle size of 0.005 to 0.5 μm as the fluorinated polymer. It may be obtained by blending.
The fluorine-containing coating composition of the present invention has a higher filling property of the fluorine-containing polymer in the lower layer portion of the obtained coating film, and can further enhance the adhesiveness with the object to be coated, and has an average particle diameter of Of a meltable fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.3 μm.
The arrangement of the particles in the coating film is based on the difference in the average particle size between the two components forming the coating film. That is, in the upper layer portion, the particles of the component having a relatively large average particle diameter are densely packed and stacked so that the volume of the gap portion is reduced, forming a densely packed structure, and forming the densely packed portion. The particles of the component having a relatively small average particle diameter enter the gap, and fill or almost fill the gap.
In the densely packed structure, the porosity expressed as a ratio of the total volume of the gap portion to the total volume of the volume of the particles having the relatively large average particle size and the volume of the gap portion, It depends on the sphericity of the particles of the component having a relatively large average particle diameter, the degree of uniform shape, and the like.
In the case where the particles of the component having a relatively large average particle diameter are spherical having the same size, and the particles are densely packed so that the volume of the gap portion is minimized, the close-packed structure Is formed, and the porosity at this time is calculated to be 25.95% in the case of close packing and 47.64% in the case of cubic packing.
In the fluorine-containing coating composition of the present invention, the particles of the two components are not actually perfectly spherical. When the actual particles are, for example, nearly spherical powders, the porosity is said to be 33 to 66% (powder engineering / basic edition, Maki Shoten, 1974 first edition, page 91).
Therefore, in the fluorine-containing coating composition of the present invention, using the fusible fluororesin as a component having a relatively large average particle diameter, and using the fluoropolymer as a component having a relatively small average particle diameter. In order to form the fusible fluororesin on the surface layer, the capacity of the fusible fluororesin relative to the sum of the capacity of the fusible fluororesin and the capacity of the fluorinated polymer is preferably 35% or more. is necessary.
In the present specification, the “capacity of the fusible fluororesin” means the volume occupied by the particles of the fusible fluororesin. In the present specification, the “capacity of the fluoropolymer” means the volume occupied by the fluoropolymer particles. When the volume of the fusible fluororesin or the volume of the fluorinated polymer is respectively dispersed in a liquid medium, of the volume of the liquid medium, the volume occupied by the particles of the fusible fluororesin, or The volume occupied by the particles of the fluoropolymer.
In order for the particles of the component having a relatively small average particle diameter to be disposed as a lower layer under the upper layer, as the component having a relatively small average particle diameter, the capacity of the gap portion in the upper layer and the volume It is preferable to mix so as to occupy the capacity corresponding to the capacity of the lower layer portion.
The capacity ratio between the fusible fluororesin and the fluorinated polymer is determined by using the specific gravity of the fusible fluororesin to be used and the specific gravity of the fluorinated polymer. It can be expressed as a weight ratio of the solid content to the molecule. The specific gravity of a general fluorine-containing polymer that can be used in the fluorine-containing coating composition of the present invention is from 1.6 to 2.2.
In the present specification, the “solid content weight ratio of the fusible fluororesin and the fluoropolymer” is the weight of the solid content of the fusible fluororesin and the weight of the solid content of the fluoropolymer. Means ratio. In the present specification, the weight of the solid content, when dispersed in a liquid medium, is the weight of the particles of the fusible fluororesin and the weight of the particles of the fluoropolymer dispersed in the liquid medium. .
As described above, the fluorine-containing coating composition of the present invention contains a meltable fluororesin having an average particle diameter of 1 to 1000 μm and a fluorine-containing polymer having an average particle diameter of 0.005 to 0.5 μm. In this case, the solid content weight of the fusible fluororesin is 35 to 99 of the sum of the solid weight of the fusible fluororesin and the solid content weight of the fluoropolymer. It is preferably 0.9%. When the weight ratio of the solid content is within this range, the lower layer portion in the coating film is sufficiently filled with the fluorine-containing polymer, and the adhesiveness between the obtained coating film and the object to be coated is improved. be able to.
The fluorine-containing coating composition of the present invention is obtained by blending a fusible fluororesin having an average particle diameter of 1 to 30 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm. In the case where the fusible fluororesin is mainly contained in the upper layer portion, the capacity of the fusible fluororesin is 35 to a total of the capacity of the fusible fluororesin and the capacity of the fluoropolymer. It may be 95%. If the capacity of the fusible fluororesin is less than 35% of the total of the capacity of the fusible fluororesin and the capacity of the fluoropolymer, the fluororesin layer is not appropriately formed as the upper layer, and defects may occur. If it exceeds 95%, the amount of the fluoropolymer is too small, and the physical properties such as the adhesiveness of the fluoropolymer required for the lower layer portion are not sufficiently exhibited. There are cases. Preferably, it is 50 to 95%, more preferably 70 to 95% of the total of the capacity of the meltable fluororesin and the capacity of the fluoropolymer.
The fluorine-containing coating composition of the present invention is obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.3 μm. In this case, the solid content weight of the meltable fluororesin is preferably 70 to 99.9% of the total of the solid weight of the meltable fluororesin and the solid content weight of the fluoropolymer. When the average particle diameter and the solid content weight ratio are within these ranges, the lower layer portion in the coating film can be sufficiently filled with the fluoropolymer to improve the adhesiveness with the object to be coated. A more preferred lower limit is 80% of the total of the solid content weight of the meltable fluororesin and the solid content weight of the fluoropolymer, and a more preferred upper limit is 98%.
As described above, the fact that the two components forming the coating film form the filling structure as described above is based on the difference between the average particle diameters of the two components and the appropriate mixing ratio of the two components. is there.
The coating film having the above-described filling structure is then dried by heating, if necessary, and then fired. As a result of the baking, the components of the upper layer are melted, and the particles of the components having a relatively large average particle diameter constituting the upper layer collect together due to their own surface tension to form a film (film formation). .
By the baking, the lower layer portion is cross-linked to form a cured film according to the type and chemical structure of the components constituting the lower layer portion, or is formed by cooling without being cross-linked after melting. . It is preferable that the lower layer is formed by crosslinking to form a cured film from the viewpoint that the components of the upper layer are easily floated.
By the above-mentioned baking, the average particle diameter is mainly contained on the surface side of the coating film, and the average particle diameter is mainly contained on the object side of the coating film. Then, a coating film is formed. When particles of the component having a relatively large average particle diameter remain in the lower layer portion, a film is formed while the remaining particles are incorporated in the main component constituting the lower layer portion.
In the present specification, of the coating film obtained through coating and baking, a layer mainly containing the above-mentioned fusible fluororesin is referred to as a fluororesin layer, and a layer mainly containing the above fluoropolymer is a fluoropolymer layer. That. The fluororesin layer may contain a small amount of the fluoropolymer and, if necessary, other components contained in the fluorinated coating composition of the present invention. The fluorine-containing polymer layer may contain a small amount of the meltable fluororesin and the other components.
Usually, the fusible fluororesin and the fluorinated polymer have a concentration gradient in each of the fluororesin layer and the fluorinated polymer layer. Such a coating film having a concentration gradient may be referred to as a gradient coating film. The boundary between these two layers can be confirmed, for example, by preparing a filter using a deflection microscope on a thinly cut cross section.
Since the fluorine-containing coating composition of the present invention forms a coating film by the above mechanism, only the fluororesin layer having a thickness of about 1 μm or so is usually obtained by a conventional inclined type coating utilizing a difference in surface tension. Compared to what was not obtained, a significantly thicker one, preferably one having a thickness of 3 to 15 μm, can be obtained.
Since the fluorine-containing coating composition of the present invention also forms a coating film by the above mechanism, by adjusting the average particle size of the fusible fluororesin and the fluoropolymer within the above range, the fluororesin The thickness of the layer can be adjusted.
Although the formation of the relatively thick fluororesin layer as described above has not been conventionally achieved by using the one-coat method, the fluorine-containing coating composition of the present invention has been realized by the one-coat method. Is what you can do.
The above-mentioned fusible fluororesin to be blended in the fluorinated coating composition of the present invention has an average particle diameter of usually 1 to 1000 µm, as described above. When it is in the above range, a film having excellent film-forming properties and a sufficient film thickness can be uniformly obtained.
When the thickness is less than 1 μm, cracks are easily generated in the coating film during firing, and a coating film having a sufficient film thickness may not be obtained. When the thickness exceeds 1000 μm, the dispersion of the fluorine-containing coating composition of the present invention is used. In addition, the powder composed of the meltable fluororesin and the fluorine-containing polymer tends to settle out, so that the dispersion state is not stable and uniform coating may be difficult. Preferably it is 1-300 micrometers, Still more preferably, it is 1-50 micrometers, More preferably, it is 1-30 micrometers.
The above-mentioned fusible fluororesin blended in the fluorinated coating composition of the present invention may have an average particle diameter of 1 to 30 μm as described above. If it is less than 1 μm, the thickness of the fluororesin layer is not sufficient, and if it exceeds 30 μm, the resulting coating film surface may have poor smoothness. The surface layer of the coating film obtained with the conventional gradient paint has a thickness of about 1 μm, and a fluororesin layer having a thickness of about 30 μm has been obtained in applications such as tubes. There is no conventional one having a fluororesin layer having a thickness of 3 to 15 μm on the surface side. However, those having a fluororesin layer having a thickness of 3 to 15 μm on the surface side of the coating film have market needs, and such a film thickness can be easily obtained. Is 2 μm, and a more preferred upper limit is 20 μm.
Examples of the meltable fluororesin include, as monomer components, chlorofluorovinyl monomers such as chlorotrifluoroethylene and trifluoroethylene; and perfluoropolymers such as tetrafluoroethylene, hexafluoroethylene and perfluoro (alkyl vinyl ether). Examples include those obtained by polymerizing one or more fluoromonomers or the like. The monomer component may further include one or more vinyl monomers having no fluorine atom such as ethylene and propylene. The perfluoro monomer has a main chain composed of a carbon atom and a fluorine atom and optionally an oxygen atom; ₂ And containing a perfluorovinyl monomer and a perfluoro (alkyl vinyl ether) monomer. The oxygen atom is usually ether oxygen.
As the above-mentioned fusible fluororesin, a monomer having a functional group such as a hydroxyl group or a carbonyl group may be used as a comonomer for copolymerizing a small amount with the above-mentioned monomer component. A monomer may be used. Examples of the cyclic structure include those having a cyclic ether structure such as a cyclic acetal structure. Preferably, at least two carbon atoms constituting the cyclic ether structure have a main chain of the meltable fluororesin. It has become a part.
Examples of the meltable fluororesin include alkylene / fluoroalkylene copolymers such as ethylene / tetrafluoroethylene copolymer [ETFE], ethylene / chlorotrifluoroethylene copolymer [ECTFE], and propylene / tetrafluoroethylene copolymer. Polymer: tetrafluoroethylene / hexafluoropropylene copolymer [FEP], tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA], tetrafluoroethylene / perfluoro (alkyl vinyl ether) / hexafluoropropylene copolymer And perfluoropolymers such as coalesced [EPA]. The perfluoropolymer has the perfluoromonomer as a monomer component.
Examples of the meltable fluororesin include tetrafluoroethylene-based copolymers such as ETFE, FEP, PFA, EPA, and propylene / tetrafluoroethylene copolymers described above; ECTFE, polychlorotrifluoroethylene [PCTFE], and the like. Chlorotrifluoroethylene copolymer; vinylidene fluoride copolymer such as polyvinylidene fluoride [PVdF] may be used.
In the present specification, the “tetrafluoroethylene-based copolymer”, the “chlorotrifluoroethylene-based copolymer”, and the “vinylidene fluoride-based copolymer” are tetrafluoroethylene and chlorotrifluoroethylene, respectively. And those copolymerized using vinylidene fluoride as a comonomer.
As the fusible fluororesin, one kind or a combination of two or more kinds can be used.
The above-mentioned perfluoropolymer is preferable as the above-mentioned fusible fluororesin, although it varies depending on the use. The above-mentioned perfluoropolymer is excellent in non-adhesiveness and corrosion resistance, and has been used in many fields using conventional methods, but it was not possible to form a thick coating film surface layer as a conventional gradient paint. For this reason, the applications have been limited. However, by using the fluorine-containing coating composition of the present invention, the above-mentioned fluororesin layer mainly containing the above-mentioned perfluoropolymer can be formed thicker by one coat method than before.
The above-mentioned perfluoropolymer is more preferably a copolymer obtained by using tetrafluoroethylene as a comonomer, and the above-mentioned perfluoromonomer as another comonomer is not particularly limited. As such a tetrafluoroethylene-based copolymer, FEP, PFA, and EPA are preferable, and FEP and PFA are more preferable, since they are particularly excellent in corrosion resistance, heat resistance, abrasion resistance, non-adhesion, and the like.
As the above-mentioned fusible fluororesin, those having a melting point of 150 to 350 ° C are preferable. When the melting point is within the above range, in baking after applying the fluorine-containing coating composition of the present invention, the layer separation between the fusible fluorine resin and the fluorine-containing polymer is promoted to adhere to the object to be coated. Properties can be improved, and a coating film excellent in coating film properties such as mechanical strength can be easily obtained.
The above-mentioned fusible fluororesin preferably has a melting point of 200 ° C. or higher. It has been difficult to form a thick fluororesin having a melting point of 200 ° C. or more on the surface side of the coating film with the conventional inclined paint. Even a resin can be suitably used.
More preferably, the fusible fluororesin has a melting point of 200 to 350 ° C.
The fusible fluororesin has a melting point within the above range, and a melt viscosity at a temperature 50 ° C. higher than the melting point is 10%. ⁶ It is preferably Pa · s or less. With such a thing, it has sufficient flowability at the time of baking after applying the fluorine-containing coating composition of the present invention, and performs sufficient layer separation between the above-mentioned fusible fluororesin and the above-mentioned fluoropolymer. And the adhesiveness with the object to be coated can be improved. If the melt viscosity at the above temperature is within the above range, for example, 10 ¹ Pa · s or more, and a more preferred lower limit is 10 ² Pa · s, and a more preferred upper limit is 10 ⁴ Pa · s.
The meltable fluororesin can be prepared as a powder, and the apparent density of the powder is usually preferably from 0.3 to 1.5 g / ml. When the amount is less than 0.3 g / ml, the dispersibility of the powder is reduced, and the baking of the foam and the poor leveling property are likely to occur at the time of baking after the application of the fluorine-containing coating composition of the present invention. When the amount exceeds ml, the powder tends to settle, and the dispersion stability in the fluorine-containing coating composition of the present invention tends to decrease. A more preferred lower limit is 0.5 g / ml, and a more preferred upper limit is 1 g / ml.
The fluorinated coating composition of the present invention is obtained by blending the fluorinated polymer with the fusible fluororesin. The above-mentioned fluorine-containing polymer is particularly suitable when the fluorine-containing coating composition of the present invention is used for applications that emphasize heat resistance and corrosion resistance.
Examples of the fluorine-containing polymer include monomer components such as vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and perfluoro (alkyl vinyl ether). Examples thereof include those obtained by polymerizing one or more fluorine vinyl monomers and, if necessary, one or more other vinyl monomers such as ethylene and propylene. Can be
Examples of the fluoropolymer include vinyl fluoride / tetrafluoroethylene copolymer, vinyl fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, vinylidene fluoride / tetrafluoroethylene copolymer, and vinylidene fluoride / Hexafluoropropylene copolymer, tetrafluoroethylene polymer [PTFE], ethylene / tetrafluoroethylene copolymer, ethylene / chlorotrifluoroethylene copolymer, propylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexa Examples thereof include a fluoropropylene copolymer and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. In addition, in this invention, it is the concept which does not use the polymer whose monomer is all the same kind for both the said meltable fluororesin and the said fluoropolymer.
When the fluorinated polymer is PTFE, the intended fluorinated resin can be formed thickly on PTFE by using the fluorinated coating composition of the present invention, and the excellent effect of this fluorinated resin layer In particular.
PTFE is often used because it is inexpensive and has excellent heat resistance. However, improvements in non-adhesion, chemical permeability, water vapor permeability, etc. are desired. A coating film having a resin disposed on the surface has been required. What has been conventionally used as a material capable of forming such a coating film is a blend of dispersions, so that the fusible fluororesin cannot selectively float on the surface in a sufficient amount, The improvement of the above properties was insufficient. The fluorine-containing coating composition of the present invention can form a gradient coating film having the fluororesin layer having a thickness of 3 to 15 μm on the surface side by using two types of fluororesins. I am satisfied with.
The PTFE may be a conventional tetrafluoroethylene homopolymer, but is preferably a modified PTFE from the viewpoint of excellent adhesion to the above-mentioned fusible fluororesin. As the modified PTFE, at least one selected from the group consisting of perfluoro (alkyl vinyl ether), chlorotrifluoroethylene, and hexafluoropropylene, together with tetrafluoroethylene, is used as a monomer component. It is obtained by copolymerization using a ratio of not more than 0.5% by mass.
The fluoropolymer may be fluororubber. When using a fluororubber as the fluoropolymer, flexibility can be imparted by the fluororubber, and non-adhesiveness, chemical resistance, and the like can be imparted by the fusible fluororesin on the coating film surface side. . In the present specification, the fluororubber means the fluoropolymer having no melting point and having a glass transition point of 5 ° C. or lower.
The fluororubber is not particularly limited, and examples thereof include a vinylidene fluoride-based copolymer containing vinylidene fluoride as a comonomer, a tetrafluoroethylene-based copolymer containing tetrafluoroethylene as a comonomer, and ethylene / hexafluoropropylene copolymer. Examples thereof include polymers and phosphazene rubber. Examples of the vinylidene fluoride copolymer include vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, and vinylidene fluoride / chlorotrifluoroethylene copolymer And the like. Examples of the tetrafluoroethylene-based copolymer include a tetrafluoroethylene / propylene copolymer and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer.
For the purpose of improving heat resistance and mechanical strength, a cross-linking agent, an acid acceptor, a cross-linking accelerator and the like are usually used in combination with the fluororubber, and a pigment and the like are further used if necessary. Examples of the crosslinking agent generally include polyamines, polyols, peroxides and the like. The acid acceptor is for trapping generated hydrofluoric acid to assist crosslinking, and examples thereof include metal oxides. Examples of the crosslinking accelerator include tertiary amines and phosphonium compounds.
The fluorine-containing polymer may be a polymer having a functional group capable of chemically bonding to an object to be coated. The object to be coated is obtained by applying the fluorine-containing coating composition of the present invention onto the object to be coated. The object to be coated may be referred to as a substrate in this specification.
The functional group capable of chemically bonding to the object to be coated may be one that contributes to a cross-linking reaction between or within the molecules of the fluoropolymer, but the fluoropolymer is By having such a functional group, even when a cross-linking reaction proceeds between or within the molecules of the above-mentioned fluoropolymer, a chemical bond is formed with the object to be coated, and it is difficult to peel off from the object to be coated. Accordingly, the fluoropolymer preferably has a functional group from the viewpoint of improving the adhesiveness to the object to be coated.
Examples of the functional group capable of chemically bonding to the object to be coated include a hydroxyl group, a glycidyl group, a carbonyl group, an isocyanate group, a thionyl group, an amino group, a phosphoric acid group, an alkoxyl group, a carboxyl group, and a salt. Carboxyl group, alkoxycarbonyl group, epoxy group and the like. When the above-mentioned fluorine-containing polymer having such a functional group is used, a coating film adhered to an object to be coated can be formed only by using a fluororesin without using a primer.
The functional group is preferably a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, and / or an epoxy group from the viewpoint of particularly excellent adhesion to an object to be coated.
In the present specification, the “carboxyl group forming a salt” means a compound in which an atom or an atomic group capable of forming a monovalent or divalent cation is bonded instead of hydrogen of a carboxyl group. I do. The carboxyl group forming the salt may be ionizable in a liquid medium described below, particularly in a liquid medium containing water or a water-soluble solvent. The atom or atomic group capable of forming the cation is not particularly limited, and examples thereof include K, Na, Ca, Fe, and NH. ₄ These may be the same or different in one molecule of the fluoropolymer and / or between a plurality of molecules of the fluoropolymer.
The above-mentioned epoxy group is generally a structure in which two atoms of carbon bonded by a carbon chain and one atom of oxygen are crosslinked and bonded, and in the carbon chain between the two atoms of carbon bonded to the oxygen. The number of carbon atoms is not particularly limited. In the present invention, a 1,2-epoxy group and a 1,3-epoxy group are preferable, and a 1,2-epoxy group is more preferable, since the reactivity is high and the compound easily contributes to a chemical bond with an object to be coated. .
The functional group that can be chemically bonded to the object to be coated may be the same type of group as the functional group derived from the polymerization initiator at the terminal of the fluorine-containing polymer. It is preferable that the above-mentioned fluorine-containing polymer is contained in the molecule separately from the one having the functional group derived from the initiator.
As the fluorine-containing polymer, a monomer having a functional group such as a hydroxyl group or a carbonyl group may be used as a comonomer for copolymerizing a small amount with the monomer component, and a monomer having a cyclic structure may be used. A monomer may be used. Examples of the monomer having a cyclic structure include those similar to those described as the monomer component of the fusible fluororesin.
The fluorinated polymer is obtained by copolymerizing a functional group-containing fluorinated ethylenic monomer (a) and a functional group-free fluorinated ethylenic monomer (b). The group-containing fluorine-containing ethylenic monomer (a) has a functional group, and the functional group is a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group or an epoxy group. The functional group-free fluorine-containing ethylenic monomer (b) does not have the functional group.
The fluoropolymer can introduce a functional group into the fluoropolymer by copolymerizing the functional group-containing fluoroethylenic monomer (a) as a monomer component, In addition, it can be introduced into the polymer chain of the fluoropolymer. By the above functional group, to obtain a coating film having excellent adhesiveness not only to an object to be coated which has conventionally been adhered but also to various objects to be coated which have been impossible or insufficient in the past. Can be.
Among the functional groups contained in the functional group-containing fluorine-containing ethylenic monomer (a), among the hydroxyl groups, carboxyl groups, carboxyl groups forming a salt, alkoxycarbonyl groups or epoxy groups, the types and combinations used are: The material may be appropriately selected depending on the type of the material such as metal and glass on the surface of the object to be coated and the use thereof, but a hydroxyl group is preferred from the viewpoint of heat resistance.
The functional group-containing fluorine-containing ethylenic monomer (a) has a functional group, and the functional group may be a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group or an epoxy group. Is not particularly limited as long as it is a vinyl group-containing monomer having a fluorine atom directly bonded to a carbon atom.

(Where X ¹ And X ² Are the same or different and are a hydrogen atom or a fluorine atom, and Rf ¹ Is a divalent alkylene group having 1 to 40 carbon atoms or a divalent fluorinated alkylene group having an ether bond having 1 to 40 carbon atoms, Y is a methylol group, a carboxyl group, a carboxyl group forming a salt, An alkoxycarbonyl group or an epoxy group, wherein the methylol group has one or two hydrogen atoms bonded to a carbon atom represented by —CF ₃ Or a fluorine-containing ethylenic monomer represented by the following formula:
Such a functional group-containing fluorinated ethylenic monomer (a) is not particularly limited.

And the like.
As the functional group-containing fluorine-containing ethylenic monomer (a), those in which Y in the above general formula (1) is a methylol group from the viewpoint of the stability of the functional group and the adhesiveness to various objects to be coated. Is more preferred.
One or more kinds of the functional group-containing fluorine-containing ethylenic monomer (a) can be used, and the functional group-containing fluorine-containing ethylenic monomer (a) having the same functional group is used. May be used alone or in combination of two or more, and the functional groups contained in the two or more kinds of the functional group-containing fluorine-containing ethylenic monomers (a) used may be different from each other.
The functional group-free fluorinated ethylenic monomer (b) has no functional group contained in the functional group-containing fluorinated ethylenic monomer (a) and is directly bonded to a carbon atom. It is a vinyl group-containing monomer having a fluorine atom.
The functional group-free fluorine-containing ethylenic monomer (b) is not particularly limited as long as it is such a substance. For example, tetrafluoroethylene, the following general formula (2)

(Where Rf ² Is -CF ₃ Or -ORf ³ It is. Rf ³ Is a perfluoroalkyl group having 1 to 5 carbon atoms. Perfluoroolefin or perfluoro (alkyl vinyl ether) such as a compound represented by the formula: or a perhaloolefin having fluorine and a halogen other than fluorine such as chlorotrifluoroethylene;
Vinylidene fluoride, vinyl fluoride, hexafluoroisobutene, the following general formula

(Where X ³ Is a hydrogen atom, a fluorine atom or a chlorine atom, and n is an integer of 1 to 5. ), A compound represented by the following general formula

(Where X ³ Is a hydrogen atom, a fluorine atom or a chlorine atom, and m is an integer of 1 to 5. And the like, and halogenated olefins having hydrogen and the like.
As the fluorine-containing ethylenic monomer containing no functional group (b), one type or two or more types can be used.
As the above-mentioned functional group-free fluorine-containing ethylenic monomer (b), tetrafluoroethylene, a par represented by the above general formula (2), from the viewpoint of excellent adhesion between the obtained coating film and the object to be coated. Perfluoro (alkyl vinyl ether) represented by the above general formula (2) such as fluoroolefin and perfluoro (propyl vinyl ether) is preferable.
As the functional group-free fluorine-containing ethylenic monomer (b), tetrafluoroethylene and the above-mentioned general formula (2) are represented by the above general formula (2) from the viewpoint of particularly excellent adhesion between the obtained coating film and the object to be coated. It is more preferable to combine with a perfluoroolefin or perfluoro (alkyl vinyl ether) represented by the above general formula (2). In this case, the number of moles of the tetrafluoroethylene is 85 to 99.9, which is the sum of the number of moles of the tetrafluoroethylene and the number of moles of the perfluoroolefin or perfluoro (alkyl vinyl ether) represented by the general formula (2). It is preferably 7%.
The number of moles of the functional group-containing fluorinated ethylenic monomer (a) is determined based on the number of moles of the functional group-containing fluorinated ethylenic monomer (a) and the number of moles of the functional group-free fluorinated ethylenic monomer (a). It is preferably 0.05 to 30% of the total number of moles of b). When the number of moles of the functional group-containing fluorine-containing ethylenic monomer (a) is less than 0.05%, the adhesion between the obtained coating film and the object to be coated is apt to decrease, and when it exceeds 30%, When the fluorinated coating composition of the present invention is baked after application, foaming becomes severe, and coating film defects are likely to occur. A more preferred upper limit is 10%, and a still more preferred upper limit is 5%.
The fluorine-containing polymer, in addition to the functional group-containing fluorine-containing ethylenic monomer (a) and the functional group-free fluorine-containing ethylenic monomer (b), as long as the heat resistance is not reduced, An ethylenic monomer having no fluorine atom may be copolymerized. In this case, the ethylenic monomer having no fluorine atom is preferably selected from ethylenic monomers having 5 or less carbon atoms in order not to lower the heat resistance. Specifically, ethylene, propylene, 1- Butene, 2-butene and the like.
The fluoropolymer particles may have a core / shell structure. As the core / shell structure, the core portion is composed of a polymer chain obtained by polymerizing the functional group-free fluorine-containing ethylenic monomer (b), and the shell portion is the functional group-containing fluorine-containing ethylene. Particles comprising a polymer chain obtained by copolymerizing the functional monomer (a) and the functional group-free fluorine-containing ethylenic monomer (b) may be used. It is preferable that the monomer component of the core portion does not contain the functional group-containing fluorine-containing ethylenic monomer (a). By introducing the functional group only into the shell portion in this way, the amount of the functional group-containing fluorine-containing ethylenic monomer (a) used can be reduced, and it is economical. Such a core / shell structure can be obtained by, for example, seed polymerization using a known method described in, for example, JP-A-4-154842 and JP-A-5-279579. Can be.
The fluorine-containing polymer may be a functional group-containing fluororesin. The functional group-containing fluororesin includes, as monomer components, one or two or more of the above-mentioned fluorinated vinyl monomers, and a monomer having a functional group such as a hydroxyl group or a carbonyl group at a side chain terminal. And obtained by copolymerization. When the fluorine-containing polymer is the functional group-containing fluororesin, the functional group at the side chain terminal reacts, so that curing by cross-linking and improvement in adhesiveness due to chemical bonding with the object to be coated are improved. Can be made possible.
It is preferable that the fluoropolymer has heat resistance at least at 200 ° C. If the composition does not have heat resistance at a temperature of less than 200 ° C., it becomes difficult to suitably use the fluorine-containing coating composition of the present invention for applications requiring heat resistance, flexibility at high temperatures and durability. The above-mentioned fluorine-containing polymer may be any one which generally has heat resistance at 200 to 350 ° C. in view of the baking temperature after application of the fluorine-containing coating composition of the present invention and the use temperature after formation of the coating film.
The fluoropolymer is excellent in heat resistance as described above, and thus differs from a copolymer obtained by copolymerizing a non-fluorine-based functional group-containing monomer, as described above. , Even when the composition is baked at a high temperature of, for example, 200 to 350 ° C after the application of the fluorine-containing coating composition of the present invention, the thermal decomposition property is low.
Since the fluorine-containing coating composition of the present invention has such low thermal decomposability, the heat-resistant fluorine-containing polymer having the above functional group has a high adhesive strength to the object to be coated, coloring, foaming, and pinhole. A coating film free from poor leveling and the like can be obtained. Further, even when the resulting coated article is used at a high temperature, the coated film maintains the adhesiveness to the article to be coated, and is unlikely to cause coating defects such as coloring, whitening, foaming and pinholes.
As the fluorine-containing polymer, a wide range of materials can be used as described above, and thus the fluorine-containing coating composition of the present invention has a wide range of applications.
As described above, the fluoropolymer has an average particle diameter of 0.005 to 0.5 μm. As the above-mentioned fluorine-containing polymer, the average particle diameter is 0.005 to 0.3 μm from the viewpoint that the filling property of the lower layer portion of the above-mentioned coating film can be enhanced and the adhesion with the object to be coated can be improved. And those having a functional group capable of chemically bonding to the object to be coated. In this case, the functional group is preferably a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, and / or an epoxy group, and these functional groups are the functional groups having these functional groups. More preferably, it is introduced by copolymerizing the contained fluorine-containing ethylenic monomer (a) as a monomer component.
When the average particle diameter of the fluoropolymer is 0.005 to 0.3 μm, in the fluorine-containing coating composition of the present invention, the functional group capable of chemically bonding the fluoropolymer to the object to be coated. Preferably, the fusible fluororesin has an average particle diameter of 1 to 1000 μm. In this case, the more preferable lower limit of the average particle diameter of the fluoropolymer is 0.01 μm, and the more preferable upper limit is 0.15 μm.
It is preferable that the fusible fluororesin and the fluorinated polymer are dispersed in a liquid medium. As the liquid medium, those usually used as a solvent are used. In the fluorine-containing coating composition of the present invention, as the solvent, a solvent containing water or a water-soluble solvent is generally preferred in view of environmental problems. The water-soluble solvent is a water-soluble organic solvent. As the solvent, a mixture of water and a water-soluble solvent, and water are more preferable.
The water-soluble solvent has a function of wetting the meltable fluororesin. When the water-soluble solvent has a high boiling point, in addition to wetting the fusible fluororesin, between the fusible fluororesins when drying after applying the fluorinated coating composition of the present invention, the It serves as a drying retarder for preventing the occurrence of cracks by connecting between the fluoropolymers and / or between the meltable fluororesin and the fluoropolymer. Even if the above water-soluble solvent has a high boiling point, if the compounding amount is appropriate, since it volatilizes sufficiently at the firing temperature after application of the fluorine-containing coating composition of the present invention, the heat resistance of the obtained coating film, It does not reduce properties such as non-stickiness.
The water-soluble solvent is not particularly limited. For example, low-boiling organic solvents having a boiling point of less than 100 ° C include methanol, ethanol, isopropanol, sec-butanol, t-butanol, acetone, and methyl ethyl ketone; Medium-boiling organic solvents such as toluene, xylene, methyl cellosolve, ethyl cellosolve, methyl isobutyl ketone, n-butanol and the like; N-methyl-2-pyrrolidone, N, N-dimethyl as high boiling organic solvents having a boiling point exceeding 150 ° C. Acetamide, N, N-dimethylformamide, ketocin, ethylene glycol, propylene glycol, glycerin, dimethyl carbitol, butyl dicarbitol, butyl cellosolve, cyclohexanol, diisobutyl ketone, 1,4-butanediol, Triethylene glycol, tetraethylene glycol, and the like. The high-boiling organic solvent is preferably an alcohol-based solvent because it has good wettability with the fusible fluororesin and is easy to handle.
One or more of these water-soluble solvents can be used. The water-soluble solvent enhances the filling property of the lower layer of the coating film and can promote the layer separation between the lower layer and the upper layer. Therefore, the high-boiling organic solvent is used as the low-boiling organic solvent and / or It is preferable to use a mixture with a boiling organic solvent.
The amount of the water-soluble solvent is preferably 0.5 to 50% of the liquid medium in the fluorine-containing coating composition of the present invention. In the case of a low-boiling organic solvent, if the amount is too small, the embrace of bubbles tends to occur, and if the amount is too large, the fluorine-containing coating composition of the present invention becomes flammable as a whole and has the advantage of an aqueous dispersion composition. May be impaired. In the case of a medium boiling organic solvent, if the amount is too small, the meltable fluororesin may return to a powder at the time of drying after applying the fluorine-containing coating composition of the present invention, and the film-forming property may be lost. If it is too much, it may remain on the coated film after firing, and the physical properties of the coated film may be reduced. In the case of a high boiling point organic solvent, if the amount is too large, it may remain in the fired coating film and deteriorate the coating film properties. A more preferred lower limit is 1% and a more preferred upper limit is 45%.
With respect to the blending amount of the water-soluble solvent, the amount of the liquid medium in the fluorine-containing coating composition of the present invention includes, for example, a dispersion medium when the above-mentioned fluorine-containing polymer is prepared as an aqueous dispersion.
As the fluorine-containing coating composition of the present invention, the average particle diameter is 1 to 1000 μm from the viewpoint that the lower layer portion of the coating film can be sufficiently filled and the adhesiveness with the object to be coated can be enhanced. A fluorinated coating composition comprising a fusible fluororesin and a fluorinated polymer having an average particle diameter of 0.005 to 0.3 μm dispersed in a liquid medium, wherein the fluorinated polymer contains a functional group-containing polymer. The fluorinated ethylenic monomer (a) is obtained by copolymerizing the fluorinated ethylenic monomer (a) and the functional group-free fluorinated ethylenic monomer (b), ) Has a functional group, and the functional group is a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group or an epoxy group, and the functional group-free fluorine-containing ethylenic group The monomer (b) preferably does not contain the above functional group.
As the fluorine-containing coating composition of the present invention, it is also possible to sufficiently fill the lower layer of the coating film, promote the layer separation between the lower layer and the upper layer, and enhance the adhesion with the object to be coated. In view of the fact that it can be obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.3 μm, The polymer has a functional group capable of chemically bonding to the object to be coated, and the solid content weight of the fusible fluororesin is the solid content weight of the fusible fluororesin and the fluorinated polymer. Those which are 70 to 99.9% of the total of solid content weight are preferred. In this case, as the functional group, a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group and / or an epoxy group are preferable, and these functional groups are the functional groups containing these functional groups. More preferably, it is introduced by copolymerizing the group-containing fluorine-containing ethylenic monomer (a) as a monomer component.
In the case of the above average particle diameter, when the compounding amount of the fusible fluororesin exceeds 99.9% by weight, the compounding amount of the fluoropolymer is too small, and the functional groups contributing to the adhesion to the object to be coated are entirely reduced. When the amount of the fusible fluororesin is less than 70% by weight, the amount of the fluorinated polymer becomes excessive, and the particles of the fluorinated polymer are coated. By filling the contact surface with the object and further laminating, the functional groups of the particles on the surface of the object to be coated react with the functional groups of the laminated particles and do not contribute to the adhesion to the object to be coated. Insufficient adhesion to painted objects. A more preferred lower limit is 80% by weight, and a more preferred upper limit is 98% by weight.
The fluorine-containing coating composition of the present invention is used in combination with the above-mentioned fusible fluorine resin and the above-mentioned fluorine-containing polymer, and if necessary or necessary, a pigment, a filler, a viscosity modifier, a thickener, a film-forming material, a stable material. Various additives such as an agent, a decomposition accelerator, a rust inhibitor and an antifoaming agent can be blended. From the viewpoint of obtaining a highly transparent coating film, it is preferable to limit the amount of these additives to the minimum necessary.
The method for preparing the fluorine-containing coating composition of the present invention is not particularly limited, and for example, a conventionally known method can be used. For example, the above-mentioned fusible fluororesin, the above-mentioned pigment, the above-mentioned fluoropolymer and the like are required. The meltable fluorine resin and the fluorine-containing polymer are mixed at an appropriate ratio so as to have the above-mentioned volume ratio or solid content weight ratio according to the following pretreatment.
The fluorine-containing coating composition of the present invention can be prepared by uniformly dispersing a meltable fluororesin and a fluoropolymer in water in the presence of a water-soluble solvent and a surfactant.
As the fusible fluororesin, a powder is produced, for example, by the method described in JP-A-63-270740, and the powder is usually dispersed in a solvent using an appropriate dispersant. Examples of the use of the dispersant include, for example, after wetting the meltable fluororesin with a solvent such as a lower alcohol, a ketone, or an aromatic hydrocarbon, a nonionic surfactant, or a dispersant such as an anionic surfactant. A dispersing method or the like can be used.
The compounding amount of the above-mentioned fusible fluororesin is 15 to 80% of the total weight of the fluorinated coating composition of the present invention. If it is less than 15%, the viscosity of the fluorine-containing coating composition of the present invention is low, so that even if it is applied to the object to be coated, sagging is likely to occur, and the film thickness of the coating film may be insufficient, and 80% If it exceeds, the fluorine-containing coating composition of the present invention may be difficult to flow, and may not be able to be coated. A preferred lower limit is 20% and a preferred upper limit is 75%. The amount of the meltable fluororesin may be appropriately selected within the above range in consideration of the coating method, adjustment of the film thickness, and the like.However, in the case of spray coating or dip coating, a relatively low concentration is used, and press coating is performed. In such a case, it is preferable that the content be 50% or more that becomes a paste.
The pigment is usually used after pulverizing and dispersing the solvent, the fluoropolymer, the surfactant, and the like by a pulverizer / disperser such as a basket mill, a dynamo mill, and a ball mill.
Since the above-mentioned fluoropolymer has a small average particle size of 0.005 to 0.5 μm, it can be dispersed as it is, and is usually synthesized by emulsion polymerization or the like and concentrated using a surfactant. .
As the surfactant which can be used in the fluorine-containing coating composition of the present invention, a powder of a fusible fluororesin in the fluorine-containing coating composition in an amount of 15 to 80% of the total weight of the fluorine-containing coating composition of the present invention. The surfactant is not particularly limited as long as it can uniformly disperse, and any of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants can be used.
Examples of the surfactant include sodium alkyl sulfate, sodium alkyl ether sulfate, triethanolamine alkyl sulfate, triethanolamine alkyl ether sulfate, ammonium alkyl sulfate, ammonium alkyl ether sulfate, alkyl ether sodium phosphate, and fluoroalkyl carboxylic acid. Anionic surfactants such as sodium; cationic surfactants such as alkyl ammonium salts and alkyl benzyl ammonium salts; polyoxyethylene alkyl ethers, polyoxyethylene phenyl ethers, polyoxyethylene alkyl esters, and propylene glycol-propylene oxide copolymers Merging, perfluoroalkyl ethylene oxide adduct, 2-ethylhexa Lumpur nonionic surfactants ethylene oxide adducts, alkyl betaine, alkylamido betaine, amphoteric surfactants such as imidazolium betaine. Among them, anionic surfactants and nonionic surfactants are preferred, and nonionic surfactants having an oxyethylene chain with a small residual amount of thermal decomposition are more preferred.
The amount of the surfactant is usually 0.01 to 50% of the meltable fluororesin. When the content is less than 0.01%, the powder of the fusible fluororesin is not uniformly dispersed and may partly float. When the content is more than 50%, the residue of the surfactant decomposed in the obtained coating film may be reduced. A large amount may remain and may be colored, or the physical properties of the coating film such as heat resistance and non-adhesiveness may be reduced. A preferred lower limit is 0.1%, a more preferred lower limit is 0.2%, a preferred upper limit is 30%, and a more preferred upper limit is 20%.
The fluorine-containing coating composition of the present invention may be appropriately diluted with a solvent, if necessary, adjusted to a viscosity that allows easy coating with a viscosity modifier or the like, formed into a coating, and coated.
The above-mentioned fluorine-containing coating composition is used for coating on an object to be coated, and the object to be coated is preferably made of a metal, a polymer compound molded body, glass or pottery.
In the present specification, the “polymer compound molded article” means a product obtained by molding a polymer compound. The polymer compound is not particularly limited and includes, for example, a resin and a rubber. However, a point that can withstand the firing temperature after application of the fluorine-containing coating composition of the present invention and the use temperature of the obtained coating film. Therefore, a heat-resistant resin such as a polyimide resin and a heat-resistant rubber such as silicone rubber are preferable.
The fluorine-containing coating composition of the present invention is obtained by subjecting an object to be coated such as aluminum, stainless steel (SUS), iron, heat-resistant resin, heat-resistant rubber or the like to a surface treatment such as degreasing or surface roughening if necessary. By applying a method such as spraying, spraying or the like, drying the obtained coating film, and baking at a temperature equal to or higher than the melting point of the fusible fluororesin, a gradient coating film can be formed.
As the inclined coating film obtained from the fluorine-containing coating composition of the present invention, a coating film having a thickness of 3 to 15 μm can be obtained as a surface layer, depending on the amount of the meltable fluororesin. Such a gradient coating has a thickness comparable to a coating obtained using a conventional two-coat method. Therefore, the fluorine-containing coating composition of the present invention can be suitably used by the one-coat method even in the field where the two-coat method is currently used.
The gradient coating film obtained from the fluorine-containing coating composition of the present invention can have a thickness of, for example, about 100 μm.
The above-mentioned inclined coating film obtained from the fluorine-containing coating composition of the present invention may be provided with a top coat such as a top coat, if necessary.
The fluorine-containing coating composition of the present invention has, as described above, mutually different average particle diameters, that is, a fusible fluororesin having an average particle diameter of 1 to 1000 μm and an average particle diameter of 0.005 to 0.5 μm. It is obtained by blending two components of a certain fluorine-containing polymer at a volume ratio or a solid content weight ratio within the above-mentioned specific range. The fluororesin layer can be formed with a thickness comparable to that of the method without generating cracks.
Although the mechanism by which the fluorine-containing coating composition of the present invention enables the thickening of the film is not clear, the meltable fluororesin to be disposed in the upper layer portion of the obtained inclined coating film is compared as in the above range. This is considered to be due to having a very large average particle size. Incidentally, in the conventional general coating, the average particle diameter of the fluororesin was relatively small, so that cracks occurred when the film thickness was more than a certain level, and the cracks could not be suppressed even by overcoating. It is probable that the conversion was not possible.
Since the fluorine-containing coating composition of the present invention can thus form the fluororesin layer thicker than before, the heat resistance, durability, abrasion resistance, corrosion resistance, and non-adhesion of the meltable fluororesin can be improved. Excellent properties such as properties can be sufficiently exhibited.
The fluorine-containing polymer of the present invention is also characterized by adjusting the average particle diameter of the fluorine-containing polymer and the average particle diameter of the fusible fluororesin, so that the fluorinated polymer is a critical surface of the fusible fluororesin. Even if it has a critical surface tension higher than the tension, it is possible to obtain a coating film in which the above-mentioned fluoropolymer layer is formed below and above the above-mentioned fluororesin layer. Therefore, according to the fluorine-containing coating composition of the present invention, the type of the component constituting the upper layer and the type of the component forming the lower layer of the obtained coating film can be arbitrarily selected, and the width of the coating film design can be varied. And room for material selection.
As described above, the fluorine-containing coating composition of the present invention can be suitably used by the one-coat method even in applications where two-coat method or two or more coats have conventionally been required. The fluorine-containing coating composition of the present invention can further be appropriately selected from a wide variety of substance groups as the above-mentioned fluorine-containing polymer, and by appropriately selecting these, the composition is applied to be suitable for use, and used. Can be offered.
The fluorine-containing coating composition of the present invention can improve the adhesiveness to an object to be coated by a one-coat method, so that it is not necessary to apply a primer. Even if the object to be coated is glass, pottery, etc., the adhesiveness can be improved, so that unlike the conventional method, for example, the surface of a glass substrate is treated with a silane coupling agent or the like, or a silicone resin is used as a coating composition. There is no need to add it inside.
The fluorine-containing coating composition of the present invention is further obtained by blending a fusible fluororesin and a fluoropolymer as described above, and an inorganic acid such as chromic acid, or polyamideimide, polyimide, poly Since it is not necessary to incorporate a heat-resistant resin such as ether sulfone, a highly transparent coating film can be obtained, so that it is preferably used, for example, in applications where the texture and design of the object to be coated are emphasized. Can be.
The fluorine-containing coating composition of the present invention can further effectively prevent scattering at the time of impact when glass, pottery or the like is to be coated.
Therefore, the fluorine-containing coating composition of the present invention is applied to an article composed of various substrates such as a metal, a polymer compound molded article, glass, and porcelain to provide corrosion resistance, abrasion resistance, heat resistance, and non-adhesion. In addition to being able to impart properties and the like, it can be used for applications that require the transparency of the coating film, the texture of the substrate itself, the design, and the like.
Examples of a material to which the fluorine-containing coating composition of the present invention can be suitably applied include, for example, electric components and the like, utilizing the fact that the obtained inclined coating films have different front and back properties.
The fluorine-containing coating composition of the present invention can also be used in rice cookers, pots, jar pots, hot plates, irons, frying pans, home bakeries, and the like for home appliances and kitchens. For industrial use, office automation [OA] Widely applied to mold release applications such as equipment rolls, OA equipment belts, papermaking rolls, film production calender rolls, and injection molds; corrosion-resistant applications such as stirring blades, tank inner surfaces, vessels, towers, and centrifuges. You.
The fluorine-containing coating composition of the present invention is used for preventing glass from scattering, for example, lighting equipment such as light bulbs; display devices such as CRTs and liquid crystal display devices; building materials such as glass windows; glass tableware and other glass containers. Tableware; laboratory equipment such as glass laboratory equipment; various glass products such as functional glass such as fire prevention glass and safety glass; and materials for these various glass products. In these cases, transparent glass Sex can be maintained.
The fluorine-containing coating composition of the present invention, by the above-mentioned fusible fluororesin, non-adhesiveness, slidability, etc. are obtained, and since the fluororesin layer is thick, the durability is excellent, and the fluorine-containing polymer is By using a fluorine-containing polymer as an elastic body, the flexibility can be improved so as not to be too hard, so that it can be suitably used particularly for an OA equipment roll or an OA equipment belt.
The above-mentioned fluorine-containing polymer, especially when it is the above-mentioned fluororubber, can particularly improve durability and flexibility. For example, for OA equipment, durability and flexibility were not sufficiently exhibited by the conventional method. When used for rolls, belts for OA equipment, and the like, the durability is dramatically improved and flexibility superior to that of the related art can be exhibited. Conventionally, rolls for OA equipment, belts for OA equipment, etc. are usually coated with PFA on a silicone rubber roll, and good abrasion resistance is required. Therefore, the fluorine-containing coating composition of the present invention is preferably used from this point of view. Can be used.
In addition, the fluorine-containing coating composition of the present invention, when using a functional group-containing fluororesin as the fluorine-containing polymer, exhibits high adhesiveness to a substrate such as metal, silicone rubber, and polyimide. By coating, it can be suitably used as a roll for OA equipment or a belt for OA equipment.
In recent years, OA equipment has been required to be more and more energy-saving, but as one of the methods for heating OA equipment belts with high thermal efficiency, IH (induction heating) method using a metal belt as the base material is proposed. Have been. The IH method utilizes the fact that an eddy current flows through a magnetic metal placed in an alternating magnetic field by electromagnetic induction and generates heat. In this method, first, when a magnetic metal belt is used as a base material, the belt generates heat, and then the surface layer of the belt is heated by heat conduction to melt the toner. The surface layer of this belt is generally a fluororesin layer. Here, in order to sufficiently melt the toner to obtain a high-quality image, a silicone rubber layer may be provided as an intermediate layer between the base material and a surface layer such as a fluororesin layer.
On the other hand, OA equipment is expected to have a shorter start-up time, and it is required that the surface layer of the belt generate heat in a shorter time. Here, in the configuration in which the silicone rubber layer is provided as the intermediate layer, there is a problem that some time lag occurs between heat generation of the belt base material and heating of the belt surface layer. Further, the metal belt was inferior in flexibility and was insufficient in durability.
These problems can be solved by providing a silicone rubber layer containing a magnetic material on at least a part of the intermediate layer, and providing a film made of the fluorine-containing coating composition of the present invention as a surface layer. That is, since the intermediate layer generates heat instead of the base material, a time lag due to heat conduction can be suppressed.
When a magnetic material is blended in the intermediate layer, it is desirable to use a belt made of polyimide or the like having low thermal conductivity as a base material in order to prevent heat conduction from the intermediate layer to the base material side. Polyimide also has excellent properties in terms of rigidity, has improved durability compared to metal belts, and can be adapted to higher speeds.
A coating film obtained by applying the above-mentioned fluorine-containing coating composition is also one of the present invention.
A coated article characterized by having the above coating film is also one of the present invention.
It is preferable that the coated object has the coating film formed on the object to be coated, and the object to be coated is made of a metal, a polymer compound molded body, glass or pottery.
The painted object is preferably a material for a light bulb.
It is preferable that the painted object is a fireproof glass material or a safety glass material.
The painted object is preferably a glass tableware material or a glass laboratory tool material.
The coated object is preferably a roll for OA equipment or a belt for OA equipment.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
Example 1
70 g of PFA powder having an average particle diameter of 12 μm obtained by pulverization, 5 g of ammonium salt of perfluorooctanoic acid, and 100 g of ion-exchanged water were placed in a SUS container, and the surface of the PFA powder was well wetted with a stirrer and dispersed. A PFA dispersion was obtained. To this dispersion, 50 g of a PTFE emulsion polymerization 60% by mass dispersion having an average particle diameter of 0.35 μm, 50 g of nonionic HS210 (manufactured by NOF Corporation) as a surfactant, and 0.5 g of sodium lauryl sulfate as a thickener were added. Then, the mixture was well dispersed to obtain a paint.
This paint was spray-coated on an aluminum plate (150 mm × 200 mm × 2 mm), dried at 80 ° C. for 30 minutes, and baked at 380 ° C. for 20 minutes to obtain a coated product having a coating thickness of 30 μm. The coating film was peeled off, the cross section was thinly cut using a microtome (manufactured by Leica AG), and a filter was prepared with a polarizing microscope. The thickness of the PFA layer was measured. Table 1 shows the results.
Example 2
Instead of using PTFE, 99.95 parts by mass of tetrafluoroethylene and 0.05 parts by mass of perfluoro (propyl vinyl ether), a concentrated PTFE having a mean particle size of 0.25 μm and a modified PTFE of 60% by mass obtained by emulsion polymerization. Prepared a coating in the same manner as in Example 1 to obtain a coating, and measured the thickness of the coating and the surface layer. Table 1 shows the results.
Examples 3 to 6
A coating material was prepared in the same manner as in Example 2 except that the type of the meltable fluororesin, the average particle size, the particle size of the modified PTFE, and the compounding ratio were as shown in Table 1, to obtain a coating film. The thickness of the surface layer was created. Table 1 shows the results.
Example 7
As the above-mentioned fluorine-containing polymer, vinylidene fluoride-based fluoro rubber having an average particle diameter of 0.2 to 0.3 μm (Daily latex GL252CR-A, manufactured by Daikin Industries, Ltd.) and an acid-accepting agent-containing paint (concentration: 50% by mass, Daikin 100 g of PFA dispersion (manufactured by Kogyo Co., Ltd.) and 120 g of the PFA dispersion used in Example 1 (mixing ratio of PFA: fluororubber 70:30) were dispersed to obtain a PFA-containing fluororubber coating. To 100 parts by mass of this coating material, 3 parts by mass of a curing agent (Daily latex GL200-B solution, manufactured by Daikin Industries, Ltd.) were blended and dispersed, applied on an aluminum foil (thickness: 100 μm), and treated at room temperature for 30 minutes. After drying for 30 minutes, baking was performed at 80 ° C. for 30 minutes and at 320 ° C. for 60 minutes to obtain a coating film.
This aluminum foil-coated film was cut into thin sections using a microtome (manufactured by Leica AG), a filter was prepared with a polarizing microscope, and enlarged 1000 times while adjusting so that boundaries could be confirmed. The thickness of the (PFA layer) was measured. Table 1 shows the results.
Example 8
Except for using the FEP dispersion used in Example 4 instead of the PFA dispersion, a coating was prepared in the same manner as in Example 7 to obtain a coating, and the thickness of the coating and the surface layer was measured. Table 1 shows the results.
Example 9
The same as Example 1 except that an emulsion polymer of flexible PFA (tetrafluoroethylene: perfluoro (propyl vinyl ether) mass ratio: 53:47) having an average particle diameter of 0.06 μm was used as the fluoropolymer. And a coating was prepared, applied and dried, and baked at 320 ° C. for 60 minutes to obtain a coating, and the thicknesses of the coating and the surface layer were measured. Table 1 shows the results.
Example 10
PFA having an average particle size of 0.07 μm obtained by emulsion polymerization using a monomer having an OH group in a side chain as a monomer component as the monomer component at 2% by mass of the total amount of the monomer component. Except for using (functional group-containing PFA), a coating material was prepared in the same manner as in Example 1, applied, dried, and baked at 330 ° C. for 60 minutes to obtain a coating film in the same manner as in Example 1. . Since the obtained coated product was firmly adhered to aluminum, the base material was changed to an aluminum foil having a thickness of 100 μm, and a coating film was prepared again by the same method. And the thickness of the surface layer were measured. Table 1 shows the results.
Comparative Examples 1 to 4
A coating material was prepared in the same manner as in Example 1 except that the type and average particle size of the fusible fluororesin, the type and average particle size of the fluoropolymer, and the compounding ratio were as shown in Table 1. To obtain a coating film, and the thickness of the coating film and the surface layer was prepared. Table 1 shows the results.

The specific gravity of the used components was 2.2 for PTFE, PFA and FEP, and 1.75 for fluororubber.
From Table 1, the volume ratio of PFA or FEP having an average particle diameter in the range of 1 to 30 μm and the above-mentioned fluoropolymer having an average particle diameter in the range of 0.005 to 0.5 μm is 35: The coatings of Examples 1 to 10 were blended so as to be 65 to 95: 5, and the obtained coating films had a surface layer thickness of 2 to 15 μm, whereas the average particle diameter of PFA or FEP was Is less than 1 μm, it was found that the formation of the surface layer was not confirmed or the thickness was 1 to 2 μm.
Production Example 1 Production of a fluorinated polymer having a functional group
Into a 3 liter glass-lined autoclave equipped with a stirrer, a valve, a pressure gauge, and a thermometer, 1500 ml of pure water and 9.0 g of ammonium perfluorooctanoate were charged, sufficiently purged with nitrogen gas, evacuated, and charged with 20 ml of ethane gas. . Then, the following equation (3)

3.8 g of perfluoro- (1,1,9,9-tetrahydro-2,5-bistrifluoromethyl-3,6-dioxa-8-nonenol) and 18 g of perfluoro (propyl vinyl ether) [PPVE] The pressure in the system was maintained at 70 ° C. using nitrogen gas.
While stirring, tetrafluoroethylene [TFE] gas was injected under pressure such that the internal pressure became 8.5 kgf / cm2G.
Next, a solution of 0.15 g of ammonium persulfate dissolved in 5.0 g of water was injected under pressure using nitrogen to start the reaction.
Since the pressure decreases as the polymerization reaction proceeds, 7.5 kgf / cm ² 8.5 kgf / cm with tetrafluoroethylene gas at the time when the temperature has decreased to G ² The pressure was increased again, and the pressure reduction and pressure increase were repeated.
While continuously supplying tetrafluoroethylene, every time about 40 g of tetrafluoroethylene gas is consumed from the start of polymerization, 1.9 g of the fluorine-containing ethylenic monomer having a hydroxyl group represented by the above formula (3) is added. The polymerization was continued by injecting a total of three times (5.7 g in total) and the polymerization was continued. When about 160 g of tetrafluoroethylene was consumed from the start of the polymerization, the supply was stopped, the autoclave was cooled, the unreacted monomer was released, and a bluish translucent was obtained. 1702 g of an aqueous dispersion of was obtained.
The concentration of the polymer in the obtained aqueous dispersion was 10.9%, and the particle diameter measured by a dynamic light scattering method was 70.7 nm.
In addition, a part of the obtained aqueous dispersion was subjected to freeze coagulation, and the precipitated polymer was washed and dried to isolate a white solid. The molar ratio composition of the obtained copolymer was TFE / PPVE / (a fluorine-containing ethylenic monomer having a hydroxyl group represented by the formula (3)) = 97.7 by 19F-NMR analysis and IR analysis. 1.2: 1.1 mol%.
The infrared spectrum is 3620 to 3400 cm ^-1 In addition, characteristic absorption of -OH was observed.
According to DSC analysis, Tm was 310 ° C., and 1% thermal decomposition temperature Td was 368 ° C. according to DTGA analysis. Using a 2 mm nozzle with a length of 8 mm using a Koka type flow tester, preheating at 372 ° C. for 5 minutes, load 7 kgf / cm ² The melt flow rate was measured to be 12.0 g / 10 minutes.
Preparation Example 1 Preparation of Fluorine-Containing Paint Composition A
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Was mixed with 26 parts by weight of a PFA resin powder (average particle size: 25 μm, apparent density: 0.8 g / ml) to prepare a uniform dispersion composition. This was designated as fluorinated coating composition A. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 95: 5.
Preparation Example 2 Preparation of Fluorine-Containing Paint Composition B
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Was mixed with and dispersed in 42 parts by weight of a fluorine-containing polymer having the above formula and 26 parts by weight of a PFA resin powder (average particle diameter: 25 μm, apparent density: 0.8 g / ml) to prepare a uniform dispersion composition. This was designated as fluorinated coating composition B. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 85:15.
Preparation Example 3 Preparation of Fluorine-Containing Paint Composition C
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Was mixed and dispersed in a PFA resin powder (average particle size: 25 μm, apparent density: 0.8 g / ml) to prepare a uniform dispersion composition. This was designated as fluorinated coating composition C. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 99.92: 0.08.
Preparation Example 4 Preparation of Fluorine-Containing Paint Composition D
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, a fluorine-containing polymer having a functional group 110 parts by weight and 26 parts by weight of a PFA resin powder (average particle diameter 25 μm, apparent density 0.8 g / ml) were mixed and dispersed to prepare a uniform dispersion composition. This was designated as fluorinated coating composition D. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 68:32.
Preparation Example 5 Preparation of Fluorine-containing Coating Composition E
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Were mixed and dispersed to prepare a uniform dispersion composition by mixing and dispersing 12 parts by weight of a fluorinated polymer having the following formula and 26 parts by weight of an FEP resin powder (average particle diameter: 25 μm, apparent density: 0.8 g / ml). This was designated as fluorinated coating composition E. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 95: 5.
Preparation Example 6 Preparation of Fluorine-Containing Paint Composition F
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Was mixed and dispersed with 42 parts by weight of a fluorinated polymer having the above formula and 26 parts by weight of FEP resin powder (average particle diameter 25 μm, apparent density 0.8 g / ml) to prepare a uniform dispersion composition. This was designated as fluorinated coating composition F. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 85:15.
Preparation Example 7 Preparation of Fluorine-Containing Paint Composition G
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, 20 parts by weight of pure water, functional group Was mixed and dispersed into a uniform dispersion composition by mixing and dispersing 0.2 part by weight of a fluorine-containing polymer having the above formula and 26 parts by weight of an FEP resin powder (average particle size: 25 μm, apparent density: 0.8 g / ml). This was designated as fluorinated coating composition G. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 99.92: 0.08.
Preparation Example 8 Preparation of Fluorine-containing Coating Composition H
4 parts by weight of isopropyl alcohol, 8 parts by weight of a nonionic surfactant (trade name: DS-401, manufactured by Daikin Industries, Ltd.), 6 parts by weight of triethylene glycol, 4 parts by weight of ethylene glycol, a fluorine-containing polymer having a functional group 110 parts by weight and 26 parts by weight of FEP resin powder (average particle diameter 25 μm, apparent density 0.8 g / ml) were mixed and dispersed to prepare a uniform dispersion composition. This was designated as fluorinated coating composition H. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 68:32.
Preparation Example 9 Preparation of Fluorine-containing Coating Composition I
50 parts by weight of a PFA dispersion (average particle diameter 0.3 μm, solid content concentration 50% by weight, trade name: AD-2CR, manufactured by Daikin Industries, Ltd.) and 12 parts by weight of a functional group-containing fluoropolymer are mixed and dispersed. A homogeneous dispersion composition was prepared. This was designated as fluorinated coating composition I. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 95: 5.
Preparation Example 10 Preparation of Fluorine-Containing Paint Composition J
50 parts by weight of FEP dispersion (average particle diameter 0.2 μm, solid content concentration 50% by weight, trade name: ND-1, manufactured by Daikin Industries, Ltd.) and 12 parts by weight of a functional group-containing fluoropolymer are mixed and dispersed. A homogeneous dispersion composition was prepared. This was designated as fluorinated coating composition J. The weight ratio of the fluorine-containing molten resin to the fluorine-containing polymer having a functional group was 95: 5.
Example 11
An aluminum plate (A-1050) is spray-coated with the fluorine-containing coating composition A, dried at 80 to 100 ° C for 30 minutes, and baked at 340 ° C for 30 minutes to obtain a fluororesin-coated coated plate having a coating of about 70 µm. Obtained.
Regarding the adhesiveness of the coating film to the aluminum plate, a strip-shaped cut is made in the obtained coating film at intervals of 1 cm, one end of the strip is peeled off from the aluminum plate, and then the jig is placed so that the coating surface faces directly above. A fluororesin-coated plate is fixed to a Tensilon universal tester (trade name, manufactured by Orientec) using a, and one end of a strip peeled from an aluminum plate is attached to a chuck located above the coating film, and this chuck is cross-headed. By moving the strip upward at a speed of 50 mm / min, the strip can be peeled off from the aluminum plate in a direction of substantially 90 °. The evaluation was made by measuring the peel strength at this time. Table 2 shows the results.
Example 12
The procedure of Example 11 was repeated except that the fluorine-containing coating composition B was used instead of the fluorine-containing coating composition A.
Example 13
The procedure of Example 11 was repeated except that the fluorine-containing coating composition C was used instead of the fluorine-containing coating composition A.
Example 14
The procedure of Example 11 was repeated except that the fluorine-containing coating composition D was used instead of the fluorine-containing coating composition A.
Example 15
The procedure of Example 11 was repeated except that the fluorine-containing coating composition E was used instead of the fluorine-containing coating composition A.
Example 16
The procedure of Example 11 was repeated except that the fluorine-containing coating composition F was used instead of the fluorine-containing coating composition A.
Example 17
The procedure of Example 11 was repeated, except that the fluorine-containing coating composition G was used instead of the fluorine-containing coating composition A.
Example 18
The procedure of Example 11 was repeated, except that the fluorine-containing coating composition H was used instead of the fluorine-containing coating composition A.
Comparative Example 5
The surface of the aluminum plate (A-1050) was spray-coated with the fluorine-containing coating composition 1, dried at 80 to 100 ° C for 30 minutes, and then baked at 340 ° C for 30 minutes. I couldn't do that.
Comparative Example 6
The surface of the aluminum plate (A-1050) was spray-coated with the fluorine-containing coating composition J, dried at 80 to 100 ° C for 30 minutes, and then baked at 340 ° C for 30 minutes. I couldn't do that.

From Table 2, in Comparative Examples 5 to 6 in which the average particle size of the fusible fluororesin is not in the range of 1 to 1000 μm, cracks occur and a thick film cannot be obtained, but the average particle size of the fusible fluororesin is In Examples 11 to 18 in the range of 1 to 1000 µm, the peel strength was relatively large, and the solid content weight ratio of the fusible fluororesin to the fluoropolymer was 70:30 to 99.9: 0.1. It was found that in Examples 11 to 12 and Examples 15 to 16, which were within the range, the peel strength was higher.
Example 19
The fluorine-containing coating composition A was spray-coated on a silicone rubber roll, dried at 80 to 100 ° C. for 30 minutes, and baked at 340 ° C. for 30 minutes to obtain a fluororesin-coated roll having a coating film of about 30 μm.
Regarding the abrasion resistance of the obtained coating film, copy paper (trade name: recycled PPC paper, manufactured by Fuji Xerox Co., Ltd.) was pressed against the surface of the fluororesin-coated roll heated to 200 ° C. with a load of 1 kg, and the roll was rotated at a rotation speed of 300 rpm. The surface of the roll is abraded by rotating, and then a wetting index standard solution (31 dyne / cm) is dropped and the time until the contact angle by a goniometer becomes 20 ° or less, or the coating film is peeled from the silicone rubber roll substrate. The time taken to perform was evaluated as a measure of durability. Table 3 shows the results.
Example 20
The procedure of Example 19 was repeated except that the fluorine-containing coating composition B was used instead of the fluorine-containing coating composition A.
Example 21
The procedure of Example 19 was repeated, except that the fluorine-containing coating composition C was used instead of the fluorine-containing coating composition A.
Example 22
The procedure of Example 19 was repeated, except that the fluorine-containing coating composition D was used instead of the fluorine-containing coating composition A.

From Table 3, in Examples 19 to 22, the abrasion resistance is relatively good, and the solid content weight ratio of the fusible fluororesin to the fluoropolymer is in the range of 70:30 to 99.9: 0.1. In Examples 19 to 20, which are inside, it was found that the wear resistance was better. Example 23
Fluorine-containing coating composition A is spray-coated on a glass plate having a thickness of 1.5 mm, dried at 80 to 100 ° C. for 30 minutes, and then baked at 340 ° C. for 30 minutes to obtain a fluororesin-coated glass having a coating film of about 70 μm. I got a board.
The impact resistance of the obtained fluororesin-coated glass sheet was measured using a Dupont-type impact deformation tester described in JIS K 5600-5-3 and mounted on a horizontally supported tester with a shooting type having a radius of 6.35 mm. Attach the base, sandwich the fluororesin-coated glass plate between the shooting mold and the receiving stand, drop a 300 g weight from the height of 100 mm onto the shooting mold, observe the state of destruction of the fluororesin-coated glass plate, The weight loss due to the scattering of
Weight loss (%) = weight of scattered matter (g) / weight before test (g) × 100
It was evaluated by obtaining the following. Table 4 shows the results.
Further, regarding the visible light transmittance of the fluororesin-coated glass plate, the light transmittance in a typical visible light region of 400 to 700 nm is measured using a U-3310 type spectrophotometer (trade name, manufactured by Hitachi, Ltd.). This was evaluated. Table 5 shows the results.
Example 24
The procedure of Example 23 was repeated except that the fluorine-containing coating composition B was used instead of the fluorine-containing coating composition A.
Example 25
The procedure of Example 23 was repeated except that the fluorine-containing coating composition C was used instead of the fluorine-containing coating composition A.
Example 26
The procedure of Example 23 was repeated except that the fluorine-containing coating composition D was used instead of the fluorine-containing coating composition A.
Example 27
The procedure of Example 23 was repeated except that the fluorine-containing coating composition E was used instead of the fluorine-containing coating composition A.
Example 28
The procedure of Example 23 was repeated except that the fluorine-containing coating composition F was used instead of the fluorine-containing coating composition A.
Example 29
The procedure of Example 23 was repeated except that the fluorine-containing coating composition G was used instead of the fluorine-containing coating composition A.
Example 30
The procedure of Example 23 was repeated except that the fluorine-containing coating composition H was used instead of the fluorine-containing coating composition A.
Comparative Example 7
A glass plate having a thickness of 1.5 mm is spray-coated with γ-aminopropyltriethoxysilane (trade name: A-1100, manufactured by Nippon Unicar) as a primer, dried at 80 to 100 ° C. for 30 minutes, and then subjected to PFA powder. A coating material (average particle diameter 20 μm, apparent density 0.88 g / ml, trade name: MP-103, manufactured by DuPont-Mitsui Fluorochemicals Co.) is electrostatically coated, baked at 340 ° C. for 30 minutes, and coated with about 70 μm. A fluororesin-coated glass plate having a film was obtained. The impact resistance of the coating was evaluated according to the procedure described in Example 23.
Comparative Example 8
The impact resistance of a 1.5 mm thick solid glass plate was evaluated according to the procedure described in Example 23.

From Table 4, it can be seen that Examples 23 to 30 can suppress the weight loss at the time of impact to the same or almost comparable to Comparative Example 7 in which the primer is coated, and the solid content of the fusible fluororesin and the fluoropolymer can be reduced. In Examples 23 to 24 and Examples 27 to 28 in which the weight ratio by weight was in the range of 70:30 to 99.9: 0.1, it was found that the weight loss was smaller.

From Table 5, Examples 23 to 30 can increase the light transmittance in the visible region as compared with Comparative Example 7 in which the primer is applied, and when the fusible fluororesin is PFA, the solid of the fusible fluororesin is solid. In Examples 23 to 25, in which the weight per minute is 70% or more of the total of the solid weight of the meltable fluororesin and the solid weight of the fluoropolymer, the light transmittance is higher, and the meltable fluororesin is FEP. In this case, it was found that the light transmittance was higher in Examples 27 to 29 in which the meltable fluororesin was 70% by weight above 500 nm.
Industrial applicability
Since the fluorine-containing coating composition of the present invention has the above-described structure, it is possible to form a layer mainly containing a fusible fluororesin with a thickness equivalent to that of the two-coat method by the one-coat method, and to provide corrosion resistance and abrasion resistance. A layer mainly containing a material having a higher critical surface tension is formed on a layer mainly containing a fusible fluororesin having good heat resistance, heat resistance, non-adhesiveness, etc. and a relatively low critical surface tension. It is possible to perform both of these steps and to form both of these layers upside down. The fluorine-containing coating composition of the present invention can further obtain a coating film having high adhesiveness to an object to be coated including glass and the like and transparency.

Claims (23)

A fluorine-containing coating composition obtained by blending a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm. The fluorine-containing coating composition according to claim 1, wherein the solid content weight of the fusible fluororesin is 35 to 99.9% of the total of the solid content weight of the fusible fluororesin and the solid content weight of the fluoropolymer. A fluorine-containing coating composition obtained by blending a fusible fluororesin having an average particle diameter of 1 to 30 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.5 μm,
A fluorine-containing coating composition, wherein the volume of the fusible fluororesin is 35 to 95% of the total of the volume of the fusible fluororesin and the volume of the fluoropolymer. 4. The fluorinated coating composition according to claim 1, wherein the fusible fluororesin and the fluorinated polymer are dispersed in a liquid medium. 5. The fluorinated coating composition according to claim 1, wherein the fluorinated polymer has a functional group. The fluorine-containing coating composition according to claim 5, wherein the functional group is a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, and / or an epoxy group. The fluorinated polymer is obtained by copolymerizing a functional group-containing fluorinated ethylenic monomer (a) and a functional group-free fluorinated ethylenic monomer (b),
The functional group-containing fluorine-containing ethylenic monomer (a) has a functional group, and the functional group includes a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, or an epoxy group. And
The fluorine-containing coating composition according to claim 5 or 6, wherein the functional group-free fluorine-containing ethylenic monomer (b) does not have the functional group. The fluorinated coating composition according to claim 5 or 6, wherein the fluorinated polymer has an average particle diameter of 0.005 to 0.3 µm. A fluorine-containing coating composition obtained by dispersing a fusible fluororesin having an average particle diameter of 1 to 1000 μm and a fluoropolymer having an average particle diameter of 0.005 to 0.3 μm in a liquid medium,
The fluorinated polymer is obtained by copolymerizing a functional group-containing fluorinated ethylenic monomer (a) and a functional group-free fluorinated ethylenic monomer (b),
The functional group-containing fluorine-containing ethylenic monomer (a) has a functional group, and the functional group includes a hydroxyl group, a carboxyl group, a carboxyl group forming a salt, an alkoxycarbonyl group, or an epoxy group. And
The fluorine-containing coating composition, wherein the functional group-free fluorine-containing ethylenic monomer (b) does not have the functional group. The fluorine-containing coating composition according to claim 9, wherein the solid content weight of the fusible fluororesin is 70 to 99.9% of the total of the solid content weight of the fusible fluororesin and the solid content weight of the fluoropolymer. The number of moles of the functional group-containing fluorinated ethylenic monomer (a) is determined based on the number of moles of the functional group-containing fluorinated ethylenic monomer (a) and the number of moles of the functional group-free fluorinated ethylenic monomer (b). The fluorine-containing coating composition according to claim 7, 9 or 10, wherein the total number of moles is 0.05 to 30%. The fluorine-containing coating composition according to claim 5, 6, 7, 8, 9, 10, or 11, wherein the fluorine-containing polymer is a functional group-containing fluorine resin. The fluorine-containing coating composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11, wherein the fluorine-containing polymer is a fluorine rubber. The fluorinated coating composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the melting fluororesin has a melting point of 200 ° C or higher. The fluorine-containing coating composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein the fusible fluororesin is a perfluoropolymer. The fluorine-containing composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, which is used for a roll for OA equipment or a belt for OA equipment. Paint composition. It is obtained by applying the fluorine-containing coating composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16. Paint film. A coated article having the coating film according to claim 17. The coating film is formed on the object to be coated,
19. The coated object according to claim 18, wherein the object to be coated is made of a metal, a molded polymer compound, glass or ceramic. The coated article according to claim 19, which is a material for a light bulb. 20. The coated article according to claim 19, which is a fire-proof glass material or a safety glass material. The coated article according to claim 19, which is a material for a glass tableware or a material for a glass laboratory tool. The coated article according to claim 19, which is a roll for OA equipment or a belt for OA equipment.