JP2004263001A

JP2004263001A - Quick-drying aqueous coating composition for road surface marking

Info

Publication number: JP2004263001A
Application number: JP2003052687A
Authority: JP
Inventors: Sadao Negayama; 定男根ヶ山; Naomi Ishii; 直美石井
Original assignee: Ganz Chemical Co Ltd
Current assignee: Ganz Chemical Co Ltd
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2004-09-24
Anticipated expiration: 2023-02-28
Also published as: JP4406539B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-pack aqueous coating composition for road surface marking which has good storage stability and manifests, after applied, good drying properties and water resistance. <P>SOLUTION: The quick-drying aqueous coating composition for road surface marking comprises 100 pts.wt., in terms of solid content, of an aqueous dispersion of a binder particle, and incorporated therewith, 5-70 pts.wt. of an aqueous dispersion of a hollow polymer particle containing an aqueous solution of a hydrophilic volatile substance therein. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、一液型の路面表示用速乾性水性塗料組成物に関する。
【０００２】
【従来の技術】
路面表示用塗料は、道路、駐車場などのコンクリートやアスファルト表面への車線、駐車スペースなどの表示や文字による指示などのために使用される特殊な塗料である。
この路面表示用塗料は、貯蔵安定性がよく、塗布後は、路面表示用速乾性で密着性、耐候性、耐摩耗性が高いといった特性が要求されるが、特に重要な性質は、貯蔵安定性と塗布後の乾燥性である。塗布後の乾燥に至るまでの時間は、道路等における車の通交遮断時間を意味するので、車の通交量の大きな道路では、できる限り乾燥時間の短い塗料が要求される。
易揮発性の有機溶剤を用いた速乾燥塗料は、塗布後迅速に乾燥するが、作業者および環境への悪影響が懸念されるうえ、引火の危険性も大きい。そこでこれらの有機溶剤系塗料に代わって水性塗料の使用が検討されてきた。
しかし一般に水性塗料は有機溶剤系塗料に比して乾燥に至る時間が長く、特に低温下や高湿下では、乾燥までに数時間以上を要することもある。そこで、一液型でありながら貯蔵安定性が高く、塗布後の乾燥時間が短く、路面への密着性、耐摩耗性および耐水性の良好な路面表示水性塗料が強く求められ、これまでにもいくつかの提案がなされてきた。
【０００３】
それらの技術の１つに、塗料の隠ぺい性、反射性および乾燥性の向上を目的として、内部が空洞の、すなわち内部が空気で満たされている中空ポリマー微粒子と造膜性樹脂水分散体（本明細書においては、バインダー粒子分散体と実質的に同義に用いられる。）を同時または別々に路面に塗布する路面表示用水性塗料が提案されている。（特許文献１、特許文献２）。これらは、塗布後、中空ポリマー微粒子の空洞に水分散体中の水分を吸収させ乾燥を早めるという技術であるが、二成分を混合すると貯蔵中に水分が中空ポリマーの空隙に移行してきて塗料の粘度が上昇するので、別々に貯蔵しておき、使用時混合するという煩雑な操作を伴う。
【０００４】
【特許文献１】特開２００１−２１２５０４号
【特許文献２】特開２００２−３０２５７号
【０００５】
【発明が解決しようとする課題】
本発明者らは、一液性で、貯蔵安定性がよく、塗布後は速乾性で、路面への密着性、耐水性、耐摩耗性も良好な路面表示用水性塗料組成物を得るために鋭意研究を重ねてきた。
【０００６】
【課題を解決するための手段】
その結果、本発明者らは、内部が親水性の揮発物質を溶解した水、たとえばアンモニア水などで満たされた中空ポリマー粒子の水分散体と造膜性樹脂すなわちバインダー樹脂の水分散体、着色顔料、充填剤等を配合した一液性の水性塗料組成物が貯蔵安定性に優れ、塗布後の乾燥が早く、耐水性、密着性等路面表示用塗料に要求される特性をすべて備えたものであることを突き止めた。この内部が親水性の揮発物質を溶解した水で満たされた中空ポリマー粒子の水分散体を用いても塗布後の乾燥性が高いということは、全くの予想外のことであった。本発明はは、その知見を基にして更に検討を重ね、完成したものである。
すなわち本発明は、
（１）親水性の揮発性物質水溶液を内包する中空ポリマー粒子水分散体をバインダー粒子水分散体の固形分１００重量部に対して、５〜７０重量部含有させた路面表示用速乾性水性塗料組成物、
（２）親水性の揮発性物質が、アンモニア、または炭素数１〜４の低級アルコールである（１）記載の路面表示用速乾性水性塗料組成物、
（３）中空ポリマー粒子水分散体の空隙率が１０〜７５％である（１）又は（２）記載の路面表示用速乾性水性塗料組成物、
（４）中空ポリマー粒子水分散体の平均粒子径が５０〜２０００ｎｍである（１）又は（２）記載の路面表示用速乾性水性塗料組成物、
（５）バインダー粒子水分散体のガラス転移温度が−１０〜５０℃である（１）記載の路面表示用速乾性水性塗料組成物、
（６）バインダー粒水分散体子の平均粒子径が５０〜４００ｎｍである（１）記載の路面表示用速乾性水性塗料組成物、
（７）揮発性物質水溶液中の揮発性物質の濃度が１００ｐｐｍ〜１０重量％である（１）記載の路面表示用速乾性水性塗料組成物、
（８）バインダー粒子水分散体が、構成モノマーとしてカルボキシル基含有ビニルモノマーを含有するアクリル共重合体である（１）記載の路面表示用速乾性水性塗料組成物、
（９）カルボキシル基含有ビニルモノマーがアクリル酸、メタクリル酸、イタコン酸、フマル酸、マレイン酸、フマル酸モノメチルエステルおよびフマル酸モノエチルエステルから選択される少なくとも１種類である（８）記載の路面表示用速乾性水性塗料組成物、および
（１０）中空ポリマー粒子分散体とバインダー粒子水分散体の固形分の合計１００重量部に、着色顔料を５０〜２００重量部、充填剤を１００〜３００重量部含有させた（１）〜（７）のいずれかに記載の路面表示用速乾性水性塗料組成物、である。
【０００７】
【発明の実施の形態】
本発明に用いられる親水性の揮発性物質を内包する中空ポリマー粒子の製造法は、たとえば特願昭５６−３２５１３号公報により知られている。そこには、乳化重合により不飽和カルボン酸単量体を共重合させてコア粒子を調製した後、エチレン性不飽和単量体をカバー重合してシエル層を形成させ、得られた粒子にアンモニア等の揮発性塩基によりコア部のカルボン酸を中和して粒子を膨潤させる方法が記載されている。
また、このような内部に揮発性塩基を内包する中空ポリマー粒子の水分散体に、凍結防止剤としての効果を兼ね備えたメタノール、エタノール等の低級アルコール類を加えると、これらのアルコール類が空洞内に浸透し、内部に揮発性塩基とアルコール類が溶解した水溶液を内包する中空ポリマー粒子の水分散体を得ることができる。
【０００８】
親水性の揮発性物質は、塗料が路面に塗布されると中空ポリマー粒子の殻（シェル）部を通過して大気中に散逸するような物質で、アンモニアの外揮発性のアミン類、たとえばジエタノールアミンやトリエタノールアミン、低級アルコール類、たとえばメタノール、エタール、ｎ−プロパノール、ｎ−ブタノール等が例として挙げられるが、アンモニア、メタノール、エタノールが好ましい。
中空ポリマー粒子の平均粒子径は５０〜２０００ｎｍ、好ましくは１００〜１５００ｎｍで、中空ポリマー粒子中の空隙率は粒子の体積の１０〜７５％、好ましくは２５〜７０％である。
また内包する揮発性物質の濃度は１０ｐｐｍ〜１０ｗｔ％、好ましくは１０００ｐｐｍ〜３ｗｔ％である。
【０００９】
本発明に使用されるバインダー粒子は、従来水性塗料用として一般に用いられるものであれば特に限定されない。しかし本発明の塗料組成物が、常温で乾燥されることが多いので、その造膜最低温度が４０℃以下、特に３０℃以下のものが好ましい。
またバインダー粒子のガラス転移温度は通常−１０〜５０℃、好ましくは−１０〜３０℃である。バインダー粒子の平均粒子径は通常５０〜４００ｎｍ、好ましくは５０〜３００ｎｍである。平均粒子径が５０ｎｍ未満では塗料の粘度が上がり、塗布性、作業性に支障をきたす場合があり、平均粒子径が４００ｎｍを超えると、乾燥性、耐水性が悪くなる場合がある。
バインダー粒子はビニル系共重合体から構成されることが望ましく、エチレン系不飽和カルボン酸を０．１〜１０重量％含有するものが特に好ましい。
このエチレン系不飽和カルボン酸としては、たとえば、アクリル酸、メタクリル酸、クロトン酸などのモノカルボン酸、例えば、マレイン酸、フマル酸、イタコン酸などの不飽和ジカルボン酸や、それらの無水物、例えば、マレイン酸メチル、イタコン酸メチルなどの不飽和ジカルボン酸のモノエステル、すなわち半エステルなどを挙げることができる。これらの中でメタクリル酸（ＭＡＡ）が特に好ましい。これらのエチレン系不飽和カルボン酸単量体は、単独で又は２種以上を組み合わせて用いることができる。またこれらのエチレン系不飽和カルボン酸単量体はアルカリ金属塩またはアンモニウム塩としても用いることができる。
このようなエチレン系不飽和カルボン酸単量体の使用量は、モノマー混合物１００重量部中、０．１〜１０重量部、好ましくは０．１〜５重量部、さらに好ましくは０．３〜３重量部の範囲である。
【００１０】
エチレン性不飽和カルボン酸以外の共重合可能なビニル単量体としては、例えば、スチレン、α−メチルスチレン、などの芳香族ビニル化合物、例えば、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸２−ヒドロキシエチル、メタクリル酸２−ヒドロキシエチル、メタクリル酸メチル、メタクリル酸エチルなどの（メタ）アクリル酸アルキルエステル、例えば、アクリルアミド、メタクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、Ｎ−メチロールアクリルアミドなどのエチレン系不飽和カルボン酸アミド、例えば、酢酸ビニルなどのカルボン酸ビニルエステル類、例えば、メチルアミノエチル（メタ）アクリレート、ジメチルアミノエチル（メタ）アクリレート、２−ビニルピリジンなどのエチレン系不飽和アミンなどを挙げることができる。これらは単独であるいは２種以上を組み合わせて用いることができる。
これらの中では、（メタ）アクリル酸アルキルエステルが好ましく、メタクリル酸メチル、アクリル酸ブチルが特に好ましい。
これらの共重合性ビニル単量体の使用量は単量体混合物１００重量部中、８０〜９．５重量部であり、好ましくは８５〜９９．９重量部である。
【００１１】
本発明におけるバインダー粒子水分散体と中空ポリマー粒子水分散体の使用割合は、前者の固形分１００重量部に対し、後者の固形分が５〜７０重量部、好ましくは１０〜５０重量部である。
【００１２】
本発明のバインダー粒子水分散体と中空ポリマー粒子水分散体を用いて路面表示用塗料組成物を得るには、両者の混合物に着色顔料（Ｂ）および充填材（Ｃ）およびその他の添加剤を混合することにより行うことができる。
【００１３】
着色顔料としては、二酸化チタン、黄鉛、カーボンブラック等の無機顔料、シアニンブルー、シアニングリーン等の有機顔料が挙げられるが、路面表示用塗料組成物には、二酸化チタンが繁用される。
着色顔料の使用割合は、アクリル共重合体の固形分１００重量部に対して、通常１０〜２００重量部、好ましくは、３０〜１００重量部である。
【００１４】
充填剤としては、炭酸カルシウム、炭酸バリウム、珪酸マグネシウム、珪酸マグネシウム、タルク、クレー、セライト、マイカ、アルミナ、シリカ、ガラス粉末等の無機充填剤が挙げられるが、炭酸カルシウムが便宜に使用される。
充填剤の使用量は、アクリル共重合体の固形分１００重量部に対して、通常１００〜３５０重量部、好ましくは、１５０〜３００重量部である。
【００１５】
路面表示用塗料組成物組成物のｐＨは通常５〜１２、好ましくは７〜１１の範囲である。このｐＨ値が５より低いときは、本発明による路面表示用塗料組成物の機械的安定性が不十分となり、１２を超えると塗装後の乾燥性が悪くなることがあるので、ｐＨ調節剤により適当な範囲に調節するのが好ましい。ｐＨ調節剤としては、アンモニア、炭酸ソーダ、水酸化ナトリウム、モルフォリン、低級アルキルアミンなどのアルカリ性物質や、硫酸等の酸性物質などが挙げられる。
【００１６】
本発明の路面表示用塗料組成物には、さらに増粘剤を配合することにより、組成物の粘性を向上させることができる。増粘剤としては、例えばカゼイン、グルー、ゼラチン等の動物性増粘剤、アルギン酸塩、でんぷん、アラビヤガム等の植物性増粘剤、ベントナイト等の鉱物性増粘剤、ポリカルボン酸塩、アクリル共重合体、架橋型アクリル共重合体、ポリビニルアルコール、ポリアクリルアミド、ポリエチレンオキシド等の高分子系増粘剤、カルボキシル化メチルセルロース、メチルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルセルロース、キサントゲン酸セルロース、カルボキシル化でんぷん等の繊維素誘導体、セチルトリメチルアンモニウムブロマイド、セチルピリジニウムブロマイド等のカチオン系増粘剤等が挙げられる。
その他、分散剤、凍結防止剤、可塑剤、消泡剤、保存剤、架橋剤などの適量を適宜加えてもよい。
【００１７】
本発明の路面表示用水性塗料組成物における固形分の占める割合は、通常５０〜８０重量％、好ましくは、５５〜７０重量％である。
このようにして得られた路面表示用水性塗料組成物は、たとえば金属、ガラス、プラスチック製の密閉容器に貯蔵する。使用時には、よく攪拌して均一化し、スプレイガンや刷毛塗りにより直接路面に塗布する。
【００１８】
【実施例】
次に、実施例、比較例および試験例を挙げて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。なお、これらにおいて、「部」および「％」は断りのない限り重量基準である。
【００１９】
重合例Ａ−１
攪拌機、温度計、還流冷却器および窒素ガス導入口を備えた重合容器に、脱イオン水５０部、ラウリル硫酸ナトリウム０．１部およびｐＨ緩衝剤として重炭酸ナトリウム０．３３部を仕込み撹拌しながら８０℃に加熱した後、窒素置換した。この中にアクリル酸ブチル４５部、メタクリル酸メチル５４部、メタクリル酸１部、ドデシルメルカプタン１．２部、ラウリル硫酸ナトリウム０．５部、脱イオン水３０部からなる乳化モノマー液の３重量％に相当する３．９５部を添加し、１０分後に１．８部のイオン水に溶解した過硫酸アンモニウム０．２８部を添加し種重合を行った。発熱開始から２０分後、残りの乳化モノマー液１２７．７５部と６．３部の脱イオン水に溶解した過硫酸アンモニウム０．１２部を撹拌下、温度を８０℃に保ちながら３時間かけて滴下し、滴下終了後１時間８０℃を維持し重合を終了させた。これを室温まで冷却した後に、希釈水、２５％アンモニア水を加え固形分を５０％、ｐＨを８〜１０に調製した。最終生成物（Ａ−１）は固形分５０．１％、ブルックフィールド粘度２７０ｍＰａ・ｓ（３０ｒｐｍ）、平均粒子径１７０ｎｍ、ｐＨ＝９．６であった。
【００２０】
重合例Ａ−２
攪拌機、温度計、還流冷却器および窒素ガス導入口を備えた重合容器に、脱イオン水４５部、ラウリル硫酸ナトリウム０．１部およびｐＨ緩衝剤として重炭酸ナトリウム０．３３部を仕込み攪拌しながら８０℃に加熱した後、窒素置換した。この中にアクリル酸ブチル４５部、メタクリル酸メチル５４部、メタクリルさん部、ドデシルメルカプタン１．２部、ラウリル硫酸ナトリウム０．５部、脱イオン水２５部からなる乳化モノマー液の２．５重量％に相当する３．１７部を添加し、１０分後に１．８部の脱イオン水に溶解した過硫酸アンモニウム０．２８部を添加し種重合を行った。発熱開始から２０分後、残りの乳化モノマー液１２３．５３部と５．７部の脱イオン水に溶解した過硫酸アンモニウム０．１２部を攪拌下、温度を８０℃に保ちながら３時間かけて滴下し、滴下終了後１時間８０℃を維持し重合を終了させた。ころを室温まで冷却した後に、希釈水、２５％アンモニア水を加え固形分を５５％、ｐＨを８〜１０に調整した。最終生成物（Ａ−２）は固形物５５．５％、ブルックフィールド粘度３７０ｍＰａ・ｓ（３０ｒｐｍ）、平均粒子径１９２ｎｍ、ｐＨ＝９．０であった。
【００２１】
重合例Ａ−３〜Ａ−８
重合例１と同様にして表１に示されるモノマー組成で重合を行った。ただし、重合例４は種重合に使用した乳化モノマー量を作成した乳化モノマーの１重量％に相当する１．３２部に変更して重合を行った。
得られたエマルジョンの性状値は表１のとおりであった。
【００２２】
【表１】

重合安定性は以下の基準により判定した。
○：反応器、攪拌ばねの汚れが殆ど無く、ろ過残留物も殆ど無かった。
△：反応器、攪拌ばねが汚れていた、あるいはろ過残留物が多かった。
×：ゲル化した、またはろ過できなかった。
【００２３】
実施例１
水系バインダー組成物Ａ−１を固形分で８５重量部に対し、中空ポリマー水分散体（ローペークＯＰ−６２、：ローム＆ハース社製、空隙率３３％、平均粒子径４００μｍ）を固形分で１５重量部配合し、表２に示す標準塗料配合により塗料化した。得られた塗料および塗膜の特性は表３のとおりであった。
【００２４】
実施例２〜９
表３に示される水系バインダー組成物と中空ポリマー水分散体の配合比により配合し、標準塗料配合により塗料化した。得られた塗料および塗膜の特性は表３のとおりであった。
【００２５】
比較例１〜８
表４に示す水系バインダー組成物を用い、標準塗料配合により塗料化した。得られた塗料および塗膜の特性は表４のとおりであった。
【００２６】
【表２】

表中ＸおよびＹは式（１）および式（２）によって決定される。
Ｘ＋Ｙ＝６１．５（１）
ａＸ＝２７００（２）
（ａ：水系バインダー組成物と中空ポリマー水分散体配合物の固形分）
【００２７】
【表３】

【００２８】
【表４】

塗料、塗膜の特性評価は以下に基づいて行った。
（１）粘度
ブルックフィールド粘度、ＢＭ度１２ｒｐｍ、２５度
（２）Ｔ１
ブルックフィールド粘度、ＢＭ型、６ｒｐｍ／６０ｒｐｍの値、２５℃
（３）乾燥性
作成した塗料を２３℃Ｘ５０％ＲＨ雰囲気かで１日養生後、同雰囲気下でガラス板にアプリケーターを用いて１０ミルの厚さで塗布した。塗膜の乾燥性は塗布後１分毎にＮｏ．２１号の黒ゴム線を置いた時の塗料の付着が認められなくなるまでの時間と、指触によるタックが感じられなくなる時間（指触乾燥）を測定した。
（４）耐水性
乾燥性と同様な方法で塗布した試験体を２３℃Ｘ５０％ＲＨ下で２０分乾燥後、２０℃に調整した水浴に浸し、１日後の塗膜の様子を観察した。判定は以下の基準で行った。
◎：全く異常が観られなかった。
○：一部フクレが観られた。
△：塗膜全体にフクレが観られた。
×：塗膜がガラス板から浮いてしまっていた。
（５）保存安定性
Ａ）−１０℃凍結安定性
−１０℃雰囲気下で３日静置後、室温で１日静置するのを１サイクルとして、これを１０サイクル行い、塗料の流動性を下記の判定基準で評価した。
◎：１０サイクル後も流動性が確保され、粘度変化が初期値に対して１０％以内であった。
○：１０サイクル後も流動性が確保されたが、粘度変化が初期値に対して１０％を超えた。
△：５〜１０サイクル目で固化した。
×：５サイクルまでに固化した。
Ｂ）４０℃保存安定性
塗料を４０℃Ｘ３０日保存した前後の粘度変化を測定し、下記の判断基準で評価した。
◎：初期の粘度の１０％以内
○：初期の粘度の１０％を超える
△：１５〜３０日の間に固化
×：１５日までに固化
【００２９】
実施例１０および１１
実施例１の水系バインダー組成物と中空ポリマー粒子水分散体配合物を使用して表２の標準塗料配合の酸化チタン、炭酸カルシウム配合量のみを表５に示される配合量に変更した場合に得られた塗料および塗膜の特性を表５に示す。
【００３０】
【表５】

【００３１】
【発明の効果】
本発明の路面表示用水性塗料用組成物は、速乾性、耐水性に優れ、かつ水性あるため安全性が高く、大気汚染の心配がないという特長を有している。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a one-pack type quick-drying aqueous coating composition for road surface display.
[0002]
[Prior art]
The road surface paint is a special paint used for indicating a lane on a concrete or asphalt surface such as a road and a parking lot, a parking space, and giving instructions by characters.
This road marking paint has good storage stability, and after application, it is required to have properties such as fast drying for road marking and high adhesion, weather resistance and abrasion resistance. Properties and drying properties after application. The time from application to drying means the time during which traffic on a road or the like is cut off. Therefore, on a road with a large traffic volume, a paint with a drying time as short as possible is required.
A quick-drying paint using a volatile organic solvent dries quickly after application. However, there is a concern that it may adversely affect workers and the environment, and there is a large risk of ignition. Therefore, the use of water-based paints instead of these organic solvent-based paints has been studied.
However, the water-based paint generally takes a longer time to dry than the organic solvent-based paint, and it may take several hours or more to dry especially under low temperature or high humidity. Therefore, there is a strong demand for a road surface-indicating water-based paint having a high storage stability, a short drying time after application, a good adhesion to a road surface, abrasion resistance and water resistance despite being a one-pack type. Some suggestions have been made.
[0003]
One of those technologies is to improve the concealing property, the reflectivity and the drying property of the paint, and to form hollow polymer fine particles having a hollow inside, that is, the inside is filled with air, and an aqueous dispersion of a film-forming resin ( In the present specification, a road surface-indicating water-based paint is proposed in which a binder particle dispersion is used substantially synonymously) or simultaneously or separately. (Patent Document 1, Patent Document 2). These are techniques in which after coating, the moisture in the aqueous dispersion is absorbed into the cavities of the hollow polymer fine particles and drying is accelerated.However, when the two components are mixed, the moisture is transferred to the voids of the hollow polymer during storage and the Since the viscosity increases, it involves a complicated operation of storing separately and mixing at the time of use.
[0004]
[Patent Document 1] JP-A-2001-221504 [Patent Document 2] JP-A-2002-30257
[Problems to be solved by the invention]
The present inventors are one-part, good storage stability, fast-drying after application, adhesion to the road surface, water resistance, abrasion resistance to obtain a good road marking aqueous coating composition. I have been conducting intensive research.
[0006]
[Means for Solving the Problems]
As a result, the present inventors have found that an aqueous dispersion of hollow polymer particles filled with water in which a volatile substance having a hydrophilic content is dissolved, such as ammonia water, and an aqueous dispersion of a film-forming resin, that is, a binder resin, are colored. One-part water-based paint composition containing pigments, fillers, etc., has excellent storage stability, quick drying after application, and has all the properties required for road marking paints such as water resistance and adhesion. I found out. It was completely unexpected that even when an aqueous dispersion of hollow polymer particles filled with water having a hydrophilic volatile substance dissolved therein was used, the drying property after application was high. The present invention has been further studied and completed based on the findings.
That is, the present invention
(1) A fast-drying water-based paint for road surface display, containing 5 to 70 parts by weight of an aqueous dispersion of hollow polymer particles containing an aqueous solution of a hydrophilic volatile substance, based on 100 parts by weight of the solid content of the aqueous dispersion of binder particles. Composition,
(2) The quick-drying aqueous coating composition for road surface display according to (1), wherein the hydrophilic volatile substance is ammonia or a lower alcohol having 1 to 4 carbon atoms.
(3) The fast-drying aqueous coating composition for road surface display according to (1) or (2), wherein the porosity of the aqueous dispersion of hollow polymer particles is 10 to 75%.
(4) The fast-drying aqueous coating composition for road surface display according to (1) or (2), wherein the aqueous dispersion of hollow polymer particles has an average particle size of 50 to 2000 nm.
(5) The quick-drying aqueous coating composition for road surface display according to (1), wherein the glass transition temperature of the aqueous dispersion of binder particles is -10 to 50 ° C.
(6) The quick-drying water-based coating composition for road surface display according to (1), wherein the average particle diameter of the aqueous binder particles is 50 to 400 nm.
(7) The quick-drying aqueous coating composition for road surface display according to (1), wherein the concentration of the volatile substance in the aqueous volatile substance solution is 100 ppm to 10% by weight.
(8) The fast-drying aqueous coating composition for road surface display according to (1), wherein the aqueous dispersion of binder particles is an acrylic copolymer containing a carboxyl group-containing vinyl monomer as a constituent monomer.
(9) The road marking according to (8), wherein the carboxyl group-containing vinyl monomer is at least one selected from acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, monomethyl fumarate and monoethyl fumarate. A quick-drying aqueous coating composition for use, and (10) a total of 100 parts by weight of solids of the hollow polymer particle dispersion and the binder particle aqueous dispersion, 50 to 200 parts by weight of a coloring pigment and 100 to 300 parts by weight of a filler. The quick-drying water-based paint composition for road marking according to any one of (1) to (7).
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
A method for producing hollow polymer particles containing a hydrophilic volatile substance used in the present invention is known, for example, from Japanese Patent Application No. 56-32513. There, an unsaturated carboxylic acid monomer is copolymerized by emulsion polymerization to prepare core particles, and then the ethylenically unsaturated monomer is cover-polymerized to form a shell layer, and ammonia is added to the obtained particles. There is described a method of neutralizing the carboxylic acid in the core portion with a volatile base such as the above to swell the particles.
In addition, when lower alcohols such as methanol and ethanol, which also have an effect as an antifreezing agent, are added to the aqueous dispersion of hollow polymer particles containing a volatile base therein, these alcohols are entrapped in the cavity. And an aqueous dispersion of hollow polymer particles containing an aqueous solution in which volatile bases and alcohols are dissolved.
[0008]
Hydrophilic volatile substances are substances that pass through the shell of hollow polymer particles and dissipate into the atmosphere when the paint is applied to the road surface. And triethanolamine and lower alcohols such as methanol, ethanol, n-propanol and n-butanol. Examples thereof include ammonia, methanol and ethanol.
The average particle diameter of the hollow polymer particles is 50 to 2000 nm, preferably 100 to 1500 nm, and the porosity in the hollow polymer particles is 10 to 75%, preferably 25 to 70% of the volume of the particles.
The concentration of the contained volatile substance is 10 ppm to 10 wt%, preferably 1000 ppm to 3 wt%.
[0009]
The binder particles used in the present invention are not particularly limited as long as they are conventionally used for aqueous paints. However, since the coating composition of the present invention is often dried at room temperature, the film forming minimum temperature is preferably 40 ° C. or lower, particularly preferably 30 ° C. or lower.
The glass transition temperature of the binder particles is usually -10 to 50C, preferably -10 to 30C. The average particle size of the binder particles is usually 50 to 400 nm, preferably 50 to 300 nm. If the average particle size is less than 50 nm, the viscosity of the coating will increase, which may impair the applicability and workability. If the average particle size exceeds 400 nm, the drying properties and water resistance may deteriorate.
The binder particles are desirably composed of a vinyl copolymer, and particularly preferably those containing 0.1 to 10% by weight of an ethylenically unsaturated carboxylic acid.
Examples of the ethylenically unsaturated carboxylic acid include, for example, acrylic acid, methacrylic acid, monocarboxylic acids such as crotonic acid, for example, maleic acid, fumaric acid, unsaturated dicarboxylic acids such as itaconic acid, and anhydrides thereof, for example. And monoesters of unsaturated dicarboxylic acids such as methyl maleate and methyl itaconate, ie, half esters. Of these, methacrylic acid (MAA) is particularly preferred. These ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. These ethylenically unsaturated carboxylic acid monomers can also be used as alkali metal salts or ammonium salts.
Such an ethylenically unsaturated carboxylic acid monomer is used in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.3 to 3 parts by weight, per 100 parts by weight of the monomer mixture. It is in the range of parts by weight.
[0010]
Examples of the copolymerizable vinyl monomer other than the ethylenically unsaturated carboxylic acid include, for example, aromatic vinyl compounds such as styrene and α-methylstyrene, for example, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic (Meth) acrylic acid alkyl esters such as 2-hydroxyethyl acid, 2-hydroxyethyl methacrylate, methyl methacrylate, and ethyl methacrylate; for example, acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylolacrylamide, etc. Ethylenically unsaturated carboxylic acid amides, for example, carboxylic acid vinyl esters such as vinyl acetate, for example, ethylenically unsaturated amides such as methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2-vinylpyridine, etc. And the like. These can be used alone or in combination of two or more.
Among these, alkyl (meth) acrylate is preferred, and methyl methacrylate and butyl acrylate are particularly preferred.
The amount of these copolymerizable vinyl monomers to be used is 80 to 9.5 parts by weight, preferably 85 to 99.9 parts by weight, per 100 parts by weight of the monomer mixture.
[0011]
The use ratio of the aqueous binder particle dispersion and the hollow polymer particle aqueous dispersion in the present invention is such that the former solid content is 100 parts by weight, and the latter solid content is 5 to 70 parts by weight, preferably 10 to 50 parts by weight. .
[0012]
In order to obtain a road surface coating composition using the aqueous dispersion of binder particles and the aqueous dispersion of hollow polymer particles of the present invention, a color pigment (B), a filler (C) and other additives are added to a mixture of both. It can be performed by mixing.
[0013]
Examples of the coloring pigment include inorganic pigments such as titanium dioxide, graphite and carbon black, and organic pigments such as cyanine blue and cyanine green. Titanium dioxide is frequently used in road surface coating compositions.
The usage ratio of the coloring pigment is usually 10 to 200 parts by weight, preferably 30 to 100 parts by weight, based on 100 parts by weight of the solid content of the acrylic copolymer.
[0014]
Examples of the filler include inorganic fillers such as calcium carbonate, barium carbonate, magnesium silicate, magnesium silicate, talc, clay, celite, mica, alumina, silica, and glass powder. Calcium carbonate is conveniently used.
The amount of the filler to be used is generally 100 to 350 parts by weight, preferably 150 to 300 parts by weight, based on 100 parts by weight of the solid content of the acrylic copolymer.
[0015]
The pH of the road surface coating composition is generally in the range of 5 to 12, preferably 7 to 11. When the pH value is lower than 5, the mechanical stability of the coating composition for road marking according to the present invention becomes insufficient, and when it exceeds 12, the drying property after coating may be deteriorated. Preferably, it is adjusted to an appropriate range. Examples of the pH adjuster include an alkaline substance such as ammonia, sodium carbonate, sodium hydroxide, morpholine, and a lower alkylamine, and an acidic substance such as sulfuric acid.
[0016]
The viscosity of the composition can be improved by further adding a thickener to the road surface coating composition of the present invention. Examples of the thickener include animal thickeners such as casein, glue, and gelatin, vegetable thickeners such as alginate, starch, and gum arabic; mineral thickeners such as bentonite; polycarboxylates; and acrylic thickeners. Polymeric thickeners such as polymers, cross-linked acrylic copolymers, polyvinyl alcohol, polyacrylamide, and polyethylene oxide; fibers such as carboxylated methylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, xanthate cellulose, and carboxylated starch And cationic viscosifiers such as hydrogen derivatives, cetyltrimethylammonium bromide and cetylpyridinium bromide.
In addition, an appropriate amount of a dispersant, an antifreezing agent, a plasticizer, an antifoaming agent, a preservative, a crosslinking agent, or the like may be appropriately added.
[0017]
The proportion of the solid content in the aqueous road surface coating composition of the present invention is usually 50 to 80% by weight, preferably 55 to 70% by weight.
The water-based road surface coating composition thus obtained is stored in a closed container made of, for example, metal, glass, or plastic. At the time of use, it is agitated and homogenized, and applied directly to the road surface by spray gun or brush coating.
[0018]
【Example】
Next, the present invention will be specifically described with reference to Examples, Comparative Examples, and Test Examples, but the present invention is not limited thereto. In these, "parts" and "%" are based on weight unless otherwise specified.
[0019]
Polymerization example A-1
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 50 parts of deionized water, 0.1 part of sodium lauryl sulfate and 0.33 part of sodium bicarbonate as a pH buffer were charged and stirred. After heating to 80 ° C., the atmosphere was replaced with nitrogen. 3% by weight of an emulsified monomer solution comprising 45 parts of butyl acrylate, 54 parts of methyl methacrylate, 1 part of methacrylic acid, 1.2 parts of dodecyl mercaptan, 0.5 part of sodium lauryl sulfate and 30 parts of deionized water. The corresponding 3.95 parts were added, and 10 minutes later, 0.28 parts of ammonium persulfate dissolved in 1.8 parts of ionic water was added to perform seed polymerization. Twenty minutes after the start of heat generation, 127.75 parts of the remaining emulsified monomer liquid and 0.12 parts of ammonium persulfate dissolved in 6.3 parts of deionized water were added dropwise with stirring at a temperature of 80 ° C. over 3 hours. After completion of the dropwise addition, the temperature was maintained at 80 ° C. for 1 hour to terminate the polymerization. After cooling to room temperature, dilution water and 25% aqueous ammonia were added to adjust the solid content to 50% and the pH to 8 to 10. The final product (A-1) had a solid content of 50.1%, a Brookfield viscosity of 270 mPa · s (30 rpm), an average particle diameter of 170 nm, and a pH of 9.6.
[0020]
Polymerization example A-2
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 45 parts of deionized water, 0.1 part of sodium lauryl sulfate and 0.33 part of sodium bicarbonate as a pH buffer were charged and stirred. After heating to 80 ° C., the atmosphere was replaced with nitrogen. 2.5% by weight of an emulsified monomer solution comprising 45 parts of butyl acrylate, 54 parts of methyl methacrylate, 54 parts of methacryl, 1.2 parts of dodecyl mercaptan, 0.5 part of sodium lauryl sulfate and 25 parts of deionized water. Was added, and 10 minutes later, 0.28 part of ammonium persulfate dissolved in 1.8 parts of deionized water was added to perform seed polymerization. Twenty minutes after the start of heat generation, 123.53 parts of the remaining emulsified monomer liquid and 0.12 parts of ammonium persulfate dissolved in 5.7 parts of deionized water were added dropwise with stirring over 3 hours while maintaining the temperature at 80 ° C. After completion of the dropwise addition, the temperature was maintained at 80 ° C. for 1 hour to terminate the polymerization. After cooling the rollers to room temperature, dilution water and 25% ammonia water were added to adjust the solid content to 55% and the pH to 8 to 10. The final product (A-2) had a solid content of 55.5%, a Brookfield viscosity of 370 mPa · s (30 rpm), an average particle diameter of 192 nm, and a pH of 9.0.
[0021]
Polymerization Examples A-3 to A-8
Polymerization was carried out in the same manner as in Polymerization Example 1 using the monomer compositions shown in Table 1. However, in Polymerization Example 4, polymerization was carried out by changing the amount of the emulsified monomer used for seed polymerization to 1.32 parts corresponding to 1% by weight of the prepared emulsified monomer.
The properties of the obtained emulsion are as shown in Table 1.
[0022]
[Table 1]

The polymerization stability was determined according to the following criteria.
：: The reactor and the stirring spring were hardly stained, and there was almost no filtration residue.
Δ: The reactor and the stirring spring were dirty, or the filtration residue was large.
×: Gelled or could not be filtered.
[0023]
Example 1
Aqueous binder composition A-1 is 85 parts by weight of solid content, and a hollow polymer aqueous dispersion (Ropaque OP-62, manufactured by Rohm & Haas Co., Ltd., porosity 33%, average particle diameter 400 μm) is 15 parts by solid content. Parts by weight were blended and made into a paint according to the standard paint formulation shown in Table 2. Table 3 shows the properties of the obtained paint and coating film.
[0024]
Examples 2 to 9
It was blended according to the blending ratio of the aqueous binder composition and the hollow polymer aqueous dispersion shown in Table 3, and formed into a paint by standard paint blending. Table 3 shows the properties of the obtained paint and coating film.
[0025]
Comparative Examples 1 to 8
The aqueous binder compositions shown in Table 4 were used to form paints with standard paint formulations. Table 4 shows the properties of the obtained paint and coating film.
[0026]
[Table 2]

X and Y in the table are determined by the equations (1) and (2).
X + Y = 61.5 (1)
aX = 2700 (2)
(A: solid content of the aqueous binder composition and the hollow polymer aqueous dispersion composition)
[0027]
[Table 3]

[0028]
[Table 4]

The properties of the paint and the coating film were evaluated based on the following.
(1) viscosity Brookfield viscosity, BM degree 12 rpm, 25 degree (2) T1
Brookfield viscosity, BM type, value of 6 rpm / 60 rpm, 25 ° C.
(3) Drying The prepared paint was cured for one day in an atmosphere of 23 ° C. and 50% RH, and then applied to a glass plate under the same atmosphere to a thickness of 10 mil using an applicator. The drying property of the coating film was No. 1 every minute after coating. The time until the adhesion of the paint when the black rubber wire of No. 21 was placed was not recognized and the time when the tack by the touch was not felt (touch dry) were measured.
(4) The test specimen applied in the same manner as in the water-resistant drying property was dried at 23 ° C. and 50% RH for 20 minutes, immersed in a water bath adjusted to 20 ° C., and the state of the coating film after one day was observed. The judgment was made according to the following criteria.
A: No abnormality was observed.
：: Some blisters were observed.
Δ: Swelling was observed on the entire coating film.
X: The coating film was floating from the glass plate.
(5) Storage stability A) -10 ° C freezing stability After leaving for 3 days in an atmosphere of -10 ° C and letting it stand for 1 day at room temperature, this was repeated for 10 cycles, and the fluidity of the paint was measured. Evaluation was made according to the following criteria.
A: Fluidity was maintained after 10 cycles, and the change in viscosity was within 10% of the initial value.
：: Fluidity was maintained after 10 cycles, but the change in viscosity exceeded 10% of the initial value.
Δ: Solidified at 5th to 10th cycles.
X: Solidified by 5 cycles.
B) Storage stability at 40 ° C. Change in viscosity before and after storage of the coating at 40 ° C. for 30 days was measured and evaluated according to the following criteria.
◎: Within 10% of initial viscosity を: Exceeding 10% of initial viscosity Δ: Solidified between 15 to 30 days ×: Solidified by 15 days
Examples 10 and 11
Using the aqueous binder composition of Example 1 and the aqueous dispersion of hollow polymer particles, only the amounts of titanium oxide and calcium carbonate in the standard paint formulation shown in Table 2 were changed to those shown in Table 5. Table 5 shows the properties of the paints and coatings thus obtained.
[0030]
[Table 5]

[0031]
【The invention's effect】
The composition for a water-based paint for road marking according to the present invention has the characteristics that it is excellent in quick-drying property and water resistance, and because it is water-based, its safety is high and there is no concern about air pollution.

Claims

A fast-drying water-based coating composition for road surface display, comprising 5 to 70 parts by weight of an aqueous dispersion of hollow polymer particles containing an aqueous solution of a hydrophilic volatile substance, based on 100 parts by weight of the solid content of the aqueous dispersion of binder particles. .

2. The quick-drying aqueous coating composition for road surface display according to claim 1, wherein the hydrophilic volatile substance is ammonia or a lower alcohol having 1 to 4 carbon atoms.

The fast-drying aqueous coating composition for road surface display according to claim 1 or 2, wherein the porosity of the aqueous dispersion of hollow polymer particles is 10 to 75%.

The fast-drying aqueous coating composition for road surface display according to claim 1 or 2, wherein the aqueous dispersion of hollow polymer particles has an average particle size of 50 to 2000 nm.

The fast-drying water-based paint composition for road surface display according to claim 1, wherein the binder particles have a glass transition temperature of -10 to 50C.

The quick-drying aqueous coating composition for road surface display according to claim 1, wherein the aqueous dispersion of the binder particles has an average particle diameter of 50 to 400 nm.

The quick-drying aqueous coating composition for road surface display according to claim 1, wherein the concentration of the volatile substance in the aqueous volatile substance solution is 100 ppm to 10% by weight.

The fast-drying aqueous coating composition for road surface display according to claim 1, wherein the aqueous dispersion of binder particles is an acrylic copolymer containing a carboxyl group-containing vinyl monomer as a constituent monomer.

9. The quick-drying road surface display according to claim 8, wherein the carboxyl group-containing vinyl monomer is at least one selected from acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, fumaric acid monomethyl ester and fumaric acid monoethyl ester. Aqueous coating composition.

10. The color polymer of 50 to 200 parts by weight and the filler of 100 to 300 parts by weight in total 100 parts by weight of the solid content of the hollow polymer particle dispersion and the binder particle aqueous dispersion. The quick-drying water-based paint composition for road surface display according to the above.