JP2004263000A - Aqueous coating composition for road surface marking - Google Patents

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 aqueous coating composition for road surface marking comprises 100 pts.wt., in terms of solid content, of a vinyl copolymer (A) comprised of constituent monomers comprising 0.1-10 wt.% of a vinyl monomer of a structure represented by general formula (1) and other polymerizable vinyl monomers, 10-200 pts.wt. of a coloring pigment (B) and 100-350 pts.wt. of a filler (C). In general formula (1), X and Z are each hydrogen, a 1-6C aliphatic hydrocarbon group, aromatic hydrocarbon group, or alicyclic hydrocarbon group; Y is a 1-6C bivalent aliphatic hydrocarbon group; and R is a 1-10C bivalent aliphatic hydrocarbon group. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

（式中、Ｘ及びＺはそれぞれ、水素、炭素数１〜６の脂肪族炭化水素基、芳香族炭化水素基または脂環族炭化水素基、Ｙは炭素数１〜６の２価の脂肪族炭化水素基、Ｒは炭素数１〜１０の２価の脂肪族炭化水素基を示す。）で示されるビニル化合物０．１〜１０重量％とその他の重合性ビニルモノマーを構成モノマーとするビニル共重合体（Ａ）の水分散体を固形分換算で１００重量部、着色顔料（Ｂ）１０〜２００重量部および充填材（Ｃ）１００〜３５０重量部を含有してなる路面表示用水性塗料組成物、
（２）その他の重合性ビニルモノマーが、ブチルアクリレート（ＢＡ）および／または２−エチルヘキシルアクリレート（２ＥＨＡ）、およびメチルメタクリレート（ＭＭＡ）および／またはスチレン（ＳＴ）を含んでなるものである（１）記載の路面表示用水性塗料組成物、
（３）構成モノマー全量に対して、その他の重合性ビニルモノマーがブチルアクリレート（ＢＡ）および／または２−エチルヘキシルアクリレート（２ＥＨＡ）を１０〜５０重量％、メチルメタクリレート（ＭＭＡ）および／またはスチレンを３０〜７０重量％含んでなるものである（１）記載の路面表示用水性塗料組成物、
（４）ビニル共重合体（Ａ）が−１０〜５０℃のガラス転移温度を有するものである（１）記載の路面表示用水性塗料組成物、
（５）ビニル共重合体（Ａ）が構成モノマーとしてさらにカルボキシル基含有ビニルモノマーを０．１〜５重量％含有するものである（１）記載の路面表示用水性塗料組成物、および
（６）ビニル共重合体（Ａ）の水分散体の平均粒子径が０．０５〜０．４μｍである（１）記載の路面表示用水性塗料組成物、
である。
【００１２】
【発明の実施の形態】
一般式（１）中、ＸおよびＺで表される炭素数１〜６の脂肪族炭化水素基としては、たとえば、メチル、エチル、ｎ−プロピル、イソプロピル、ｎ−ブチル、イソブチル、ｎ−ペンチル、ｎ−ヘキシルなどが、炭素数６の芳香族炭化水素基としてはフェニル基が、炭素数３〜６の脂環族炭化水素基としてはシクロペンチル、シクロヘキシル基等が挙げられるが、中でも炭素数１〜４の脂肪族炭化水素基が好ましく用いられる。Ｙで示される炭素数１〜６の２価の脂肪族炭化水素基としては、たとえば、メチレン、エチレン、ｎ−プロピレン、イソプロピレン、ｎ−ブチレン、イソブチレン、ｎ−ペンチレン、ｎ−ヘキシレンなどが挙げられるが、中でも炭素数１〜４の脂肪族炭化水素基が好ましい。Ｒで示される炭素数１〜１０の２価の脂肪族炭化水素基としては、たとえば、メチレン、エチレン、ｎ−プロピレン、イソプロピレン、ｎ−ブチレン、イソブチレン、ｎ−ベンチレン、ｎ−ヘキシレン、ｎ−ヘプチレン、ｎ−オクチレン、ｎ−ノニレン、ｎ−デシレンなどが挙げられるが、中でも炭素数１〜６のものが好ましい。
一般式（１）で示されるビニル化合物の具体例としては、例えば（メタ）アクリルアミドメチルメチレンウレア、（メタ）アクリルアミドエチルメチレンウレア、（メタ）アクリルアミドエチルエチレンウレア、（メタ）アクリルアミドブチルエチレンウレア等が挙げられるが、特に（メタ）アクリルアミド−Ｃ_１−１０アルキレン−エチレンウレアが好ましい。
一般式（１）の化合物のビニル共重合体（Ａ）中に占める割合は０．１〜１０重量％、好ましくは０．３〜５重量％である。化合物（１）の割合が１０重量％を越えると重合安定性や速乾性が低下することがある。
【００１３】
ブチルアクリレート（ＢＡ）と２−エチルヘキシルアクリレート（２ＥＨＡ）は、いずれか一方のみでもよく、両者の混合物でもよい。混合物である場合の、両者の混合比は、任意である。ブチルアクリレート（ＢＡ）および／または２−エチルヘキシルアクリレート（２ＥＨＡ）のアクリル共重合体（Ａ）中の占める割合は、１０〜５０重量％、好ましくは２０〜４５重量％である。
【００１４】
メチルメタクリレート（ＭＭＡ）とスチレン（ＳＴ）は、いずれか一方のみでもよく、両者の混合物でもよい。混合物である場合の、両者の混合比は、任意である。メチルメタクリレート（ＭＭＡ）および／またはスチレン（ＳＴ）のアクリル共重合体（Ａ）中の占める割合は、３０〜７０重量％、好ましくは３５〜６０重量％である。
ビニル共重合体（Ａ）は構成モノマーとしてさらにカルボキシル基含有ビニルモノマーを含有していてもよい。このカルボキシル基含有ビニルモノマーとしては、例えば、（メタ）アクリル酸、フマル酸、琥珀酸、マレイン酸、イタコン酸等が挙げられるが、メタクリル酸（ＭＡＡ）が好ましい。
【００１５】
以下に本発明に用いるビニル共重合体の水分散体の製造方法について説明する。
まず、一般式（１）で示されるビニル化合物、ブチルアクリレート（ＢＡ）および／または２−エチルヘキシルアクリレート（２ＥＨＡ）、メチルメタクリレート（ＭＭＡ）および／またはスチレン（ＳＴ）、必要により、カルボキシル基含有ビニルモノマーを含んでなるモノマー混合物を従来から知られている乳化重合の方法、例えば水のような水性媒体中にモノマー混合物、重合開始剤、界面活性剤、および乳化重合に必要なその他の添加剤の存在下に乳化重合する。
【００１６】
重合開始剤としては、従来乳化重合において知られている通常の重合開始剤を用いることができる。
このような重合開始剤としては、例えば、過硫酸アンモニウム、過硫酸ナトリウム等の過硫酸塩、過酸化水素水、ｔ−ブチルハイドロパーオキサイド等の水性ラジカル重合開始剤又はこれらの混合物が挙げられる。重合開始剤の使用量はモノマー全重量に対して通常０．１〜５重量％、好ましくは０．１〜２重量％である。このような重合開始剤はまた、還元剤と組合せレドックス系を形成することができる。そのような還元剤としては亜硫酸塩、亜硫酸水素塩、ピロ亜硫酸塩、ホルムアルデヒドスルホン酸塩等のアルカリ金属塩やアンモニウム塩、Ｌ−アスコルビン酸、酒石酸などのカルボン酸類が挙げられ、その使用量はモノマー全重量に対して０．１〜５重量％、好ましくは０．１〜２重量％である。
なお、本発明のビニル共重合体の製造法において、還元剤として硫酸第一鉄、硫酸アンモニウム第一鉄、ナフテン酸第一銅などの鉄、銅、ニッケル、コバルト、クロモ、モリブテン、バナジウム、セリウムのような遷移金属の塩なども用いることができるが、路面表示用塗料組成物に着色などが観られる場合がある。
【００１７】
本発明における乳化重合に用いられる界面活性剤はアニオン性、ノニオン性、および両性界面活性剤の少なくとも１種を用いることができる。アニオン性界面活性剤の例としてはアルキルまたはアルキルアリル硫酸塩、アルキルまたはアルキリアリルスルホン酸塩、ジアルキルスルホコハク酸塩、ポリオキシエチレンアルキルエーテル硫酸塩などのアルカリ金属塩、またはアンモニウム塩が挙げられる。ノニオン系界面活性剤としては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アルキルフェニルエーテル、ポリオキシエチレン脂肪酸エステル等が挙げられる。両性界面活性剤としてはベタイン、アミノ酸の誘導体が挙げられる。これら界面活性剤の使用量はモノマー全重量に対して０．１〜５重量％、好ましくは０．３〜３重量％である。この使用量が０．１重量％よりも少ない場合は反応が不安定となり、凝集物が生成する場合がある。反対に５重量％よりも多い場合は路面表示塗料としての乾燥性、耐水性が悪くなる場合がある。
【００１８】
また、本発明においては、必要に応じて、乳化重合をエチレンジアミン４酢酸ナトリウムなどのキレート剤、ポリカルボン酸塩などの分散剤、リン酸塩、炭酸塩などの無機塩、チオール化合物、ハロゲン化合物などの連鎖移動剤の存在下に行ってもよい。
重合は通常０〜１００℃の温度で、単量体の添加率が９９％以上に達するまで行われる。
【００１９】
ビニル共重合体水分散体の平均粒子径の範囲は通常０．０５〜０．４μｍであり、好ましくは０．１〜０．３μｍである。平均粒子径が０．０５μｍ未満では塗料の粘度が高くなり過ぎて、塗料の塗布性、作業性に支障をきす場合があり、平均粒子経が０．４μｍを越えると、路面表示塗料としての乾燥性、耐水性が悪くなる場合がある。
このようにして得られたビニル共重合体のエマルジョンに、着色顔料、充填材、その他の配合物を加え、均一になるように攪拌される。
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（Ａ）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。
【００２０】
充填材としては、炭酸カルシウム、炭酸バリウム、珪酸マグネシウム、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材が挙げられるが、炭酸カルシウムが便宜に使用される。
充填材の使用量は、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。
【００２１】
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を越えると塗装後の乾燥性が悪くなることがある。
組成物のｐＨの調節は、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、硫酸等の酸性物質のｐＨ調整剤を適宜加えることにより行うことができる。
【００２２】
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、さらに分散剤、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。
このようにして調製された塗料用組成物は、たとえば金属製、ガラス製、プラスチック製の密閉容器に貯蔵しておけば長期に亘って安定に保存することができる。
この塗料組成物の使用に際しては、容器内容物を振盪、撹拌して均一な組成部とし、刷毛塗り、スプレー法等公知の方法で塗布すればよい。
【００２３】
【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。
【００２４】
実施例１
攪拌機、温度計、還流冷却器及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部及び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、メタクリ酸メチル５３．５部、メタクリル酸１部、メタクリルアミドエチルエチレンウレア０．５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部を攪拌下、８０℃に保ちながら３時間かけて滴下し、滴下終了後さらに１時間、８０℃を維持して重合を終了させた。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９〜１０に調整した。最終生成物は固形分５０．２％、ブルックフィールド粘度３５０ｍＰａ・ｓ（３０ｒｐｍ）、平均粒子径１７２ｎｍ、ｐＨ＝９．６のエマルジョンであった。
【００２５】
実施例２〜７
実施例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い、それぞれエマルジョンを得た。
【００２６】
実施例８
種重合に使用した乳化モノマー液の量を、乳化モノマー液の１重量％に相当する１．３２重量部使用した以外は、実施例１と同様に重合を行った。
【００２７】
実施例９〜１１
実施例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。
【００２８】
比較例１〜７
実施例１と同様にして表２に示されるモノマー組成で重合を行った。
【００２９】
比較例８
種重合に使用した乳化モノマー液の量を、乳化モノマー液の１重量％に相当する１．３２重量部使用した以外は、比較例２と同様に重合を行った。
実施例および比較例で得られたエマルジョンの物性値は、表１および表２のとおりであった。
【００３０】
実験例１
表３に示す標準配合例により塗料化した塗料組成物及び塗膜の特性を表４および表５に示した。
【００３１】
【表１】

【００３２】
【表２】

重合安定性は以下の基準により判定した。
○：反応器、攪拌ばねの汚れがほとんど無く、ろ過残留物もほとんど無かった。
△：反応器、攪拌ばねが汚れていた、或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。
ＢＡ：アクリル酸ブチル
２ＥＨＡ：アクリル酸２−エチルヘキシル
ＭＭＡ：メタクリル酸メチル
ＳＴ：スチレン
ＭＡＡ：メタクリル酸
ＭＡＥＥＵ：メタクリルアミドエチルエチレンウレア
ＤＶＢ：ジビニルベンゼン
【００３３】
【表３】標準塗料配合

【００３４】
【表４】

【００３５】
【表５】

塗料、塗膜の物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型、１２ｒｐｍ、２５℃
（２）ＴＩ：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２０℃×６５％ＲＨ雰囲気下で１日養生後、同雰囲気下でガラス板に１０ミルの厚さで塗料を塗布した。塗膜の乾燥性は塗布後１分毎にＮｏ．２１号の黒ゴム栓を置いた時の塗料の付着が認められなくなる時間と、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２０℃×６５％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い
○：一部フクレが観られる
△：塗膜全体にフクレが観られる
×：塗膜がガラス板から浮いてしまっている
（５）保存安定性：
（ｉ）−１０℃凍結安定性：
−１０℃雰囲気下で３日静置後、室温で１日静置を１サイクルとして、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は確保されたが、粘度変化が初期値に対して１０％を超えた。
△：５〜１０サイクルで固化した。
×：５サイクルまでに固化した。
（ｉｉ）４０℃保存安定性：
塗料を４０℃×３０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％以内であった。
○：初期の粘度の１０％を超えた。
△：１５〜３０日の間に固化した。
×：１５日までに固化した。
【００３６】
実験例２
実施例１のアクリルエマルジョンを使用して標準塗料配合の酸化チタン、炭酸カルシウムの配合量を表６に示される配合量に変更して得られた実施例１２および１３の塗料及び、塗膜の特性は表６に示すとおりであった。
【００３７】
【表６】

【００３８】
【発明の効果】
本発明の路面表示用水性塗料組成物は、貯蔵安定性に優れ、塗布後は、速乾性、耐水性に優れた塗布層を形成する。また、本発明の路面表示用水性塗料組成物は、水性であるため安全性が高く、大気汚染の心配がない水性塗料組成物である。[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a quick-drying vinyl-based water-based coating composition for road marking.
[0002]
[Prior art]
A road surface paint is a special paint used to display lanes, parking spaces, and the like on concrete or asphalt surfaces such as roads and parking lots.
One of the important characteristics that the road marking paint should have is that it dries as soon as possible on the road after application. The time from application to drying means the time during which the traffic of a car on a road or the like is cut off. Therefore, on a road where traffic is heavy, a paint having 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 and has already been put to practical use.
However, the water-soluble paint has a longer drying time after application than the organic solvent-based paint, and may have several hours or more to dry especially under low temperature or high humidity. Therefore, there is a strong demand for a water-based road marking paint having high storage stability, a short drying time after application, high adhesion to a road surface, and excellent abrasion resistance and water resistance. Has been done.
[0003]
As a water-based paint for road surface display, a technology has been proposed in which a predetermined amount of an oligomer having a reactive functional group such as an acryloyl group is blended with a water-based emulsion to improve the drying property and the stain resistance (Patent Document 1). Since the molecular weight of the polymer in the emulsion constituting the paint is as low as 10,000 to 100,000, there is a problem that the drying property, the abrasion resistance, the stain resistance, the coating strength and the adhesion to the road surface are insufficient. is there. In addition, this coating is economically disadvantageous because the reactive oligomer used for improving the stain resistance is expensive, and at the same time, among the reactive groups of the oligomer, the acryloyl group is used in air. Since the radical reactivity is low and the crosslinking reaction of the dicyclopentenyl group does not proceed rapidly in the presence of the metal oxide, it takes a long time to exhibit the stain resistance.
[0004]
Therefore, in order to produce an aqueous coating composition having a shorter drying time, various techniques using a pH-sensitive binder have been devised as a method of using a base or an acid or a combination thereof to accelerate coagulation.
[0005]
As one of them, there has been proposed an aqueous coating composition (Patent Document 2) in which a copolymer is synthesized by using a polyfunctional amine as a part of a monomer, and the pH is increased until the copolymer becomes a nonionic state. However, there is still room for improvement in drying properties after coating.
[0006]
An aqueous coating composition comprising a film-forming latex polymer weak base functional synthetic latex polymer and a volatile base has also been proposed (Patent Document 3). However, weak base functional polymers are insoluble in water due to cross-linking or high molecular weight, and a significant portion of the weak base moiety is buried under the surface of the water-insoluble particles, thus uniformly coating the functionality. This coating composition may also be difficult to utilize as a result of the inherently limited ability to disperse in the composition.
[0007]
On the other hand, methacrylamide-ethyl-ethyleneurea is used as a component of a monomer, and a coating material for a metal-based material such as iron or aluminum is formed from an aqueous dispersion of a vinyl copolymer obtained by emulsion polymerization with another copolymerizable vinyl monomer. (Patent Document 4) is proposed, but the performance as a road surface paint is unknown.
[0008]
[Patent Document 1] JP-A-6-271789 [Patent Document 2] JP-A-3-157463 [Patent Document 3] European Patent 0409594 [Patent Document 4] JP-A-9-255894 [0009]
[Problems to be solved by the invention]
An object of the present invention is to provide an aqueous coating composition for road surface display, which is one-pack type, has good storage stability, is dried quickly after application, and has good adhesion to road surfaces, abrasion resistance and water resistance. It is in.
[0010]
[Means for Solving the Problems]
As a result of intensive studies on various aqueous resin emulsions, the present inventors have found that an aqueous coating composition having the following composition satisfies the above conditions, and have further studied to complete the present invention.
[0011]
That is, the present invention
(1) General formula (1)
Embedded image

(Wherein, X and Z are each hydrogen, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group or an alicyclic hydrocarbon group, and Y is a divalent aliphatic having 1 to 6 carbon atoms. A hydrocarbon group, R represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms), and 0.1 to 10% by weight of a vinyl compound represented by the following formula: A water-based road surface coating composition comprising 100 parts by weight of an aqueous dispersion of the polymer (A) in terms of solid content, 10 to 200 parts by weight of a coloring pigment (B) and 100 to 350 parts by weight of a filler (C). object,
(2) The other polymerizable vinyl monomer comprises butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA), and methyl methacrylate (MMA) and / or styrene (ST) (1). A water-based coating composition for road marking according to the description,
(3) Other polymerizable vinyl monomers are 10 to 50% by weight of butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA) and 30% by weight of methyl methacrylate (MMA) and / or styrene based on the total amount of the constituent monomers. The aqueous coating composition for road surface display according to (1), which comprises about 70% by weight.
(4) The aqueous coating composition for road marking according to (1), wherein the vinyl copolymer (A) has a glass transition temperature of -10 to 50 ° C.
(5) The aqueous coating composition for road surface display according to (1), wherein the vinyl copolymer (A) further contains 0.1 to 5% by weight of a carboxyl group-containing vinyl monomer as a constituent monomer, and (6) The aqueous coating composition for road surface display according to (1), wherein the aqueous dispersion of the vinyl copolymer (A) has an average particle size of 0.05 to 0.4 μm,
It is.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
In the general formula (1), examples of the aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by X and Z include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, Examples of n-hexyl and the like include a phenyl group as an aromatic hydrocarbon group having 6 carbon atoms, and a cyclopentyl and cyclohexyl group as an alicyclic hydrocarbon group having 3 to 6 carbon atoms. 4 aliphatic hydrocarbon groups are preferably used. Examples of the divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by Y include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, n-hexylene and the like. Among them, an aliphatic hydrocarbon group having 1 to 4 carbon atoms is preferable. Examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms represented by R include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-benylene, n-hexylene, and n-hexylene. Heptylene, n-octylene, n-nonylene, n-decylene and the like can be mentioned, among which those having 1 to 6 carbon atoms are preferable.
Specific examples of the vinyl compound represented by the general formula (1) include, for example, (meth) acrylamidomethylmethyleneurea, (meth) acrylamidoethylmethyleneurea, (meth) acrylamidoethylethyleneurea, (meth) acrylamidobutylethyleneurea, and the like. Among them, (meth) acrylamide-C _1-10 alkylene-ethylene urea is particularly preferred.
The proportion of the compound of the general formula (1) in the vinyl copolymer (A) is 0.1 to 10% by weight, preferably 0.3 to 5% by weight. When the ratio of the compound (1) exceeds 10% by weight, the polymerization stability and the quick-drying property may decrease.
[0013]
Only one of butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) may be used, or a mixture of both may be used. In the case of a mixture, the mixing ratio of both is arbitrary. The proportion of butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA) in the acrylic copolymer (A) is 10 to 50% by weight, preferably 20 to 45% by weight.
[0014]
Either methyl methacrylate (MMA) or styrene (ST) may be used alone, or a mixture of both may be used. In the case of a mixture, the mixing ratio of both is arbitrary. The proportion of methyl methacrylate (MMA) and / or styrene (ST) in the acrylic copolymer (A) is 30 to 70% by weight, preferably 35 to 60% by weight.
The vinyl copolymer (A) may further contain a carboxyl group-containing vinyl monomer as a constituent monomer. Examples of the carboxyl group-containing vinyl monomer include (meth) acrylic acid, fumaric acid, succinic acid, maleic acid, and itaconic acid, and methacrylic acid (MAA) is preferable.
[0015]
Hereinafter, a method for producing an aqueous dispersion of a vinyl copolymer used in the present invention will be described.
First, a vinyl compound represented by the general formula (1), butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA) and / or styrene (ST), and if necessary, a carboxyl group-containing vinyl monomer The method of emulsion polymerization of a monomer mixture comprising a monomer mixture comprising a monomer mixture, a polymerization initiator, a surfactant, and other additives necessary for emulsion polymerization in an aqueous medium such as water. Emulsion polymerization is carried out below.
[0016]
As the polymerization initiator, a usual polymerization initiator conventionally known in emulsion polymerization can be used.
Examples of such a polymerization initiator include persulfates such as ammonium persulfate and sodium persulfate, aqueous radical polymerization initiators such as aqueous hydrogen peroxide and t-butyl hydroperoxide, and mixtures thereof. The amount of the polymerization initiator to be used is generally 0.1 to 5% by weight, preferably 0.1 to 2% by weight, based on the total weight of the monomers. Such polymerization initiators can also form redox systems in combination with reducing agents. Examples of such a reducing agent include alkali metal salts and ammonium salts such as sulfites, bisulfites, pyrosulfites, and formaldehyde sulfonates, and carboxylic acids such as L-ascorbic acid and tartaric acid. It is from 0.1 to 5% by weight, preferably from 0.1 to 2% by weight, based on the total weight.
In the method for producing a vinyl copolymer of the present invention, ferrous sulfate, ferrous ammonium sulfate, iron such as cuprous naphthenate, copper, nickel, cobalt, chromo, molybdenum, vanadium, and cerium as reducing agents. Such transition metal salts can be used, but coloring may be observed in the road surface coating composition.
[0017]
As the surfactant used in the emulsion polymerization in the present invention, at least one of anionic, nonionic and amphoteric surfactants can be used. Examples of anionic surfactants include alkali metal salts such as alkyl or alkyl allyl sulfates, alkyl or alkylaryl sulfonates, dialkyl sulfosuccinates, polyoxyethylene alkyl ether sulfates, or ammonium salts. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and polyoxyethylene fatty acid ester. Examples of the amphoteric surfactant include betaine and amino acid derivatives. These surfactants are used in an amount of 0.1 to 5% by weight, preferably 0.3 to 3% by weight, based on the total weight of the monomers. If the amount is less than 0.1% by weight, the reaction becomes unstable and aggregates may be formed. On the other hand, when the content is more than 5% by weight, the drying property and the water resistance as a road surface display paint may be deteriorated.
[0018]
In the present invention, if necessary, emulsion polymerization may be carried out using a chelating agent such as sodium ethylenediaminetetraacetate, a dispersant such as a polycarboxylate, an inorganic salt such as a phosphate or a carbonate, a thiol compound, a halogen compound, or the like. May be performed in the presence of a chain transfer agent.
The polymerization is usually performed at a temperature of 0 to 100 ° C. until the monomer addition rate reaches 99% or more.
[0019]
The average particle size of the aqueous dispersion of the vinyl copolymer is usually from 0.05 to 0.4 μm, preferably from 0.1 to 0.3 μm. If the average particle diameter is less than 0.05 μm, the viscosity of the paint becomes too high, which may hinder the applicability and workability of the paint. If the average particle diameter exceeds 0.4 μm, drying as a road surface paint may occur. Properties and water resistance may deteriorate.
A coloring pigment, a filler, and other compounds are added to the vinyl copolymer emulsion thus obtained, and the mixture is stirred to be uniform.
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 as a road surface paint.
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 (A).
[0020]
Examples of the filler include inorganic fillers such as calcium carbonate, barium carbonate, 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.
[0021]
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 road surface coating composition according to the present invention becomes insufficient, and when it exceeds 12, the drying property after coating may deteriorate.
The pH of the composition can be adjusted by appropriately adding a pH adjuster for an alkaline substance such as ammonia, sodium carbonate, sodium hydroxide, morpholine, or a lower alkylamine, or an acidic substance such as sulfuric acid.
[0022]
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.
The coating composition thus prepared can be stably stored for a long period of time by storing it in a metal, glass, or plastic closed container, for example.
When using the coating composition, the contents of the container may be shaken and stirred to form a uniform composition portion, and the composition may be applied by a known method such as brushing or spraying.
[0023]
【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.
[0024]
Example 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. While heating to 80 ° C., the atmosphere was replaced with nitrogen. In this, 45 parts of butyl acrylate, 53.5 parts of methyl methacrylate, 1 part of methacrylic acid, 0.5 part of methacrylamidoethylethylene urea, 1.2 parts of dodecyl mercaptan, 0.5 part of sodium lauryl sulfate, deionized water 3.95 parts corresponding to 3% by weight of the emulsified monomer liquid composed of 30 parts was added, and after 10 minutes, 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 the exotherm, 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 80 ° C. over 3 hours. After the completion of the dropwise addition, the polymerization was terminated at 80 ° C. for another hour. After cooling to room temperature, dilution water and 25% aqueous ammonia were added to adjust the solid content to 50% and the pH to 9 to 10. The final product was an emulsion having a solid content of 50.2%, a Brookfield viscosity of 350 mPa · s (30 rpm), an average particle diameter of 172 nm, and a pH of 9.6.
[0025]
Examples 2 to 7
Polymerization was carried out in the same manner as in Example 1 with the monomer compositions shown in Table 1 to obtain respective emulsions.
[0026]
Example 8
The polymerization was carried out in the same manner as in Example 1 except that the amount of the emulsified monomer liquid used in the seed polymerization was 1.32 parts by weight corresponding to 1% by weight of the emulsified monomer liquid.
[0027]
Examples 9 to 11
Polymerization was carried out in the same manner as in Example 1 with the monomer composition shown in Table 1.
[0028]
Comparative Examples 1 to 7
Polymerization was carried out in the same manner as in Example 1 using the monomer compositions shown in Table 2.
[0029]
Comparative Example 8
Polymerization was carried out in the same manner as in Comparative Example 2 except that the amount of the emulsified monomer liquid used in the seed polymerization was 1.32 parts by weight corresponding to 1% by weight of the emulsified monomer liquid.
The physical properties of the emulsions obtained in Examples and Comparative Examples are as shown in Tables 1 and 2.
[0030]
Experimental example 1
Tables 4 and 5 show the properties of the coating composition and the coating film formed according to the standard formulation examples shown in Table 3.
[0031]
[Table 1]

[0032]
[Table 2]

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 there were many filtration residues.
×: Gelled or could not be filtered.
BA: butyl acrylate 2EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate ST: styrene MAA: MAEEU methacrylate: methacrylamidoethyl ethylene urea DVB: divinylbenzene
[Table 3] Standard paint formulation

[0034]
[Table 4]

[0035]
[Table 5]

The physical properties of the paints and coatings were evaluated based on the following.
(1) Viscosity: Brookfield viscosity, BM type, 12 rpm, 25 ° C
(2) TI: Brookfield viscosity, BM type, value of 6 rpm / 60 rpm, 25 ° C.
(3) Dryness:
The prepared paint was cured for one day in an atmosphere of 20 ° C. × 65% RH, and then a paint of 10 mil was applied to a glass plate under the same atmosphere. The drying property of the coating film was No. 1 every minute after coating. The time when the adhesion of the paint was not observed when the black rubber stopper of No. 21 was placed, and the time when the tack by finger touch was not felt (touch dry) were measured.
(4) Water resistance:
The test specimen coated in the same manner as the drying property was dried at 20 ° C. × 65% RH for 20 minutes, immersed in a water bath adjusted to 20 ° C., and observed one day later.
The judgment was made according to the following criteria.
◎: No abnormality was observed at all. ○: Some blisters were observed. △: Bubbles were observed over the entire coating film. X: The coating film floated from the glass plate. (5) Storage stability:
(I) -10 ° C freezing stability:
After standing for 3 days in an atmosphere of −10 ° C., 10 cycles were performed with 1 day of standing at room temperature as one cycle, and the fluidity of the paint was evaluated according to the following criteria.
A: Fluidity was maintained after 10 cycles, and the change in viscosity was within 10% of the initial value.
：: The fluidity was maintained after 10 cycles, but the viscosity change exceeded 10% of the initial value.
Δ: solidified in 5 to 10 cycles.
X: Solidified by 5 cycles.
(Ii) Storage stability at 40 ° C .:
The viscosity change before and after the coating was stored at 40 ° C. for 30 days was measured and evaluated according to the following criteria.
A: Within 10% of the initial viscosity.
：: Exceeded 10% of the initial viscosity.
Δ: solidified between 15 and 30 days.
×: solidified by 15 days.
[0036]
Experimental example 2
Properties of paints and coatings of Examples 12 and 13 obtained by using the acrylic emulsion of Example 1 and changing the blending amounts of titanium oxide and calcium carbonate in the standard paint formulation to the blending amounts shown in Table 6. Was as shown in Table 6.
[0037]
[Table 6]

[0038]
【The invention's effect】
The water-based road surface coating composition of the present invention has excellent storage stability, and after application, forms a coated layer having excellent quick-drying properties and water resistance. In addition, the water-based paint composition for road surface display of the present invention is a water-based paint composition having high safety because it is water-based and free from concern about air pollution.

Claims (6)

General formula (1)

(Wherein, X and Z are each hydrogen, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group or an alicyclic hydrocarbon group, and Y is an aliphatic hydrocarbon group having 1 to 6 carbon atoms. , R represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.) A vinyl copolymer (A) containing 0.1 to 10% by weight of a vinyl compound represented by An aqueous coating composition for road marking, comprising 100 parts by weight of an aqueous dispersion in terms of solid content, 10 to 200 parts by weight of a coloring pigment (B) and 100 to 350 parts by weight of a filler (C). The road surface according to claim 1, wherein the other polymerizable vinyl monomer comprises butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA), and methyl methacrylate (MMA) and / or styrene (ST). Water-based paint composition for display. Other polymerizable vinyl monomers are butyl acrylate (BA) and / or 2-ethylhexyl acrylate (2EHA) in an amount of 10 to 50% by weight and methyl methacrylate (MMA) and / or styrene in an amount of 30 to 70% by weight based on the total amount of the constituent monomers. The aqueous coating composition for road marking according to claim 1, wherein The aqueous coating composition for road surface display according to claim 1, wherein the vinyl copolymer (A) has a glass transition temperature of -10 to 50C. The road surface display aqueous coating composition according to claim 1, wherein the vinyl copolymer (A) further contains 0.1 to 5% by weight of a carboxyl group-containing vinyl monomer as a constituent monomer. The aqueous coating composition for road surface display according to claim 1, wherein the aqueous dispersion of the vinyl copolymer (A) has an average particle size of 0.05 to 0.4 m.