JP3895827B2

JP3895827B2 - Copolymer aqueous dispersion and resin composition for water-based paint containing the same

Info

Publication number: JP3895827B2
Application number: JP13527597A
Authority: JP
Inventors: 研哉鈴木; 浩美原川
Original assignee: Kansai Paint Co Ltd
Current assignee: Kansai Paint Co Ltd
Priority date: 1997-05-26
Filing date: 1997-05-26
Publication date: 2007-03-22
Anticipated expiration: 2017-05-26
Also published as: JPH10324720A

Description

【０００１】
【発明の属する技術分野】
本発明は、初期乾燥性及び初期塗膜の耐水性に優れ、常温乾燥型の塗料、インキ、接着剤などの用途に有用な共重合体水分散液、及びこれを含む水性塗料用樹脂組成物に関する。
【０００２】
【従来技術及びその課題】
近年、塗料、インキ、接着剤などの分野では、省資源、環境衛生、無公害、非危険物化（消防法）などの点から、有機溶剤型から水性への転換が進められている。一般に常温乾燥用水性塗料には、ビヒクル成分としてアクリル系共重合体エマルションが使用されている。該アクリル系共重合体エマルションは、塗装後のエマルション粒子同士の融着により成膜するものであり、かかる融着による造膜性を確保する点から、共重合体のガラス転移温度を高く設計することが困難であった。このため、該共重合体エマルションを用いた水性塗料による塗膜は、膜の強靭性、耐汚染性に劣り、耐水性についても脆弱さは否めなかった。
【０００３】
そこで本出願人は、該水性塗料のエマルションの造膜時の問題を解決するため、カルボニル基含有共重合体エマルション及びヒドラジド化合物を用いてエマルション粒子間を比較的分子量の小さい架橋剤で架橋させることを提案し（特開平４−２４９５８７号公報）、これにより造膜性を補強し、耐汚染性、耐水性だけでなく、初期乾燥性の向上も実現した。
【０００４】
しかしながら上記カルボニル基含有共重合体エマルションの製造にあたって、エマルション粒子に要求される目的によっては共重合成分である単量体の種類や量が定められるため、共重合体中に相応のカルボニル基が導入できない場合があり、また耐水性の面で十分乾燥後は問題ないが初期塗膜の時点では難があった。これに対し、例えば特開昭５７−３８５０号公報にはカルボニル基含有共重合体エマルション粒子を核と殻を有する複層構造とすることが提案されている。この方策では、エマルション粒子に要求される目的に応じて共重合成分の選択の幅が広がるという利点を有するが、硬化性、初期乾燥性、また初期塗膜の耐水性が不十分であった。
【０００５】
【課題を解決するための手段】
本発明者らは、上記問題を解決すべく鋭意検討した結果、カルボニル基含有共重合体の共重合成分として多ビニル化合物を特定量用いることにより、予めエマルション粒子内をある程度架橋させ機械的性能を低下させることなく初期乾燥性及び初期塗膜の耐水性を改善し得ることを見出し本発明に到達した。
【０００６】
即ち本発明は、（ａ）ダイアセトンアクリルアミド及び／又はダイアセトンメタクリルアミドを０〜２５重量％、（ｂ）多価アルコ−ルの重合性不飽和モノカルボン酸エステル、多塩基酸の重合性不飽和アルコ−ルエステル及び２個以上のビニル基で置換された芳香族化合物から選ばれる少なくとも１種の１分子中に少なくとも２個の重合性不飽和結合を有する多ビニル化合物を０．１〜４重量％、（ｃ）（メタ）アクリル酸、マレイン酸、クロトン酸、β−カルボキシエチルアクリレ−ト、２−アクリルアミド−２−メチルプロパンスルホン酸、アリルスルホン酸、スチレンスルホン酸ナトリウム塩、スルホエチルメタクリレ−ト及びそのナトリウム塩やアンモニウム塩、（メタ）アクリルアミド、ジメチルアミノプロピル（メタ）アクリルアミド、ジメチルアミノエチル（メタ）アクリレ−ト、グリシジル（メタ）アクリレ−トとアミン類との付加物、ポリオキシエチレン鎖を有する（メタ）アクリレ−トから選ばれる少なくとも１種の水溶性エチレン性不飽和単量体を０．１〜８重量％、及び（ｄ）その他のエチレン性不飽和単量体を６３〜９９．８重量％含有する単量体混合物を、乳化剤の存在下で乳化重合させることにより得られる共重合体（Ｉ）をコア成分とし、これを含む水分散液中に、（ｅ）ダイアセトンアクリルアミド及び／又はダイアセトンメタクリルアミドを０．５〜２５重量％、（ｆ）（メタ）アクリル酸、マレイン酸、クロトン酸、β−カルボキシエチルアクリレ−ト、２−アクリルアミド−２−メチルプロパンスルホン酸、アリルスルホン酸、スチレンスルホン酸ナトリウム塩、スルホエチルメタクリレ−ト及びそのナトリウム塩やアンモニウム塩、（メタ）アクリルアミド、ジメチルアミノプロピル（メタ）アクリルアミド、ジメチルアミノエチル（メタ）アクリレ−ト、グリシジル（メタ）アクリレ−トとアミン類との付加物、ポリオキシエチレン鎖を有する（メタ）アクリレ−トから選ばれる少なくとも１種の水溶性エチレン性不飽和単量体を０．１〜８重量％、及び（ｇ）その他のエチレン性不飽和単量体を６７〜９９．４重量％含有する単量体混合物を加えて乳化重合させることにより得られる共重合体（II）をシェル成分とすることを特徴とするアクリル系共重合体水分散液、及びこのアクリル系共重合体水分散液を含有し、さらに架橋剤として１分子当たり少なくとも２個以上のヒドラジド基を有するヒドラジド化合物を、該共重合体水分散液中に含まれるカルボニル基１モルに対してヒドラジド化合物中のヒドラジド基が０．０１〜２モルとなるよう配合することを特徴とする水性塗料用樹脂組成物を提供するものである。
【０００７】
【発明の実施の形態】
本発明において使用する１分子中に少なくとも１個のカルボニル基を有する重合性不飽和単量体（ａ）としては、例えばアクロレイン、ダイアセトンアクリルアミド、ダイアセトンメタクリルアミド、ホルミルスチロ−ル、４〜７個の炭素原子を有するビニルアルキルケトン（例えばビニルメチルケトン、ビニルエチルケトン、ビニルブチルケトン）等が挙げられる。このうち特にダイアセトンアクリルアミド、ダイアセトンメタクリルアミドが好適である。
【０００８】
本発明において使用する１分子中に少なくとも２個の重合性不飽和結合を有する多ビニル化合物（ｂ）としては、多価アルコ−ルの重合性不飽和モノカルボン酸エステル、多塩基酸の重合性不飽和アルコ−ルエステル及び２個以上のビニル基で置換された芳香族化合物などが包含され、その具体例としては、例えばアリル（メタ）アクリレ−ト、エチレングリコ−ルジ（メタ）アクリレ−ト、トリエチレングリコ−ルジ（メタ）アクリレ−ト、テトラエチレングリコ−ルジ（メタ）アクリレ−ト、１，３−ブチレングリコ−ルジ（メタ）アクリレ−ト、トリメチロ−ルプロパントリ（メタ）アクリレ−ト、１，４−ブタンジオ−ルジ（メタ）アクリレ−ト、ネオペンチルグリコ−ルジ（メタ）アクリレ−ト、１，６−ヘキサンジオ−ルジ（メタ）アクリレ−ト、ペンタエリスリト−ルジ（メタ）アクリレ−ト、ペンタエリスリト−ルテトラ（メタ）アクリレ−ト、グリセロ−ルジ（メタ）アクリレ−ト、１，１，１−トリスヒドロキシメチルエタンジ（メタ）アクリレ−ト、１，１，１−トリスヒドロキシメチルエタントリ（メタ）アクリレ−ト、１，１，１−トリスヒドロキシメチルプロパントリ（メタ）アクリレ−ト、トリアリルイソシアヌレ−ト、ジアリルテレフタレ−ト、ジビニルベンゼンなどが挙げられる。
【０００９】
本発明において使用する水溶性エチレン性不飽和単量体（ｃ）は、単量体（ａ）と共重合可能であり、そのままで又は、中和もしくは４級塩化によって強い親水性を示すモノマ−であって、アニオン性、カチオン性、ノニオン性のいずれのモノマ−であってもよい。該単量体（ｃ）としては、アニオン系では、例えば（メタ）アクリル酸、マレイン酸、クロトン酸、β−カルボキシエチルアクリレ−ト、２−アクリルアミド−２−メチルプロパンスルホン酸、アリルスルホン酸、スチレンスルホン酸ナトリウム塩、スルホエチルメタクリレ−ト及びそのナトリウム塩やアンモニウム塩など；カチオン系では、例えば（メタ）アクリルアミド、ジメチルアミノプロピル（メタ）アクリルアミド、ジメチルアミノエチル（メタ）アクリレ−ト、さらにグリシジル（メタ）アクリレ−トとアミン類との付加物など；ノニオン系ではポリオキシエチレン鎖を有する（メタ）アクリレ−トなどが挙げられる。
【００１０】
本発明において使用するその他のエチレン性不飽和単量体（ｄ）としては、例えばメチル（メタ）アクリレ−ト、エチル（メタ）アクリレ−ト、プロピル（メタ）アクリレ−ト、ブチル（メタ）アクリレ−ト、２−エチルヘキシル（メタ）アクリレ−ト、シクロヘキシル（メタ）アクリレ−ト、ラウリル（メタ）アクリレ−ト、イソボルニル（メタ）アクリレ−トなどの（メタ）アクリル酸の炭素数１〜２４個のアルキル又はシクロアルキルエステル；２−ヒドロキシエチル（メタ）アクリレ−ト、ヒドロキシプロピル（メタ）アクリレ−トなどの（メタ）アクリル酸の炭素数２〜８個のヒドロキシアルキルエステル；スチレン、ビニルトルエンなどのビニル芳香族化合物；Ｎ−ビニルピロリドン、エチレン、ブタジエン、クロロプレン、プロピオン酸ビニル、酢酸ビニル、（メタ）アクリロニトリルなどが挙げられ、これらは所望の性能に応じて適宜使用される。
【００１１】
本発明の第１の共重合体水分散液［Ｉ］は、単量体（ａ）を０．１〜３０重量％、好ましくは０．５〜２５重量％、単量体（ｂ）を０．０５〜５重量％、好ましくは０．１〜４重量％、単量体（ｃ）を０〜１０重量％、好ましくは０．１〜８重量％、及び単量体（ｄ）を５５〜９９．８５重量％、好ましくは６３〜９９．３重量％含有する単量体混合物を、乳化剤の存在下で乳化重合させることにより得られるものである。乳化剤としては、アニオン性界面活性剤、ノニオン性界面活性剤などが挙げられ、該乳化剤の１種又は２種以上の存在下で過硫酸塩や過酸化物等の重合開始剤を使用して乳化重合することができる。
【００１２】
上記単量体（ａ）が０．１重量％未満は、架橋剤成分との硬化性に劣り、一方３０重量％を越えると、得られる塗膜がワレ等を生じやすく、単量体（ｂ）が０．０５重量％未満は、初期塗膜の耐水性や硬化性が不十分となり、一方５重量％を越えるとエマルション粒子の造膜性が低下し、単量体（ｃ）が１０重量％を越えると親水性が強くなりすぎ塗膜の耐水性が悪くなるので好ましくない。
【００１３】
本発明の第２の共重合体水分散液［ＩＩ］は、まずコア成分を形成する単量体混合物を、乳化剤の存在下で重合開始剤を使用して第１段階の乳化重合を行い共重合体（Ｉ）水分散液を得た後、該水分散液中に、シェル成分を形成する単量体混合物を重合開始剤を使用して第２段階の乳化重合を行い、コア−シェル粒子水分散液として得られるものである。第２段階の乳化重合時には、通常、乳化剤を添加しないか、あるいは添加したとしても新しい粒子を形成しない程度の量とすることが望ましい。
【００１４】
コア成分である共重合体（Ｉ）は、上記単量体（ａ）を０〜３０重量％、好ましくは０〜２５重量％、単量体（ｂ）を０．０５〜５重量％、好ましくは０．１〜４重量％、単量体（ｃ）を０〜１０重量％、好ましくは０．１〜８重量％、及び単量体（ｄ）を５５〜９９．９５重量％、好ましくは６３〜９９．８重量％含有する単量体混合物を用いることにより得られる。
【００１５】
該共重合体（Ｉ）において、単量体（ａ）が一方３０重量％を越えると得られる塗膜がワレ等を生じやすく、また単量体（ｂ）が０．０５重量％未満は、初期塗膜の耐水性や硬化性が不十分となり、一方５重量％を越えると、エマルション粒子の造膜性が低下し、単量体（ｃ）が１０重量％を越えると、親水性が強くなりすぎ塗膜の耐水性が悪くなるので好ましくない。
【００１６】
一方シェル成分である共重合体（II）は、カルボニル基含有重合性不飽和単量体（ｅ）を０．１〜３０重量％、好ましくは０．５〜２５重量％、水溶性エチレン性不飽和単量体（ｆ）を０〜１０重量％、好ましくは０．１〜８重量％、及びその他のエチレン性不飽和単量体（ｇ）を６０〜９９．９重量％、好ましくは６７〜９９．４重量％含有する単量体混合物を用いることにより得られる。
【００１７】
該共重合体（II）において、上記単量体（ｅ）が０．１重量％未満は、架橋剤成分との硬化性に劣り、一方３０重量％を越えると、得られる塗膜がワレ等を生じやすく、単量体（ｆ）が１０重量％を越えると親水性が強くなりすぎ塗膜の耐水性が悪くなるので好ましくない。
【００１８】
上記カルボニル基含有重合性不飽和単量体（ｅ）としては、前記単量体（ａ）の説明で列記したものから適宜選択して使用でき、上記水溶性エチレン性不飽和単量体（ｆ）としては、前記単量体（ｃ）の説明で列記したものから適宜選択して使用できる。さらにその他のエチレン性不飽和単量体（ｇ）としては、前記単量体（ｄ）の説明で列記したものから適宜選択して使用できる。
【００１９】
コア成分である共重合体（Ｉ）とシェル成分である共重合体（II）の固形分重量比は、造膜性、初期耐水性の点から、（Ｉ）１００重量部に対し（II）が４００〜２５重量部、好ましくは３００〜３０重量部となるようにするのが適当である。
【００２０】
本発明の水性塗料用樹脂組成物は、上記共重合体水分散液［Ｉ］及び／又は［ＩＩ］をビヒクル成分として含有するものである。さらに必要に応じて、このものに従来塗料分野で使用されている、公知のエマルジョン、例えば酢酸ビニルエマルジョン、アクリル樹脂エマルジョン、酢ビ−アクリルエマルジョン、エチレン−酢ビエマルジョンなどを固形分量で全ビヒクル成分中に占める割合が５０重量％以下となる量配合してもよい。
【００２１】
本発明組成物は、さらに架橋剤として１分子当たり少なくとも２個以上のヒドラジド基を有するヒドラジド化合物を含有するものである。
【００２２】
該ヒドラジド化合物としては、例えば、蓚酸ジヒドラジド、マロン酸ジヒドラジド、こはく酸ジヒドラジド、グルタル酸ジヒドラジド、アジピン酸ジヒドラジド、セバシン酸ジヒドラジドなどの２〜１８個の炭素原子を有する飽和脂肪族カルボン酸ジヒドラジド；マレイン酸ジヒドラジド、フマル酸ジヒドラジド、イタコン酸ジヒドラジドなどのモノオレフィン性不飽和ジカルボン酸のジヒドラジド；炭酸ジヒドラジド、ビスセミカルバジド、ポリイソシアネート化合物とポリオキシエチレン鎖等の親水性基含有活性水素化合物との反応物にヒドラジン誘導体を反応させてなる水系セミカルバジド化合物（特開平８−１５１３５８号参照）；フタル酸、テレフタル酸又はイソフタル酸ジヒドラジド、ならびにピロメリット酸のジヒドラジド、トリヒドラジド又はテトラヒドラジド；ニトリロトリ酢酸トリヒドラジド、クエン酸トリヒドラジド、１，２，４−ベンゼントリヒドラジド；エチレンジアミンテトラ酢酸テトラヒドラジド、１，４，５，８−ナフトエ酸テトラヒドラジド；カルボン酸低級アルキルエステル基を有する低重合体をヒドラジン又はヒドラジン水化物（ヒドラジンヒドラ−ド）と反応させてなるポリヒドラジド（特公昭５２−２２８７８号参照）などが挙げられる。
【００２３】
上記ヒドラジド化合物は、疎水性が強すぎると水分散化が困難となり、均一な架橋塗膜が得られないことから適度な親水性を有する比較的低分子量の化合物を使用することが好適であり、上記例示中では、例えば、アジピン酸ジヒドラジド、こはく酸ジヒドラジドなどのジカルボン酸のジヒドラジドが好適である。
【００２４】
上記ヒドラジド化合物の添加量は、前記［Ｉ］及び［ＩＩ］成分中のカルボニル基１モルに対し、ヒドラジド基の量が０．０１〜２．０モル、好ましくは０．０５〜１．５モルとなる量が適当である。
【００２５】
本発明組成物を用いて、さらに塗料を製造するにあたっては、顔料、充填剤、骨材、顔料分散剤、湿潤剤、消泡剤、可塑剤、造膜助剤、有機溶剤、防腐剤、防かび剤、ｐＨ調整剤、防錆剤など、それぞれの目的に応じて適宜選択し組合わせて配合することができる。
【００２６】
【実施例】
以下、実施例を挙げて本発明をさらに詳細に説明する。
【００２７】
共重合体水分散液［Ｉ］の製造
実施例１
容量２リットルの４つ口フラスコに脱イオン水２８．５重量部、Ｎｅｗｃｏｌ７０７ＳＦ（日本乳化剤社製、ポリオキシエチレン鎖を有するアニオン性界面活性剤、不揮発分３０％）０．１重量部を加え、窒素置換後、８５℃に保った。この中に下記組成をエマルション化してなるプレエマルションの３重量％分及び０．５重量部の過硫酸アンモニウムを１０重量部の脱イオン水に溶解させた溶液１０．５重量部の２５重量％分を添加し、添加２０分後から残りのプレエマルション及び残りの過硫酸アンモニウム水溶液を４時間かけて滴下した。
【００２８】

滴下終了後、これをさらに２時間８５℃に保持した後、４０〜６０℃に降温した。次いでアンモニア水でｐＨ８〜９に調整し、固形分５５重量％の共重合体水分散液［Ｉ−１］を得た。エマルションのｐＨは８．３であった。
【００２９】
実施例２〜４及び比較例１、２
滴下するプレエマルション中のモノマ−を表１に示す組成とする以外は実施例１と同様の方法で共重合体水分散液［Ｉ−２］〜［Ｉ−６］を得た。各共重合体水分散液の性状値を表１に示す。
【００３０】
【表１】

【００３１】
共重合体水分散液［ＩＩ］の製造
実施例５
容量２リットルの４つ口フラスコに脱イオン水２８．５重量部、Ｎｅｗｃｏｌ７０７ＳＦ（日本乳化剤社製、ポリオキシエチレン鎖を有するアニオン性界面活性剤、不揮発分３０％）０．１重量部を加え、窒素置換後、８５℃に保った。
この中に下記組成をエマルション化してなるプレエマルション（コア用）の３重量％分及び０．５重量部の過硫酸アンモニウムを１０重量部の脱イオン水に溶解させた溶液１０．５重量部の２５重量％分を添加し、添加２０分後からプレエマルションの６７重量％分及び過硫酸アンモニウム水溶液の５０重量％分を２時間かけて滴下した。
【００３２】

滴下終了後、これをさらに２時間８５℃に保持した後、この中に下記組成をエマルション化してなるプレエマルション（シェル用）の３０重量％分及び上記過硫酸アンモニウム水溶液の２５重量％分を２時間かけて滴下した。
【００３３】

滴下終了後、これをさらに２時間８５℃に保持した後、４０〜６０℃に降温した。次いでアンモニア水でｐＨ８〜９に調整し、固形分５５重量％の共重合体水分散液［ＩＩ−１］を得た。エマルションのｐＨは８．４であった。
【００３４】
実施例６〜８及び比較例３、４
滴下するコア用及びシェル用のプレエマルション中のモノマ−を表２に示す組成とし、コア用及びシェル用のプレエマルションの使用比を表２に示す割合とする以外は実施例５と同様の方法で共重合体水分散液［ＩＩ−２］〜［ＩＩ−６］を得た。各共重合体水分散液の性状値を表２に示す。
【００３５】
【表２】

【００３６】
樹脂組成物の作成
実施例９〜１６及び比較例５〜８
容量２リットルの容器に各共重合体水分散液を仕込み、さらに各共重合体水分散液中のカルボニル基に対してヒドラジド基が表３に示すモル量になるようアジピン酸ジヒドラジドを配合して仕込み撹拌混合し、さらにアンモニア水でｐＨ７〜９に調整して、夫々の樹脂混合液を得た。
【００３７】
得られた各樹脂混合液を下記性能試験に供した。結果を表３に示す。
【００３８】
（＊１）溶剤膨潤率
ガラス板に上記の通り得られた各樹脂混合液をドクタ−ブレ−ドにて乾燥膜厚で６０μｍになるように塗装し、温度２０℃及び相対湿度７５％の条件下で１週間乾燥させた後、ガラス板から乾燥膜を剥離して４×４ｃｍの大きさにカットし、これをキシレン中に２０℃で２４時間浸漬した。次いで膜を取り出し表面のキシレンを除去して該膜重量Ｓ（ｇ）を測定した後、これを１３０℃で１時間乾燥させその膜重量Ｄ（ｇ）を測定した。次式に従って溶剤膨潤率（％）を算出した。
【００３９】
溶剤膨潤率（％）＝（Ｓ／Ｄ）×１００
（＊２）ゲル分率
ガラス板に上記の通り得られた各樹脂混合液をドクタ−ブレ−ドにて乾燥膜厚で６０μｍになるように塗装し、温度２０℃及び相対湿度７５％の条件下で１週間乾燥させた後、ガラス板から乾燥膜を剥離してこれをアセトン中に浸漬し、還流温度で２４時間抽出させた後、次式に従ってゲル分率を算出した。
【００４０】
ゲル分率（％）＝（抽出した後の膜の重量／抽出前の膜の重量）×１００
（＊３）初期耐水性
ガラス板に上記の通り得られた各樹脂混合液をドクタ−ブレ−ドにて乾燥膜厚で６０μｍになるように塗装し、温度２０℃及び相対湿度７５％の条件下で１時間乾燥させた後、２０℃の上水中に試験板を半没し、３０分後に試験板を引上げて塗面を目視で評価した。
【００４１】
○：異常なし
△：少し白化（ブル−イング）
×：著しく白化
【００４２】
【発明の効果】
本発明によれば、カルボニル基含有共重合体の共重合成分として多ビニル化合物を特定量用いることにより、予めエマルション粒子内をある程度架橋させ、さらにカルボニルとヒドラジドで粒子間を架橋させることで、特に塗装初期における耐水性が良好である常温乾燥型の水性塗料用樹脂組成物が得られる。従って本発明の組成物は、屋外での使用に非常に適しており、建築外装用塗料のビヒクル成分として有用である。
【００４３】
【表３】

[0001]
BACKGROUND OF THE INVENTION
The present invention is excellent in initial drying property and water resistance of an initial coating film, and is useful in applications such as room temperature drying type paints, inks, adhesives, and the like, and an aqueous copolymer resin dispersion containing the same. About.
[0002]
[Prior art and its problems]
In recent years, in the fields of paints, inks, adhesives, and the like, the shift from organic solvent types to water-based materials has been promoted from the viewpoints of resource saving, environmental sanitation, pollution-free, non-hazardous substances (fire fighting law), and the like. In general, an acrylic copolymer emulsion is used as a vehicle component in a water-based paint for room temperature drying. The acrylic copolymer emulsion is formed by fusing the emulsion particles after coating, and the glass transition temperature of the copolymer is designed to be high from the viewpoint of securing the film forming property by such fusing. It was difficult. For this reason, the coating film by the water-based paint using this copolymer emulsion is inferior to the toughness of a film | membrane and stain resistance, and the water resistance cannot be denied.
[0003]
Therefore, in order to solve the problem at the time of film formation of the emulsion of the water-based paint, the present applicant uses a carbonyl group-containing copolymer emulsion and a hydrazide compound to crosslink between the emulsion particles with a crosslinking agent having a relatively low molecular weight. (Japanese Patent Laid-Open No. Hei 4-249487), thereby enhancing the film-forming property and realizing not only contamination resistance and water resistance, but also improved initial drying properties.
[0004]
However, in the production of the above carbonyl group-containing copolymer emulsion, the type and amount of the monomer as the copolymer component are determined depending on the purpose required of the emulsion particles, so that a corresponding carbonyl group is introduced into the copolymer. In some cases, there was no problem after drying sufficiently in terms of water resistance, but there was difficulty at the time of the initial coating film. On the other hand, for example, Japanese Patent Application Laid-Open No. 57-3850 proposes that the carbonyl group-containing copolymer emulsion particles have a multilayer structure having a core and a shell. This measure has the advantage that the selection range of the copolymerization component is widened depending on the purpose required of the emulsion particles, but the curability, initial drying property, and water resistance of the initial coating film are insufficient.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have used a specific amount of a polyvinyl compound as a copolymer component of the carbonyl group-containing copolymer, thereby preliminarily cross-linking the emulsion particles to some extent. The present inventors have found that the initial drying property and the water resistance of the initial coating film can be improved without lowering the present invention.
[0006]
That is, the present invention relates to (a) 0 to 25% by weight of diacetone acrylamide and / or diacetone methacrylamide , (b) a polymerizable unsaturated monocarboxylic acid ester of a polyhydric alcohol, and a polymerizable non-polymerizable polybasic acid. 0.1 to 4 weights of a polyvinyl compound having at least two polymerizable unsaturated bonds in one molecule selected from a saturated alcohol ester and an aromatic compound substituted with two or more vinyl groups %, (C) (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate And its sodium and ammonium salts, (meth) acrylamide, dimethylaminopropyl (meth) acrylate Amide, dimethylaminoethyl (meth) acrylate - DOO, glycidyl (meth) acrylate - adducts of bets and an amine, having a polyoxyethylene chain (meth) acrylate - at least one water-soluble ethylenically selected from preparative Emulsion polymerization of a monomer mixture containing 0.1 to 8% by weight of an unsaturated monomer and (d) 63 to 99.8% by weight of another ethylenically unsaturated monomer in the presence of an emulsifier (E) 0.5 to 25% by weight of (e) diacetone acrylamide and / or diacetone methacrylamide in the aqueous dispersion containing the copolymer (I) obtained as a core component, (f) (Meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene Sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium and ammonium salts, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate and 0.1 to 8% by weight of at least one water-soluble ethylenically unsaturated monomer selected from adducts with amines, (meth) acrylates having a polyoxyethylene chain , and (g) other An acrylic copolymer comprising a copolymer (II) obtained by emulsion polymerization by adding a monomer mixture containing 67 to 99.4% by weight of an ethylenically unsaturated monomer. polymer aqueous dispersion, and it contains the acrylic copolymer aqueous dispersion, further at least two per molecule as a crosslinking agent An aqueous solution characterized in that the hydrazide compound having a hydrazide group is blended so that the hydrazide group in the hydrazide compound is 0.01 to 2 mol with respect to 1 mol of the carbonyl group contained in the aqueous copolymer dispersion. A resin composition for paints is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the polymerizable unsaturated monomer (a) having at least one carbonyl group in one molecule used in the present invention include acrolein, diacetone acrylamide, diacetone methacrylamide, formylstyrene, 4 to 7 And vinyl alkyl ketones having the following carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the like. Of these, diacetone acrylamide and diacetone methacrylamide are particularly suitable.
[0008]
Examples of the polyvinyl compound (b) having at least two polymerizable unsaturated bonds in one molecule used in the present invention include polymerizable unsaturated monocarboxylic acid esters of polyhydric alcohols, and polymerizability of polybasic acids. Examples include unsaturated alcohol esters and aromatic compounds substituted with two or more vinyl groups. Specific examples thereof include allyl (meth) acrylate, ethylene glycol di (meth) acrylate, Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1 , 4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol (medium) ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethane (Meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, Examples include diallyl terephthalate and divinylbenzene.
[0009]
The water-soluble ethylenically unsaturated monomer (c) used in the present invention is a monomer that can be copolymerized with the monomer (a) and exhibits strong hydrophilicity as it is or by neutralization or quaternary chlorination. Any of anionic, cationic and nonionic monomers may be used. As the monomer (c), in the anionic system, for example, (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid Styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt and ammonium salt, etc .; in cationic systems, for example, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, Furthermore, adducts of glycidyl (meth) acrylate and amines and the like; nonionic compounds include (meth) acrylate having a polyoxyethylene chain.
[0010]
Examples of other ethylenically unsaturated monomers (d) used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. 1 to 24 carbon atoms of (meth) acrylic acid such as -to, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, etc. Alkyl or cycloalkyl esters of 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and other (meth) acrylic acid hydroxyalkyl esters having 2 to 8 carbon atoms; styrene, vinyltoluene, etc. Vinyl aromatic compounds: N-vinylpyrrolidone, ethylene, butadiene, chloroprene, Vinyl propionate, vinyl acetate, include (meth) acrylonitrile, which are used as appropriate according to the desired performance.
[0011]
In the first aqueous copolymer dispersion [I] of the present invention, the monomer (a) is 0.1 to 30% by weight, preferably 0.5 to 25% by weight, and the monomer (b) is 0%. 0.05 to 5 wt%, preferably 0.1 to 4 wt%, monomer (c) 0 to 10 wt%, preferably 0.1 to 8 wt%, and monomer (d) 55 to It is obtained by emulsion polymerization of a monomer mixture containing 99.85% by weight, preferably 63 to 99.3% by weight, in the presence of an emulsifier. Examples of the emulsifier include anionic surfactants and nonionic surfactants, and emulsification using a polymerization initiator such as persulfate or peroxide in the presence of one or more of the emulsifiers. Can be polymerized.
[0012]
When the monomer (a) is less than 0.1% by weight, the curability with the crosslinking agent component is inferior. On the other hand, when the monomer (a) exceeds 30% by weight, the resulting coating film is easily cracked, and the monomer (b ) Is less than 0.05% by weight, the water resistance and curability of the initial coating film are insufficient. On the other hand, if it exceeds 5% by weight, the film-forming property of the emulsion particles is lowered, and the monomer (c) is 10% by weight. If it exceeds 50%, the hydrophilicity becomes too strong, and the water resistance of the coating film becomes poor.
[0013]
In the second copolymer aqueous dispersion [II] of the present invention, first, a monomer mixture forming a core component is subjected to a first stage emulsion polymerization using a polymerization initiator in the presence of an emulsifier. After obtaining the polymer (I) aqueous dispersion, the monomer mixture forming the shell component is subjected to the second stage emulsion polymerization using the polymerization initiator in the aqueous dispersion, and the core-shell particles It is obtained as an aqueous dispersion. In the second stage of emulsion polymerization, it is usually desirable not to add an emulsifier or to an amount that does not form new particles even if added.
[0014]
The copolymer (I) as the core component is the above monomer (a) in an amount of 0 to 30% by weight, preferably 0 to 25% by weight, and the monomer (b) in an amount of 0.05 to 5% by weight, preferably Is 0.1 to 4% by weight, monomer (c) is 0 to 10% by weight, preferably 0.1 to 8% by weight, and monomer (d) is 55 to 99.95% by weight, preferably It is obtained by using a monomer mixture containing 63 to 99.8% by weight.
[0015]
In the copolymer (I), if the monomer (a) exceeds 30% by weight, the resulting coating film tends to crack, and if the monomer (b) is less than 0.05% by weight, The water resistance and curability of the initial coating film become insufficient. On the other hand, if it exceeds 5% by weight, the film-forming property of the emulsion particles decreases, and if the monomer (c) exceeds 10% by weight, the hydrophilicity is strong. It becomes unpreferable because the water resistance of the coating film becomes too bad.
[0016]
On the other hand, the copolymer (II) as the shell component contains 0.1 to 30% by weight, preferably 0.5 to 25% by weight of the carbonyl group-containing polymerizable unsaturated monomer (e). The saturated monomer (f) is 0 to 10% by weight, preferably 0.1 to 8% by weight, and the other ethylenically unsaturated monomer (g) is 60 to 99.9% by weight, preferably 67 to It is obtained by using a monomer mixture containing 99.4% by weight.
[0017]
In the copolymer (II), when the monomer (e) is less than 0.1% by weight, the curability with the crosslinking agent component is inferior. When the monomer (f) exceeds 10% by weight, the hydrophilicity becomes too strong, and the water resistance of the coating film is deteriorated.
[0018]
The carbonyl group-containing polymerizable unsaturated monomer (e) can be appropriately selected from those listed in the description of the monomer (a), and the water-soluble ethylenically unsaturated monomer (f ) Can be appropriately selected from those listed in the description of the monomer (c). Further, the other ethylenically unsaturated monomer (g) can be appropriately selected from those listed in the description of the monomer (d).
[0019]
The solid content weight ratio of the copolymer (I) as the core component and the copolymer (II) as the shell component is (II) with respect to 100 parts by weight of (I) from the viewpoint of film forming property and initial water resistance. Is suitably 400 to 25 parts by weight, preferably 300 to 30 parts by weight.
[0020]
The resin composition for water-based paints of the present invention contains the copolymer aqueous dispersion [I] and / or [II] as a vehicle component. Further, if necessary, a known emulsion, such as a vinyl acetate emulsion, an acrylic resin emulsion, a vinyl acetate acrylic emulsion, an ethylene vinyl acetate emulsion, etc., which has been used in the past in the field of paints, is added to the whole vehicle component in a solid amount. You may mix | blend the quantity which will occupy the ratio for 50 weight% or less.
[0021]
The composition of the present invention further contains a hydrazide compound having at least two hydrazide groups per molecule as a crosslinking agent.
[0022]
Examples of the hydrazide compound include saturated aliphatic carboxylic acid dihydrazides having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide; maleic acid Dihydrazide of monoolefinic unsaturated dicarboxylic acid such as dihydrazide, fumarate dihydrazide, itaconic acid dihydrazide; hydrazine as a reaction product of dihydrazide carbonate, bissemicarbazide, polyisocyanate compound and active hydrogen compound containing hydrophilic group such as polyoxyethylene chain An aqueous semicarbazide compound obtained by reacting a derivative (see JP-A-8-151358); phthalic acid, terephthalic acid or isophthalic acid dihydrazide, and pyromellitic acid dihydrazide; Rihydrazide or tetrahydrazide; nitrilotriacetic acid trihydrazide, citric acid trihydrazide, 1,2,4-benzenetrihydrazide; ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide; carboxylic acid lower alkyl ester group And a polyhydrazide obtained by reacting a low polymer having a hydrazine or a hydrazine hydrate (hydrazine hydride) (see Japanese Patent Publication No. 52-22878).
[0023]
When the hydrazide compound is too hydrophobic, it is difficult to disperse in water, and it is preferable to use a relatively low molecular weight compound having moderate hydrophilicity because a uniform crosslinked coating film cannot be obtained. In the above examples, for example, dihydrazides of dicarboxylic acids such as adipic acid dihydrazide and succinic acid dihydrazide are suitable.
[0024]
The amount of the hydrazide compound added is 0.01 to 2.0 mol, preferably 0.05 to 1.5 mol, based on 1 mol of the carbonyl group in the components [I] and [II]. Is appropriate.
[0025]
In the production of paints using the composition of the present invention, pigments, fillers, aggregates, pigment dispersants, wetting agents, antifoaming agents, plasticizers, film-forming aids, organic solvents, preservatives, A fungicide, a pH adjuster, a rust inhibitor, and the like can be appropriately selected and combined in accordance with each purpose.
[0026]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0027]
Production of copolymer aqueous dispersion [I] Example 1
Add 28.5 parts by weight of deionized water to a 2 liter four-necked flask and 0.1 part by weight of Newcol 707SF (manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, nonvolatile content 30%), After nitrogen substitution, the temperature was kept at 85 ° C. In this, 3% by weight of a pre-emulsion obtained by emulsifying the following composition and 25% by weight of 10.5 parts by weight of a solution obtained by dissolving 0.5 parts by weight of ammonium persulfate in 10 parts by weight of deionized water After 20 minutes from the addition, the remaining pre-emulsion and the remaining aqueous ammonium persulfate solution were added dropwise over 4 hours.
[0028]

After completion of the dropwise addition, this was further maintained at 85 ° C. for 2 hours, and then cooled to 40-60 ° C. Next, the pH was adjusted to 8-9 with aqueous ammonia to obtain a copolymer aqueous dispersion [I-1] having a solid content of 55% by weight. The pH of the emulsion was 8.3.
[0029]
Examples 2 to 4 and Comparative Examples 1 and 2
Copolymer aqueous dispersions [I-2] to [I-6] were obtained in the same manner as in Example 1 except that the monomer in the pre-emulsion to be dropped was changed to the composition shown in Table 1. The property values of each copolymer aqueous dispersion are shown in Table 1.
[0030]
[Table 1]

[0031]
Production of copolymer aqueous dispersion [II] Example 5
Add 28.5 parts by weight of deionized water to a 2 liter four-necked flask and 0.1 part by weight of Newcol 707SF (manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, nonvolatile content 30%), After nitrogen substitution, the temperature was kept at 85 ° C.
10.5 parts by weight of a solution prepared by dissolving 3 parts by weight of a pre-emulsion (for core) obtained by emulsifying the following composition and 0.5 parts by weight of ammonium persulfate in 10 parts by weight of deionized water. After adding 20% by weight, 67% by weight of the pre-emulsion and 50% by weight of the aqueous ammonium persulfate solution were added dropwise over 2 hours.
[0032]

After completion of the dropwise addition, this was further maintained at 85 ° C. for 2 hours, and then 30% by weight of a pre-emulsion (for shell) obtained by emulsifying the following composition therein and 25% by weight of the aqueous ammonium persulfate solution for 2 hours. It was dripped over.
[0033]

After completion of the dropwise addition, this was further maintained at 85 ° C. for 2 hours, and then cooled to 40-60 ° C. Next, the pH was adjusted to 8-9 with aqueous ammonia to obtain a copolymer aqueous dispersion [II-1] having a solid content of 55% by weight. The pH of the emulsion was 8.4.
[0034]
Examples 6-8 and Comparative Examples 3, 4
The monomer in the pre-emulsion for core and shell to be dropped is set to the composition shown in Table 2, and the same method as in Example 5 except that the use ratio of the pre-emulsion for core and shell is set to the ratio shown in Table 2. Copolymer aqueous dispersions [II-2] to [II-6] were obtained. Table 2 shows the property values of each copolymer aqueous dispersion.
[0035]
[Table 2]

[0036]
Preparation of resin compositions Examples 9-16 and Comparative Examples 5-8
Each copolymer aqueous dispersion is charged into a 2 liter container, and adipic acid dihydrazide is blended so that the hydrazide group has a molar amount shown in Table 3 with respect to the carbonyl group in each copolymer aqueous dispersion. The mixture was stirred and mixed, and further adjusted to pH 7 to 9 with aqueous ammonia to obtain respective resin mixed solutions.
[0037]
Each obtained resin liquid mixture was used for the following performance test. The results are shown in Table 3.
[0038]
(* 1) Solvent swelling ratio Each resin mixture obtained as described above was applied to a glass plate with a doctor blade so that the dry film thickness was 60 μm, and the temperature was 20 ° C. and the relative humidity was 75%. After drying for 1 week, the dried film was peeled off from the glass plate, cut into a size of 4 × 4 cm, and immersed in xylene at 20 ° C. for 24 hours. Next, the film was taken out, xylene on the surface was removed, and the film weight S (g) was measured. Then, the film was dried at 130 ° C. for 1 hour, and the film weight D (g) was measured. The solvent swelling ratio (%) was calculated according to the following formula.
[0039]
Solvent swelling rate (%) = (S / D) × 100
(* 2) Each resin mixture obtained as described above was applied to a gel fraction glass plate with a doctor blade so that the dry film thickness was 60 μm, and the temperature was 20 ° C. and the relative humidity was 75%. After drying for 1 week, the dried film was peeled from the glass plate, immersed in acetone and extracted at reflux temperature for 24 hours, and then the gel fraction was calculated according to the following formula.
[0040]
Gel fraction (%) = (weight of membrane after extraction / weight of membrane before extraction) × 100
(* 3) Each resin mixture obtained as described above was applied to the initial water-resistant glass plate with a doctor blade so that the dry film thickness was 60 μm, and the temperature was 20 ° C. and the relative humidity was 75%. After drying for 1 hour below, the test plate was submerged in water at 20 ° C. After 30 minutes, the test plate was pulled up and the coated surface was visually evaluated.
[0041]
○: No abnormality △: Slightly whitening (Blouing)
×: Remarkably whitening [0042]
【The invention's effect】
According to the present invention, by using a specific amount of a polyvinyl compound as a copolymerization component of a carbonyl group-containing copolymer, the emulsion particles are crosslinked to some extent in advance, and further, the particles are crosslinked with carbonyl and hydrazide. A room temperature drying type resin composition for water-based paints having good water resistance at the initial stage of coating is obtained. Therefore, the composition of the present invention is very suitable for outdoor use, and is useful as a vehicle component of paint for building exteriors.
[0043]
[Table 3]

Claims

(A) 0-25 wt% diacetone acrylamide and / or diacetone methacrylamide , (b) polymerizable unsaturated monocarboxylic acid ester of polyhydric alcohol, polymerizable unsaturated alcohol ester of polybasic acid, and 0.1 to 4% by weight of a polyvinyl compound having at least two polymerizable unsaturated bonds in one molecule of at least one selected from aromatic compounds substituted with two or more vinyl groups , (c) (Meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its Sodium salt and ammonium salt, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethyl Ruaminoechiru (meth) acrylate - DOO, glycidyl (meth) acrylate - adducts of bets and an amine, having a polyoxyethylene chain (meth) acrylate - at least one water-soluble selected from preparative ethylenically unsaturated monomer Obtained by emulsion polymerization of a monomer mixture containing 0.1 to 8% by weight of the product and (d) 63 to 99.8% by weight of other ethylenically unsaturated monomers in the presence of an emulsifier. Copolymer (I) as a core component, and 0.5 to 25% by weight of (e) diacetone acrylamide and / or diacetone methacrylamide in an aqueous dispersion containing this, (f) (meth) acrylic Acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium Lium salt, sulfoethyl methacrylate and its sodium and ammonium salts, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate and amines 0.1 to 8% by weight of at least one water-soluble ethylenically unsaturated monomer selected from adducts with (meth) acrylate having a polyoxyethylene chain , and (g) other ethylenic monomers Acrylic copolymer characterized in that a copolymer (II) obtained by adding a monomer mixture containing 67 to 99.4% by weight of an unsaturated monomer and emulsion polymerization is used as a shell component. Water dispersion.

(A) 0-25 wt% diacetone acrylamide and / or diacetone methacrylamide , (b) polymerizable unsaturated monocarboxylic acid ester of polyhydric alcohol, polymerizable unsaturated alcohol ester of polybasic acid, and 0.1 to 4% by weight of a polyvinyl compound having at least two polymerizable unsaturated bonds in one molecule of at least one selected from aromatic compounds substituted with two or more vinyl groups , (c) (Meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its Sodium salt and ammonium salt, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethyl Ruaminoechiru (meth) acrylate - DOO, glycidyl (meth) acrylate - adducts of bets and an amine, having a polyoxyethylene chain (meth) acrylate - at least one water-soluble selected from preparative ethylenically unsaturated monomer Obtained by emulsion polymerization of a monomer mixture containing 0.1 to 8% by weight of the product and (d) 63 to 99.8% by weight of other ethylenically unsaturated monomers in the presence of an emulsifier. Copolymer (I) as a core component, and 0.5 to 25% by weight of (e) diacetone acrylamide and / or diacetone methacrylamide in an aqueous dispersion containing this, (f) (meth) acrylic Acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium Lium salt, sulfoethyl methacrylate and its sodium and ammonium salts, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate and amines 0.1 to 8% by weight of at least one water-soluble ethylenically unsaturated monomer selected from adducts with (meth) acrylate having a polyoxyethylene chain , and (g) other ethylenic monomers Contains an acrylic copolymer aqueous dispersion containing, as a shell component, a copolymer (II) obtained by emulsion polymerization by adding a monomer mixture containing 67 to 99.4% by weight of an unsaturated monomer In addition, a hydrazide compound having at least two hydrazide groups per molecule as a crosslinking agent is contained in the aqueous copolymer dispersion. The aqueous coating resin composition hydrazide group of the hydrazide compound to the carbonyl group one mole is characterized by blending so as to be 0.01 to 2 mol of the.