JP3942150B2 - Emulsion-type adhesive composition - Google Patents

Abstract

An emulsion type adhesive composition is obtained by polymerizing an ethylenically unsaturated monomer (E) having alkyl (meth)acrylate (e1) as main component, in presence of a resin emulsion (II) obtained by polymerizing an emulsification liquid (I). The emulsification liquid (I) is obtained by emulsifying a fat-soluble component containing ethylenically unsaturated monomer (A) and tackifier (B). An emulsion type adhesive composition is obtained by polymerizing an ethylenically unsaturated monomer (E) having alkyl (meth)acrylate (e1) as main component, in presence of a resin emulsion (II). The resin emulsion (II) is obtained by polymerizing an emulsification liquid (I) in the presence of a polymerization initiator (D). The emulsification liquid (I) is obtained by emulsifying a fat-soluble component containing ethylenically unsaturated monomer (A) having alkyl (meth)acrylate (a1) as main component, and tackifier (B) using an emulsifier (C) in an aqueous medium. The average particle diameter of the fat soluble component is 1 mum or less.

Description

【００２６】
【化２】

【００２７】
【化３】

【００２８】
【化４】

【００２９】
【化５】

【００３０】
【化６】

【００３１】
【化７】

【００３２】
〔ここで、一般式（１）〜（７）において、Ｒ₁はアルキル基、Ｒ₂は水素又はメチル基、Ｒ₃はアルキレン基、ｎは１以上の整数、ｍ、ｌは１以上の整数（ｍ＋ｌ＝３）、Ｘは水素、ＳＯ₃ＮＨ₄、ＳＯ₃Ｎａのいずれかである。〕
【００３３】
上記界面活性剤として具体的には、「アデカリアソープＳＥ−２０Ｎ」（アニオン性）、「アデカリアソープＳＥ−１０Ｎ」（アニオン性）、「アデカリアソープＮＥ−１０」（ノニオン性）、「アデカリアソープＮＥ−２０」（ノニオン性）、「アデカリアソープＮＥ−３０」（ノニオン性）、「アデカリアソープＮＥ−４０」（ノニオン性）、「アデカリアソープＳＤＸ−７３０」（アニオン性）、「アデカリアソープＳＤＸ−７３１」（アニオン性）〔以上、旭電化（株）製〕、「エレミノールＪＳ−２」（アニオン性）、「エレミノールＲＳ−３０」（アニオン性）〔以上、三洋化成（株）製〕、「ラテムルＳ−１８０Ａ」（アニオン性）、「ラテムルＳ−１８０」（アニオン性）〔以上、花王（株）製〕、「アクアロンＢＣ−０５」（アニオン性）、「アクアロンＢＣ−１０」（アニオン性）、「アクアロンＢＣ−２０」（アニオン性）、「アクアロンＨＳ−０５」（アニオン性）、「アクアロンＨＳ−１０」（アニオン性）、「アクアロンＨＳ−２０」（アニオン性）、「アクアロンＲＮ−１０」（ノニオン性）、「アクアロンＲＮ−２０」（ノニオン性）、「アクアロンＲＮ−３０」（ノニオン性）、「アクアロンＲＮ−５０」（ノニオン性）、「ニューフロンティアＳ−５１０」（アニオン）〔以上、第一工業製薬（株）製〕、「フォスフィノ−ルＴＸ」（アニオン性）〔東邦化学工業（株）製〕）等の市販品が挙げられる。
【００３４】
上記乳化剤（Ｃ）の配合量は、エチレン性不飽和単量体（Ａ）と粘着付与剤（Ｂ）の合計１００重量部に対して、０．５〜１０重量部であることが好ましく、より好ましくは０．８〜７重量部、特に好ましくは１〜５重量部である。乳化剤（Ｃ）が０．５重量部未満では油溶成分の粒子径を１μｍ以下にすることが難しく、又重合も不安定となり、１０重量部を越えると重合が不安定となったり、塗膜の耐水性が低下し好ましくない。
尚、乳化剤（Ｃ）は乳化液［Ｉ］に添加する以外に、一部を予め重合缶に添加しておいてもよい。
【００３５】
次に、（メタ）アクリル酸アルキルエステル（ａ１）、架橋性を有する単量体（ａ２）及びその他の共重合可能な単量体（ａ３）を含有するエチレン性不飽和単量体（Ａ）と粘着付与剤（Ｂ）からなる油溶成分を、水媒体中で乳化剤（Ｃ）を用いて、油溶成分の平均粒子径が１．０μｍ以下となるように乳化させた乳化液［Ｉ］を得る方法について説明する。
【００３６】
各成分の仕込み方法としては、予め粘着付与剤（Ｂ）をエチレン性不飽和単量体（Ａ）に溶解し、その他の成分を仕込むことが好ましい。
水の使用量は、エチレン性不飽和単量体（Ａ）と粘着付与剤（Ｂ）の合計量１００重量部に対して、７０〜５００重量部であることが好ましく、より好ましくは８０〜３００重量部、特に好ましくは８５〜２００重量部である。水の使用量が７０重量部未満では乳化液［Ｉ］が高粘度となり、又、重合安定性も低下することとなり、５００重量部を越えると生成する乳化液［Ｉ］の濃度が低くなり、結果として生成するエマルジョン型粘着剤組成物の濃度が低くなり、塗工時（被膜化する際）の乾燥性が低下し好ましくない。
【００３７】
乳化液［Ｉ］は、エチレン性不飽和単量体（Ａ）と粘着付与剤（Ｂ）からなる油溶成分を、水媒体中で乳化剤を用いて乳化させたものであり、該油溶成分の平均粒子径は１．０μｍ以下、好ましくは０．０５〜０．７μｍ、特に好ましくは０．１〜０．５μｍであればよい。乳化液［Ｉ］において油溶成分の平均粒子径が１．０μｍを越えると重合時に多量の凝集物が生成するとともに、エマルジョンの放置安定性が悪く、塗膜の接着力、特にポリオレフィンに対する接着力が充分でなかったり、耐水性が低下したりして本発明の効果が得られない。
【００３８】
油溶成分の平均粒子径を１．０μｍ以下とする方法としては、特に限定されず、各成分を混合し、任意の撹拌装置、乳化装置等で乳化処理を行えばよいが、本発明においては特に、一旦油溶成分の平均粒子径が１．０μｍを越える乳化液［Ｉ’］とした後、次いで油溶成分の平均粒子径を１．０μｍ以下とした乳化液［Ｉ］とすることが好ましい。
【００３９】
乳化液［Ｉ’］は、各成分を混合し、ホモディスパー、パドル翼等の撹拌翼を取り付けた撹拌装置を用いて予備乳化を行い、油溶成分の平均粒子径が１．０μｍを越える乳化液としたもので、該乳化液［Ｉ’］に更に乳化処理を施し、油溶成分の平均粒子径が１．０μｍ以下である乳化液［Ｉ］とすることが好ましい。
【００４０】
乳化液［Ｉ’］を更に分散させ、油溶成分の平均粒子径が１．０μｍ以下である乳化液［Ｉ］とする方法としては、特に限定されないが、高圧ホモジナイザー処理、超音波処理、ハイドロシャー等の乳化装置による方法が挙げられ、特に高圧ホモジナイザー処理が効率よく、粒子径分布の狭い乳化液が得られる点で好ましい。高圧ホモジナイザーを用いる際の圧力は１０〜１５００ｋｇ／ｃｍ²にすることが好ましく、更に好ましくは、３０〜１０００ｋｇ／ｃｍ²である。
【００４１】
乳化時の温度は、乳化中に混合物が反応しない程度の温度であれば問題なく、通常５〜６０℃程度が適当である。又、乳化液の通過（Ｐａｓｓ）回数は１〜５回程度が好ましい。
【００４２】
上記の乳化液［Ｉ］を調製後、該乳化液［Ｉ］を重合開始剤（Ｄ）の存在下で重合して樹脂エマルジョン［II］を調製するのであるが、その方法としては、▲１▼乳化液［Ｉ］全量をそのまま昇温して重合する、▲２▼乳化液［Ｉ］の一部を昇温して重合を開始し、残りの乳化液［Ｉ］（必要に応じて重合開始剤（Ｄ）も滴下）を滴下又は分割添加して重合を継続する、▲３▼反応缶に水（必要に応じて一部の乳化剤（Ｃ）、及び重合開始剤（Ｄ）を仕込んでおいてもよい）を仕込んで昇温した後、乳化液［Ｉ］を全量滴下又は分割添加して重合する等が挙げられる。但し、これらに限定されるものではない。
【００４３】
重合開始剤（Ｄ）の使用量は、エチレン性不飽和単量体（Ａ）１００重量部に対して、０．０５〜５重量部であることが好ましく、更に好ましくは０．１〜３重量部である。重合開始剤が０．０５重量部未満では重合速度が遅くなり、５重量部を越えると樹脂の分子量が低くなり、保持力が低下し好ましくない。
【００４４】
重合開始剤（Ｄ）としては、特に制限されず、水溶性、油溶性のいずれのものも用いることが可能で、具体的には、アルキルパーオキサイド、ｔ−ブチルヒドロパーオキサイド、クメンヒドロパーオキサイド、ｐ−メタンヒドロパーオキサイド、イソブチルパーオキサイド、ラウロリルパーオキサイド、３，５，５−トリメチルヘキサノイルパーオキサイド、オクタノイルパーオキサイド、ｔ−ブチルクミルパーオキサイド、ベンゾイルパーオキサイド、ジクロルベンゾイルパーオキサイド、ジクミルパーオキサイド、ジ−ｔ−ブチルパーオキサイド、１，１−ビス（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、３，３，５−トリメチルシクロヘキサノンパーオキサイド、メチルシクロヘキサノンパーオキサイド、ジ−イソブチルパーオキシジカーボネート、ジ−２−エチルヘキシルパーオキシジカーボネート、ｔ−ブチルパーオキシイソブチレート等の有機過酸化物、アゾビスイソブチロニトリル、ジメチルアゾジイソブチレート、２，２−アゾビス（２，４−ジメチルバレロニトリル）、２，２−アゾビス（２−メチルブチロニトリル）、過硫酸カリウム、過硫酸ナトリウム、過硫酸アンモニウム、過酸化水素、４，４’−アゾビス−４−シアノバレリックアシッドのアンモニウム（アミン）塩、２，２’−アゾビス（２−メチルアミドオキシム）ジヒドロクロライド、２，２’−アゾビス（２−メチルブタンアミドオキシム）ジヒドロクロライドテトラヒドレート、２，２’−アゾビス｛２−メチル−Ｎ−〔１，１−ビス（ヒドロキシメチル）−２−ヒドロキシエチル〕−プロピオンアミド｝、２，２’−アゾビス〔２−メチル−Ｎ−（２−ヒドロキシエチル）−プロピオンアミド〕、各種レドックス系触媒（この場合酸化剤としては、過硫酸アンモニウム、過硫酸カリウム、過酸化水素、ｔ−ブチルハイドロパーオキサイド、ベンゾイルパーオキサイド、キュメンハイドロパーオキサイド、ｐ−メンタンハイドロパーオキサイド等が、還元剤としては亜硫酸ナトリウム、酸性亜硫酸ナトリウム、ロンガリット、アスコルビン酸等が用いられる。）等が挙げられる。
【００４５】
尚、該重合開始剤（Ｄ）は重合缶内に予め加えておいてもよいし、重合開始直前に加えてもよいし、必要に応じて、重合途中に追加添加してもよいし、又、乳化の前のエチレン性不飽和単量体（Ａ）及び粘着付与剤（Ｂ）の混合液に予め添加したり、該乳化後の乳化液［Ｉ］に添加してもよい。
添加に当たっては重合開始剤（Ｄ）を別途溶媒に溶解して添加したり、溶解した重合開始剤（Ｄ）を更に乳化状にして添加してもよい。又、必要に応じて、重合時に、重合時のｐＨ調整のため、ｐＨ緩衝剤を併用してもよい。
【００４６】
上記重合方法における重合条件としては、特に限定されないが、例えば、▲１▼の方法では、通常４０〜１００℃程度の温度範囲が適当であり、昇温開始後０．５〜８時間程度反応を行う。
▲２▼の方法では、乳化液［Ｉ］の５〜９５重量％を４０〜９０℃で０．１〜５時間重合した後、又は重合しながら、残りの乳化液［Ｉ］を０．１〜５時間程度かけて滴下又は分割添加して、その後同温度で１〜３時間程度熟成する。
▲３▼の方法では、水を乳化液［Ｉ］の５〜３００重量％となるように仕込み、４０〜９０℃に昇温し、乳化液［Ｉ］を０．５〜５時間程度かけて滴下又は分割添加し、その後同温度で１〜３時間程度熟成する。
【００４７】
かくして樹脂エマルジョン［II］が得られるが、かかる樹脂エマルジョン［II］の樹脂成分の平均粒子径は０．０５〜０．５μｍ、更には０．１〜０．３μｍの微粒子であることが好ましい。又、樹脂エマルジョン［II］の樹脂分濃度は１０〜６５重量％とすることが好ましく、特には２０〜５５重量％が好ましい。
【００４８】
本発明では、かかる樹脂エマルジョン［II］の存在下に、粘着付与剤（Ｂ）を追加することなく、更に、（メタ）アクリル酸アルキルエステル（ｅ１）を主成分とするエチレン性不飽和単量体（Ｅ）を重合することにより、エマルジョン型粘着剤組成物を得るのである。
【００４９】
本発明で用いられるエチレン性不飽和単量体（Ｅ）としては、（メタ）アクリル酸アルキルエステル（ｅ１）を主成分とするものであり、かかる（メタ）アクリル酸アルキルエステル（ｅ１）としては、上記（メタ）アクリル酸アルキルエステル（ａ１）と同様のものが挙げられる。中でも、アルキル基の炭素数が１〜８の（メタ）アクリル酸アルキルエステルが好ましく、特にはメチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ−ブチル（メタ）アクリレート、２−エチルヘキシルアクリレートが好ましく用いられる。
【００５０】
又、エチレン性不飽和単量体（Ｅ）として、カルボキシル基含有不飽和単量体（ｅ２）を含有することが好ましく、又はカルボキシル基含有不飽和単量体（ｅ２）及び架橋性基含有不飽和単量体〔但し、カルボキシル基含有不飽和単量体（ｅ２）を除く〕（ｅ３）を含有することが好ましい。
【００５１】
カルボキシル基含有不飽和単量体（ｅ２）としては、上記架橋性を有する単量体（ａ２）の▲１▼カルボキシル基含有単量体と同様のものが挙げられ、架橋性基含有不飽和単量体〔但し、カルボキシル基含有不飽和単量体（ｅ２）を除く〕（ｅ３）としては、上記架橋性を有する単量体（ａ２）の▲２▼水酸基含有単量体、▲３▼エポキシ基含有単量体、▲４▼アルコキシシリル基含有単量体、▲５▼アミド基やメチロール基、ケト基を含有する単量体、▲６▼多官能性モノマー等が挙げられ、特にケト基を含有する単量体、多官能性モノマーを用いることが好ましい。
【００５２】
更に、その他共重合可能な単量体（ｅ４）を用いることも可能で、かかる共重合可能な単量体（ｅ４）として、上記の共重合可能な単量体（ａ３）と同様のものが挙げられる。
【００５３】
かかるエチレン性不飽和単量体（Ｅ）において、（メタ）アクリル酸アルキルエステル（ｅ１）、カルボキシル基含有不飽和単量体（ｅ２）、架橋性基含有不飽和単量体〔但し、カルボキシル基含有不飽和単量体（ｅ２）を除く〕（ｅ３）、及び共重合可能な単量体（ｅ４）の含有割合は、（メタ）アクリル酸アルキルエステル（ｅ１）が５０〜９９重量％、カルボキシル基含有不飽和単量体（ｅ２）１〜１０重量％、架橋性基含有不飽和単量体（ｅ３）が０〜５重量％、共重合可能な単量体（ｅ４）が０〜４９重量％であることが好ましく、より好ましくは（メタ）アクリル酸アルキルエステル（ｅ１）が７０〜９８．４５重量％、カルボキシル基含有不飽和単量体（ｅ２）が１．５〜８重量％、架橋性基含有不飽和単量体（ｅ３）が０．０５〜３重量％、共重合可能な単量体（ｅ４）が０〜２８．４５重量％であり、特に好ましくは（メタ）アクリル酸アルキルエステル（ｅ１）が８０〜９７．９重量％、カルボキシル基含有不飽和単量体（ｅ２）が２〜６重量％、架橋性基含有不飽和単量体（ｅ３）が０．１〜２重量％、共重合可能な単量体（ｅ４）が０〜１７．９重量％である。
【００５４】
（メタ）アクリル酸アルキルエステル（ｅ１）が５０重量％未満では充分な接着力、タックが得られず、９９重量％を越えると保持力や基材密着性、耐水白化性が低下し好ましくない。カルボキシル基含有不飽和単量体（ｅ２）が１重量％未満では充分な接着力、基材密着力、耐水白化性が得られず、１０重量％を越えるとポリオレフィンに対する接着力が低下したり、重合が不安定となる場合がある。架橋性基含有不飽和単量体（ｅ３）が５重量％を越えると接着力、タックが低下したり、耐水白化性が低下し好ましくない。共重合可能な単量体（ｅ４）が４９重量％を越えると接着力、タックが低下し好ましくない。
【００５５】
上記で得られた樹脂エマルジョン［II］の存在下に、上記のエチレン性不飽和単量体（Ｅ）を重合するに当たっては、特に限定されないが、（ｅ１）〜（ｅ４）のエチレン性不飽和単量体（Ｅ）を、水媒体中で予備乳化させた乳化液［イ］を、樹脂エマルジョン［II］の存在下で重合することが重合安定性の点から好ましい。
【００５６】
予備乳化させた乳化液［イ］を得る際には乳化剤を用いることが好ましく、かかる乳化剤としては、上記の乳化剤（Ｃ）と同様のものが挙げられ、１種又は２種以上併用して用いられる。
【００５７】
更に、エチレン性不飽和単量体（Ｅ）を予備乳化させた乳化液［イ］を重合するに際しては上記と同様の重合開始剤（Ｄ）が用いられる。
尚、該重合開始剤（Ｄ）は、重合缶内に予め加えておいてもよいし、重合開始直前に加えてもよいし、必要に応じて重合途中に追加添加してもよいし、又、乳化の前の（Ｅ）の混合液に予め添加したり、該乳化後の乳化液［イ］に添加してもよい。添加に当たっては重合開始剤（Ｄ）を別途溶媒に溶解して添加したり、溶解した重合開始剤（Ｄ）を更に乳化状にして添加してもよい。
【００５８】
上記の各成分の仕込方法としては、特に限定されないが、水に乳化剤（Ｃ）を溶解した後その他の成分を仕込む方法、又は、エチレン性不飽和単量体（Ｅ）の混合液に乳化剤（Ｃ）を溶解した後その他の成分を仕込む方法等が好ましい。
【００５９】
乳化剤（Ｃ）の配合量は、エチレン性不飽和単量体（Ｅ）１００重量部に対して０．３〜７重量部とすることが好ましく、更に好ましくは０．５〜５重量部である。０．３重量部未満では、充分な乳化性能を保持できず重合安定性が低下することとなり、７重量部を越えると接着力、基材密着力及び耐水性が低下し好ましくない。
【００６０】
水の使用量は、エチレン性不飽和単量体（Ｅ）１００重量部に対して２５〜２００重量部が好ましく、更には３０〜１５０重量部とすることが好ましく、２５重量部未満では乳化液［イ］が高粘度となり、又、重合安定性も低下することとなり、２００重量部を越えると得られるエマルジョンの濃度が低くなり、塗工する際の乾燥性が低下し好ましくない。
【００６１】
次に、乳化液［イ］を前記の樹脂エマルジョン［II］の存在下で昇温して重合を開始するのであるが、重合開始剤（Ｄ）の使用量は、エチレン性不飽和単量体（Ｅ）１００重量部に対して０．０３〜５重量部、特には０．０５〜３重量部であることが好ましい。かかる使用量が上記範囲より少ない場合は重合速度が遅くなり、上記範囲を越えると樹脂の分子量が低くなり、保持力が低下し好ましくない。
【００６２】
重合に当たっては、例えば樹脂エマルジョン［II］と乳化液［イ］を混合した後、そのまま昇温して重合する方法、樹脂エマルジョン［II］中に乳化液［イ］の一部を混合し昇温して重合を開始し、残りの乳化液［イ］を全量滴下又は、分割、連続滴下して重合を継続する方法、樹脂エマルジョン［II］の存在下に乳化液［イ］を滴下又は分割、連続滴下して重合する方法等が挙げられるが、これらに限定されるものではない。
重合条件としては、特に制限されないが、通常４０〜９０℃程度の範囲で行うことが好ましい。
【００６３】
重合終了後は、アンモニア水、各種水溶性のアミン、水酸化ナトリウム水、水酸化カリウム水等のアルカリ液を添加し、ｐＨ５〜９、好ましくは６〜８に調整することにより、本発明のエマルジョン型粘着剤組成物として有用なエマルジョンが得られる。
【００６４】
かかるエマルジョンの粒子径は１００〜２５０μｍ、特には１３０〜２００μｍの微粒子であることが好ましい。
又、上記で得られたエマルジョンにおいては、樹脂エマルジョン［II］の含有量が、全固形分に対して固形分換算で１０〜８０重量％であることが好ましく、より好ましくは２０〜６０重量％、特に好ましくは２５〜５０重量％である。該含有量が１０重量％未満ではポリオレフィンに対する接着力が充分でなく、８０重量％を越えると保持力が低下したり、耐水白化性が低下し好ましくない。
【００６５】
本発明では、更に架橋剤（Ｆ）を配合してなるとき、本発明の効果を顕著に発揮するものであり、かかる架橋剤（Ｆ）としては、特に限定されず、例えばカルボジイミド系化合物、オキサゾリン系化合物、アジリジン系化合物、ヒドラジン系化合物、イソシアネート系化合物、メラミン系化合物、エポキシ系化合物、金属塩や金属錯塩等が挙げられるが、中でも、カルボジイミド系化合物、オキサゾリン系化合物、アジリジン系化合物、ヒドラジン系化合物から選ばれる少なくとも１種の化合物が好適に用いられる。更にはカルボジイミド系化合物、ヒドラジン系化合物が特に好ましい。
【００６６】
カルボジイミド系化合物としては、カルボジイミド基を少なくとも２個以上含有するものであればよく、例えば「カルボジライト」（日清紡製）等が挙げられる。
【００６７】
オキサゾリン系化合物としては、オキサゾリン基を少なくとも２個以上含有するものであればよく、例えば「エポクロス」（日本触媒社製）等が挙げられる。アジリジン系化合物としては、アジリジン基を少なくとも２個以上含有するものであればよく、例えば「ケミタイト」（日本触媒製）等が挙げられる。
ヒドラジン系化合物としては、ヒドラジン基を少なくとも２個以上含有するものであればよく、例えば蓚酸ジヒドラジド、マロン酸ジヒドラジド、コハク酸ジヒドラジド、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、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等が挙げられる。
【００６８】
イソシアネート系化合物としては、例えばトルイレンジイソシアネート、４，４’−ジフェニルメタンジイソシアネート、ヘキサメチレンジイソシアネート、キシリレンジイソシアネート、メタキシリレンジイソシアネート、１，５−ナフタレンジイソシアネート、水素化ジフェニルメタンジイソシアネート、水素化トルイレンジイソシアネート、水素化キシリレンジイソシアネート、イソホロンジイソシアネート、テトラメチルキシレンジイソシアネート、等のイソシアネート化合物、「スミジュールＮ」（住友バイエルウレタン社製）の如きビュレットポリイソシアネート化合物、「デスモジュールＩＬ、ＨＬ」（バイエルＡ．Ｇ．社製）、「コロネートＥＨ」（日本ウレタン社製）の如きイソシアヌレート環を有するポリイソシアネート化合物、「スミジュールＬ」（住友バイエルウレタン社製）の如きアダクトポリイソシアネート化合物、「コロネートＨＬ」（日本ポリウレタン社製）の如きアダクトポリイソシアネート化合物等が挙げられる。又、ブロックイソシアネートを使用してもかまわない。
【００６９】
メラミン系化合物としては、例えば（ヘキサメトキシ）メチロールメラミン、メトキシメチロールユリア等が挙げられる。
エポキシ系化合物としては、例えば「デコナール」（ナガセ化成工業社製）、「デナキャスト」（ナガセ化成工業社製）等が挙げられる。
【００７０】
金属塩、金属錯塩としては、例えばアルミニウム、鉄、銅、亜鉛、スズ、チタン、ニッケル、アンチモン、マグネシウム、バナジウム、クロム、ジルコニウム等の多価金属のエチレンジアミン四酢酸（ＥＤＴＡ）のキレート塩や酢酸−アンモニウム錯塩、アンモニウム−カーボネート錯塩等が挙げられる。
【００７１】
かかる架橋剤（Ｆ）の配合量については、その種類によっても異なるが、エマルジョン中の固形分１００重量部に対して、通常０．０５〜１０重量部であることが好ましく、より好ましくは０．０８〜５重量部、特に好ましくは０．１〜３重量部である。かかる配合量が０．０５重量部未満では充分な保持力や耐水白化性が得られず、１０重量部を越えると接着力やタックが低下し好ましくない。
【００７２】
又、本発明では必要に応じて、塗工性改良剤、増粘剤、防腐・防黴剤、防錆剤、凍結融解安定剤、可塑剤、高沸点溶剤、顔料、充填剤等を得られたエマルジョンに適宜添加したり、重合前や重合途中に添加したりすることができる。
【００７３】
かくして得られる本発明のエマルジョン型粘着剤組成物は、（メタ）アクリル酸アルキルエステル（ａ１）を主成分とするエチレン性不飽和単量体（Ａ）及び粘着付与剤（Ｂ）からなる油溶成分を、水媒体中で乳化剤（Ｃ）を用いて、油溶成分の平均粒子径が１．０μｍ以下となるように乳化させた乳化液［Ｉ］を、重合開始剤（Ｄ）の存在下で重合して得られる樹脂エマルジョン［II］の存在下に、粘着付与剤（Ｂ）を追加することなく、更に、（メタ）アクリル酸アルキルエステル（ｅ１）を主成分とするエチレン性不飽和単量体（Ｅ）を重合してなるため、重合時の凝集物生成がほとんどなく、放置安定性にも優れる上、接着性（特にポリオレフィンに対する接着性）、保持力、基材密着性、耐水性（特に耐水白化性）に優れた効果を有するものである。
【００７４】
【実施例】
以下、実施例を挙げて本発明を具体的に説明する。
尚、実施例中「％」、「部」とあるのは、断りのない限り重量基準を意味する。
【００７５】
実施例１
〔樹脂エマルジョン［II］の調製（１段目重合）〕
２−エチルヘキシルアクリレート（ａ１）５５．８部、ｎ−ブチルアクリレート（ａ１）３０部、メチルメタクリレート（ａ１）１０部、アクリル酸（ａ２）４部、トリプロピレングリコールジアクリレート（ａ２）０．２部、及び「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）５０部を含む混合液を、水１９０部に第二燐酸ソーダ１２水塩１．０部、乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）４．５部を溶解した水溶液に加え、ホモディスパーを用いて撹拌混合し予備乳化を行った。かかる乳化液［Ｉ’］の油溶成分の平均粒子径は５μｍであった。尚、平均粒子径はダイナミック光散乱光度計「ＤＬＳ−７００」（大塚電子社製）を用い、散乱強度分布より算出した（以下同様）。
次いで、この乳化液［Ｉ’］を高圧ホモジナイザー（ＧＡＵＬＩＮ社製）を用いて、圧力５０ｋｇ／ｃｍ²で１Ｐａｓｓ処理した後、更に圧力３００ｋｇ／ｃｍ²で３Ｐａｓｓ処理し、油溶成分の平均粒子径が０．１５μｍの乳化液［Ｉ］３４５．５部を得た。
【００７６】
又、重合開始剤として過硫酸アンモニウム１．０部を水１９．０部に溶解し、開始剤液を調製した。
【００７７】
次に、重合缶に水５０部、上記乳化液［Ｉ］１７２．８部を仕込み、昇温して内温が８０℃となったところで、上記開始剤液の２５％を添加し、８０℃で３０分間重合を行った後、残りの乳化液［Ｉ］及び開始剤液の２５％を３０分かけて８０℃で滴下し重合を行った。その後更に８０℃で１時間追い込み重合を行い、樹脂エマルジョン［II］（平均粒子径０．１４μｍ、樹脂分濃度４３．９％）を得た。尚、樹脂分濃度は、樹脂エマルジョン１ｇを１１０℃で３時間乾燥した後の残分より算出した（以下同様）。
【００７８】
〔本発明のエマルジョン型粘着剤組成物の調製（２段目重合）〕
次に、２−エチルヘキシルアクリレート（ｅ１）１３０．２部、ｎ−ブチルアクリレート（ｅ１）７０．０部、メチルメタクリレート（ｅ１）２３．３部、アクリル酸（ｅ２）９．３部、トリプロピレングリコールジアクリレート（ｅ３）０．４７部よりなる混合物を、水１１０部に乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）１．６部を溶解した水溶液に加え、ホモディスパーを用いて撹拌混合し予備乳化を行い、乳化液［イ］３４４．９部を得た。
そして、この乳化液［イ］を開始剤液の３３％と共に、上記で得られた樹脂エマルジョン［II］中に、３時間かけて８０℃で滴下し、滴下終了後、更に開始剤液の１７％を添加した。その後更に８０℃で２時間追い込み重合を行った。
重合終了後、冷却し、５％アンモニア水でｐＨを７．５に調整し、不揮発分４９％、粘度１５００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。尚、粘度は、Ｂ型粘度計を用い、２５℃の条件下で測定した（以下同様）。
得られたエマルジョンについて、以下の評価を行った。
【００７９】
（粗粒子量）
得られたエマルジョン１００ｇを２００ｍｅｓｈ網でろ過し、ろ過成分（凝集物：粗粒子）を１００℃で３時間乾燥して、該粗粒子の重量（ｍｇ／Ｅｍ１００ｇ）を測定した。
【００８０】
更に、得られたエマルジョン１００部に、架橋剤（Ｆ）としてカルボジイミド系化合物（日清紡社製、「Ｖ−０４」）１．０部、塗工性改良剤としてフッ素系塗れ剤（ネオス社製、「ＦＴ−１００」）０．０５部、増粘剤（旭電化社製「ＵＨ−５４１」）を適量添加混合し、粘度を１００００ｍＰａ・ｓに調整し、エマルジョン型粘着剤組成物を得た。
得られたエマルジョン型粘着剤組成物について、以下の評価を行った。
【００８１】
（放置安定性）
得られたエマルジョン型粘着剤組成物を４０℃下で６ヶ月間静置した後の増粘及び沈降物や分離の有無を観察し、以下の通り評価した。
○・・・増粘、沈降物又は分離なし
×・・・増粘、沈降物又は分離あり
【００８２】
更に、得られたエマルジョン型粘着剤組成物について、該粘着剤組成物を乾燥後の厚みが２０μｍになるように離型紙上に塗布し、１００℃で５分間乾燥させた後、５０μｍのＰＥＴフィルム基材又はアルミ蒸着基材を貼り合わせて粘着フィルムを作製し、以下の粘着物性を評価した。
【００８３】
（接着力）
上記粘着フィルム（ＰＥＴフィルム基材）において、離型紙を剥がした後、▲１▼ステンレス板（ＳＵＳ３０４）、▲２▼ポリエチレン板（日本テストパネル標準試験板）に、２０℃、６５％ＲＨにて接着させて、ＪＩＳ Ｚ ０２３７の粘着力の測定法に準じて１８０度剥離強度（ｇｆ／２５ｍｍ）を測定した。
【００８４】
（保持力）
上記粘着フィルム（ＰＥＴフィルム基材）において、離型紙を剥がした後、ステンレス板（ＳＵＳ３０４）の試験板に貼り付け面積が２５ｍｍ×２５ｍｍになるように貼着し、▲１▼８０℃×５０％ＲＨの条件下にて１ｋｇの荷重をかけて、ＪＩＳ Ｚ ０２３７の保持力の測定法に準じて、２４時間後の該フィルムのズレ（ｍｍ）又はフィルムの落下時間（ｍｉｎ）を測定した。
【００８５】
（ボールタック）
Ｊ．ｄｏｗ式ボールタック測定機を用い、２０℃、６５％ＲＨの条件下にて、テストピース２５ｍｍ×１００ｍｍ、角度３０°で、テストピース上（糊面）で停止する最大径のボールＮｏ．を測定した。
【００８６】
（基材密着性）
上記粘着フィルム（アルミ蒸着基材）において、ステンレス板（ＳＵＳ３０４）に対して接着力の測定と同様の測定を行い、その剥離強度（ｇ／２５ｍｍ）と剥離状態より評価した。評価基準は以下の通りである。
［剥離状態］
Ａ・・・被着体界面剥離又は凝集破壊
Ｂ・・・基材界面剥離
［総合評価］
○・・・剥離状態は被着体界面剥離又は凝集破壊であり、剥離強度は１０００ｇ／２５ｍｍ以上であった。
△・・・剥離状態は基材界面剥離であり、剥離強度は１０００ｇ／２５ｍｍ以上であった。
×・・・剥離状態は基材界面剥離であり、剥離強度は１０００ｇ／２５ｍｍ未満であった。
【００８７】
（耐水白化性）
上記粘着フィルム（ＰＥＴフィルム基材：２５ｍｍ幅）の離型紙を剥がし、ガラス板に貼り付けたものを、６０℃の温水に３日間浸漬した後、水から取り出し、直ちに透過率（％）を測定した。尚、透過率は日本電色工業社製の「ＳＺ−Σ８０ ＣＯＬＯＲ ＭＥＡＳＵＲＩＮＧ ＳＹＳＴＥＭ」を用い、測定時のブランクには温水に未浸漬のテストピース（粘着フィルムをガラス板に貼り付けたもの）を用いた。
【００８８】
実施例２
〔樹脂エマルジョン［II］の調製（１段目重合）〕
２−エチルヘキシルアクリレート（ａ１）３０．９部、ｎ−ブチルアクリレート（ａ１）６０部、メチルメタクリレート（ａ１）５部、アクリル酸（ａ２）４部、トリプロピレングリコールジアクリレート（ａ２）０．１部、及び「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）５０部を含む混合液を、水１９０部に第二燐酸ソーダ１２水塩１．０部、乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）４．５部を溶解した水溶液に加え、ホモディスパーを用いて撹拌混合し予備乳化を行った。かかる乳化液［Ｉ’］の油溶成分の平均粒子径は５μｍであった。
次いで、この乳化液［Ｉ’］を高圧ホモジナイザー（ＧＡＵＬＩＮ社製）を用いて、圧力５０ｋｇ／ｃｍ²で１Ｐａｓｓ処理した後、更に圧力３００ｋｇ／ｃｍ²で３Ｐａｓｓ処理し、油溶成分の平均粒子径が０．１５μｍの乳化液［Ｉ］３４５．５部を得た。
【００８９】
又、重合開始剤として過硫酸アンモニウム１．０部を水１９．０部に溶解し、開始剤液を調製した。
【００９０】
次に、重合缶に水５０部、上記乳化液［Ｉ］１７２．８部を仕込み、昇温して内温が８０℃となったところで、上記開始剤液の２５％を添加し、８０℃で３０分間重合を行った後、残りの乳化液［Ｉ］及び開始剤液の２５％を３０分かけて８０℃で滴下し重合を行った。その後更に８０℃で１時間追い込み重合を行い、樹脂エマルジョン［II］（平均粒子径０．１４μｍ、樹脂分濃度４３．９％）を得た。
【００９１】
〔本発明のエマルジョン型粘着剤組成物の調製（２段目重合）〕
次に、２−エチルヘキシルアクリレート（ｅ１）７２．１部、ｎ−ブチルアクリレート（ｅ１）１４０部、メチルメタクリレート（ｅ１）１１．７部、アクリル酸（ｅ２）９．３部、トリプロピレングリコールジアクリレート（ｅ３）０．２３部よりなる混合物を、水１１０部に乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）１．６部を溶解した水溶液に加え、ホモディスパーを用いて撹拌混合し予備乳化を行い、乳化液［イ］３４４．９部を得た。
そして、この乳化液［イ］を開始剤液の３３％と共に、上記で得られた樹脂エマルジョン［II］中に、３時間かけて８０℃で滴下し、滴下終了後、更に開始剤液の１７％を添加した。その後更に８０℃で２時間追い込み重合を行った。
重合終了後、冷却し、５％アンモニア水でｐＨを７．５に調整し、不揮発分４９％、粘度１８００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
【００９２】
更に、得られたエマルジョン１００部に、架橋剤（Ｆ）としてオキサゾリン系化合物（日本触媒社製、「エポクロスＫ−２０１０Ｅ」）２部、塗工性改良剤としてフッ素系塗れ剤（ネオス社製、「ＦＴ−１００」）０．０５部、増粘剤（旭電化社製「ＵＨ−５４１」）を適量添加混合し、粘度を１００００ｍＰａ・ｓに調整し、エマルジョン型粘着剤組成物を得た。
得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９３】
実施例３
実施例１において、架橋剤（Ｆ）としてアジリジン系化合物の２，２−ビスヒドロキシメチルブタノール−トリス（日本触媒社製、「ケミタイトＰＺ−３３」）０．３部に変更した以外は同様に行い、エマルジョン型粘着剤組成物を得た。得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９４】
実施例４
実施例１において、１段目重合で２−エチルヘキシルアクリレート（ａ１）を５５．０部に、トリプロピレングリコールジアクリレート（ａ２）０．２部をダイアセトンアクリルアミド（ａ２）１．０部に変更し、更に２段目重合で２−エチルヘキシルアクリレート（ａ１）を１２８．３部に、トリプロピレングリコールジアクリレート（ｅ３）０．４７部をダイアセトンアクリルアミド（ｅ３）２．３部に変更した以外は同様に行い、不揮発分４９％、粘度１６００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
【００９５】
更に、得られたエマルジョン１００部に、架橋剤（Ｆ）としてヒドラジン系化合物のアジピン酸ジヒドラジド（大塚化学社製）０．１５部、塗工性改良剤としてフッ素系塗れ剤（ネオス社製、「ＦＴ−１００」）０．２部、増粘剤（旭電化社製「ＵＨ−５４１」）を適量添加混合し、粘度を１００００ｍＰａ・ｓに調整し、エマルジョン型粘着剤組成物を得た。
得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９６】
実施例５
実施例１において、「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）の代わりに、「ベンセルＤ−１２５」（重合ロジンエステル系粘着付与剤：荒川化学社製）を用いた以外は同様に行い、不揮発分４９％、粘度１５００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
更に、得られたエマルジョンを実施例１と同様にしてエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９７】
実施例６
実施例１において、「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）の代わりに、「ＹＳ−ポリスターＮ−１２５」（テルペン−フェノール樹脂系粘着付与剤：ヤスハラケミカル社製）を用いた以外は同様に行い、不揮発分４９％、粘度１４００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
更に、得られたエマルジョンを実施例１と同様にしてエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９８】
実施例７
実施例１において、１段目重合、２段目重合ともに、アクリル酸の量を半分に減らし、減らした分だけ２−エチルヘキシルアクリレートの量を増やした以外は同様に行い、不揮発分４９．５％、粘度８００ｍＰａ・ｓ、粒子径０．１６μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
更に、架橋剤（Ｆ）としてのカルボジイミド系化合物（日清紡社製、「Ｖ−０４」）を１．５部にした以外は実施例１と同様に行いエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【００９９】
実施例８
実施例１において、１段目重合、２段目重合ともに、アクリル酸の量を１．５倍に増やし、増やした分だけ２−エチルヘキシルアクリレートの量を減らした以外は同様に行い、不揮発分４７．５％、粘度２０００ｍＰａ・ｓ、粒子径０．１８μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
、更に、架橋剤（Ｆ）としてのカルボジイミド系化合物（日清紡社製、「Ｖ−０４」）を０．７５部にした以外は実施例１と同様に行いエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【０１００】
実施例９
実施例４において、１段目重合、２段目重合ともに、ダイアセトンアクリルアミドの量を３分の１に減らし、減らした分だけ２−エチルヘキシルアクリレートの量を増やした以外は同様に行い、不揮発分４９％、粘度１２００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
更に、架橋剤（Ｆ）としてのアジピン酸ジヒドラジド（大塚化学社製）を０．２部にした以外は実施例１と同様に行いエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【０１０１】
実施例１０
実施例４において、１段目重合、２段目重合ともに、ダイアセトンアクリルアミドの量を２倍に増やし、増やした分だけ２−エチルヘキシルアクリレートの量を減らした以外は同様に行い、不揮発分４９％、粘度１９００ｍＰａ・ｓ、粒子径０．１７μｍのエマルジョンを得た。
得られたエマルジョンについて、実施例１と同様の評価を行った。
更に、架橋剤（Ｆ）としてのアジピン酸ジヒドラジド（大塚化学社製）を０．１部にした以外は実施例１と同様に行いエマルジョン型粘着剤組成物を得、得られたエマルジョン型粘着剤組成物について、実施例１と同様にして放置安定性評価及び粘着物性評価を行った。
【０１０２】
比較例１
実施例１において、乳化液［Ｉ’］（油溶成分の平均粒子径５μｍ）を高圧ホモジナイザー（ＧＡＵＬＩＮ社製）で処理することなく、そのまま重合（１段目重合）を行い、樹脂エマルジョン（平均粒子径０．１２μｍ、樹脂分濃度４３．９％）を得、かかる樹脂エマルジョンを用いて、実施例１と同様にして２段目重合を行い、不揮発分４８．５％、粘度２０００ｍＰａ・ｓ、粒子径０．１５μｍのエマルジョンを得、更にエマルジョン型粘着剤組成物を得た。
得られたエマルジョン及びエマルジョン型粘着剤組成物について、実施例１と同様の評価を行った。
【０１０３】
比較例２
２−エチルヘキシルアクリレート（ａ１）５５．８部、ｎ−ブチルアクリレート（ａ１）３０部、メチルメタクリレート（ａ１）１０部、アクリル酸（ａ２）４部、トリプロピレングリコールジアクリレート（ａ２）０．２部、及び「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）５０部を含む混合液を、水１９０部に第二燐酸ソーダ１２水塩１．０部、乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）４．５部を溶解した水溶液に加え、ホモディスパーを用いて撹拌混合し予備乳化を行った。かかる乳化液［Ｉ’］の油溶成分の平均粒子径は５μｍであった。
次いで、この乳化液を高圧ホモジナイザー（ＧＡＵＬＩＮ社製）を用いて、圧力５０ｋｇ／ｃｍ²で１Ｐａｓｓ処理した後、更に圧力３００ｋｇ／ｃｍ²で３Ｐａｓｓ処理し、油溶成分の平均粒子径が０．１５μｍの乳化液［Ｉ］３４５．５部を得た。
【０１０４】
又、重合開始剤として過硫酸アンモニウム０．５部を水９．５部に溶解し、開始剤液を調製した。
【０１０５】
次に、重合缶に水５０部、上記乳化液［Ｉ］１７２．８部を仕込み、昇温して内温が８０℃となったところで、上記開始剤液の５０％を添加し、８０℃で３０分間重合を行った後、残りの乳化液［Ｉ］及び開始剤液をそれぞれ３０分かけて８０℃で滴下し重合を行い、更に８０℃で１時間追い込み重合を行った。
その後、冷却し、１０％アンモニア水でｐＨを７．５に調整し、不揮発分４３％、粘度８０ｍＰａ・ｓ、粒子径０．１４μｍのエマルジョンを得た。
更に、得られたエマルジョンを用いて、実施例１と同様に行いエマルジョン型粘着剤組成物を得た。
得られたエマルジョン及びエマルジョン型粘着剤組成物について、実施例１と同様の評価を行った。
【０１０６】
比較例３
比較例２において、「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）を１５部、水を９７．２部、第二燐酸ソーダ１２水塩を０．３部、乳化剤（旭電化社製、「ＳＥ−１０Ｎ」）（Ｃ）を３．５部に変更したい以外同様に行い、油溶成分の平均粒子径が０．２０μｍの乳化液［Ｉ］を得、更に、重合缶の水を１０部に変更し、同様に重合を行い、不揮発分４８．５％、粘度１５０ｍＰａ・ｓ、粒子径０．２０μｍのエマルジョンを得た。
更に、得られたエマルジョンを用いて、実施例１と同様に行いエマルジョン型粘着剤組成物を得た。
得られたエマルジョン及びエマルジョン型粘着剤組成物について、実施例１と同様の評価を行った。
【０１０７】
比較例４
実施例１において、「スーパーエステルＡ−１２５」（ロジンエステル系粘着付与剤：荒川化学社製）（Ｂ）を省略した以外は同様に１段目重合、２段目重合を行い、不揮発分４３％、粘度１００ｍＰａ・ｓ、粒子径０．１５μｍのエマルジョンを得た後、別途エマルジョン化した「スーパーエステルＡ−１２５」を実施例１と同量となるように添加しエマルジョンを得、更に実施例１と同様に架橋剤（Ｆ）、塗工性改良剤、増粘剤を加え、エマルジョン型粘着剤組成物を得た。得られたエマルジョン及びエマルジョン型粘着剤組成物について、実施例１と同様の評価を行った。
実施例と比較例の評価結果を表１〜３に示す。
【０１０８】

【０１０９】

【０１１０】

【０１１１】
【発明の効果】
本発明のエマルジョン型粘着剤組成物は、（メタ）アクリル酸アルキルエステル（ａ１）を主成分とするエチレン性不飽和単量体（Ａ）及び粘着付与剤（Ｂ）からなる油溶成分［Ｉ］を、水媒体中で乳化剤（Ｃ）を用いて、油溶成分の平均粒子径が１．０μｍ以下となるように乳化させた乳化液［Ｉ］を、重合開始剤（Ｄ）の存在下で重合して得られる樹脂エマルジョン［II］の存在下に、粘着付与剤（Ｂ）を追加することなく、更に、（メタ）アクリル酸アルキルエステル（ｅ１）を主成分とするエチレン性不飽和単量体（Ｅ）を重合してなるため、重合時の凝集物生成がほとんどなく、放置安定性にも優れる上、接着性（特にポリオレフィンに対する接着性）、保持力、基材密着性、耐水性（特に耐水白化性）に優れた効果を有するものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an emulsion-type pressure-sensitive adhesive composition, and more specifically, an emulsion-type pressure-sensitive adhesive composition excellent in adhesion (particularly adhesion to polyolefin), holding power, substrate adhesion, and water resistance (particularly water whitening resistance). It is about things.
[0002]
[Prior art]
The acrylate copolymer emulsion can be used as an adhesive or a pressure-sensitive adhesive because the balance of adhesiveness (or tackiness) and cohesive force can be changed by changing the composition thereof. And in this case, in order to improve adhesiveness (or adhesiveness), adding tackifying resin is performed widely.
[0003]
However, since the tackifying resin is insoluble in water, there are a method in which it is dissolved in a solvent and a method in which it is emulsified in water and added as an emulsion. Since the particles of the acrylic emulsion are not uniformly mixed, the obtained adhesive or pressure-sensitive adhesive often has a problem that the adhesiveness is lowered or the water resistance is also lowered.
[0004]
In order to solve such problems, (1) in Japanese Patent Application Laid-Open No. 54-233641, an acrylic monomer, a crosslinkable functional group-containing copolymerizable monomer, a polymer compound previously dissolved in at least one of the two components, and A water-dispersed adhesive composition obtained by emulsion polymerization of an emulsion containing a surfactant is disclosed in (2) Japanese Patent Application Laid-Open No. 58-185668 in which tackifying is applied to a mixture of a crosslinkable monomer and (meth) acrylate. Polymerization is carried out while continuously adding a formulation in which resin is dissolved or dispersed, or an emulsion formulation in which this formulation is dispersed in water containing an emulsifier, to a polymerization solution containing water, an emulsifier and a polymerization catalyst. The resulting copolymer emulsion type adhesives have been proposed.
[0005]
Further, (3) JP-A-2000-313865 discloses a monomer having an alkyl (meth) acrylate having an alkyl group of 9 to 14 carbon atoms of 9 to 14% by weight and having a carboxyl group, a hydroxyl group or an amide group. In 100 parts by weight of a mixed monomer containing 5 to 2.5% by weight, 0.5 to 5 parts by weight of a tackifier resin and an oil-soluble polymerization initiator are dissolved, and this is emulsified and dispersed in an aqueous emulsifier solution to obtain an average particle size There has been proposed an emulsion-type pressure-sensitive adhesive obtained by polymerization after forming monomer oil droplets of 1 μm or less.
[0006]
[Problems to be solved by the invention]
However, in the disclosed techniques of (1) and (2) above, the method for emulsifying and dispersing a mixed solution in which a tackifier resin is dissolved or dispersed has not been studied. As a result of detailed studies by the present inventors, When the polymerization was carried out using an emulsion emulsified and dispersed by the method, it was found that when the amount of the tackifying resin used was increased, the polymerization became unstable and the standing stability of the resulting emulsion was lowered. .
In addition, the disclosed techniques (1) to (3) are not yet satisfactory in terms of adhesion (particularly adhesion to polyolefin), substrate adhesion, and water resistance (particularly water whitening resistance). Improvement is desired.
[0007]
Therefore, the present invention provides an emulsion-type pressure-sensitive adhesive composition that is excellent in adhesiveness (particularly adhesiveness to polyolefin), holding power, substrate adhesion, and water resistance (particularly water whitening resistance). It is for the purpose.
[0008]
[Means for Solving the Problems]
  However, as a result of intensive studies to solve such problems, the present inventors have obtained an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid alkyl ester (a1) and a tackifier ( An emulsion [I] obtained by emulsifying the oil-soluble component consisting of B) in an aqueous medium using an emulsifier (C) so that the average particle size of the oil-soluble component is 1.0 μm or less is used as a polymerization initiator. In the presence of the resin emulsion [II] obtained by polymerization in the presence of (D),Without adding tackifier (B)Furthermore, the present inventors have found that an emulsion-type pressure-sensitive adhesive composition obtained by polymerizing an ethylenically unsaturated monomer (E) containing a (meth) acrylic acid alkyl ester (e1) as a main component meets the above-mentioned purpose. Was completed.
[0009]
In the present invention, the ethylenically unsaturated monomer (E) contains the carboxyl group-containing unsaturated monomer (e2), or the carboxyl group-containing unsaturated monomer (e2) and the crosslinkability. A group-containing unsaturated monomer (excluding the carboxyl group-containing unsaturated monomer (e2)) (e3) is preferably contained in terms of adhesion to the substrate and water whitening resistance.
Moreover, in this invention, when a crosslinking agent (F) is further mix | blended, the effect of this invention is exhibited notably.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described.
The ethylenically unsaturated monomer (A) used in the present invention is mainly composed of (meth) acrylic acid alkyl ester (a1), and as such (meth) acrylic acid alkyl ester (a1), For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate (Meth) acrylic having 1 to 8 carbon atoms in the alkyl group such as 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, etc. Acid alkyl esters and nonyl (meta Acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, isododecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, Examples thereof include (meth) acrylic acid alkyl esters having 9 or more carbon atoms in an alkyl group such as tetradecyl (meth) acrylate. Among them, (meth) acrylic acid alkyl esters having 1 to 8 carbon atoms in the alkyl group are preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl acrylate are particularly preferable. Used.
[0011]
The ethylenically unsaturated monomer (A) may contain a crosslinkable monomer (a2). Examples of the crosslinkable monomer (a2) include (1) Carboxyl group-containing monomer, (2) Hydroxyl group-containing monomer, (3) Epoxy group-containing monomer, (4) Alkoxysilyl group-containing monomer, (5) Amide group, methylol group, keto group Monomer, (6) polyfunctional monomer and the like.
[0012]
(1) Examples of the carboxyl group-containing monomer include acrylic acid, acrylic acid dimer, methacrylic acid, crotonic acid, itaconic acid, maleic acid and the like.
(2) Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate.
(3) Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.
[0013]
(4) As alkoxysilyl group-containing monomers, γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ -(Meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (Meth) acryloxypropyldimethylethoxysilane, γ- (meth) acryloxypropyltrichlorosilane, γ- (meth) acryloxypropylmethyldichlorosilane, γ- (meth) acryloxypropyldimethylchlorosilane, γ- (meth) acryl Roxypropyl tripropio Sisilane, γ- (meth) acryloxypropylmethyldipropoxysilane, γ- (meth) acryloxypropyltributoxysilane, γ- (meth) acryloxybutyltrimethoxysilane, γ- (meth) acryloxypentyltrimethoxy Silane, γ- (meth) acryloxyhexyltrimethoxysilane, γ- (meth) acryloxyhexyltriethoxysilane, γ- (meth) acryloxyoctyltrimethoxysilane, γ- (meth) acryloxydecyltrimethoxysilane, γ- (meth) acryloxydodecyltrimethoxysilane, γ- (meth) acryloxyoctadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane Orchid, vinylmethyldipropoxysilane and the like.
[0014]
(5) Monomers containing amide groups, methylol groups, or keto groups include acrylamide, methacrylamide, N-methylol acrylamide, butoxy N-methylol acrylamide, diacetone acrylamide, 2- (acetoacetoxy) ethyl (meth). Examples thereof include acrylate and allyl acetoacetate.
[0015]
(6) As polyfunctional monomers, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, Dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) Chryrate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, glycerin methacrylate acrylate, tris (meth) acryloyloxyphosphate, glycerin di (meth) acrylate, diallyl terephthalate, tetraallyloxyethane, divinylbenzene And tri (meth) allyl isocyanurate.
These crosslinkable monomers (a2) are used alone or in combination of two or more.
[0016]
Among them, acrylic acid, methacrylic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxy Propylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, vinyltriethoxysilane, N-methylolacrylamide, diacetone acrylamide, 2- (acetoacetoxy) ethyl methacrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, tripropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate , Triethylene glycol di (meth) acrylate, diallyl terephthalate, divinylbenzene and the like are particularly preferably used.
[0017]
In the present invention, a copolymerizable monomer (a3) can also be used. As the copolymerizable monomer (a3), acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, Examples include vinyl acetate, vinyl propionate, vinyl chloride, alkyl vinyl ether, dimethylaminoethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and the like.
[0018]
In the ethylenically unsaturated monomer (A), the content ratio of the (meth) acrylic acid alkyl ester (a1), the crosslinkable monomer (a2), and the copolymerizable monomer (a3) is The (meth) acrylic acid alkyl ester (a1) is 50 to 100% by weight, the crosslinkable monomer (a2) is 0 to 20% by weight, and the copolymerizable monomer (a3) is 0 to 50% by weight. %, More preferably (meth) acrylic acid alkyl ester (a1) is 70 to 100% by weight, crosslinkable monomer (a2) is 0 to 10% by weight, copolymerizable monomer The body (a3) is 0 to 30% by weight, particularly preferably the (meth) acrylic acid alkyl ester (a1) is 80 to 100% by weight, the crosslinkable monomer (a2) is 0 to 5% by weight, The copolymerizable monomer (a3) is 0 to 20 It is the amount%.
[0019]
If the (meth) acrylic acid alkyl ester (a1) is less than 50% by weight, sufficient adhesive strength and tackiness may not be obtained, and the transparency of the coating film may be reduced. If the crosslinkable monomer (a2) exceeds 20% by weight, the transparency of the coating film may be lowered or the polymerization may become unstable. When the copolymerizable monomer (a3) exceeds 50% by weight, the adhesive strength and tack may be lowered, and the transparency of the coating film may be lowered.
[0020]
The tackifier (B) used in the present invention may be any one that dissolves or disperses in the ethylenically unsaturated monomer (A). For example, “Superester A-75” (manufactured by Arakawa Chemical Co., Ltd.) , Rosin esters such as “Superester A-100” (Arakawa Chemical Co., Ltd.), “Superester A-125” (Arakawa Chemical Co., Ltd.), “Pencel D125” (Arakawa Chemical Co.), “Pencel D160” (Arakawa) Chemical Co., Ltd.), “Rekatak PCJ” (Rika Fine)TechPolymeric rosin esters such as “Nikanol HP-100” (Mitsubishi Gas Chemical Co., Ltd.), “Nikanol HP-150” (Mitsubishi Gas Chemical Co., Ltd.), “Nikanol H-80” xylene resins, etc. Terpene phenol resins such as “Polystar T-115” (manufactured by Yashara Chemical Co., Ltd.), “Mytec G125” (manufactured by Yashara Chemical Co., Ltd.), “FTR-6120” (manufactured by Mitsui Petrochemical Co., Ltd.), “FTR-6100” (Mitsui Petrochemical Co., Ltd.) In addition, petroleum resins such as Coumarone Indene resin, terpene resin, styrene resin, ethylene / vinyl acetate resin and the like can be mentioned.
[0021]
Further, a styrene-butadiene block polymer, a styrene-isoprene block polymer, an ethylene-isoprene-styrene block polymer, a vinyl chloride / vinyl acetate polymer, an acrylic rubber, or the like called an elastomer can also be used.
[0022]
In the present invention, the ethylenically unsaturated monomer (A) and the tackifier (B) are mixed to form an oil-soluble component, and the mixing ratio is 100% for the ethylenically unsaturated monomer (A) 100. It is preferable that a tackifier (B) is 5-400 weight part with respect to a weight part, More preferably, it is 8-300 weight part, Especially preferably, it is 10-200 weight part. When the tackifier (B) is less than 5 parts by weight, sufficient adhesiveness, particularly adhesion to polyolefin cannot be obtained, and when it exceeds 400 parts by weight, polymerization becomes unstable, and sufficient adhesiveness and tack are obtained. It is not preferable because it disappears.
[0023]
An oil-soluble component comprising an ethylenically unsaturated monomer (A) and a tackifier (B) is emulsified using an emulsifier (C) in an aqueous medium to prepare an emulsion [I]. The emulsifier (C) is not particularly limited as long as it has a function capable of emulsifying each component in an aqueous medium. For example, a reactive (ionic or nonionic) surfactant, a non-reactive agent (Ionic or nonionic) surfactants or the like are used alone or in combination. Among these, in consideration of water resistance, it is preferable to use a reactive surfactant.
[0024]
The reactive surfactant may be an ionic or nonionic surfactant having radical reactivity with the ethylenically unsaturated monomer (A). Examples of the reactive surfactant include the following: Those having a structure as represented by the general formulas (1) to (7) may be mentioned.
[0025]
[Chemical 1]

[0026]
[Chemical 2]

[0027]
[Chemical 3]

[0028]
[Formula 4]

[0029]
[Chemical formula 5]

[0030]
[Chemical 6]

[0031]
[Chemical 7]

[0032]
[In the general formulas (1) to (7), R₁Is an alkyl group, R₂Is hydrogen or methyl group, R_ThreeIs an alkylene group, n is an integer of 1 or more, m, l is an integer of 1 or more (m + 1 = 3), X is hydrogen, SO_ThreeNH_Four, SO_ThreeOne of Na. ]
[0033]
Specific examples of the surfactant include “Adekalia Soap SE-20N” (anionic), “Adekalia Soap SE-10N” (anionic), “Adekalia Soap NE-10” (nonionic), “ ADEKA rear soap NE-20 (nonionic), ADEKA rear soap NE-30 (nonionic), ADEKA rear soap NE-40 (nonionic), ADEKA rear soap SDX-730 (anionic) "Adekaria soap SDX-731" (anionic) [above, manufactured by Asahi Denka Co., Ltd.], "Eleminol JS-2" (anionic), "Eleminol RS-30" (anionic) [above, Sanyo Chemical “Latemul S-180A” (anionic), “Latemul S-180” (anionic) [above, manufactured by Kao Corporation], “AQUALON BC-05 (Anionic), “Aqualon BC-10” (anionic), “Aqualon BC-20” (anionic), “Aqualon HS-05” (anionic), “Aquaron HS-10” (anionic), “ Aqualon HS-20 (anionic), Aqualon RN-10 (nonionic), Aqualon RN-20 (nonionic), Aqualon RN-30 (nonionic), Aqualon RN-50 ( Nonionic), “New Frontier S-510” (anion) [manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], “Phosfinol TX” (anionic) [manufactured by Toho Chemical Co., Ltd.]), etc. Goods.
[0034]
The amount of the emulsifier (C) is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the total of the ethylenically unsaturated monomer (A) and the tackifier (B). Preferably it is 0.8-7 weight part, Most preferably, it is 1-5 weight part. When the emulsifier (C) is less than 0.5 parts by weight, it is difficult to make the particle size of the oil-soluble component 1 μm or less, and the polymerization becomes unstable. When the amount exceeds 10 parts by weight, the polymerization becomes unstable. This is not preferable because the water resistance is reduced.
The emulsifier (C) may be partially added to the polymerization can in advance in addition to the emulsion [I].
[0035]
Next, an ethylenically unsaturated monomer (A) containing a (meth) acrylic acid alkyl ester (a1), a crosslinkable monomer (a2), and another copolymerizable monomer (a3) And an oil-soluble component consisting of a tackifier (B) using an emulsifier (C) in an aqueous medium so that the average particle size of the oil-soluble component is 1.0 μm or less [I] The method of obtaining is described.
[0036]
As a preparation method of each component, it is preferable to previously dissolve the tackifier (B) in the ethylenically unsaturated monomer (A) and prepare other components.
It is preferable that the usage-amount of water is 70-500 weight part with respect to 100 weight part of total amounts of an ethylenically unsaturated monomer (A) and a tackifier (B), More preferably, it is 80-300. Part by weight, particularly preferably 85 to 200 parts by weight. If the amount of water used is less than 70 parts by weight, the emulsion [I] will have a high viscosity and the polymerization stability will also be reduced. If it exceeds 500 parts by weight, the concentration of the resulting emulsion [I] will be low, As a result, the concentration of the resulting emulsion-type pressure-sensitive adhesive composition is lowered, and the drying property during coating (when forming a film) is lowered, which is not preferable.
[0037]
The emulsion [I] is an oil-soluble component composed of an ethylenically unsaturated monomer (A) and a tackifier (B) emulsified in an aqueous medium using an emulsifier, and the oil-soluble component The average particle size of 1.0 μm or less, preferably 0.05 to 0.7 μm, particularly preferably 0.1 to 0.5 μm. If the average particle size of the oil-soluble component exceeds 1.0 μm in the emulsion [I], a large amount of aggregates are produced during polymerization, and the emulsion is not stable and the adhesive strength of the coating film, especially the adhesive strength to polyolefin. However, the effect of the present invention cannot be obtained due to insufficient water resistance or reduced water resistance.
[0038]
The method of setting the average particle size of the oil-soluble component to 1.0 μm or less is not particularly limited, and each component may be mixed and emulsified with an arbitrary stirring device, emulsifying device, or the like. In particular, once the oil-soluble component average particle diameter exceeds 1.0 μm, the emulsion [I ′] is used, and then the oil-soluble component average particle diameter is 1.0 μm or less. preferable.
[0039]
The emulsified liquid [I ′] is prepared by mixing each component and preliminarily emulsifying using a stirrer equipped with a stirring blade such as a homodisper or paddle blade, and the average particle size of the oil-soluble component exceeds 1.0 μm. Preferably, the emulsion [I ′] is further emulsified to give an emulsion [I] having an oil-soluble component average particle size of 1.0 μm or less.
[0040]
A method of further dispersing the emulsion [I ′] to obtain an emulsion [I] in which the average particle size of the oil-soluble component is 1.0 μm or less is not particularly limited. Examples include a method using an emulsifier such as a shear, and high-pressure homogenizer treatment is particularly effective in that an emulsion having a narrow particle size distribution can be obtained. The pressure when using a high-pressure homogenizer is 10 to 1500 kg / cm.²Preferably, it is preferably 30 to 1000 kg / cm.²It is.
[0041]
There is no problem as long as the temperature during emulsification is such that the mixture does not react during emulsification, and usually about 5 to 60 ° C. is appropriate. Further, the number of times the emulsion is passed is preferably about 1 to 5 times.
[0042]
After preparing the above emulsion [I], the emulsion [I] is polymerized in the presence of a polymerization initiator (D) to prepare a resin emulsion [II]. ▼ Emulsified liquid [I] is heated and polymerized as it is. (2) A part of emulsion [I] is heated to initiate polymerization, and the remaining emulsion [I] (polymerized as needed). Initiator (D) is also added dropwise) or added in portions, and polymerization is continued. (3) Water (some emulsifier (C) and polymerization initiator (D) are charged if necessary) into the reaction can. In other words, the emulsion [I] may be added dropwise or dividedly and polymerized after the temperature is raised. However, it is not limited to these.
[0043]
The amount of the polymerization initiator (D) used is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (A). Part. If the polymerization initiator is less than 0.05 parts by weight, the polymerization rate is slow, and if it exceeds 5 parts by weight, the molecular weight of the resin is lowered and the holding power is lowered, which is not preferable.
[0044]
The polymerization initiator (D) is not particularly limited, and any water-soluble or oil-soluble one can be used. Specifically, alkyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide. , P-methane hydroperoxide, isobutyl peroxide, laurolyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide , Dicumyl peroxide, di-t-butyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide Oxide, di Organic peroxides such as isobutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butylperoxyisobutyrate, azobisisobutyronitrile, dimethylazodiisobutyrate, 2,2-azobis ( 2,4-dimethylvaleronitrile), 2,2-azobis (2-methylbutyronitrile), potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4'-azobis-4-cyanovaleric Ammonium (amine) salt of acid, 2,2'-azobis (2-methylamidooxime) dihydrochloride, 2,2'-azobis (2-methylbutanamidoxime) dihydrochloride tetrahydrate, 2,2'-azobis {2-Methyl-N- [1,1-bis (hydroxymethyl) -2- Droxyethyl] -propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], various redox catalysts (in this case, as the oxidizing agent, ammonium persulfate, potassium persulfate, Hydrogen peroxide, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide and the like are used, and sodium sulfite, acidic sodium sulfite, Rongalite, ascorbic acid and the like are used as the reducing agent. Etc.
[0045]
The polymerization initiator (D) may be added in advance to the polymerization vessel, or may be added immediately before the start of polymerization, or may be added during the polymerization, if necessary. , May be added in advance to a mixed solution of the ethylenically unsaturated monomer (A) and the tackifier (B) before emulsification, or may be added to the emulsified solution [I] after emulsification.Yes.
In addition, the polymerization initiator (D) may be separately dissolved in a solvent and added, or the dissolved polymerization initiator (D) may be further emulsified and added. If necessary, a pH buffering agent may be used at the time of polymerization in order to adjust the pH during the polymerization.
[0046]
The polymerization conditions in the above polymerization method are not particularly limited. For example, in the method (1), a temperature range of about 40 to 100 ° C. is usually appropriate, and the reaction is performed for about 0.5 to 8 hours after the start of temperature increase. Do.
In the method (2), 5-95% by weight of the emulsion [I] is polymerized at 40-90 ° C. for 0.1-5 hours, or while polymerization, the remaining emulsion [I] is 0.1%. It is added dropwise or dividedly over about 5 hours, and then ripened at the same temperature for about 1 to 3 hours.
In the method (3), water is charged so as to be 5 to 300% by weight of the emulsion [I], the temperature is raised to 40 to 90 ° C., and the emulsion [I] is added over about 0.5 to 5 hours. Add dropwise or dividedly, and then age at the same temperature for 1 to 3 hours.
[0047]
Thus, a resin emulsion [II] is obtained, and the resin component of the resin emulsion [II] is preferably fine particles having an average particle diameter of 0.05 to 0.5 μm, more preferably 0.1 to 0.3 μm. Further, the resin content concentration of the resin emulsion [II] is preferably 10 to 65% by weight, particularly preferably 20 to 55% by weight.
[0048]
  In the present invention, in the presence of the resin emulsion [II],Without adding tackifier (B)Furthermore, an emulsion-type pressure-sensitive adhesive composition is obtained by polymerizing the ethylenically unsaturated monomer (E) mainly composed of the (meth) acrylic acid alkyl ester (e1).
[0049]
The ethylenically unsaturated monomer (E) used in the present invention is mainly composed of (meth) acrylic acid alkyl ester (e1), and as such (meth) acrylic acid alkyl ester (e1), The same thing as the said (meth) acrylic-acid alkylester (a1) is mentioned. Among them, (meth) acrylic acid alkyl esters having 1 to 8 carbon atoms in the alkyl group are preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl acrylate are particularly preferable. Used.
[0050]
The ethylenically unsaturated monomer (E) preferably contains a carboxyl group-containing unsaturated monomer (e2), or the carboxyl group-containing unsaturated monomer (e2) and the crosslinkable group-containing unsaturated monomer. It is preferable to contain a saturated monomer (however, excluding the carboxyl group-containing unsaturated monomer (e2)) (e3).
[0051]
Examples of the carboxyl group-containing unsaturated monomer (e2) include those similar to the monomer (a2) (1) carboxyl group-containing monomer of the crosslinkable group. The monomer (excluding the carboxyl group-containing unsaturated monomer (e2)) (e3) includes the above-mentioned monomer (a2) having a crosslinkability (2) hydroxyl group-containing monomer and (3) epoxy Group-containing monomers, (4) alkoxysilyl group-containing monomers, (5) amide groups, methylol groups, monomers containing keto groups, and (6) polyfunctional monomers, especially keto groups. It is preferable to use a monomer containing a polyfunctional monomer.
[0052]
Furthermore, other copolymerizable monomers (e4) can also be used, and examples of the copolymerizable monomer (e4) include those similar to the copolymerizable monomer (a3). Can be mentioned.
[0053]
In such ethylenically unsaturated monomer (E), (meth) acrylic acid alkyl ester (e1), carboxyl group-containing unsaturated monomer (e2), crosslinkable group-containing unsaturated monomer [however, carboxyl group (Excluding unsaturated monomer (e2))] (e3) and copolymerizable monomer (e4) are contained in an amount of 50 to 99% by weight of (meth) acrylic acid alkyl ester (e1), carboxyl 1 to 10% by weight of the group-containing unsaturated monomer (e2), 0 to 5% by weight of the crosslinkable group-containing unsaturated monomer (e3), and 0 to 49% of the copolymerizable monomer (e4). %, More preferably (meth) acrylic acid alkyl ester (e1) is 70 to 98.45% by weight, carboxyl group-containing unsaturated monomer (e2) is 1.5 to 8% by weight, The unsaturated group-containing unsaturated monomer (e3) is 0. 5 to 3% by weight, copolymerizable monomer (e4) is 0 to 28.45% by weight, particularly preferably (meth) acrylic acid alkyl ester (e1) is 80 to 97.9% by weight, carboxyl The group-containing unsaturated monomer (e2) is 2 to 6% by weight, the crosslinkable group-containing unsaturated monomer (e3) is 0.1 to 2% by weight, and the copolymerizable monomer (e4) is 0. ˜17.9% by weight.
[0054]
If the (meth) acrylic acid alkyl ester (e1) is less than 50% by weight, sufficient adhesion and tack cannot be obtained, and if it exceeds 99% by weight, the holding power, adhesion to the substrate and water whitening resistance are undesirably lowered. If the carboxyl group-containing unsaturated monomer (e2) is less than 1% by weight, sufficient adhesive strength, substrate adhesion, and water whitening resistance cannot be obtained, and if it exceeds 10% by weight, the adhesion to polyolefin decreases. Polymerization may become unstable. When the crosslinkable group-containing unsaturated monomer (e3) exceeds 5% by weight, the adhesive strength and tack are lowered, and the water whitening resistance is lowered. When the copolymerizable monomer (e4) exceeds 49% by weight, the adhesive strength and tack are lowered, which is not preferable.
[0055]
The polymerization of the ethylenically unsaturated monomer (E) in the presence of the resin emulsion [II] obtained above is not particularly limited, but the ethylenically unsaturated groups (e1) to (e4) are not limited. From the viewpoint of polymerization stability, it is preferable to polymerize the emulsion [I] obtained by pre-emulsifying the monomer (E) in an aqueous medium in the presence of the resin emulsion [II].
[0056]
When obtaining the pre-emulsified emulsion [i], it is preferable to use an emulsifier, and examples of such an emulsifier include those similar to the above-mentioned emulsifier (C), and one or more of them are used in combination. It is done.
[0057]
Furthermore, when polymerizing the emulsion [i] in which the ethylenically unsaturated monomer (E) is pre-emulsified, the same polymerization initiator (D) as described above is used.
The polymerization initiator (D) may be added in advance to the polymerization tank, may be added immediately before the start of polymerization, or may be added during the polymerization as necessary, or Alternatively, it may be added in advance to the mixed solution (E) before emulsification, or may be added to the emulsified solution [i] after the emulsification. In addition, the polymerization initiator (D) may be separately dissolved in a solvent and added, or the dissolved polymerization initiator (D) may be further emulsified and added.
[0058]
Although it does not specifically limit as the preparation method of said each component, The method of preparing other components after melt | dissolving the emulsifier (C) in water, or the emulsifier ( A method of charging other components after dissolving C) is preferred.
[0059]
The blending amount of the emulsifier (C) is preferably 0.3 to 7 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (E). . If it is less than 0.3 parts by weight, sufficient emulsification performance cannot be maintained and the polymerization stability is lowered, and if it exceeds 7 parts by weight, the adhesive force, the base material adhesion force and the water resistance are lowered, which is not preferable.
[0060]
The amount of water used is preferably 25 to 200 parts by weight, more preferably 30 to 150 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (E). [B] has a high viscosity and also lowers the polymerization stability. When the amount exceeds 200 parts by weight, the concentration of the resulting emulsion is lowered, and the drying property during coating is lowered, which is not preferable.
[0061]
Next, the emulsion [i] is heated in the presence of the resin emulsion [II] to start polymerization. The amount of the polymerization initiator (D) used is an ethylenically unsaturated monomer. (E) It is preferable that it is 0.03-5 weight part with respect to 100 weight part, especially 0.05-3 weight part. When the amount used is less than the above range, the polymerization rate is slow, and when it exceeds the above range, the molecular weight of the resin is lowered, and the holding power is lowered, which is not preferable.
[0062]
In the polymerization, for example, a method in which the resin emulsion [II] and the emulsion [i] are mixed and then heated to polymerize as it is, a part of the emulsion [a] is mixed in the resin emulsion [II] and the temperature is raised. The polymerization is then started, and the remaining emulsion [i] is dropped or divided in its entirety, or divided, continuously dropped to continue polymerization, and the emulsion [ii] is dropped or divided in the presence of the resin emulsion [II]. Although the method of superposing | polymerizing by dripping continuously is mentioned, It is not limited to these.
Although it does not restrict | limit especially as polymerization conditions, Usually, it is preferable to carry out in about 40-90 degreeC.
[0063]
After completion of the polymerization, an emulsion of the present invention is prepared by adding an alkaline solution such as aqueous ammonia, various water-soluble amines, aqueous sodium hydroxide, aqueous potassium hydroxide, etc., and adjusting the pH to 5-9, preferably 6-8. An emulsion useful as a mold pressure-sensitive adhesive composition is obtained.
[0064]
The particle diameter of such an emulsion is preferably 100 to 250 μm, particularly 130 to 200 μm.
Further, in the emulsion obtained above, the content of the resin emulsion [II] is preferably 10 to 80% by weight, more preferably 20 to 60% by weight in terms of solid content with respect to the total solid content. Particularly preferred is 25 to 50% by weight. If the content is less than 10% by weight, the adhesion to polyolefin is not sufficient, and if it exceeds 80% by weight, the holding power is lowered and the water whitening resistance is lowered, which is not preferable.
[0065]
In the present invention, when the crosslinking agent (F) is further blended, the effects of the present invention are remarkably exhibited. The crosslinking agent (F) is not particularly limited, and examples thereof include carbodiimide compounds and oxazolines. Compounds, aziridine compounds, hydrazine compounds, isocyanate compounds, melamine compounds, epoxy compounds, metal salts and metal complex salts, among others, carbodiimide compounds, oxazoline compounds, aziridine compounds, hydrazine compounds At least one compound selected from compounds is preferably used. Furthermore, carbodiimide compounds and hydrazine compounds are particularly preferable.
[0066]
The carbodiimide compound may be any compound containing at least two carbodiimide groups, and examples thereof include “carbodilite” (manufactured by Nisshinbo).
[0067]
Any oxazoline-based compound may be used as long as it contains at least two oxazoline groups, and examples thereof include “Epocross” (manufactured by Nippon Shokubai Co., Ltd.). Any aziridine-based compound may be used as long as it contains at least two aziridine groups. Examples thereof include “Chemite” (manufactured by Nippon Shokubai Co., Ltd.).
As the hydrazine-based compound, any compound containing at least two hydrazine groups may be used. And acid dihydrazide, itaconic acid dihydrazide, and the like.
[0068]
Examples of the isocyanate compound include toluylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate, 1,5-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluylene diisocyanate, Isocyanate compounds such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, burette polyisocyanate compounds such as “Sumijour N” (manufactured by Sumitomo Bayer Urethane Co., Ltd.), “Desmodur IL, HL” (Bayer AG) Polyisocyanate having an isocyanurate ring such as “Coronate EH” (manufactured by Nippon Urethane Co., Ltd.) Compound, "Sumidur L" such as adduct polyisocyanate compounds of (Sumitomo Bayer Urethane Co., Ltd.), "Coronate HL", such as adduct polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd.), and the like. A blocked isocyanate may also be used.
[0069]
Examples of the melamine compound include (hexamethoxy) methylol melamine, methoxymethylol urea and the like.
Examples of the epoxy compound include “Deconal” (manufactured by Nagase Kasei Kogyo Co., Ltd.), “Denacast” (manufactured by Nagase Kasei Kogyo Co., Ltd.), and the like.
[0070]
Examples of the metal salt and metal complex salt include a chelate salt of ethylenediaminetetraacetic acid (EDTA) of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, and acetic acid- Examples include ammonium complex salts and ammonium-carbonate complex salts.
[0071]
About the compounding quantity of this crosslinking agent (F), although it changes also with the kind, it is preferable that it is 0.05-10 weight part normally with respect to 100 weight part of solid content in an emulsion, More preferably, it is 0.00. It is 08-5 weight part, Most preferably, it is 0.1-3 weight part. When the blending amount is less than 0.05 parts by weight, sufficient holding power and water whitening resistance cannot be obtained, and when it exceeds 10 parts by weight, the adhesive strength and tack are lowered, which is not preferable.
[0072]
Further, in the present invention, coating property improvers, thickeners, antiseptic / antifungal agents, rust inhibitors, freeze / thaw stabilizers, plasticizers, high boiling point solvents, pigments, fillers, and the like can be obtained as necessary. It can be added appropriately to the emulsion, or added before or during the polymerization.
[0073]
  The emulsion-type pressure-sensitive adhesive composition of the present invention thus obtained is an oil-soluble composition comprising an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid alkyl ester (a1) and a tackifier (B). In the presence of the polymerization initiator (D), an emulsion [I] obtained by emulsifying the components using an emulsifier (C) in an aqueous medium so that the average particle size of the oil-soluble component is 1.0 μm or less. In the presence of a resin emulsion [II] obtained by polymerization withWithout adding tackifier (B)Furthermore, since the ethylenically unsaturated monomer (E) containing the (meth) acrylic acid alkyl ester (e1) as a main component is polymerized, there is almost no aggregate formation at the time of polymerization, and the storage stability is excellent. In addition, it has excellent effects on adhesion (particularly adhesion to polyolefin), holding power, substrate adhesion, and water resistance (particularly water whitening resistance).
[0074]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
In the examples, “%” and “part” mean weight basis unless otherwise specified.
[0075]
Example 1
[Preparation of resin emulsion [II] (first stage polymerization)]
2-ethylhexyl acrylate (a1) 55.8 parts, n-butyl acrylate (a1) 30 parts, methyl methacrylate (a1) 10 parts, acrylic acid (a2) 4 parts, tripropylene glycol diacrylate (a2) 0.2 parts , And "Superester A-125" (rosin ester tackifier: Arakawa Chemical Co., Ltd.) (B) 50 parts of a mixed solution, 190 parts of water, 1.0 part of dibasic sodium phosphate 12 hydrate, emulsifier (SEAN, manufactured by Asahi Denka Co., Ltd.) (C) In addition to an aqueous solution in which 4.5 parts were dissolved, the mixture was stirred and mixed using a homodisper to perform preliminary emulsification. The average particle diameter of the oil-soluble component of the emulsion [I ′] was 5 μm. The average particle diameter was calculated from the scattering intensity distribution using a dynamic light scattering photometer “DLS-700” (manufactured by Otsuka Electronics Co., Ltd.) (the same applies hereinafter).
Subsequently, this emulsified liquid [I ′] was subjected to a pressure of 50 kg / cm using a high-pressure homogenizer (manufactured by GAULIN).²After 1 pass treatment with a pressure of 300 kg / cm²To obtain an emulsion [I] (345.5 parts) having an oil-soluble component average particle size of 0.15 μm.
[0076]
Further, 1.0 part of ammonium persulfate as a polymerization initiator was dissolved in 19.0 parts of water to prepare an initiator solution.
[0077]
Next, 50 parts of water and 172.8 parts of the emulsion [I] were charged into a polymerization can. When the temperature was raised and the internal temperature reached 80 ° C., 25% of the initiator solution was added to the polymerization can. Then, the remaining emulsion [I] and 25% of the initiator solution were added dropwise at 80 ° C. over 30 minutes for polymerization. Thereafter, the polymerization was further carried out at 80 ° C. for 1 hour to obtain a resin emulsion [II] (average particle size 0.14 μm, resin concentration 43.9%). The resin concentration was calculated from the residue after drying 1 g of resin emulsion at 110 ° C. for 3 hours (the same applies hereinafter).
[0078]
[Preparation of emulsion-type pressure-sensitive adhesive composition of the present invention (second stage polymerization)]
Next, 130.2 parts of 2-ethylhexyl acrylate (e1), 70.0 parts of n-butyl acrylate (e1), 23.3 parts of methyl methacrylate (e1), 9.3 parts of acrylic acid (e2), tripropylene glycol A mixture of 0.47 parts of diacrylate (e3) is added to an aqueous solution in which 1.6 parts of an emulsifier ("SE-10N" manufactured by Asahi Denka Co., Ltd.) (C) is dissolved in 110 parts of water, and a homodisper is used. The mixture was stirred and pre-emulsified to obtain 344.9 parts of an emulsified liquid [I].
And this emulsified liquid [I] is dripped at 80 degreeC over 3 hours in the resin emulsion [II] obtained above with 33% of initiator liquid, and also after completion | finish of dripping, it is 17 of initiator liquid. % Was added. Thereafter, the polymerization was further carried out at 80 ° C. for 2 hours.
After completion of the polymerization, the mixture was cooled and adjusted to pH 7.5 with 5% aqueous ammonia to obtain an emulsion having a nonvolatile content of 49%, a viscosity of 1500 mPa · s, and a particle size of 0.17 μm. The viscosity was measured using a B-type viscometer at 25 ° C. (the same applies hereinafter).
The following evaluation was performed about the obtained emulsion.
[0079]
(Rough particle amount)
100 g of the obtained emulsion was filtered through a 200 mesh net, the filtered components (aggregates: coarse particles) were dried at 100 ° C. for 3 hours, and the weight of the coarse particles (mg / Em 100 g) was measured.
[0080]
Furthermore, to 100 parts of the obtained emulsion, 1.0 part of a carbodiimide compound (Nisshinbo Co., Ltd., “V-04”) is used as a crosslinking agent (F), and a fluorine-based coating agent (manufactured by Neos Co., Ltd.) “FT-100”) 0.05 part, a thickener (“UH-541” manufactured by Asahi Denka Co., Ltd.) was added and mixed in an appropriate amount, and the viscosity was adjusted to 10,000 mPa · s to obtain an emulsion-type pressure-sensitive adhesive composition.
The following evaluation was performed about the obtained emulsion type adhesive composition.
[0081]
(Left stability)
The resulting emulsion-type pressure-sensitive adhesive composition was allowed to stand for 6 months at 40 ° C., and then the presence or absence of thickening and sedimentation or separation was observed and evaluated as follows.
○ ・ ・ ・ No thickening, sediment or separation
× ・ ・ ・ Thickening, sediment or separation
[0082]
Further, the obtained emulsion-type pressure-sensitive adhesive composition was coated on release paper so that the thickness after drying was 20 μm, dried at 100 ° C. for 5 minutes, and then a 50 μm PET film. A base material or an aluminum vapor deposition base material was bonded together to produce an adhesive film, and the following adhesive physical properties were evaluated.
[0083]
(Adhesive strength)
In the above adhesive film (PET film base material), after releasing the release paper, (1) stainless plate (SUS304), (2) polyethylene plate (Japan test panel standard test plate) at 20 ° C. and 65% RH. It was made to adhere and 180 degree peel strength (gf / 25mm) was measured according to the measuring method of the adhesive strength of JISZ0237.
[0084]
(Holding power)
In the above adhesive film (PET film substrate), after releasing the release paper, it was attached to a test plate of stainless steel plate (SUS304) so that the application area was 25 mm × 25 mm. (1) 80 ° C. × 50% A load of 1 kg was applied under the condition of RH, and the displacement (mm) of the film or the drop time (min) of the film after 24 hours was measured according to the measuring method of holding power of JIS Z 0237.
[0085]
(Ball tack)
J. et al. Using a dow type ball tack measuring machine, the ball No. having the maximum diameter that stops on the test piece (glue surface) at a test piece of 25 mm × 100 mm and an angle of 30 ° under the conditions of 20 ° C. and 65% RH. Was measured.
[0086]
(Base material adhesion)
In the said adhesive film (aluminum vapor deposition base material), the measurement similar to the measurement of adhesive force was performed with respect to the stainless steel plate (SUS304), and it evaluated from the peeling strength (g / 25mm) and a peeling state. The evaluation criteria are as follows.
[Peeling state]
A: Adherent interface peeling or cohesive failure
B ... Base material interface peeling
[Comprehensive evaluation]
○: The peeled state was the adherend interface peeling or cohesive failure, and the peel strength was 1000 g / 25 mm or more.
Δ: The peeled state was substrate interface peeling, and the peel strength was 1000 g / 25 mm or more.
X: The peeled state was substrate interface peeling, and the peel strength was less than 1000 g / 25 mm.
[0087]
(Water whitening resistance)
The release film of the above adhesive film (PET film substrate: 25 mm width) was peeled off, and the one attached to the glass plate was immersed in warm water at 60 ° C. for 3 days, then taken out of the water and immediately measured for transmittance (%). did. The transmittance is “SZ-Σ80 COLOR MEASURING SYSTEM” manufactured by Nippon Denshoku Industries Co., Ltd., and a test piece that is not immersed in warm water (adhesive film attached to a glass plate) is used as a blank for measurement. It was.
[0088]
Example 2
[Preparation of resin emulsion [II] (first stage polymerization)]
2-ethylhexyl acrylate (a1) 30.9 parts, n-butyl acrylate (a1) 60 parts, methyl methacrylate (a1) 5 parts, acrylic acid (a2) 4 parts, tripropylene glycol diacrylate (a2) 0.1 part , And "Superester A-125" (rosin ester tackifier: Arakawa Chemical Co., Ltd.) (B) 50 parts of a mixed solution, 190 parts of water, 1.0 part of dibasic sodium phosphate 12 hydrate, emulsifier (SEAN, manufactured by Asahi Denka Co., Ltd.) (C) In addition to an aqueous solution in which 4.5 parts were dissolved, the mixture was stirred and mixed using a homodisper to perform preliminary emulsification. The average particle diameter of the oil-soluble component of the emulsion [I ′] was 5 μm.
Subsequently, this emulsified liquid [I ′] was subjected to a pressure of 50 kg / cm using a high-pressure homogenizer (manufactured by GAULIN).²After 1 pass treatment with, further pressure 300kg / cm²To obtain an emulsion [I] (345.5 parts) having an oil-soluble component average particle size of 0.15 μm.
[0089]
Further, 1.0 part of ammonium persulfate as a polymerization initiator was dissolved in 19.0 parts of water to prepare an initiator solution.
[0090]
Next, 50 parts of water and 172.8 parts of the emulsion [I] were charged into a polymerization can. When the temperature was raised and the internal temperature reached 80 ° C., 25% of the initiator solution was added to the polymerization can. Then, the remaining emulsion [I] and 25% of the initiator solution were added dropwise at 80 ° C. over 30 minutes for polymerization. Thereafter, the polymerization was further carried out at 80 ° C. for 1 hour to obtain a resin emulsion [II] (average particle size 0.14 μm, resin concentration 43.9%).
[0091]
[Preparation of emulsion-type pressure-sensitive adhesive composition of the present invention (second stage polymerization)]
Next, 72.1 parts of 2-ethylhexyl acrylate (e1), 140 parts of n-butyl acrylate (e1), 11.7 parts of methyl methacrylate (e1), 9.3 parts of acrylic acid (e2), tripropylene glycol diacrylate (E3) A mixture of 0.23 parts is added to an aqueous solution in which 1.6 parts of an emulsifier (manufactured by Asahi Denka Co., Ltd., “SE-10N”) (C) is dissolved in 110 parts of water, and stirred and mixed using a homodisper. Then, preliminary emulsification was performed to obtain 344.9 parts of an emulsified liquid [I].
And this emulsified liquid [I] is dripped at 80 degreeC over 3 hours in the resin emulsion [II] obtained above with 33% of initiator liquid, and also after completion | finish of dripping, it is 17 of initiator liquid. % Was added. Thereafter, the polymerization was further carried out at 80 ° C. for 2 hours.
After completion of the polymerization, the mixture was cooled and adjusted to pH 7.5 with 5% aqueous ammonia to obtain an emulsion having a nonvolatile content of 49%, a viscosity of 1800 mPa · s, and a particle size of 0.17 μm.
The obtained emulsion was evaluated in the same manner as in Example 1.
[0092]
Furthermore, to 100 parts of the obtained emulsion, 2 parts of an oxazoline-based compound (manufactured by Nippon Shokubai Co., Ltd., “Epocross K-2010E”) as a crosslinking agent (F) and a fluorine-based coating agent (manufactured by Neos, “FT-100”) 0.05 part, a thickener (“UH-541” manufactured by Asahi Denka Co., Ltd.) was added and mixed in an appropriate amount, and the viscosity was adjusted to 10,000 mPa · s to obtain an emulsion-type pressure-sensitive adhesive composition.
The obtained emulsion-type pressure-sensitive adhesive composition was subjected to standing stability evaluation and pressure-sensitive physical property evaluation in the same manner as in Example 1.
[0093]
Example 3
The same procedure as in Example 1 was carried out except that the crosslinking agent (F) was changed to 0.3 part of 2,2-bishydroxymethylbutanol-Tris (manufactured by Nippon Shokubai Co., Ltd., “Chemite PZ-33”) as an aziridine compound. An emulsion-type pressure-sensitive adhesive composition was obtained. The obtained emulsion-type pressure-sensitive adhesive composition was subjected to standing stability evaluation and pressure-sensitive physical property evaluation in the same manner as in Example 1.
[0094]
Example 4
In Example 1, 2-ethylhexyl acrylate (a1) was changed to 55.0 parts in the first stage polymerization, and 0.2 parts of tripropylene glycol diacrylate (a2) was changed to 1.0 part of diacetone acrylamide (a2). Further, in the second stage polymerization, the same except that 2-ethylhexyl acrylate (a1) was changed to 128.3 parts and tripropylene glycol diacrylate (e3) 0.47 parts to diacetone acrylamide (e3) 2.3 parts And an emulsion having a nonvolatile content of 49%, a viscosity of 1600 mPa · s, and a particle size of 0.17 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
[0095]
Furthermore, 0.15 part of adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as a hydrazine compound as a crosslinking agent (F) was added to 100 parts of the obtained emulsion, and a fluorine-based paint (manufactured by Neos Co., Ltd., “ FT-100 ") 0.2 part, a thickener (" UH-541 "manufactured by Asahi Denka Co., Ltd.) was added and mixed in an appropriate amount, and the viscosity was adjusted to 10,000 mPa · s to obtain an emulsion-type pressure-sensitive adhesive composition.
The obtained emulsion-type pressure-sensitive adhesive composition was subjected to standing stability evaluation and pressure-sensitive physical property evaluation in the same manner as in Example 1.
[0096]
Example 5
In Example 1, instead of “Superester A-125” (rosin ester tackifier: Arakawa Chemical Co., Ltd.) (B), “Bencel D-125” (polymerized rosin ester tackifier: Arakawa Chemical Co., Ltd.) In the same manner as above, an emulsion having a nonvolatile content of 49%, a viscosity of 1500 mPa · s, and a particle size of 0.17 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Further, the emulsion obtained was used in the same manner as in Example 1 to obtain an emulsion-type pressure-sensitive adhesive composition, and the obtained emulsion-type pressure-sensitive adhesive composition was subjected to standing stability evaluation and pressure-sensitive adhesive property evaluation in the same manner as in Example 1. went.
[0097]
Example 6
In Example 1, instead of “Superester A-125” (rosin ester-based tackifier: Arakawa Chemical Co., Ltd.) (B), “YS-Polystar N-125” (terpene-phenol resin-based tackifier: Except for using Yasuhara Chemical Co., Ltd.), an emulsion having a nonvolatile content of 49%, a viscosity of 1400 mPa · s, and a particle size of 0.17 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Further, the emulsion obtained was used in the same manner as in Example 1 to obtain an emulsion-type pressure-sensitive adhesive composition, and the obtained emulsion-type pressure-sensitive adhesive composition was subjected to standing stability evaluation and pressure-sensitive adhesive property evaluation in the same manner as in Example 1. went.
[0098]
Example 7
In Example 1, both the first-stage polymerization and the second-stage polymerization were carried out in the same manner except that the amount of acrylic acid was reduced by half and the amount of 2-ethylhexyl acrylate was increased by the reduced amount, and the non-volatile content was 49.5%. An emulsion having a viscosity of 800 mPa · s and a particle size of 0.16 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Furthermore, an emulsion-type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 1.5 parts of the carbodiimide compound (Nisshinbo Co., Ltd., “V-04”) as the crosslinking agent (F) was obtained. The emulsion type pressure-sensitive adhesive composition was evaluated in terms of standing stability and pressure-sensitive adhesive properties in the same manner as in Example 1.
[0099]
Example 8
In Example 1, both the first-stage polymerization and the second-stage polymerization were carried out in the same manner except that the amount of acrylic acid was increased 1.5 times and the amount of 2-ethylhexyl acrylate was decreased by the increased amount. An emulsion having a viscosity of 5%, a viscosity of 2000 mPa · s, and a particle size of 0.18 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Further, an emulsion-type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that the carbodiimide compound (Nisshinbo Co., Ltd., “V-04”) as the crosslinking agent (F) was changed to 0.75 part. The emulsion type pressure-sensitive adhesive composition thus obtained was evaluated for standing stability and pressure-sensitive adhesive properties in the same manner as in Example 1.
[0100]
Example 9
In Example 4, both the first-stage polymerization and the second-stage polymerization were performed in the same manner except that the amount of diacetone acrylamide was reduced to one third and the amount of 2-ethylhexyl acrylate was increased by the reduced amount. An emulsion having a viscosity of 49%, a viscosity of 1200 mPa · s, and a particle size of 0.17 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Furthermore, an emulsion-type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 0.2 part of adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as the crosslinking agent (F) was obtained, and the obtained emulsion-type pressure-sensitive adhesive was obtained. The composition was subjected to standing stability evaluation and adhesive physical property evaluation in the same manner as in Example 1.
[0101]
Example 10
In Example 4, both the first-stage polymerization and the second-stage polymerization were performed in the same manner except that the amount of diacetone acrylamide was doubled and the amount of 2-ethylhexyl acrylate was decreased by the increased amount, and the nonvolatile content was 49%. An emulsion having a viscosity of 1900 mPa · s and a particle size of 0.17 μm was obtained.
The obtained emulsion was evaluated in the same manner as in Example 1.
Furthermore, an emulsion-type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 0.1 part of adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as the crosslinking agent (F) was obtained, and the obtained emulsion-type pressure-sensitive adhesive was obtained. The composition was subjected to standing stability evaluation and adhesive physical property evaluation in the same manner as in Example 1.
[0102]
Comparative Example 1
In Example 1, the emulsion [I ′] (average particle size of oil-soluble component 5 μm) was polymerized as it was without treating it with a high-pressure homogenizer (manufactured by Gaulin), and the resin emulsion (average) A particle size of 0.12 μm and a resin content concentration of 43.9%) was obtained, and using this resin emulsion, second-stage polymerization was carried out in the same manner as in Example 1, and a non-volatile content of 48.5%, a viscosity of 2000 mPa · s, An emulsion having a particle size of 0.15 μm was obtained, and further an emulsion-type pressure-sensitive adhesive composition was obtained.
Evaluation similar to Example 1 was performed about the obtained emulsion and emulsion type adhesive composition.
[0103]
Comparative Example 2
2-ethylhexyl acrylate (a1) 55.8 parts, n-butyl acrylate (a1) 30 parts, methyl methacrylate (a1) 10 parts, acrylic acid (a2) 4 parts, tripropylene glycol diacrylate (a2) 0.2 parts , And "Superester A-125" (rosin ester tackifier: Arakawa Chemical Co., Ltd.) (B) 50 parts of a mixed solution, 190 parts of water, 1.0 part of dibasic sodium phosphate 12 hydrate, emulsifier (SEAN, manufactured by Asahi Denka Co., Ltd.) (C) In addition to an aqueous solution in which 4.5 parts were dissolved, the mixture was stirred and mixed using a homodisper to perform preliminary emulsification. The average particle diameter of the oil-soluble component of the emulsion [I ′] was 5 μm.
Subsequently, this emulsified liquid was subjected to a pressure of 50 kg / cm using a high-pressure homogenizer (manufactured by GAULIN).²After 1 pass treatment with, further pressure 300kg / cm²To obtain an emulsion [I] (345.5 parts) having an oil-soluble component average particle size of 0.15 μm.
[0104]
Further, 0.5 part of ammonium persulfate as a polymerization initiator was dissolved in 9.5 parts of water to prepare an initiator solution.
[0105]
Next, 50 parts of water and 172.8 parts of the above emulsion [I] were charged into a polymerization can, and when the temperature was raised and the internal temperature reached 80 ° C., 50% of the initiator solution was added, and 80 ° C. Then, the remaining emulsion [I] and the initiator solution were added dropwise at 80 ° C. over 30 minutes to carry out polymerization, and the polymerization was further carried out at 80 ° C. for 1 hour.
Thereafter, the mixture was cooled and adjusted to pH 7.5 with 10% aqueous ammonia to obtain an emulsion having a nonvolatile content of 43%, a viscosity of 80 mPa · s, and a particle size of 0.14 μm.
Furthermore, using the obtained emulsion, it carried out similarly to Example 1 and obtained the emulsion type adhesive composition.
Evaluation similar to Example 1 was performed about the obtained emulsion and emulsion type adhesive composition.
[0106]
Comparative Example 3
In Comparative Example 2, 15 parts of “Superester A-125” (rosin ester-based tackifier: Arakawa Chemical Co., Ltd.) (B), 97.2 parts of water, and 0.3% of dibasic sodium phosphate 12 hydrate were used. Part, emulsifier (Asahi Denka Co., Ltd., “SE-10N”) (C) was carried out in the same manner except that it was changed to 3.5 parts, and an emulsion [I] having an oil-soluble component average particle size of 0.20 μm was obtained. Further, the water in the polymerization can was changed to 10 parts, and polymerization was carried out in the same manner to obtain an emulsion having a non-volatile content of 48.5%, a viscosity of 150 mPa · s, and a particle size of 0.20 μm.
Furthermore, using the obtained emulsion, it carried out similarly to Example 1 and obtained the emulsion type adhesive composition.
Evaluation similar to Example 1 was performed about the obtained emulsion and emulsion type adhesive composition.
[0107]
Comparative Example 4
In Example 1, except that “Superester A-125” (rosin ester-based tackifier: Arakawa Chemical Co., Ltd.) (B) was omitted, the first-stage polymerization and the second-stage polymerization were performed in the same manner, and the non-volatile content 43 %, A viscosity of 100 mPa · s, and an emulsion having a particle size of 0.15 μm were obtained, and “Superester A-125” separately emulsified was added in the same amount as in Example 1 to obtain an emulsion. In the same manner as in No. 1, a crosslinking agent (F), a coatability improver, and a thickener were added to obtain an emulsion-type pressure-sensitive adhesive composition. Evaluation similar to Example 1 was performed about the obtained emulsion and emulsion type adhesive composition.
The evaluation result of an Example and a comparative example is shown to Tables 1-3.
[0108]

[0109]

[0110]

[0111]
【The invention's effect】
  The emulsion-type pressure-sensitive adhesive composition of the present invention comprises an oil-soluble component [I] comprising an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid alkyl ester (a1) and a tackifier (B). ] In the presence of the polymerization initiator (D), the emulsified liquid [I] is emulsified using an emulsifier (C) in an aqueous medium so that the average particle size of the oil-soluble component is 1.0 μm or less. In the presence of a resin emulsion [II] obtained by polymerization withWithout adding tackifier (B)Furthermore, since the ethylenically unsaturated monomer (E) containing the (meth) acrylic acid alkyl ester (e1) as a main component is polymerized, there is almost no aggregate formation at the time of polymerization, and the storage stability is excellent. In addition, it has excellent effects on adhesion (particularly adhesion to polyolefin), holding power, substrate adhesion, and water resistance (particularly water whitening resistance).

Claims (8)

Using an emulsifier (C) in an aqueous medium, an oil-soluble component composed of an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid alkyl ester (a1) and a tackifier (B) In the presence of the resin emulsion [II] obtained by polymerizing the emulsion [I] emulsified so that the average particle size of the oil-soluble component is 1.0 μm or less in the presence of the polymerization initiator (D). In addition, without adding a tackifier (B), it is further characterized by polymerizing an ethylenically unsaturated monomer (E) containing (meth) acrylic acid alkyl ester (e1) as a main component. An emulsion-type pressure-sensitive adhesive composition.   The emulsion-type pressure-sensitive adhesive composition according to claim 1, wherein the ethylenically unsaturated monomer (E) contains a carboxyl group-containing unsaturated monomer (e2).   The emulsion-type pressure-sensitive adhesive according to claim 2, wherein the content of the carboxyl group-containing unsaturated monomer (e2) is 1 to 10% by weight based on the ethylenically unsaturated monomer (E). Composition.   The ethylenically unsaturated monomer (E) is a carboxyl group-containing unsaturated monomer (e2) and a crosslinkable group-containing unsaturated monomer [excluding the carboxyl group-containing unsaturated monomer (e2)] The emulsion-type pressure-sensitive adhesive composition according to claim 1, comprising (e3).   The content of the carboxyl group-containing unsaturated monomer (e2) is 1 to 10% by weight based on the ethylenically unsaturated monomer (E), and the crosslinkable group-containing unsaturated monomer [however, the carboxyl group The content of (e3) is 0.05 to 5% by weight with respect to the ethylenically unsaturated monomer (E), excluding the unsaturated monomer (e2). The emulsion-type pressure-sensitive adhesive composition described.   6. The crosslinkable group-containing unsaturated monomer (excluding the carboxyl group-containing unsaturated monomer (e2)) (e3) is a keto group-containing unsaturated monomer. The emulsion-type pressure-sensitive adhesive composition described.   Furthermore, a crosslinking agent (F) is mix | blended, The emulsion type adhesive composition in any one of Claims 1-6 characterized by the above-mentioned.   The emulsion-type pressure-sensitive adhesive composition according to claim 7, wherein the crosslinking agent (F) is at least one compound selected from a carbodiimide compound, an oxazoline compound, an aziridine compound, and a hydrazine compound.