JP2004002863A - Method for production of acryl based block copolymer and pressure sensitive adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic block copolymer having excellent heat resistance by narrowing molecular weight distribution, and expressing a high adhesive strength independent of a kind of objects of adhesion. <P>SOLUTION: The acrylic block copolymer is expressed by formula (A-B)n or formula B-(A-B)n or formula (A-B)n-A, and the block A is a copolymer comprising vinyl monomers mainly comprising alkyl (meth)acrylate in which the alkyl group comprises a 1-12C, and the block (B) is a copolymer comprising vinyl monomers mainly comprising (meth)acrylic acid, and n is an integer of 1-3, the weight average molecular weight of the block B is 5,000-50x10<SP>4</SP>and the total weight average molecular weight (Mw) is 1x10<SP>4</SP>-400x10<SP>4</SP>and (Mw/Mn) is 1.0-1.5. <P>COPYRIGHT: (C)2004,JPO

Description

【００３６】
【化２】

【００３７】
上記一般式（１）及び上記一般式（２）中、Ｒ^１〜Ｒ^１０は、水素原子、炭素数１〜５の炭化水素基又はケイ素を含む炭化水素基を表す。Ｒ^１〜Ｒ^１０は、隣接するＲ基と炭化水素基を介して結合していてもよい。Ｍは、３価のＳｃ、３価のＹ、２価のランタノイド系希土類金属元素又は３価のランタノイド系希土類金属元素（Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ）を表す。Ｚは、炭素数１〜３のアルキレン基又はアルキルシリル基を表す。Ｄは、溶媒分子を表す。ｎは、０〜３の整数である。
【００３８】
上記一般式（１）又は上記一般式（２）で表される化合物の具体例としては特に限定されず、例えば、ビスシクロペンタジエニルルテチウムハイドライド、ビスシクロペンタジエニルルテチウムメチル、ビスシクロペンタジエニルルテチウムビストリメチルシリルメチル、ビスペンタメチルシクロペンタジエニルルテチウムハイドライド、ビスペンタメチルシクロペンタジエニルルテチウムメチル、ビスペンタメチルシクロペンタジエニルルテチウムビストリメチルシリルメチル、ビスシクロペンタジエニルイッテルビュウムハイドライド、ビスシクロペンタジエニルイッテルビュウムメチル、ビスペンタメチルシクロペンタジエニルイッテルビュウムハイドライド、ビスペンタメチルシクロペキンタジエニルイッテルビュウムハイドライド、ビスペンタメチルシクロペンタジエニルイッテルビュウムメチル、ビスペンタメチルシクロペンタジエニルイッテルビュウムビストリメチルシリルメチル、ビスシクロペンタジエニルサマリウムハイドライド、ビスシクロペンタジエニルサマリウムメチル、ビスペンタメチルシクロペンタジエニルサマリウムハイドライド、ビスペンタメチルシクロペンタジエニルサマリウムメチル、ビスペンタメチルシクロペンタジエニルサマリウムビストリメチルシリルメチル、ビスシクロペンタジエニルヨールピウムハイドライド、ビスシクロペンタジエニルヨーロピウムメチル、ビスペンタメチルシクロペンタジエニルヨーロピウムハイドライド、ビスペンタメチルシクロペンタジエニルヨーロピウムメチル、ビスペンタメチルシクロペンタジエニルネオジウムメチル、ビスペンタメチルシクロペンタジエニルセリウムハイドライド、ビスペンタメチルシクロペンタジエニルイットリウムメチル、ビスペンタメチルシクロペンタジエニルスカンジウムハイドライド、ビスペンタメチルシクロペンタジエニルスカンジウムメチル、ビスインデニルルテチウムメチル、エチレンビスインデニルルテチウムメチル、エチレンビスシクロペンタジエニルルテチウムメチル等が挙げられる。
【００３９】
上記有機金属化合物の製造方法としては特に限定されず、例えば、ジャーナル・オブ・ジ・アメリカン・ケミカル・ソサエティー（Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．）（トビン・ジェイ・マークス（Ｔｏｂｉｎ　Ｊ．Ｍａｒｋｓ）、１０７巻、８０９１頁、１９８５年）、ジャーナル・オブ・ジ・アメリカン・ケミカル・ソサエティー（ウィリアム・ジェイ・エバンス（Ｗｉｌｌｉａｍ　Ｊ．Ｅｖａｎｓ）、１０５巻、１４０１頁、１９８３年）、アメリカン・ケミカル・ソサエティー・シンポジウム（Ａ．Ｃ．Ｓ．Ｓｙｍｐ．）（ピー・エル・ワトソン（Ｐ．Ｌ．Ｗａｔｓｏｎ）、４９５頁、１９８３年）、ＷＯ　８６０５７８８（トビン・ジェイ・マークス）等に記載されているような公知の方法等により製造することができる。
【００４０】
上記重合においては、その重合温度は、−１００〜１００℃が好ましい。−１００℃未満であると、重合溶媒の粘度が高くなるので、重合制御が難しくなり、１００℃を超えると、沸点又はそれに近い温度になるので、重合制御が難しくなる。より好ましくは、−１００〜５０℃、更に好ましくは、−１００〜２５℃である。
【００４１】
また、重合圧力は、１〜５０気圧が好ましい。より好ましくは、１〜５気圧である。
上記重合においては、生成したポリマーを加水分解して保護基を外すことにより、最終的に別発明１のアクリル系共重合体（Ｉ）を得ることができる。
【００４２】
上記アクリル系ブロック共重合体（Ｉ）は、（Ａ−Ｂ）ｎで表されるブロック共重合体、Ｂ−（Ａ−Ｂ）ｎで表されるブロック共重合体、及び、（Ａ−Ｂ）ｎ−Ａで表されるブロック共重合体のうちの少なくとも１種で表される。ｎは１〜３の整数である。
【００４３】
上記アクリル系ブロック共重合体（Ｉ）を構成するブロックＡは、アルキル基の炭素数が１〜１２の（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマーからなる共重合体である。上記（メタ）アクリル酸アルキルエステルとしては特に限定されず、例えば、上記別発明１の説明で例示したもの等が挙げられる。
【００４４】
上記（メタ）アクリル酸アルキルエステル以外のビニル系モノマーとしては特に限定されず、例えば、上記別発明１の説明で例示したもの等が挙げられる。
上記ブロックＡの重量平均分子量（Ｍｗ）は、１０００〜２００万が好ましい。１０００未満であると、上記アクリル系ブロック共重合体（Ｉ）の耐熱性が低下し、２００万を超えると、上記アクリル系ブロック共重合体（Ｉ）の塗工性、加工性等が低下する。より好ましくは、５０００〜２００万である。
【００４５】
上記アクリル系ブロック共重合体（Ｉ）を構成するブロックＢは、（メタ）アクリル酸を主成分とするビニル系モノマーからなる共重合体である。上記（メタ）アクリル酸以外のビニル系モノマーとしては特に限定されず、例えば、上記別発明１の説明で例示したもの等が挙げられる。
【００４６】
上記ブロックＢの重量平均分子量（Ｍｗ）は、５０００〜５０万である。５０００未満であると、上記アクリル系ブロック共重合体（Ｉ）の耐熱性が低下し、５０万を超えると、上記アクリル系ブロック共重合体（Ｉ）の塗工性、加工性等が低下するので、上記範囲に限定される。好ましくは、１万〜５０万である。
【００４７】
上記ブロックＢ中に含まれる（メタ）アクリル酸の含有量は、上記アクリル系ブロック共重合体（Ｉ）１００重量部に対して、０．５〜４０重量部が好ましい。０．５重量部未満であると、耐熱性、及び、高極性被着体に対する接着力に劣り、４０重量部を超えると、上記アクリル系ブロック共重合体（Ｉ）の極性及びＴｇが高くなりすぎ、低極性被着体に対する接着力が低下する。
【００４８】
本発明のアクリル系ブロック共重合体（Ｉ）の重量平均分子量（Ｍｗ）は、１万〜４００万である。１万未満であると、充分な耐熱性が得られず、４００万を超えると、塗工性、加工性等が低下するので、上記範囲に限定される。好ましくは、２万〜８０万である。
【００４９】
上記アクリル系ブロック共重合体（Ｉ）の重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比（Ｍｗ／Ｍｎ）は、１．０〜２．０である。２．０を超えると、充分な耐熱性が得られないので、上記範囲に限定される。好ましくは、１．０〜１．５である。
【００５０】
本発明のアクリル系ブロック共重合体（Ｉ）は、有機金属化合物の存在下に重合されたものであることが好ましい。
上記重合の具体的な方法としては、例えば、アルキル基の炭素数が１〜１２の（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマーからなる共重合体であるブロックＡを、３価有機Ｓｃ化合物と、３価有機Ｙ化合物と、２価ランタノイド系希土類金属及び３価ランタノイド系希土類金属から選択された少なくとも１種の元素を含む有機金属化合物とからなる群より選択された少なくとも１種の有機金属化合物を開始剤として用いて、−１００〜１００℃の温度で転化率が９０％以上となるまで重合する工程（１）、並びに、（メタ）アクリル酸を主成分とするビニル系モノマーからなるブロックＢを、３価有機Ｓｃ化合物と、３価有機Ｙ化合物と、２価ランタノイド系希土類金属及び３価ランタノイド系希土類金属から選択された少なくとも１種の元素を含む有機金属化合物とからなる群より選択された少なくとも１種の有機金属化合物を開始剤として用いて、−１００〜１００℃の温度で転化率が９０％以上となるまで重合する工程（２）、の上記工程（１）及び上記工程（２）を組み合わせて実施し、上記ブロックＢの主成分モノマーとして、一般式、
ＣＨ_２＝Ｃ（Ｒ^１）ＣＯＯＳｉＲ^２（Ｒ^３）（Ｒ^４）
（式中、Ｒ^１は、メチル基又は水素原子を表す。Ｒ^２、Ｒ^３、Ｒ^４は、独立して、炭素数１〜４のアルキル基又はフェニル基を表す。）で表される（メタ）アクリル酸３置換シリルを使用し、重合した後、生成したポリマーを加水分解して保護基を外すことにより製造する方法等が挙げられる。
【００５１】
上記重合においては、まず、工程（１）として、上記アルキル基の炭素数が１〜１２の（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマーを、上記有機金属化合物を開始剤として用いて、転化率が９０％以上になるまで重合させ、ブロックＡを重合する。好ましくは、転化率９５％以上である。
【００５２】
上記重合においては、次に、工程（２）として、上記（メタ）アクリル酸を主成分とするビニル系モノマーを上記有機金属化合物を開始剤として用いて重合させ、ブロックＢを重合する。
【００５３】
上記工程（１）及び上記工程（２）においては、重合温度は、−１００〜１００℃が好ましい。−１００℃未満であると、重合溶媒の粘度が高くなるので重合制御が困難となり、１００℃を超えると、沸点又はそれに近い温度になるので、重合制御が困難となるため、上記範囲に限定される。好ましくは、−１００〜５０℃、より好ましくは、−１００〜２５℃である。
【００５４】
また、重合圧力は、１〜５０気圧が好ましい。より好ましくは、１〜５気圧である。
上記工程（１）及び上記工程（２）の重合は、不活性ガス雰囲気下、溶媒存在下で行われる。上記不活性ガス及び上記溶媒としては特に限定されず、例えば、別発明１の説明で例示したもの等が挙げられる。
【００５５】
上記工程（１）及び上記工程（２）において用いられる上記有機金属化合物は、上記アクリル系共重合体（Ｉ）の製造方法の説明において詳述したものと同様のものである。
【００５６】
上記（メタ）アクリル酸３置換シリルとしては特に限定されず、例えば、上記アクリル系共重合体（Ｉ）の製造方法の説明で例示したもの等が挙げられる。
上記工程（１）及び上記工程（２）は、交互に少なくとも１回行われるが、工程（１）を行った後、工程（２）を行ってもよく、その逆であってもよい。
【００５７】
上記重合においては、生成したポリマーを加水分解して保護基を外すことにより、最終的に本発明のアクリル系ブロック共重合体（Ｉ）を得ることができる。別発明１のアクリル系共重合体（Ｉ）は、分子量分布が極めて狭いために、高温での弾性率が高く、優れた耐熱性を有する。また、本発明のアクリル系ブロック共重合体（Ｉ）は、分子量分布が狭く、低極性ブロックと高極性ブロックとを併せ持つものである。このため、同一組成のランダム共重合体に比べて、低Ｔｇであるが、高温サイドの弾性率が高く、タックと耐熱性とのバランスに優れている。
【００５８】
従来のラジカル重合法や、ＥＰ−Ａ−４０２号公報、ＥＰ−Ａ−２１９号公報に記載されているアルキルリチウムやアルキルマグネシウムを開始剤として用いるアニオン重合法では、（メタ）アクリル酸アルキルエステルを重合すると、高分子量のものを得ることが難しかったり、分子量分布が大きくなりすぎたりしてしまう。このため、高分子量かつ分子量分布の制御されたブロック共重合体を得ることができなかった。また、重合温度が高いと、連鎖移動反応や停止反応等の副反応が起こり、重合のリビング性が低下し、ポリマーの分子量分布が更に広がる問題があった。しかしながら、上記において詳述した重合方法によれば、このような問題がなく、優れた物性を有するアクリル系ブロック共重合体を得ることができる。
【００５９】
本発明２は、本発明のアクリル系ブロック共重合体（Ｉ）からなる粘着剤組成物である。
本発明のアクリル系ブロック共重合体（Ｉ）は、上述のように優れた物性を有するものであるので、上記粘着剤組成物は、耐熱性に優れ、かつ、ガラス、金属等の高極性被着体や、ポリエチレン、ポリプロピレン等の低極性被着体に対して良好な接着性を発揮することができる。
【００６０】
本発明のアクリル系ブロック共重合体（Ｉ）を架橋することにより、上記粘着剤組成物の凝集力、耐熱性をより高めることができる。上記架橋を行うための架橋剤としては特に限定されず、例えば、有機化合物架橋剤、有機金属化合物架橋剤、金属塩架橋剤等を挙げることができる。
【００６１】
上記有機化合物架橋剤としては特に限定されず、例えば、Ｎ，Ｎ−メキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）、トリメチロールプロパン−トリ−β−アジリジニルプロピオネート、ビスイソフタロイル−１−（２−メチルアジリジン）等のアジリジン化合物；トリレンジイソシアネート、水素化トリレンジイソシアネート、トリメチロールプロパンのトリレンジイソシアネート付加物、トリフェニルメタントリイソシアネート、メチレンビス（４−フェニルメタン）トリイソシアネート、イソホロンジイソシアネート、ヘキサメチレンジイソシアネート等のイソシアネート化合物；ビスフェノールＡ、エピクロルヒドリン型のエポキシ樹脂、エチレングリコールジグリシジルエーテル、１，６−ヘキサンジオールジグリシジルエーテル、トリグリシジルエーテル、トリメチロールプロパントリグリシジルエーテル、ジグリシジルアニリン、ジグリシジルアミン、Ｎ，Ｎ，Ｎ，Ｎ−テトラグリシジル−ｍ−キシレンジアミン、１，３−ビス（Ｎ，Ｎ−ジグリシジルアミノメチル）シクロヘキサン等のエポキシ化合物；アミノ樹脂；メラミン樹脂等が挙げられる。
【００６２】
上記有機金属化合物架橋剤としては特に限定されず、例えば、アルミニウム、鉄、銅、錫、亜鉛、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アセチルアセトンやアセト酢酸エステルの配位化合物等が挙げられる。
【００６３】
上記金属塩架橋剤としては特に限定されず、例えば、塩化第二銅、塩化アルミニウム、塩化第二鉄、硫酸アルミニウム、硫酸銅、塩化第二錫、塩化亜鉛、塩化ニッケル、塩化マグネシウム、酢酸クロム、酢酸銅等が挙げられる。
【００６４】
上記架橋剤は、単独で用いてもよく、２種以上を併用してもよい。
上記架橋剤の添加量は、本発明のアクリル系ブロック共重合体（Ｉ）１００重量部に対して０．００１〜５重量部が好ましい。０．００１未満であると、本発明２の粘着剤組成物の耐熱性が劣り、５重量部を超えると、本発明２の粘着剤組成物の接着性が劣る。
【００６５】
本発明２の粘着剤組成物には、必要に応じて、更に、粘着付与樹脂、充填剤、酸化防止剤、紫外線吸収剤、カルボン酸金属塩等を添加することができる。
上記粘着付与樹脂としては特に限定されず、例えば、Ｃ５系（水添）石油樹脂、Ｃ６系（水添）石油樹脂、（水添）ロジン樹脂、（水添）ロジンエステル樹脂、（水添）テルペン樹脂、（水添）テルペンフェノール樹脂、（水添）クマロンインデン樹脂、不均化ロジン樹脂、不均化ロジンエステル樹脂、重合ロジン樹脂、重合ロジンエステル樹脂等が挙げられる。これらは単独で用いてもよく、２種以上を併用してもよい。
【００６６】
上記充填剤としては特に限定されず、例えば、炭酸カルシウム、酸化チタン、マイカ、タルク等が挙げられる。
上記酸化防止剤としては特に限定されず、例えば、フェノール系のもの、アミン系のもの等が挙げられる。
【００６７】
上記紫外線吸収剤としては特に限定されず、例えば、ベンゾトリアゾール系のもの等が挙げられる。
上記カルボン酸金属塩としては特に限定されず、例えば、ステアリン酸ナトリウム、ステアリン酸マグネシウム、ステアリン酸カルシウム、ステアリン酸亜鉛、ステアリン酸バリウム、パルミチン酸ナトリウム等が挙げられる。
【００６８】
本発明２の粘着剤組成物は、例えば、粘着テープ、粘着シート等の粘着剤層として好適に用いることができる。
【００６９】
【実施例】
以下に本発明の実施例を掲げて更に詳しく説明するが、本発明はこれら実施例に限定されるものではない。
【００７０】
実施例１
アルゴン置換した１０００ｍｌのフラスコに、ナトリウム／カリウム合金で乾燥し、蒸留したトルエン５００ｇと、ビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２：Ｃｐ^＊＝Ｃ_５（ＣＨ_３）_５０．５ｇ（１．２ｍｍｏｌ）とをトルエン５０ｍｌに溶かした溶液を加え、磁気攪拌機で均一になるまで攪拌しながら液温を０℃に調整した。これにカルシウムハイドライド及びモレキュラーシーブにより乾燥したアクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇとアクリル酸トリメチルシリル（ＴＭＳＡ）３ｇとを加え、０℃で１時間攪拌した。この時点で系中の未反応モノマーをガスクロマトグラフィーで測定したところ、ｎ−ＢＡ、ＴＭＳＡは検出できず、モノマーの重合転化率は略１００％であることが確認された。これに５０ｇのメタノールを加えて重合を停止させた。
【００７１】
この溶液に水５０ｇを加え、７０℃で１時間攪拌し、ＴＭＳＡの保護基を外し、真空加熱乾燥させて、ＢＡ−アクリル酸共重合体を得た。このポリマーの一部をＴＨＦに溶解させ、ＧＰＣ（ゲル透過クロマトグラフィー）測定を行った。測定は標準架橋ポリスチレンを基準とし、ＴＨＦを分離剤として使用し、検出は屈折計を用いて測定した。ポリマーの重量平均分子量（Ｍｗ）、及び、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比である分子量分布（Ｍｗ／Ｍｎ）を表１に示した。
【００７２】
残りのポリマーをトルエンで固形分が４０重量部になるように希釈した後、アクリル系ポリマー固形分換算１００重量部に対して、架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ、相互薬工社製）０．１５重量部を添加し、攪拌してアクリル系粘着剤組成物を得た。これをコロナ放電処理した３８μｍのＰＥＴフィルム上にアプリケーターで塗布乾燥し、２５μｍの厚みの粘着剤層を形成し、その上にシリコン離型処理したＰＥＴフィルムをラミネートし、アクリル系粘着剤ラミネート体を得た。得られたアクリル系粘着剤ラミネート体について、保持力試験、定荷重剥離試験及び１８０°ピール力試験を下記方法により実施した。結果を表１に示した。
【００７３】
保持力試験
アクリル系粘着剤ラミネート体を２５ｍｍ幅のテープ状に切り、離型ＰＥＴを剥がして、２５ｍｍ×２５ｍｍの面積で、２３℃の温度下、ＳＵＳ３０４板に対して２ｋｇのローラーで一往復して貼付し、図１に示すようにして、１００℃のオーブン中で２ｋｇの重りを吊り下げ、１時間後の粘着剤層のずれ、又は、１時間以内のテープの落下時間を測定した。
【００７４】
定荷重剥離試験
アクリル系粘着剤ラミネート体を２０ｍｍ幅のテープ状に切り、離型ＰＥＴを剥がして、２５ｍｍ×１００ｍｍの面積で、２３℃の温度下、ＳＵＳ３０４板に対して２ｋｇのローラーで一往復して貼付し、図２に示すようにして、８０℃のオーブン中で１００ｇの重りを架けて、１時間後の剥がれ長さ、又は、１時間以内の落下時間を測定した。
【００７５】
１８０°ピール力試験
ＳＰ粘着力
ＪＩＳ　Ｚ　０２３７に準拠して、ＳＵＳ３０４板に、２５ｍｍ幅に切ったアクリル系粘着剤ラミネート体を貼り付け、２３℃で２０分放置後、測定温度２３℃、１８０°方向、引張速度３００ｍｍ／分の条件で、ピール力を測定した。
【００７６】
ポリエチレン粘着力
ポリエチレン樹脂板（ハイゼックス１３００Ｊ、三井石油化学工業社製）に、２５ｍｍ幅に切ったアクリル系粘着剤ラミネート体を貼り付け、２３℃で２０分放置後、測定温度２３℃、１８０°方向、引張速度３００ｍｍ／分の条件で、ピール力を測定した。
【００７７】
実施例２
アクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇの代わりに、アクリル酸２−エチルヘキシル（２ＥＨＡ）５０ｇを用いたこと以外は、実施例１と同様に行った。結果を表１に示した。
【００７８】
実施例３
架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ）０．１５重量部の代わりに、イソホロンジイソシアネート（ＩＰＤＩ）０．１５重量部を用いたこと以外は、実施例１と同様に行った。結果を表１に示した。
【００７９】
実施例４
重合開始剤としてビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２）０．５ｇの代わりに、ビスペンタメチルシクロペンタジエニルイッテルビュウムビストリメチルシリルメチル（Ｃｐ^＊ _２ＹｂＣＨ（ＳｉＭｅ_３）_２）０．６ｇを用い、重合時間を１０時間とし、重合温度を−７８℃としたこと以外は、実施例１と同様に行った。結果を表１に示した。
【００８０】
比較例１
重合開始剤としてビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２）０．５ｇの代わりに、ベンゾイルパーオキサイド（ＢＰＯ）０．１０ｇを用い、アクリル酸トリメチルシリル（ＴＭＳＡ）３ｇの代わりに、アクリル酸（ＡＡｃ）２．５ｇを用い、溶媒のトルエン量を５００ｇから５０ｇとし、重合時間を１０時間とし、重合温度を７０℃としたこと以外は、実施例１と同様に行った。結果を表１に示した。
【００８１】
【表１】

【００８２】
実施例５
アルゴン置換した１０００ｍｌのフラスコに、ナトリウム／カリウム合金で乾燥し、蒸留したトルエン５００ｇと、ビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２：Ｃｐ^＊＝Ｃ_５（ＣＨ_３）_５０．５ｇ（１．２ｍｍｏｌ）とをトルエン５０ｍｌに溶かした溶液を加え、磁気攪拌機で均一になるまで攪拌しながら、液温を０℃に調整した。これに第１モノマーとしてカルシウムハイドライド及びモレキュラーシーブにより乾燥したアクリル酸ｎ−ブチル（ｎ−ＢＡ）３ｇとメタクリル酸メチル（ＭＭＡ）７ｇとを加え、０℃で１０分間攪拌した。１０分後系中のポリマー溶液から１ｍｌを抜き出し、未反応モノマーをガスクロマトグラフィーで測定したところ、ｎ−ＢＡ、ＭＭＡは検出できず、モノマーの重合添加率は略１００％であることが確認された。
【００８３】
更にポリマー溶液をＴＨＦで希釈し、ＧＰＣ（ゲル透過クロマトグラフィー）測定を行った。測定は標準架橋ポリスチレンを基準とし、ＴＨＦを分離剤として使用し、検出は屈折計を用いて測定した。ポリマーの重量平均分子量（Ｍｗ）、及び、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比である分子量分布（Ｍｗ／Ｍｎ）を表２に示した。
【００８４】
次に、重合溶液系に第２モノマーとしてアルカリハイドライド及びモレキュラーシーブにより乾燥したアクリル酸２−エチルヘキシル（２ＥＨＡ）３５ｇとアクリル酸ｎ−ブチル（ｎ−ＢＡ）５ｇとを加え、０℃で１時間重合した。１時間後、重合溶液系に５０ｇのメタノールを加えて重合を停止させた。この溶液を真空加熱乾燥させて、Ｐ（ｎ−ＢＡ／ＭＭＡ）−ｂｌｏｃｋ−Ｐ（２ＥＨＡ／ｎ−ＢＡ）ブロック共重合体を得た。このポリマーの一部をＴＨＦに溶解させ、ＧＰＣ測定を行った。ポリマーの重量平均分子量（Ｍｗ）、及び、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比である分子量分布（Ｍｗ／Ｍｎ）を表２に示した。
【００８５】
残りのポリマーをトルエンで固形分が４０重量部になるように希釈し、これをコロナ放電処理した３８μｍのＰＥＴフィルム上にアプリケーターで塗布乾燥し、２５μｍの厚みの粘着剤層を形成し、その上にシリコン離型処理したＰＥＴフィルムをラミネートし、アクリル系粘着剤ラミネート体を得た。得られたアクリル系粘着剤ラミネート体について、保持力試験、ボールタック試験及び１８０°ピール力試験を実施した。保持力試験及び１８０°ピール力試験は実施例１と同様にして行った。ボールタック試験は下記方法で行った。結果を表２に示した。
【００８６】
ボールタック試験
ＪＩＳ　Ｚ　０２３７に準拠して、測定温度２３℃でボールタックを測定した。
【００８７】
実施例６
第１モノマーとしてアクリル酸ｎ−ブチル（ｎ−ＢＡ）３ｇの代わりに、メチルメタクリレート（ＭＭＡ）１０ｇを用い、第２モノマーとしてアクリル酸２−エチルヘキシル（２ＥＨＡ）３５ｇとアクリル酸ｎ−ブチル（ｎ−ＢＡ）５ｇの代わりに、ｎ−ＢＡ３７ｇとメタクリル酸トリメチルシリル（ＴＭＳＭＡ）３ｇを使用し、第２ブロックの重合時間を１０分とし、１０分後このポリマー溶液から１ｍｌを抜き出し、ＧＰＣ測定に供し、残りのポリマー溶液に第３モノマーとしてメタクリル酸エチル（ＥＭＡ）１０ｇを加え、１時間重合し、得られたポリマーを加水分解し、ＴＭＳＭＡの保護基を外したこと以外は、実施例５と同様に行った。結果を表２に示した。
【００８８】
実施例７
第１ブロックのモノマーとしてアクリル酸ｎ−ブチル（ｎ−ＢＡ）３ｇとメタクリル酸メチル（ＭＭＡ）４ｇとメタクリル酸トリメチルシリル（ＴＭＳＭＡ）１ｇの混合液を用い、第２ブロックのモノマーとして、アクリル酸ｎ−ブチル（ｎ−ＢＡ）１０ｇとメタクリル酸メチル（ＭＭＡ）３ｇ、アクリル酸２−エチルヘキシル（２ＥＨＡ）２５ｇの混合液を用いたこと以外は、実施例５と同様に行った。結果を表２に示した。
【００８９】
実施例８
重合開始剤としてビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２）０．５ｇの代わりに、ビスペンタメチルシクロペンタジエニルイッテルビュウムビストリメチルシリルメチル（Ｃｐ^＊ _２ＹｂＣＨ（ＳｉＭｅ_３）_２）０．６ｇを用い、第１ブロックのモノマーとしてアクリル酸ｎ−ブチル（ｎ−ＢＡ）１２ｇとメタクリル酸メチル（ＭＭＡ）２６ｇとの混合液を用い、第２ブロックのモノマーとしてアクリル酸ｎ−ブチル（ｎ−ＢＡ）１ｇ、アクリル酸２−エチルヘキシル（２ＥＨＡ）１ｇ、アクリル酸ｔ−ブチル（ｔ−ＢＡ）１ｇを使用し、第１ブロックの重合時間を１時間とし、第２ブロックの重合時間を２時間とし、重合後に、重合溶液に水１０ｇ、メタノール３０ｇ、ｐ−トルエンスルホン酸２ｇを加えて、７０℃で５時間攪拌し、ｔ−ＢＡの保護基（ｔ−ブチル基）を外し、架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ、相互薬工社製）０．１５重量部を用いたこと以外は、実施例５と同様に行った。結果を表２に示した。
【００９０】
比較例２
アクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇを、アクリル酸ｎ−ブチル（ｎ−ＢＡ）３０ｇ、メタクリル酸メチル（ＭＭＡ）２０ｇに代えた以外は比較例１と同様に行った。結果を表２に示した。
【００９１】
【表２】

【００９２】
実施例９
アルゴン置換した１０００ｍｌのフラスコに、ナトリウム／カリウム合金で乾燥し、蒸留したトルエン５００ｇと、ビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２：Ｃｐ^＊＝Ｃ_５（ＣＨ_３）_５０．５ｇ（１．２ｍｍｏｌ）とをトルエン５０ｍｌに溶かした溶液を加え、磁気攪拌機で均一になるまで攪拌しながら、液温を０℃に調整した。これに第１モノマーとしてカルシウムハイドライド及びモレキュラーシーブにより乾燥したメタクリル酸トリメチルシリル（ＴＭＳＭＡ）３ｇを加え、０℃で５分間攪拌した。１０分後系中のポリマー溶液から１ｍｌを抜き出し、未反応モノマーをガスクロマトグラフィーで測定したところ、ＴＭＳＭＡは検出できず、モノマーの重合転化率は略１００％であることが確認された。
【００９３】
更にポリマー溶液をＴＨＦで希釈し、ＧＰＣ（ゲル透過クロマトグラフィー）測定を行った。測定は標準架橋ポリスチレンを基準とし、ＴＨＦを分離剤として使用し、検出は屈折計を用いて測定した。ポリマーの重量平均分子量（Ｍｗ）、及び、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比である分子量分布（Ｍｗ／Ｍｎ）を表３に示した。
【００９４】
次に、重合溶液系に第２モノマーとしてカルシウムハイドライド及びモレキュラーシーブにより乾燥したアクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇを加え、０℃で１時間重合した。１時間後、重合溶液系に５０ｇのメタノールを加えて重合を停止させた。この溶液に水５０ｇを加え、７０℃で１時間攪拌し、ＴＭＳＭＡの保護基を外し、真空加熱乾燥させて、ＢＡ−アクリル酸共重合体を得た。このポリマーの一部をＴＨＦに溶解させ、ＧＰＣ測定を行った。ポリマーの重量平均分子量（Ｍｗ）、及び、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比である分子量分布（Ｍｗ／Ｍｎ）を表３に示した。
【００９５】
残りのポリマーをトルエンで固形分が４０重量部になるように希釈した後、アクリル系ポリマー固形分換算１００重量部に対して、架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ、相互薬工社製）０．１５重量部を添加し、攪拌してアクリル系粘着剤組成物を得た。これをコロナ放電処理した３８μｍのＰＥＴフィルム上にアプリケーターで塗布乾燥し、２５μｍの厚みの粘着剤層を形成し、その上にシリコン離型処理したＰＥＴフィルムをラミネートし、アクリル系粘着剤ラミネート体を得た。得られたアクリル系粘着剤ラミネート体について、保持力試験、ボールタッタ試験及び１８０°ピール試験を実施した。保持力試験及び１８０°ピール力試験は実施例１と同様にして、ボールタック試験は実施例５と同様にして行った。結果を表３に示した。
【００９６】
実施例１０
第２ブロックのモノマーとして、メタクリル酸メチル２ｇを用い、第２ブロックの重合時間を２０分とし、２０分後このポリマー溶液から１ｍｌを抜き出し、ＧＰＣ測定に供し、残りのポリマー溶液に、第３モノマーとしてアクリル酸２−エチルヘキシル（２ＥＨＡ）３５ｇを加え、１時間重合し、ラミネート体作成時に架橋剤を使用しなかったこと以外は、実施例９と同様に行った。結果を表３に示した。
【００９７】
実施例１１
メタクリル酸トリメチルシリル（ＴＭＳＭＡ）３ｇの代わりに、アクリル酸ｎ−ブチル（ｎ−ＢＡ）２５ｇとメタクリル酸メチル（ＭＭＡ）５ｇとの混合液を用い、第２ブロックのモノマーとして、アクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇの代わりに、アクリル酸トリメチルシリル（ＴＭＳＡ）５ｇを用い、架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ）０．１５重量部の代わりに、イソホロンジイソシアネート（ＩＰＤＩ）０．１５重量部を用い、第１ブロックの重合時間を１時間としたこと以外は、実施例９と同様に行った。結果を表３に示した。
【００９８】
実施例１２
重合開始剤としてビスペンタメチルシクロペンタジエニルサマリウムハイドライド（［Ｃｐ^＊ _２ＳｍＨ］_２）０．５ｇの代わりに、ビスペンタメチルシクロペンタジエニルイッテルビュウムビストリメチルシリルメチル（Ｃｐ^＊ _２ＹｂＣＨ（ＳｉＭｅ_３）_２）０．６ｇを用い、第１ブロックのモノマーとしてメタクリル酸トリメチルシリル（ＴＭＳＭＡ）３ｇの代わりに、アクリル酸ｎ−ブチル（ｎ−ＢＡ）１５ｇとアクリル酸２−エチルヘキシル（２ＥＨＡ）２５ｇとメタクリル酸メチル（ＭＭＡ）５ｇとの混合液を用い、第２ブロックのモノマーとしてアクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇの代わりに、アクリル酸ｔ−ブチル（ｔ−ＢＡ）４ｇを用い、第１ブロックの重合時間を２時間とし、第２ブロックの重合時間を５時間とし、重合温度を−７８℃とし、重合後に重合溶液に水１０ｇ、メタノール３０ｇとｐ−トルエンスルホン酸２ｇを加えて、７０℃で５時間攪拌し、ｔ−ＢＡの保護基（ｔ−ブチル基）を外し、架橋剤としてＮ，Ｎ′−ヘキサメチレン−１，６−ビス（１−アジリジンカルボキシアミド）（ＨＤＵ、相互薬工社製）０．１５重量部を用いたこと以外は、実施例９と同様に行った。結果を表３に示した。
【００９９】
比較例３
アクリル酸ｎ−ブチル（ｎ−ＢＡ）５０ｇをアクリル酸ｎ−ブチル（ｎ−ＢＡ）３５ｇとメタクリル酸エチル１０ｇとメタクリル酸（ＭＡｃ）４ｇに代えたこと以外は比較例１と同様に行った。結果を表３に示した。
【０１００】
【表３】

【０１０１】
【発明の効果】
本発明のアクリル系ブロック共重合体及び粘着剤組成物は、上述の構成からなるので、耐熱性に優れ、また、被着体の表面極性に影響されない高い接着力を発揮する。
【図面の簡単な説明】
【図１】保持力試験を説明するための概略図である。
【図２】定荷重剥離試験を説明するための概略図である。
【符号の説明】
１…ＳＵＳ板
２…粘着剤層
３…ＰＥＴフィルム
４…重り[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an acrylic block copolymer having a narrow molecular weight distribution, excellent heat resistance, and a high adhesive force not affected by the surface polarity of an adherend, a method for producing the same, and a pressure-sensitive adhesive composition using the same. .
[0002]
[Prior art]
Acrylic copolymers are widely used as pressure-sensitive adhesives in pressure-sensitive adhesive layers such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets, hot-melt pressure-sensitive adhesives, and hot-melt adhesives. Such an acrylic pressure-sensitive adhesive is superior in heat resistance and weather resistance as compared with a rubber-based pressure-sensitive adhesive, has good adhesiveness and transparency, and has a lower cost than a silicone-based pressure-sensitive adhesive. Widely used because there is. As such an acrylic copolymer, a (meth) acrylic acid alkyl ester-based random copolymer is generally used.
[0003]
Patent Document 1 listed below discloses a pressure-sensitive adhesive composition using a (meth) acrylic acid alkyl ester-based random copolymer.
However, the pressure-sensitive adhesive composition comprising only such a (meth) acrylic acid alkyl ester-based random copolymer has poor melting properties. For example, when a pressure-sensitive adhesive sheet is produced, the pressure-sensitive adhesive composition can be applied to a base sheet. There is a problem. In addition, the adhesive properties such as initial adhesive strength, temporal adhesive strength, and holding power are also insufficient, so that they cannot be used in fields requiring high performance.
[0004]
Further, the acrylic copolymer is excellent in heat resistance, but when exposed to a high temperature, it exhibits fluidity, decreases cohesive strength, and generates adhesive residue. In recent years, the demand level for the performance of acrylic copolymers has tended to become more and more advanced, so they are more excellent in heat resistance, maintain excellent cohesive force at high temperatures, maintain peel resistance, and prevent adhesive residue etc. from occurring Performance is also required.
[0005]
As a method for improving the heat resistance, a method in which a sufficient cohesive force is exhibited even at a high temperature by increasing the degree of polymerization of the acrylic copolymer can be considered. However, when taking a solvent-type acrylic polymer as an example, the use of those having a weight average molecular weight of around 1.5 million is the limit due to the current polymerization technology and coating technology, and further restrictions derived from costs and the like, and increases the degree of polymerization. Sufficient cohesion cannot be ensured only by relying on the means.
[0006]
Therefore, in order to obtain a sufficient cohesion, it is necessary to increase the degree of polymerization of the polymer and to perform crosslinking. However, when a polymer is crosslinked, the cohesive strength increases, but on the other hand, the adhesive strength decreases, so that it is difficult to balance with the cohesive force. For example, the balance between peel resistance and heat resistance is difficult. For example, there is a limit to the balance between contradictory physical properties, and it is difficult to maintain a good balance between adhesive properties.
[0007]
As a method of improving heat resistance, there is a method of increasing Tg (glass transition temperature) of the acrylic pressure-sensitive adhesive composition. However, in this case, poor adhesion or a decrease in adhesive strength at low temperatures is caused, and there is a limit to the balance between heat resistance and workability at low temperatures.
[0008]
Patent Document 2 below discloses a polymer obtained by graft-polymerizing a polymerizable polymer having a high Tg on a main chain mainly composed of a (meth) acrylic acid alkyl ester.
[0009]
Patent Literature 3 below discloses an attempt to satisfy the balance of coating properties and adhesive properties by changing the structure, composition, average molecular weight, and the like of an ABA type acrylic block copolymer. .
[0010]
These combine polymers having different Tg by graft polymerization or block polymerization, and increase the adhesive force and cohesive force near room temperature by physical crosslinking based on the phase separation structure of the obtained copolymer, while increasing the temperature under high temperature. In U.S. Pat. No. 4, the melting property is enhanced by utilizing the property that physical crosslinks are reversibly collapsed and melted, and it is possible to apply a hot-melt adhesive to a substrate.
[0011]
However, these adhesives still have insufficient balance of adhesive properties such as initial adhesive strength, temporal adhesive strength, and holding power, balance between these adhesive properties and melting properties, and cohesive strength at high temperatures.
[0012]
In recent years, applications to adhesives in the electric and electronic fields and bonding in the automotive parts field have advanced, and qualities such as heat resistance, adhesiveness, and removability have been more strongly required. It is getting tougher. Acrylic copolymers are usually produced by solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc. using a radical polymerization initiator, but polymers based on these radical polymerizations have a molecular weight distribution (weight average molecular weight). (Mw) / number-average molecular weight (Mn)] is as wide as 2.0 to 5, and heat resistance is not always sufficient because low molecular weights are mixed.
[0013]
In general, acrylic random copolymers generally use a monomer containing a carboxylic acid such as (meth) acrylic acid or hydroxyethyl (meth) acrylate or a hydroxyl group in order to improve metal adhesion. However, as the amount of copolymerization of these monomers increases, the Tg of the copolymer itself increases, resulting in a disadvantage that tackiness at low temperatures is remarkably reduced, and low polarities such as polyethylene and polypropylene are caused. The adhesion force to the adherend is reduced, and the addition of a tackifier resin becomes essential.
[0014]
Patent Document 4 listed below discloses a technique using a resin acid ester compound having a specific hydroxyl group-containing vinyl monomer as a tackifier resin. However, this has the disadvantage that, although the tack at low temperatures is improved, the cohesion is not sufficient.
[0015]
[Patent Document 1]
JP-A-6-41501 [Patent Document 2]
JP-A-59-75975 [Patent Document 3]
JP-A-2-103277 [Patent Document 4]
JP-A-3-281587
[Problems to be solved by the invention]
In view of the above, the present invention obtains excellent heat resistance by narrowing the molecular weight distribution, and exhibits an acrylic block copolymer capable of expressing high adhesive force regardless of the type of adherend, a method for producing the same, and a method for producing the same. An object of the present invention is to provide a pressure-sensitive adhesive composition using the same.
[0017]
[Means for Solving the Problems]
The acrylic block copolymer of the present invention has the general formula (AB) n
A block copolymer represented by
General formula B- (AB) n
A block copolymer represented by:
General formula (AB) nA
At least one acrylic block copolymer selected from the group consisting of block copolymers represented by the formula: wherein the block A is an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group. The block B is a copolymer composed of a vinyl monomer composed mainly of (meth) acrylic acid, and the block B is a copolymer composed of a vinyl monomer composed mainly of (meth) acrylic acid. It is an integer, the weight average molecular weight of the block B is 5,000 to 500,000, and the total weight average molecular weight (Mw) is 10,000 to 4,000,000, and the weight average molecular weight (Mw) and the number average The ratio (Mw / Mn) to the molecular weight (Mn) is 1.0 to 2.0. Hereinafter, this is also referred to as “acrylic block copolymer (I)”.
[0018]
Hereinafter, the present invention will be described in detail, but another invention 1 related to the present invention will be described first for use in describing the present invention.
The acrylic copolymer according to another invention 1 comprises 80 to 99.5 parts by weight of a vinyl monomer mainly composed of an alkyl (meth) acrylate having an alkyl group of 1 to 12 carbon atoms and (meth) acrylic acid. 0.5 to 20 parts by weight of a (meth) acrylic copolymer, wherein the (meth) acrylic copolymer has a weight average molecular weight (Mw) of 100,000 or more, and The ratio (Mw / Mn) between (Mw) and the number average molecular weight (Mn) is from 1.0 to 1.5. Hereinafter, this is also referred to as “acrylic copolymer (I)”.
[0019]
Hereinafter, another invention 1 will be described in detail.
The acrylic copolymer (I) is a (meth) acrylic copolymer composed of a vinyl monomer having an alkyl (meth) acrylate as a main component and (meth) acrylic acid.
[0020]
The alkyl (meth) acrylate is not particularly limited as long as the alkyl group has 1 to 12 carbon atoms. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, N-butyl acrylate, isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, acrylic acid Decyl, lauryl acrylate, benzyl acrylate, phenyl acrylate, boronyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, i-methacrylate Butyl, s-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, methacrylic acid Examples include benzyl, phenyl methacrylate, boronyl methacrylate, and isobornyl methacrylate. These may be used alone or in combination of two or more.
[0021]
The vinyl monomer other than the alkyl (meth) acrylate is not particularly limited, and includes, for example, N-vinylpyrrolidone, vinyl acetate, styrene, acrylonitrile, tetrafurfuryl acrylate, polyethylene glycol acrylate, and the like.
[0022]
The acrylic copolymer (I) is composed of 80 to 99.5 parts by weight of a vinyl monomer mainly composed of an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms and 0 to (meth) acrylic acid. 0.5 to 20 parts by weight. When the amount of the (meth) acrylic acid is less than 0.5 part by weight, the holding power and the heat resistance decrease, and when the amount exceeds 20 parts by weight, the tack decreases and the wettability to the adherend decreases. As a result, the adhesive strength is reduced, so that it is limited to the above range.
[0023]
The weight average molecular weight (Mw) of the acrylic copolymer (I) is 100,000 or more. When the weight-average molecular weight is less than 100,000, sufficient heat resistance cannot be obtained, and thus the content is limited to the above range. Preferably, it is 300,000 or more.
[0024]
The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer (I) is 1.0 to 1.5. If Mw / Mn exceeds 1.5, sufficient heat resistance cannot be obtained, so that the range is limited to the above range. Preferably, it is 1.0 to 1.3.
[0025]
It is preferable that the acrylic copolymer (I) of another invention 1 is polymerized in the presence of an organometallic compound.
As a specific method of the polymerization, for example, a vinyl monomer having an alkyl group having 1 to 12 carbon atoms and an alkyl (meth) acrylate as a main component, and a general formula CH ₂ ＣC (R ¹ ) COOSiR ² (R ³ ) (R ⁴ )
(In the formula, R ¹ represents a methyl group or a hydrogen atom; R ² , R ³ , and R ⁴ independently represent an alkyl group having 1 to 4 carbon atoms or a phenyl group.) An organic metal containing at least one element selected from a trivalent organic Sc compound, a trivalent organic Y compound, a divalent lanthanoid-based rare earth metal and a trivalent lanthanoid-based rare earth metal A method in which at least one type of organometallic compound selected from the group consisting of compounds is used as an initiator, polymerization is performed at a temperature of -100 to 100 ° C, and the resulting polymer is hydrolyzed to remove a protecting group to polymerize. And the like.
[0026]
In the above polymerization, in an inert gas atmosphere, in the presence of a solvent, the alkyl group has a vinyl monomer having an alkyl (meth) acrylate having 1 to 12 carbon atoms as a main component, and is represented by the above general formula. Polymerized with the trisubstituted silyl (meth) acrylate.
[0027]
The inert gas is not particularly limited, and includes, for example, nitrogen, argon, helium and the like.
The solvent is not particularly limited as long as it is sufficiently dehydrated and degassed, and examples thereof include halogenated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride; and aromatic hydrocarbons such as benzene, toluene, and xylene. Aliphatic hydrocarbons such as hexane and heptane; alicyclic hydrocarbons such as cyclohexane and cycloheptane; ethers such as tetrahydrofuran and diethyl ether.
[0028]
The tri-substituted silyl (meth) acrylate represented by the above general formula constitutes the acrylic copolymer (I) of another invention 1 by finally removing the tri-substituted silyl group as a protecting group. Things.
[0029]
The trisubstituted silyl (meth) acrylate represented by the above general formula is not particularly limited. For example, trimethylsilyl acrylate, triethylsilyl acrylate, tri-n-butylsilyl acrylate, phenyldimethylsilyl acrylate, diphenylmethyl acrylate Examples include silyl, t-butyldimethylsilyl acrylate, trimethylsilyl methacrylate, triethylsilyl methacrylate, tri-n-butylsilyl methacrylate, phenyldimethylsilyl methacrylate, diphenylmethylsilyl methacrylate, and t-butyldimethylsilyl methacrylate.
[0030]
Further, instead of the trisubstituted silyl (meth) acrylate represented by the above general formula, t-butyl (meth) acrylate, trimethyl zinc (meth) acrylate, trimethyl tin (meth) acrylate, or the like may be used. it can.
[0031]
In the above polymerization, the amount of the trisubstituted silyl (meth) acrylate represented by the above general formula is preferably 0.8 to 80 parts by weight. If the amount is less than 0.8 parts by weight, the holding power is reduced, and if it is more than 80 parts by weight, the tacking force and the peeling force are reduced. More preferably, it is 2 to 40 parts by weight.
[0032]
Examples of the vinyl monomer having as a main component an alkyl (meth) acrylate having 1 to 12 carbon atoms of the alkyl group, and trisubstituted silyl (meth) acrylate represented by the above general formula include calcium hydride, It is preferable to use a material that has been sufficiently dried with a molecular sieve or the like and distilled under an inert gas immediately before polymerization.
[0033]
In the above polymerization, an organometallic compound is used as an initiator. The organometallic compound is preferably dissolved in a solvent before polymerizing the monomer, for example.
[0034]
The organometallic compound comprises a trivalent organic Sc compound, a trivalent organic Y compound, and an organometallic compound containing at least one element selected from divalent lanthanoid-based rare earth metals and trivalent lanthanoid-based rare earth metals. At least one organometallic compound selected from the group. As the organometallic compound, a compound represented by the following general formula (1) or the following general formula (2) is suitably used.
[0035]
Embedded image

[0036]
Embedded image

[0037]
In the general formulas (1) and (2), R ^{1 to} R ¹⁰ represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a hydrocarbon group containing silicon. R ^{1 to} R ¹⁰ may be bonded to an adjacent R group via a hydrocarbon group. M is trivalent Sc, trivalent Y, divalent lanthanide rare earth metal element or trivalent lanthanoid rare earth metal element (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy , Ho, Er, Tm, Yb, Lu). Z represents an alkylene group or an alkylsilyl group having 1 to 3 carbon atoms. D represents a solvent molecule. n is an integer of 0 to 3.
[0038]
Specific examples of the compound represented by the general formula (1) or the general formula (2) are not particularly limited. For example, biscyclopentadienyl lutetium hydride, biscyclopentadienyl lutetium methyl, biscyclopentadiene Enyl lutetium bistrimethylsilylmethyl, bispentamethylcyclopentadienyl lutetium hydride, bispentamethylcyclopentadienyl lutetium methyl, bispentamethylcyclopentadienyl lutetium bistrimethylsilylmethyl, biscyclopentadienyl ytterbium hydride, biscyclo Pentadienyl ytterbium methyl, bispentamethylcyclopentadienyl ytterbium hydride, bispentamethylcyclopequintadienyl ytterbium hydride Bispentamethylcyclopentadienyl ytterbium methyl, bispentamethylcyclopentadienyl ytterbium bistrimethylsilylmethyl, biscyclopentadienyl samarium hydride, biscyclopentadienyl samarium methyl, bispentamethylcyclopentadienyl samarium Hydride, bispentamethylcyclopentadienyl samarium methyl, bispentamethylcyclopentadienyl samarium bistrimethylsilylmethyl, biscyclopentadienyl iodilpium hydride, biscyclopentadienyl europium methyl, bispentamethylcyclopentadienyl Europium hydride, bispentamethylcyclopentadienyl europium methyl, bispentamethylcyclopentadienyl Neodymium methyl, bispentamethylcyclopentadienyl cerium hydride, bispentamethylcyclopentadienyl yttrium methyl, bispentamethylcyclopentadienyl scandium hydride, bispentamethylcyclopentadienyl scandium methyl, bisindenyl lutetium methyl, ethylene Bisindenyl lutetium methyl, ethylene biscyclopentadienyl lutetium methyl and the like can be mentioned.
[0039]
The method for producing the organometallic compound is not particularly limited, and examples thereof include, for example, Journal of the American Chemical Society (J. Am. Chem. Soc.) (Tobin J. Marks), 107, 8091, 1985), Journal of the American Chemical Society (William J. Evans, William J. Evans, 105, 1401, 1983), American Chemical Society. Publicly known as described in Symposium (A.C.S.Symp.) (PL Watson, 495, p. 1983), WO 8605788 (Tobin Jay Marks), etc. And the like.
[0040]
In the above polymerization, the polymerization temperature is preferably from -100 to 100C. When the temperature is lower than -100 ° C, the viscosity of the polymerization solvent becomes high, so that the control of polymerization becomes difficult. When the temperature exceeds 100 ° C, the temperature becomes a boiling point or a temperature close to the boiling point. More preferably, the temperature is -100 to 50C, and still more preferably -100 to 25C.
[0041]
The polymerization pressure is preferably 1 to 50 atm. More preferably, the pressure is 1 to 5 atm.
In the above polymerization, the acrylic polymer (I) of another invention 1 can be finally obtained by hydrolyzing the produced polymer to remove the protecting group.
[0042]
The acrylic block copolymer (I) includes a block copolymer represented by (AB) n, a block copolymer represented by B- (AB) n, and (AB) ) Represented by at least one of the block copolymers represented by nA. n is an integer of 1 to 3.
[0043]
The block A constituting the acrylic block copolymer (I) is a copolymer composed of a vinyl monomer having an alkyl group having 1 to 12 carbon atoms and an alkyl (meth) acrylate as a main component. The alkyl (meth) acrylate is not particularly limited, and includes, for example, those exemplified in the description of the another invention 1.
[0044]
The vinyl-based monomer other than the above (meth) acrylic acid alkyl ester is not particularly limited, and examples thereof include those exemplified in the description of the above-mentioned another invention 1.
The weight average molecular weight (Mw) of the block A is preferably 1,000 to 2,000,000. When it is less than 1,000, the heat resistance of the acrylic block copolymer (I) decreases, and when it exceeds 2,000,000, the coatability, processability, etc. of the acrylic block copolymer (I) decrease. . More preferably, it is 5000 to 2,000,000.
[0045]
The block B constituting the acrylic block copolymer (I) is a copolymer composed of a vinyl monomer having (meth) acrylic acid as a main component. The vinyl-based monomer other than the above (meth) acrylic acid is not particularly limited, and examples thereof include those exemplified in the description of the above another invention 1.
[0046]
The weight average molecular weight (Mw) of the block B is 5000 to 500,000. When it is less than 5,000, the heat resistance of the acrylic block copolymer (I) decreases, and when it exceeds 500,000, the coatability, processability, etc. of the acrylic block copolymer (I) decrease. Therefore, it is limited to the above range. Preferably, it is 10,000 to 500,000.
[0047]
The content of (meth) acrylic acid in the block B is preferably 0.5 to 40 parts by weight based on 100 parts by weight of the acrylic block copolymer (I). When the amount is less than 0.5 part by weight, heat resistance and adhesion to a highly polar adherend are inferior, and when it exceeds 40 parts by weight, the polarity and Tg of the acrylic block copolymer (I) increase. Too low, and the adhesion to the low-polarity adherend is reduced.
[0048]
The weight average molecular weight (Mw) of the acrylic block copolymer (I) of the present invention is 10,000 to 4,000,000. If it is less than 10,000, sufficient heat resistance cannot be obtained, and if it is more than 4,000,000, coating properties, workability and the like are reduced, so that it is limited to the above range. Preferably, it is 20,000 to 800,000.
[0049]
The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic block copolymer (I) is 1.0 to 2.0. If it exceeds 2.0, sufficient heat resistance cannot be obtained, so that it is limited to the above range. Preferably, it is 1.0 to 1.5.
[0050]
The acrylic block copolymer (I) of the present invention is preferably polymerized in the presence of an organometallic compound.
As a specific method of the polymerization, for example, a block A, which is a copolymer composed of a vinyl monomer having an alkyl group having 1 to 12 carbon atoms and an alkyl (meth) acrylate ester as a main component, may be trivalent. At least one selected from the group consisting of an organic Sc compound, a trivalent organic Y compound, and an organic metal compound containing at least one element selected from divalent lanthanoid rare earth metals and trivalent lanthanoid rare earth metals (1) using an organometallic compound as an initiator to polymerize at a temperature of −100 to 100 ° C. until the conversion becomes 90% or more, and a vinyl monomer containing (meth) acrylic acid as a main component Selected from a trivalent organic Sc compound, a trivalent organic Y compound, a divalent lanthanoid-based rare earth metal and a trivalent lanthanoid-based rare earth metal And at least one organometallic compound selected from the group consisting of organometallic compounds containing at least one element as an initiator, the conversion is 90% or more at a temperature of -100 to 100 ° C. The step (1) and the step (2) of the step (2) of polymerizing until the step (2) are carried out in combination.
CH ₂ ＣC (R ¹ ) COOSiR ² (R ³ ) (R ⁴ )
(In the formula, R ¹ represents a methyl group or a hydrogen atom; R ² , R ³ , and R ⁴ independently represent an alkyl group having 1 to 4 carbon atoms or a phenyl group.) After the polymerization using trisubstituted silyl (meth) acrylate, the resulting polymer is hydrolyzed to remove the protecting group, and the like.
[0051]
In the above polymerization, first, as a step (1), a vinyl-based monomer mainly containing an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group is used, and the organometallic compound is used as an initiator. The block A is polymerized until the conversion reaches 90% or more. Preferably, the conversion is 95% or more.
[0052]
In the above polymerization, as a step (2), the vinyl monomer having (meth) acrylic acid as a main component is polymerized using the organometallic compound as an initiator to polymerize the block B.
[0053]
In the steps (1) and (2), the polymerization temperature is preferably from -100 to 100C. If the temperature is lower than -100 ° C, the viscosity of the polymerization solvent becomes high, so that the polymerization control becomes difficult.If it is higher than 100 ° C, the temperature becomes a boiling point or a temperature close thereto, so that the polymerization control becomes difficult. You. Preferably, it is -100 to 50C, more preferably -100 to 25C.
[0054]
The polymerization pressure is preferably 1 to 50 atm. More preferably, the pressure is 1 to 5 atm.
The polymerization in the step (1) and the step (2) is performed in an inert gas atmosphere in the presence of a solvent. The inert gas and the solvent are not particularly limited, and include, for example, those exemplified in the description of the separate invention 1.
[0055]
The organometallic compound used in the step (1) and the step (2) is the same as that described in detail in the description of the method for producing the acrylic copolymer (I).
[0056]
The trisubstituted silyl (meth) acrylate is not particularly limited, and examples thereof include those exemplified in the description of the method for producing the acrylic copolymer (I).
The steps (1) and (2) are alternately performed at least once. However, the step (2) may be performed after the step (1), or vice versa.
[0057]
In the above polymerization, the resulting polymer is hydrolyzed to remove the protecting group, whereby the acrylic block copolymer (I) of the present invention can be finally obtained. The acrylic copolymer (I) of another invention 1 has a very narrow molecular weight distribution, and therefore has a high elastic modulus at high temperatures and excellent heat resistance. The acrylic block copolymer (I) of the present invention has a narrow molecular weight distribution and has both a low-polarity block and a high-polarity block. For this reason, although the Tg is lower than that of the random copolymer having the same composition, the elastic modulus on the high temperature side is high, and the balance between tack and heat resistance is excellent.
[0058]
In a conventional radical polymerization method or an anion polymerization method using alkyl lithium or alkyl magnesium as an initiator described in EP-A-402 or EP-A-219, an alkyl (meth) acrylate is used. When polymerized, it is difficult to obtain a polymer having a high molecular weight, or the molecular weight distribution becomes too large. For this reason, a block copolymer having a high molecular weight and a controlled molecular weight distribution could not be obtained. In addition, when the polymerization temperature is high, side reactions such as chain transfer reaction and termination reaction occur, and there is a problem that the living property of polymerization is reduced and the molecular weight distribution of the polymer is further widened. However, according to the polymerization method described in detail above, an acrylic block copolymer having no such problems and excellent physical properties can be obtained.
[0059]
The present invention 2 is a pressure-sensitive adhesive composition comprising the acrylic block copolymer (I) of the present invention.
Since the acrylic block copolymer (I) of the present invention has excellent physical properties as described above, the pressure-sensitive adhesive composition has excellent heat resistance and a high polarity coating property such as glass and metal. Good adhesion to adherends and low-polarity adherends such as polyethylene and polypropylene can be exhibited.
[0060]
By crosslinking the acrylic block copolymer (I) of the present invention, the cohesive strength and heat resistance of the pressure-sensitive adhesive composition can be further increased. The crosslinking agent for performing the crosslinking is not particularly limited, and examples thereof include an organic compound crosslinking agent, an organometallic compound crosslinking agent, and a metal salt crosslinking agent.
[0061]
The organic compound crosslinking agent is not particularly limited, and examples thereof include N, N-mexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, and bisisopropane. Aziridine compounds such as phthaloyl-1- (2-methylaziridine); tolylene diisocyanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylene bis (4-phenylmethane) tri Isocyanate compounds such as isocyanate, isophorone diisocyanate and hexamethylene diisocyanate; bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, 1,6-hexanediol diisocyanate Lysidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine, N, N, N, N-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-di Epoxy compounds such as glycidylaminomethyl) cyclohexane; amino resins; and melamine resins.
[0062]
The organometallic compound crosslinking agent is not particularly limited, for example, aluminum, iron, copper, tin, zinc, titanium, nickel, antimony, magnesium, vanadium, chromium, acetylacetone or acetoacetate of a polyvalent metal such as zirconium. And coordination compounds.
[0063]
The metal salt crosslinking agent is not particularly limited, for example, cupric chloride, aluminum chloride, ferric chloride, aluminum sulfate, copper sulfate, stannic chloride, zinc chloride, nickel chloride, magnesium chloride, chromium acetate, Copper acetate and the like can be mentioned.
[0064]
The crosslinking agents may be used alone or in combination of two or more.
The amount of the crosslinking agent to be added is preferably 0.001 to 5 parts by weight based on 100 parts by weight of the acrylic block copolymer (I) of the present invention. When it is less than 0.001, the heat resistance of the pressure-sensitive adhesive composition of the present invention 2 is poor, and when it exceeds 5 parts by weight, the adhesiveness of the pressure-sensitive adhesive composition of the present invention 2 is poor.
[0065]
The pressure-sensitive adhesive composition of the present invention 2 may further contain a tackifier resin, a filler, an antioxidant, an ultraviolet absorber, a metal carboxylate, and the like, if necessary.
The tackifying resin is not particularly limited. For example, C5 (hydrogenated) petroleum resin, C6 (hydrogenated) petroleum resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) Examples include terpene resins, (hydrogenated) terpene phenol resins, (hydrogenated) coumarone indene resins, disproportionated rosin resins, disproportionated rosin ester resins, polymerized rosin resins, and polymerized rosin ester resins. These may be used alone or in combination of two or more.
[0066]
The filler is not particularly limited, and examples thereof include calcium carbonate, titanium oxide, mica, and talc.
The antioxidant is not particularly limited, and examples thereof include phenol-based and amine-based agents.
[0067]
The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole-based ones.
The metal carboxylate is not particularly restricted but includes, for example, sodium stearate, magnesium stearate, calcium stearate, zinc stearate, barium stearate, sodium palmitate and the like.
[0068]
The pressure-sensitive adhesive composition of the present invention 2 can be suitably used as a pressure-sensitive adhesive layer such as a pressure-sensitive adhesive tape or a pressure-sensitive adhesive sheet.
[0069]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
[0070]
Example 1
In a 1000 ml flask purged with argon, 500 g of toluene dried and distilled with a sodium / potassium alloy, and bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ : Cp ^* = C ₅ (CH ₃ ) ₅ ) A solution prepared by dissolving 0.5 g (1.2 mmol) in 50 ml of toluene was added thereto, and the solution temperature was adjusted to 0 ° C. while stirring the mixture with a magnetic stirrer until the mixture became uniform, to which acrylic acid and acrylic acid dried by molecular sieve were added. 50 g of n-butyl (n-BA) and 3 g of trimethylsilyl acrylate (TMSA) were added, and the mixture was stirred for 1 hour at 0 ° C. At this point, unreacted monomers in the system were measured by gas chromatography to find n-BA , TMSA cannot be detected, and the polymerization conversion of the monomer is approximately 100%. The polymerization was terminated by adding 50 g of methanol thereto.
[0071]
50 g of water was added to this solution, and the mixture was stirred at 70 ° C. for 1 hour to remove the protective group of TMSA, and dried by heating under vacuum to obtain a BA-acrylic acid copolymer. A part of this polymer was dissolved in THF, and GPC (gel permeation chromatography) measurement was performed. The measurement was based on standard crosslinked polystyrene, using THF as a separating agent, and the detection was measured using a refractometer. Table 1 shows the weight average molecular weight (Mw) of the polymer and the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
[0072]
After diluting the remaining polymer with toluene so that the solid content becomes 40 parts by weight, N, N'-hexamethylene-1,6-bis ( 0.15 parts by weight of 1-aziridinecarboxamide) (HDU, manufactured by Mutual Pharmaceutical Co., Ltd.) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition. This was coated and dried on a 38 μm PET film subjected to corona discharge treatment with an applicator to form an adhesive layer having a thickness of 25 μm, and a PET film subjected to a silicone release treatment was laminated thereon, and an acrylic adhesive laminate was formed. Obtained. The obtained acrylic pressure-sensitive adhesive laminate was subjected to a holding force test, a constant load peeling test and a 180 ° peel force test by the following methods. The results are shown in Table 1.
[0073]
Holding force test The acrylic pressure-sensitive adhesive laminate was cut into a 25 mm width tape, the release PET was peeled off, and it was reciprocated once with a 2 kg roller on a SUS304 plate at an area of 25 mm × 25 mm at a temperature of 23 ° C. As shown in FIG. 1, a 2 kg weight was hung in an oven at 100 ° C., and the displacement of the pressure-sensitive adhesive layer after one hour or the tape falling time within one hour was measured.
[0074]
Constant load peeling test Acrylic adhesive laminate was cut into 20mm wide tape, peeled off PET, and reciprocated once with a 2kg roller on SUS304 plate at an area of 25mm x 100mm at 23 ° C. Then, as shown in FIG. 2, a 100 g weight was placed in an oven at 80 ° C., and the peeling length after one hour or the drop time within one hour was measured.
[0075]
180 ° peel force test SP Adhesive strength According to JIS Z 0237, an acrylic pressure-sensitive adhesive laminate cut to a width of 25 mm was stuck to a SUS304 plate, left at 23 ° C for 20 minutes, and then measured at a temperature of 23 ° C and 180 ° The peel force was measured under the conditions of a direction and a tensile speed of 300 mm / min.
[0076]
Polyethylene adhesive strength An acrylic adhesive laminate cut to a width of 25 mm was attached to a polyethylene resin plate (HIZEX 1300J, manufactured by Mitsui Petrochemical Industries, Ltd.), left at 23 ° C. for 20 minutes, and measured at a temperature of 23 ° C. and 180 ° direction The peel force was measured under the conditions of a tensile speed of 300 mm / min.
[0077]
Example 2
Example 1 was repeated except that 50 g of 2-ethylhexyl acrylate (2EHA) was used instead of 50 g of n-butyl acrylate (n-BA). The results are shown in Table 1.
[0078]
Example 3
Except that 0.15 parts by weight of isophorone diisocyanate (IPDI) was used instead of 0.15 parts by weight of N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) (HDU) as a crosslinking agent Was performed in the same manner as in Example 1. The results are shown in Table 1.
[0079]
Example 4
Instead of 0.5 g of bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ ) as a polymerization initiator, bispentamethylcyclopentadienyl ytterbium bistrimethylsilylmethyl (Cp ^* ₂ YbCH (SiMe _{3) 2} ) The procedure of Example 1 was repeated, except that 0.6 g was used, the polymerization time was 10 hours, and the polymerization temperature was -78 ° C. The results are shown in Table 1.
[0080]
Comparative Example 1
Instead of 0.5 g of bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ ) as a polymerization initiator, 0.10 g of benzoyl peroxide (BPO) is used, and 3 g of trimethylsilyl acrylate (TMSA) is used. The procedure of Example 1 was repeated, except that 2.5 g of acrylic acid (AAc) was used, the amount of toluene in the solvent was changed from 500 g to 50 g, the polymerization time was changed to 10 hours, and the polymerization temperature was changed to 70 ° C. The results are shown in Table 1.
[0081]
[Table 1]

[0082]
Example 5
In a 1000 ml flask purged with argon, 500 g of toluene dried and distilled with a sodium / potassium alloy, and bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ : Cp ^* = C ₅ (CH ₃ ) ₅ ) A solution prepared by dissolving 0.5 g (1.2 mmol) in 50 ml of toluene was added thereto, and the temperature was adjusted to 0 ° C. while stirring the mixture with a magnetic stirrer until the mixture became uniform. 3 g of n-butyl acrylate (n-BA) and 7 g of methyl methacrylate (MMA) were added and stirred for 10 minutes at 0 ° C. After 10 minutes, 1 ml was extracted from the polymer solution in the system, and unreacted monomer was removed. Was measured by gas chromatography, n-BA and MMA could not be detected. It was confirmed that the polymerization addition ratio of the monomer was approximately 100%.
[0083]
Further, the polymer solution was diluted with THF, and GPC (gel permeation chromatography) measurement was performed. The measurement was based on standard crosslinked polystyrene, using THF as a separating agent, and the detection was measured using a refractometer. Table 2 shows the weight average molecular weight (Mw) of the polymer and the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
[0084]
Next, 35 g of 2-ethylhexyl acrylate (2EHA) and 5 g of n-butyl acrylate (n-BA) dried with an alkali hydride and molecular sieve as the second monomer were added to the polymerization solution system, and polymerized at 0 ° C. for 1 hour. did. One hour later, 50 g of methanol was added to the polymerization solution system to terminate the polymerization. This solution was dried by heating under vacuum to obtain a P (n-BA / MMA) -block-P (2EHA / n-BA) block copolymer. A part of this polymer was dissolved in THF, and GPC measurement was performed. Table 2 shows the weight average molecular weight (Mw) of the polymer and the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
[0085]
The remaining polymer was diluted with toluene so as to have a solid content of 40 parts by weight, and this was applied to a corona discharge-treated 38 μm PET film with an applicator and dried to form a 25 μm thick adhesive layer. Was laminated with a PET film subjected to a silicone release treatment to obtain an acrylic pressure-sensitive adhesive laminate. The obtained acrylic pressure-sensitive adhesive laminate was subjected to a holding force test, a ball tack test, and a 180 ° peel force test. The holding force test and the 180 ° peel force test were performed in the same manner as in Example 1. The ball tack test was performed by the following method. The results are shown in Table 2.
[0086]
Ball tack test The ball tack was measured at a measurement temperature of 23 ° C. in accordance with JIS Z 0237.
[0087]
Example 6
Instead of 3 g of n-butyl acrylate (n-BA) as the first monomer, 10 g of methyl methacrylate (MMA) was used, and 35 g of 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (n-BA) were used as the second monomer. Instead of 5 g of BA), 37 g of n-BA and 3 g of trimethylsilyl methacrylate (TMSMA) were used, and the polymerization time of the second block was set to 10 minutes. After 10 minutes, 1 ml of the polymer solution was withdrawn and subjected to GPC measurement. Was performed in the same manner as in Example 5 except that 10 g of ethyl methacrylate (EMA) was added as a third monomer to the polymer solution of the above, polymerization was carried out for 1 hour, the obtained polymer was hydrolyzed, and the protecting group of TMSMA was removed. Was. The results are shown in Table 2.
[0088]
Example 7
A mixed solution of 3 g of n-butyl acrylate (n-BA), 4 g of methyl methacrylate (MMA) and 1 g of trimethylsilyl methacrylate (TMSMA) was used as the monomer of the first block, and n-butyl acrylate was used as the monomer of the second block. Example 5 was carried out in the same manner as in Example 5 except that a mixed solution of 10 g of butyl (n-BA), 3 g of methyl methacrylate (MMA), and 25 g of 2-ethylhexyl acrylate (2EHA) was used. The results are shown in Table 2.
[0089]
Example 8
Instead of 0.5 g of bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ ) as a polymerization initiator, bispentamethylcyclopentadienyl ytterbium bistrimethylsilylmethyl (Cp ^* ₂ YbCH (SiMe _{3) 2} ) 0.6 g, a mixed solution of 12 g of n-butyl acrylate (n-BA) and 26 g of methyl methacrylate (MMA) as the monomer of the first block, and n-acrylic acid as the monomer of the second block Using 1 g of -butyl (n-BA), 1 g of 2-ethylhexyl acrylate (2EHA), and 1 g of t-butyl acrylate (t-BA), the polymerization time of the first block was 1 hour, and the polymerization of the second block was 1 hour. After 2 hours, 10 g of water, 30 g of methanol, p-toluene were added to the polymerization solution after the polymerization. 2 g of sulfonic acid was added, and the mixture was stirred at 70 ° C. for 5 hours to remove the protective group (t-butyl group) of t-BA, and N, N′-hexamethylene-1,6-bis (1-aziridine) was used as a crosslinking agent. Carboxamide) (HDU, manufactured by Mutual Pharmaceutical Company) was used in the same manner as in Example 5, except that 0.15 parts by weight was used. The results are shown in Table 2.
[0090]
Comparative Example 2
Comparative Example 1 was repeated except that 50 g of n-butyl acrylate (n-BA) was replaced with 30 g of n-butyl acrylate (n-BA) and 20 g of methyl methacrylate (MMA). The results are shown in Table 2.
[0091]
[Table 2]

[0092]
Example 9
In a 1000 ml flask purged with argon, 500 g of toluene dried and distilled with a sodium / potassium alloy, and bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ : Cp ^* = C ₅ (CH ₃ ) ₅ ) A solution prepared by dissolving 0.5 g (1.2 mmol) in 50 ml of toluene was added thereto, and the temperature was adjusted to 0 ° C. while stirring the mixture with a magnetic stirrer until the mixture became uniform. 3 g of trimethylsilyl methacrylate (TMSMA) dried by the above method was added and stirred for 5 minutes at 0 ° C. After 10 minutes, 1 ml was withdrawn from the polymer solution in the system, and the unreacted monomer was measured by gas chromatography. And the polymerization conversion of the monomer is approximately 100% Was confirmed.
[0093]
Further, the polymer solution was diluted with THF, and GPC (gel permeation chromatography) measurement was performed. The measurement was based on standard crosslinked polystyrene, using THF as a separating agent, and the detection was measured using a refractometer. Table 3 shows the weight average molecular weight (Mw) of the polymer and the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
[0094]
Next, calcium hydride as a second monomer and 50 g of n-butyl acrylate (n-BA) dried with molecular sieve were added to the polymerization solution system, and polymerization was performed at 0 ° C. for 1 hour. One hour later, 50 g of methanol was added to the polymerization solution system to terminate the polymerization. 50 g of water was added to this solution, and the mixture was stirred at 70 ° C. for 1 hour to remove the protective group of TMSMA, and dried by heating under vacuum to obtain a BA-acrylic acid copolymer. A part of this polymer was dissolved in THF, and GPC measurement was performed. Table 3 shows the weight average molecular weight (Mw) of the polymer and the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
[0095]
After diluting the remaining polymer with toluene so that the solid content becomes 40 parts by weight, N, N'-hexamethylene-1,6-bis ( 0.15 parts by weight of 1-aziridinecarboxamide) (HDU, manufactured by Mutual Pharmaceutical Co., Ltd.) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition. This was coated and dried on a 38 μm PET film subjected to corona discharge treatment with an applicator to form an adhesive layer having a thickness of 25 μm, and a PET film subjected to a silicone release treatment was laminated thereon, and an acrylic adhesive laminate was formed. Obtained. The obtained acrylic pressure-sensitive adhesive laminate was subjected to a holding force test, a ball tutter test, and a 180 ° peel test. The holding force test and the 180 ° peel force test were performed in the same manner as in Example 1, and the ball tack test was performed in the same manner as in Example 5. The results are shown in Table 3.
[0096]
Example 10
As the monomer of the second block, 2 g of methyl methacrylate was used, and the polymerization time of the second block was set to 20 minutes. After 20 minutes, 1 ml was withdrawn from the polymer solution and subjected to GPC measurement. Was carried out in the same manner as in Example 9 except that 35 g of 2-ethylhexyl acrylate (2EHA) was added, polymerization was carried out for 1 hour, and no cross-linking agent was used at the time of preparing the laminate. The results are shown in Table 3.
[0097]
Example 11
Instead of 3 g of trimethylsilyl methacrylate (TMSMA), a mixed solution of 25 g of n-butyl acrylate (n-BA) and 5 g of methyl methacrylate (MMA) was used, and n-butyl acrylate ( Instead of 50 g of n-BA), 5 g of trimethylsilyl acrylate (TMSA) was used, and 0.15 parts by weight of N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) (HDU) was used as a crosslinking agent. Was performed in the same manner as in Example 9 except that 0.15 parts by weight of isophorone diisocyanate (IPDI) was used and the polymerization time of the first block was set to 1 hour. The results are shown in Table 3.
[0098]
Example 12
Instead of 0.5 g of bispentamethylcyclopentadienyl samarium hydride ([Cp ^* ₂ SmH] ₂ ) as a polymerization initiator, bispentamethylcyclopentadienyl ytterbium bistrimethylsilylmethyl (Cp ^* ₂ YbCH (SiMe _{3) 2} ) 0.6 g, and instead of 3 g of trimethylsilyl methacrylate (TMSMA) as a monomer of the first block, 15 g of n-butyl acrylate (n-BA), 25 g of 2-ethylhexyl acrylate (2EHA) and 25 g of methacrylic acid Using a mixture of 5 g of methyl (MMA) and 4 g of t-butyl acrylate (t-BA) instead of 50 g of n-butyl acrylate (n-BA) as a monomer of the second block, And the polymerization time of the second block is 5:00 After the polymerization, 10 g of water, 30 g of methanol and 2 g of p-toluenesulfonic acid were added to the polymerization solution, and the mixture was stirred at 70 ° C. for 5 hours, and the protective group of t-BA (t-butyl group) was added. ) Was removed and 0.15 parts by weight of N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) (HDU, manufactured by Mutual Pharmaceutical Co., Ltd.) was used as a crosslinking agent. Performed similarly to 9. The results are shown in Table 3.
[0099]
Comparative Example 3
Comparative Example 1 was repeated except that 50 g of n-butyl acrylate (n-BA) was replaced with 35 g of n-butyl acrylate (n-BA), 10 g of ethyl methacrylate, and 4 g of methacrylic acid (MAc). The results are shown in Table 3.
[0100]
[Table 3]

[0101]
【The invention's effect】
Since the acrylic block copolymer and the pressure-sensitive adhesive composition of the present invention have the above-described constitution, they have excellent heat resistance and exhibit a high adhesive force that is not affected by the surface polarity of the adherend.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a holding force test.
FIG. 2 is a schematic diagram illustrating a constant load peel test.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... SUS plate 2 ... Adhesive layer 3 ... PET film 4 ... Weight

Claims (4)

General formula (AB) n
A block copolymer represented by
General formula B- (AB) n
A block copolymer represented by:
General formula (AB) nA
At least one acrylic block copolymer selected from the group consisting of block copolymers represented by
The block A is a copolymer composed of a vinyl monomer having an alkyl group having 1 to 12 carbon atoms and an alkyl (meth) acrylate as a main component,
The block B is a copolymer composed of a vinyl monomer having (meth) acrylic acid as a main component,
N is an integer of 1 to 3,
The weight average molecular weight of the block B is 5,000 to 500,000, and
The total weight average molecular weight (Mw) is 10,000 to 4,000,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 1.0 to 2.0. An acrylic block copolymer, characterized in that: The acrylic block copolymer according to claim 1, wherein the acrylic block copolymer is polymerized in the presence of an organometallic compound. The method for producing an acrylic block copolymer according to claim 1, wherein the copolymer comprises a vinyl monomer having an alkyl group having 1 to 12 carbon atoms and an alkyl (meth) acrylate as a main component. Block A, which is united,
At least one selected from the group consisting of a trivalent organic Sc compound, a trivalent organic Y compound, and an organometallic compound containing at least one element selected from divalent lanthanoid-based rare earth metals and trivalent lanthanoid-based rare earth metals. A step (1) of using one kind of organometallic compound as an initiator and polymerizing at a temperature of -100 to 100 ° C until the conversion becomes 90% or more, and
The block B composed of a vinyl monomer having (meth) acrylic acid as a main component was selected from a trivalent organic Sc compound, a trivalent organic Y compound, a divalent lanthanoid rare earth metal, and a trivalent lanthanoid rare earth metal. Using at least one organometallic compound selected from the group consisting of an organometallic compound containing at least one element as an initiator, polymerization is performed at a temperature of -100 to 100 ° C until the conversion becomes 90% or more. Step (2),
And the step (1) and the step (2) are performed in combination.
As a main component monomer of the block B,
General formula,
CH ₂ ＣC (R ¹ ) COOSiR ² (R ³ ) (R ⁴ )
(Wherein, R ¹ represents a methyl group or a hydrogen atom; R ² , R ³ , and R ⁴ independently represent an alkyl group having 1 to 4 carbon atoms or a phenyl group). A method for producing an acrylic block copolymer, comprising using a tri-substituted silyl (meth) acrylate for polymerization and then hydrolyzing a produced polymer to remove a protecting group. A pressure-sensitive adhesive composition comprising the acrylic block copolymer according to claim 1.

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