JP3549168B2 - Removable adhesive and its adhesive sheets - Google Patents
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- JP3549168B2 JP3549168B2 JP31267494A JP31267494A JP3549168B2 JP 3549168 B2 JP3549168 B2 JP 3549168B2 JP 31267494 A JP31267494 A JP 31267494A JP 31267494 A JP31267494 A JP 31267494A JP 3549168 B2 JP3549168 B2 JP 3549168B2
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【０００１】
【産業上の利用分野】
本発明は、アクリル系共重合体を主成分とした再剥離用粘着剤と、これをシ―ト状やテ―プ状などの形態とした粘着シ―ト類とに関する。
【０００２】
【従来の技術】
再剥離用粘着シ―ト類は、表面保護、マスキングなどの目的に使用される。従来より、この種のシ―ト類としては、種々の基材の片面にアクリル系粘着剤やゴム系粘着剤を塗布したものが知られている。
【０００３】
【発明が解決しようとする課題】
しかし、従来公知の再剥離用粘着シ―ト類は、常温において５〜５０ｍ／分程度の実用的な剥離速度での剥離が重く、また経時での粘着力の上昇性が大きく、剥離作業性に劣る問題があつた。この問題の解決のため、架橋密度を高め粘着剤の凝集力を向上させて弱粘着としたものが知られるが、このものは、貼り付け保存中に粘着シ―ト類の端部から剥がれが生じやすかつた。
【０００４】
本発明は、このような事情に鑑み、実用的な剥離速度での剥離が軽く、また経時での粘着力の上昇性が小さい、剥離作業性にすぐれたものであり、しかも貼り付け保存中の端末剥がれがみられない再剥離用粘着剤と、これをシ―ト状やテ―プ状などの形態とした粘着シ―ト類を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明者らは、上記の目的を達成するために、鋭意検討した結果、特定の単量体構成からなるアクリル系共重合体を主成分として、これを特定のゲル分となるまで架橋構造化することにより、剥離作業性にすぐれるとともに、貼り付け保存中の端末剥がれがみられない再剥離用粘着剤とその粘着シ―ト類が得られることを見い出し、本発明を完成するに至つた。
【０００６】
すなわち、本発明は、下記のａ〜ｃ成分またはこれとｄ成分；
ａ）一般式（１）：ＣＨ２ ＝Ｃ（Ｒ１ ）ＣＯＯＲ２ （式中、Ｒ１ は水素またはメチル基、Ｒ２ は炭素数２〜１４のアルキル基である）で表されるアクリル系単量体５０〜９４重量％
または両者が結合しこれとＮ原子とで複素環を構成する有機基である）で表されるＮ，Ｎ−ジ置換（メタ）アクリルアミド３５〜５重量％
ｃ）カルボキシル基含有単量体またはその無水物１０〜１重量％
ｄ）上記のａ〜ｃ成分と共重合可能な単量体２０〜０重量％
からなる単量体混合物の共重合体を主成分とし、かつゲル分が７０％以上であることを特徴とする再剥離用粘着剤と、この再剥離用粘着剤からなる層を基材の片面または両面に有することを特徴とするシ―ト状やテ―プ状などの形態とされた粘着シ―ト類とに係るものである。
【０００７】
【発明の構成・作用】
本発明におけるａ成分としてのアクリル系単量体は、たとえば、一般式（１）中のＲ２ がブチル基、イソブチル基、イソアミル基、ヘキシル基、ヘプチル基、２−エチルヘキシル基、イソオクチル基、イソノニル基、イソデシル基などのアルキル基からなるアクリル酸またはメタクリル酸のエステルが挙げられる。Ｒ２ の炭素数が２未満では粘着剤の濡れ性が低下して初期接着性が悪くなり、１４を超えると接着力に劣り、いずれも好ましくない。
【０００８】
このａ成分としてのアクリル系単量体は、単量体全体量の５０〜９４重量％、好ましくは６０〜９０重量％の範囲で、その１種または２種以上が用いられる。５０重量％未満では、アクリル系粘着剤としての性能を発揮できず、また９４重量％を超えると、そのぶん後述するｂ，ｃ成分の絶対量が不足し、目的とする粘着力および剥離作業性にすぐれる再剥離用粘着剤が得られない。
【０００９】
本発明におけるｂ成分としてのＮ，Ｎ−ジ置換（メタ）アクリルアミドには、一般式（２）中のＲ４ ，Ｒ５ がいずれもアルキル基である非環状の（メタ）アクリルアミドと、同Ｒ４ ，Ｒ５ が結合しこれとＮ原子とで複素環を構成する環状の（メタ）アクリルアミドとが含まれ、再剥離用粘着剤の使用目的に応じて、そのいずれか一方または両方が用いられる。
【００１０】
非環状の（メタ）アクリルアミドとしては、Ｎ，Ｎ−ジエチル（メタ）アクリルアミド、Ｎ，Ｎ−ジメチル（メタ）アクリルアミドなどが挙げられる。また、環状の（メタ）アクリルアミドとしては、Ｎ−（メタ）アクリロイルモルホリン、Ｎ−（メタ）アクリロイルピロリドン、Ｎ−（メタ）アクリロイルピペリジン、Ｎ−（メタ）アクリロイルピロリジン、Ｎ−（メタ）アクリロイル−４−ピペリドンなどが挙げられる。
【００１１】
このｂ成分としてのＮ，Ｎ−ジ置換（メタ）アクリルアミドは、単量体全体量の３５〜５重量％、好ましくは３０〜８重量％、より好ましくは２５〜１０重量％の範囲で、その１種または２種以上が用いられる。３５重量％を超えると、粘着剤の濡れ性が低下して、粘着力が低下し、５重量％未満となると、架橋構造化による粘着力と剥離作業性とのバランス特性をとりにくい。
【００１２】
本発明におけるｃ成分としてのカルボキシル基含有単量体またはその無水物としては、たとえば、アクリル酸、イタコン酸、マレイン酸、クロトン酸などや、無水フタル酸などが挙げられ、使用目的に応じて、その１種または２種以上が適宜選択使用される。使用量は、単量体全体量の１０〜１重量％、好ましくは９〜１．５重量％、より好ましくは８〜２重量％の範囲とするのがよい。１０重量％を超えると、粘着性に劣り、また１重量％未満となると、凝集力が不足し、いずれもの場合も良好な粘着特性を発現させにくい。
【００１３】
本発明におけるｄ成分としての単量体は、上記のａ〜ｃ成分の単量体と共重合可能なものであればよく、たとえば、酢酸ビニル、スチレン、（メタ）アクリル酸グリシジル、（メタ）アクリル酸２−ヒドロキシプロピル、（メタ）アクリル酸メチル、Ｎ−ビニル−２−ピロリドンなどが挙げられる。このｄ成分の単量体は、必要により、単量体全体量の２０重量％以下、好ましくは１５重量％以下の範囲で、その１種または２種以上が用いられる。２０重量％を超えると、アクリル系粘着剤としての粘着特性を発現しにくい。
【００１４】
本発明のアクリル系共重合体は、上記のａ〜ｃ三成分またはこれとｄ成分からなる単量体混合物を、常法により、溶液重合法、塊状重合法、乳化重合法、懸濁重合法などの方法で共重合させることにより、得ることができる。
【００１５】
本発明の再剥離用粘着剤は、上記のアクリル系共重合体を主成分とし、ゲル分が７０％以上、好ましくは７５〜９５％程度となるまで架橋構造化したものである。ゲル分が７０％未満では、実用的な剥離速度での剥離が重く、また経時での粘着力の上昇性が大きくて、剥離作業性に劣り、さらに再剥離用粘着剤としては致命的である剥離後の被着体への糊残りの発生という問題がある。
【００１６】
なお、上記のゲル分とは、約５００ｍｇの粘着剤を試料として用意し、これを、ソツクスレ−抽出器を用い、アセトン中で５０℃、４時間抽出したのち、あるいはトルエン中に室温で２日間浸漬したのち、１３０℃で１時間乾燥後、粘着剤の初期重量（Ｇ０）と不溶分重量（Ｇｔ）とから、〔Ｇｔ／Ｇ０〕×１００（％）として、計算される値である。
【００１７】
粘着剤の架橋構造化は、電子線照射や熱架橋などの手法によつてもよいが、好ましくは架橋剤を用いてこれと共重合体中に含まれるカルボキシル基などの官能基との反応を行わせる、いわゆる官能基間による架橋反応を行わせるのがよい。この目的に用いるとくに好適な架橋剤としては、多官能性エポキシ化合物と多官能性イソシアネ―ト化合物を挙げることができる。
【００１８】
多官能性エポキシ化合物は、分子中に２個以上のエポキシ基を有するもので、ソルビト―ルテトラグリシジルエ―テル、トリメチロ―ルプロパングリシジルエ―テル、テトラグリシジル−１，３−ビスアミノメチルシクロヘキサン、テトラグリシジルメタキシレンジアミン、トリグリシジル−ｐ−アミノフエノ―ルなどがある。多官能性イソシアネ―ト化合物は、分子中に２個以上のイソシアネ―ト基を有するもので、ジフエニルメタンジイソシアネ―ト、トリレンジイソシアネ―ト、ヘキサメチレンジイソシアネ―トなどがある。
【００１９】
これらの架橋剤は、アクリル系共重合体の組成や分子量などに応じて、粘着剤のゲル分が前記範囲となる使用割合で、その１種または２種以上が用いられる。その際、反応を促進させるために、粘着剤に通常用いられるジブチルスズラウレ―トなどの架橋触媒を加えるようにしてもよい。
【００２０】
本発明の再剥離用粘着剤には、上記成分のほか、必要により、フエノ―ル系樹脂、クマロンインデン系樹脂、ロジン系樹脂などの粘着付与剤が含まれていてもよい。また、着色剤、充填剤、老化防止剤などの他の公知の添加剤を適宜含ませることもできる。粘着剤の前記のゲル分は、これらの添加剤を含む粘着剤全体として、前記範囲内に設定されておればよい。
【００２１】
本発明の粘着シ―ト類は、このような再剥離用粘着剤からなる層を、基材の片面または両面に、所望の厚さに設けて、シ―ト状やテ―プ状などの形態としたものである。基材上に設けるには、再剥離用粘着剤の溶液または分散液を、基材上に直接塗布し乾燥するか、あるいは剥離フイルムに塗布し乾燥したものを基材上に貼り合わせて転写すればよい。塗布，乾燥の工程中またはその後のエ―ジング中に、前記した架橋反応を行わせることができる。
【００２２】
基材としては、オレフイン系樹脂、ポリエステル系樹脂、塩化ビニル系樹脂、酢酸ビニル系樹脂、ポリイミド系樹脂などのプラスチツクフイルムや、クレ―プ紙、和紙などの不織布、発泡フイルムなどの種々のものが用いられる。これらの基材は、１種または２種以上を組み合わせて使用でき、また片面または両面にコロナ処理などの表面処理を施したものであつてもよい。
【００２３】
【発明の効果】
本発明によれば、表面保護、マスキングなどの各種の再剥離用の用途に対し、実用的な剥離速度での剥離が軽く、また経時での粘着力の上昇性が小さく、剥離作業性にすぐれており、しかも貼り付け保存中の端末剥がれがみられない再剥離用粘着剤とその粘着シ―ト類を提供することができる。
【００２４】
【実施例】
つぎに、本発明の実施例を記載してより具体的に説明する。なお、以下において、部とあるのは重量部を意味する。
【００２５】
実施例１
冷却管、窒素導入管、温度計および撹拌装置を備えた反応容器に、アクリル酸２−エチルヘキシル８０部、Ｎ−アクリロイルモルホリン２０部、アクリル酸３部、重合開始剤として２，２´−アゾビスイソブチロニトリル０．１５部、酢酸エチル１００部を入れ、６０℃で１２時間重合して、ポリマ―溶液を得た。
【００２６】
このポリマ―溶液に、ポリマ―固形分１００部に対して、テトラグリシジル−１，３−ビスアミノメチルシクロヘキサン４部を加えて、混合したのち、厚さが６０μｍのポリエチレンフイルム上に、塗布し、乾燥することにより、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。またこれとは別に、剥離フイルム上に塗布し、乾燥して、ゲル分測定用のサンプルを作製し、これを用いて本文詳記の方法により再剥離用粘着剤のゲル分を測定した。
【００２７】
実施例２
実施例１で得たポリマ―溶液に、ポリマ―固形分１００部に対して、トリレンジイソシアネ―ト５部を加えて、混合したのち、実施例１と同様にして、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。また、実施例１と同様にして、ゲル分測定用のサンプルを作製し、これを用いて再剥離用粘着剤のゲル分を測定した。
【００２８】
実施例３
単量体組成を、アクリル酸ｎ−ブチル８０部、Ｎ−イソプロピルアクリルアミド２０部、アクリル酸３部に変更した以外は、実施例１と同様にして、ポリマ―溶液を得た。このポリマ―溶液に、ポリマ―固形分１００部に対して、テトラグリシジル−１，３−ビスアミノメチルシクロヘキサン１部を加えて、混合したのち、実施例１と同様にして、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。また、実施例１と同様にして、ゲル分測定用のサンプルを作製し、これを用いて再剥離用粘着剤のゲル分を測定した。
【００２９】
比較例１
単量体組成を、アクリル酸エチル２０部、アクリル酸ｎ−ブチル８０部、アクリル酸５部に変更した以外は、実施例１と同様にして、ポリマ―溶液を得た。このポリマ―溶液に、ポリマ―固形分１００部に対して、テトラグリシジル−１，３−ビスアミノメチルシクロヘキサン６部を加えて、混合したのち、実施例１と同様にして、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。また、実施例１と同様にして、ゲル分測定用のサンプルを作製し、これを用いて再剥離用粘着剤のゲル分を測定した。
【００３０】
比較例２
比較例１で得たポリマ―溶液に、ポリマ―固形分１００部に対して、トリレンジイソシアネ―ト７部を加えて、混合したのち、実施例１と同様にして、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。また、実施例１と同様にして、ゲル分測定用のサンプルを作製し、これを用いて再剥離用粘着剤のゲル分を測定した。
【００３１】
比較例３
実施例１で得たポリマ―溶液に、ポリマ―固形分１００部に対して、トリレンジイソシアネ―ト２部を加えて、混合したのち、実施例１と同様にして、厚さが５μｍの再剥離用粘着剤の層を有する粘着テ―プを作製した。また、実施例１と同様にして、ゲル分測定用のサンプルを作製し、これを用いて再剥離用粘着剤のゲル分を測定した。
【００３２】
以上の実施例１〜３および比較例１〜３で作製した再剥離用粘着剤の層を有する各粘着テ―プについて、以下の要領で、初期および加熱促進による経日保存後の剥離力を調べ、また経日保存後の剥離作業性、端末剥がれを調べた。結果を、各実施例および比較例で測定した再剥離用粘着剤のゲル分とともに、後記の表１（実施例１〜３）および表２（比較例１〜３）に示す。
【００３３】
＜剥離力＞
各粘着テ―プを裁断して、２０ｍｍ×１００ｍｍの大きさの試験片を作製し、この試験片を、被着体としてのステンレス板およびアクリル樹脂板に、２Ｋｇのロ―ラを１往復させる方法で圧着し、２０分放置後、２３℃，６５％ＲＨの雰囲気下、剥離速度０．３ｍ／分および３０ｍ／分の条件で、１８０度剥離力を測定して、表中、「Ａ」の欄に示す初期の剥離力とした。
【００３４】
また、上記同様に圧着した試験片を、５０℃の雰囲気中で２日間および７日間保存したのち、上記同様にして１８０度剥離力を測定した。これらの測定値を、表中、「Ｂ」（２日間保存後）および「Ｃ」（７日間保存後）の欄に示す加熱促進による経日保存後の剥離力とした。
【００３５】
＜剥離作業性＞
剥離力の測定の場合と同様に被着体に圧着した試験片について、５０℃の雰囲気中で７日間保存したのち、実用的な剥離速度である３０ｍ／分の条件で、実際に手で剥離し、そのときの剥離性の良否を、以下の基準にて評価した。
○…軽い力で容易に剥離可能である
△…剥離可能であるが、強い力を必要とするため剥離作業性が非常に悪い
×…剥離途中で基材の破れが発生し剥離不可能である
【００３６】
＜端末剥がれ＞
剥離力の測定の場合と同様に被着体に圧着した試験片について、５０℃の雰囲気中で７日間保存したのち、端部からの浮きの発生を目視により観察した。その結果を、以下の基準にて評価した。
○…浮きの発生がみられない
△…端部からの浮きの発生が一部みられる
×…筋状の浮きまたは端部からの浮きの発生が大きくみられる
【００３７】
【表１】
【表２】
上記の表１および表２の結果より、本発明の実施例１〜３の再剥離用粘着剤の層を有する各粘着テ―プは、比較例１〜３の粘着テ―プに比べて、３０ｍ／分の実用的な剥離速度での剥離が軽く、また経時での粘着力の上昇性が小さくて、剥離作業性にすぐれており、しかも貼り付け保存中の端末剥がれもみられず、再剥離用として非常に適した性能を備えていることがわかる。[0001]
[Industrial applications]
The present invention relates to a removable pressure-sensitive adhesive containing an acrylic copolymer as a main component and pressure-sensitive adhesive sheets in the form of a sheet or tape.
[0002]
[Prior art]
Removable adhesive sheets are used for purposes such as surface protection and masking. Heretofore, as this kind of sheets, there are known those obtained by applying an acrylic adhesive or a rubber adhesive on one surface of various substrates.
[0003]
[Problems to be solved by the invention]
However, the conventionally known pressure-sensitive adhesive sheets for re-peeling are heavy at a practical peeling speed of about 5 to 50 m / min at room temperature, and have a large increase in the adhesive force with time, and the workability of the peeling is large. There was an inferior problem. In order to solve this problem, it is known that the crosslink density is increased and the cohesive force of the adhesive is increased to make the adhesive weak, but this adhesive does not peel off from the end of the adhesive sheet during sticking and storage. Prone.
[0004]
In view of such circumstances, the present invention is light in peeling at a practical peeling speed, has a small increase in adhesive force over time, is excellent in peeling workability, and furthermore, during paste storage. It is an object of the present invention to provide a re-peelable pressure-sensitive adhesive in which terminal peeling is not observed and pressure-sensitive adhesive sheets in the form of a sheet or tape.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in order to achieve the above object, and as a result, as a main component, an acrylic copolymer having a specific monomer configuration, forming a crosslinked structure until a specific gel component is obtained. By doing so, it was found that an exfoliating workability was excellent, and that a re-peeling adhesive and its adhesive sheets without peeling off of the terminal during sticking and preservation were obtained, which led to the completion of the present invention. .
[0006]
That is, the present invention provides the following components a to c or components d and d:
a) Acrylic compound represented by the general formula (1): CH 2 ＣC (R 1 ) COOR 2 (wherein R 1 is hydrogen or a methyl group, and R 2 is an alkyl group having 2 to 14 carbon atoms) 50-94% by weight of monomer
Or an N, N-disubstituted (meth) acrylamide represented by the following formula:
c) 10 to 1% by weight of a carboxyl group-containing monomer or an anhydride thereof
d) 20 to 0% by weight of a monomer copolymerizable with the above components a to c
A re-peelable pressure-sensitive adhesive characterized in that the re-peelable pressure-sensitive adhesive is mainly composed of a copolymer of a monomer mixture consisting of Alternatively, the present invention relates to pressure-sensitive adhesive sheets having a shape such as a sheet or a tape, which are provided on both sides.
[0007]
[Configuration and operation of the invention]
The acrylic monomer as the component a in the present invention is, for example, a compound in which R 2 in the general formula (1) is butyl, isobutyl, isoamyl, hexyl, heptyl, 2-ethylhexyl, isooctyl, isononyl. And acrylic acid or methacrylic acid esters comprising an alkyl group such as an isodecyl group. If the carbon number of R 2 is less than 2, the wettability of the pressure-sensitive adhesive is lowered and the initial adhesiveness is deteriorated.
[0008]
One or more acrylic monomers as the component a are used in the range of 50 to 94% by weight, preferably 60 to 90% by weight of the total amount of the monomers. If the content is less than 50% by weight, the performance as an acrylic pressure-sensitive adhesive cannot be exhibited. If the content exceeds 94% by weight, the absolute amounts of the components b and c described below will be insufficient, and the desired adhesive strength and peeling workability will be required. No excellent peeling adhesive can be obtained.
[0009]
The N, N-disubstituted (meth) acrylamide as the component b in the present invention includes a non-cyclic (meth) acrylamide in which both R 4 and R 5 in the general formula (2) are alkyl groups, 4 , a cyclic (meth) acrylamide in which R 5 is bonded to form a heterocyclic ring with this and an N atom is included, and either or both of them are used depending on the purpose of use of the removable pressure-sensitive adhesive. .
[0010]
Examples of the acyclic (meth) acrylamide include N, N-diethyl (meth) acrylamide and N, N-dimethyl (meth) acrylamide. Examples of the cyclic (meth) acrylamide include N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloyl- 4-piperidone and the like.
[0011]
The N, N-disubstituted (meth) acrylamide as the component b is contained in an amount of 35 to 5% by weight, preferably 30 to 8% by weight, more preferably 25 to 10% by weight based on the total amount of the monomer. One or more kinds are used. If the amount exceeds 35% by weight, the wettability of the pressure-sensitive adhesive decreases, and the adhesive strength decreases. If the amount is less than 5% by weight, it is difficult to obtain a balance between the adhesive force due to the cross-linked structure and the peeling workability.
[0012]
Examples of the carboxyl group-containing monomer or an anhydride thereof as the component c in the present invention include acrylic acid, itaconic acid, maleic acid, crotonic acid, and the like, and phthalic anhydride. One or two or more thereof are appropriately selected and used. The amount used is in the range of 10 to 1% by weight, preferably 9 to 1.5% by weight, more preferably 8 to 2% by weight of the total amount of the monomers. If it exceeds 10% by weight, the adhesiveness is poor, and if it is less than 1% by weight, the cohesive strength is insufficient, and in any case, it is difficult to exhibit good adhesive properties.
[0013]
The monomer as the component d in the present invention may be any copolymerizable with the monomers of the above components a to c, and examples thereof include vinyl acetate, styrene, glycidyl (meth) acrylate and (meth) acrylate. Examples thereof include 2-hydroxypropyl acrylate, methyl (meth) acrylate, and N-vinyl-2-pyrrolidone. If necessary, one or more of the monomers of the d component may be used in an amount of 20% by weight or less, preferably 15% by weight or less of the total amount of the monomers. If it exceeds 20% by weight, it is difficult to exhibit the adhesive properties as an acrylic adhesive.
[0014]
The acrylic copolymer of the present invention is obtained by subjecting the above-described three components a to c or a monomer mixture composed of this and the d component to a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, and a suspension polymerization method in a conventional manner. It can be obtained by copolymerizing by such a method.
[0015]
The removable pressure-sensitive adhesive of the present invention has the above-mentioned acrylic copolymer as a main component and has a crosslinked structure until the gel content becomes 70% or more, preferably about 75 to 95%. When the gel content is less than 70%, the peeling at a practical peeling rate is heavy, and the adhesive force over time is large, so that the peeling workability is inferior and is fatal as an adhesive for re-peeling. There is a problem that glue remains on the adherend after peeling.
[0016]
The above-mentioned gel content means that about 500 mg of an adhesive was prepared as a sample, and this was extracted in acetone at 50 ° C. for 4 hours using a Soxhlet extractor or in toluene at room temperature for 2 days. After immersion, after drying at 130 ° C. for 1 hour , a value calculated as [G t / G 0 ] × 100 (%) from the initial weight (G 0 ) of the adhesive and the weight of the insoluble matter (G t ). It is.
[0017]
The cross-linking structuring of the pressure-sensitive adhesive may be performed by a method such as electron beam irradiation or thermal cross-linking.However, preferably, a cross-linking agent is used to react with the functional group such as a carboxyl group contained in the copolymer. It is preferable to carry out a so-called crosslinking reaction between functional groups. Crosslinking agents particularly suitable for this purpose include polyfunctional epoxy compounds and polyfunctional isocyanate compounds.
[0018]
The polyfunctional epoxy compound has two or more epoxy groups in the molecule, and is a sorbitol tetraglycidyl ether, a trimethylolpropane glycidyl ether, a tetraglycidyl-1,3-bisaminomethylcyclohexane. , Tetraglycidyl metaxylene diamine, triglycidyl-p-aminophenol and the like. The polyfunctional isocyanate compound has two or more isocyanate groups in the molecule. Examples thereof include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate. is there.
[0019]
One or more of these cross-linking agents are used at a usage ratio in which the gel content of the pressure-sensitive adhesive falls within the above range, depending on the composition, molecular weight, and the like of the acrylic copolymer. At that time, in order to promote the reaction, a crosslinking catalyst such as dibutyltin laurate which is usually used for the pressure-sensitive adhesive may be added.
[0020]
The removable pressure-sensitive adhesive of the present invention may contain a tackifier such as a phenol-based resin, a coumarone-indene-based resin, or a rosin-based resin, if necessary, in addition to the above components. In addition, other known additives such as a coloring agent, a filler and an antioxidant can be appropriately contained. The gel component of the pressure-sensitive adhesive may be set within the above range as the whole pressure-sensitive adhesive containing these additives.
[0021]
The pressure-sensitive adhesive sheets of the present invention are provided with a layer made of such a pressure-sensitive adhesive for re-peeling on one or both sides of a base material to a desired thickness, such as a sheet or tape. It is a form. To provide on the substrate, apply the solution or dispersion of the re-peelable adhesive directly on the substrate and dry it, or apply it on a release film and dry it and paste it on the substrate and transfer it. Just fine. The cross-linking reaction described above can be performed during the coating and drying steps or during aging thereafter.
[0022]
Examples of the base material include plastic films such as olefin resin, polyester resin, vinyl chloride resin, vinyl acetate resin, and polyimide resin, nonwoven fabrics such as crepe paper and Japanese paper, and various types of foam films. Used. These substrates can be used alone or in combination of two or more, and may be ones or both surfaces which have been subjected to a surface treatment such as a corona treatment.
[0023]
【The invention's effect】
According to the present invention, for various re-peeling applications such as surface protection and masking, the peeling at a practical peeling rate is light, and the increase in adhesive force over time is small, and the peeling workability is excellent. In addition, it is possible to provide a re-peelable pressure-sensitive adhesive and the pressure-sensitive adhesive sheet without peeling off the terminal during the storage by pasting.
[0024]
【Example】
Next, an embodiment of the present invention will be described in more detail. In the following, “parts” means “parts by weight”.
[0025]
Example 1
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 80 parts of 2-ethylhexyl acrylate, 20 parts of N-acryloylmorpholine, 3 parts of acrylic acid, and 2,2′-azobis as a polymerization initiator 0.15 parts of isobutyronitrile and 100 parts of ethyl acetate were added, and polymerized at 60 ° C. for 12 hours to obtain a polymer solution.
[0026]
To this polymer solution, 4 parts of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to 100 parts of the polymer solid content, mixed, and then applied on a polyethylene film having a thickness of 60 μm. By drying, an adhesive tape having a 5 μm-thick re-peelable adhesive layer was prepared. Separately from this, the sample was applied on a release film and dried to prepare a sample for gel content measurement, and the gel content of the adhesive for re-peeling was measured using the sample by the method described in detail in the text.
[0027]
Example 2
To the polymer solution obtained in Example 1, 5 parts of tolylene diisocyanate was added to 100 parts of the polymer solid content and mixed. An adhesive tape having a removable adhesive layer was prepared. In the same manner as in Example 1, a sample for gel content measurement was prepared, and the gel content of the removable adhesive was measured using this sample.
[0028]
Example 3
A polymer solution was obtained in the same manner as in Example 1, except that the monomer composition was changed to 80 parts of n-butyl acrylate, 20 parts of N-isopropylacrylamide, and 3 parts of acrylic acid. To this polymer solution, 1 part of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to 100 parts of the polymer solid content and mixed. An adhesive tape having a removable adhesive layer was prepared. In the same manner as in Example 1, a sample for gel content measurement was prepared, and the gel content of the removable adhesive was measured using this sample.
[0029]
Comparative Example 1
A polymer solution was obtained in the same manner as in Example 1, except that the monomer composition was changed to 20 parts of ethyl acrylate, 80 parts of n-butyl acrylate, and 5 parts of acrylic acid. To this polymer solution, 6 parts of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to 100 parts of the polymer solid content and mixed. An adhesive tape having a removable adhesive layer was prepared. In the same manner as in Example 1, a sample for gel content measurement was prepared, and the gel content of the removable adhesive was measured using this sample.
[0030]
Comparative Example 2
To the polymer solution obtained in Comparative Example 1, 7 parts of tolylene diisocyanate was added to 100 parts of the polymer solid content and mixed. An adhesive tape having a removable adhesive layer was prepared. In the same manner as in Example 1, a sample for gel content measurement was prepared, and the gel content of the removable adhesive was measured using this sample.
[0031]
Comparative Example 3
To the polymer solution obtained in Example 1, 2 parts of tolylene diisocyanate was added to 100 parts of the polymer solids and mixed, and then, as in Example 1, a mixture having a thickness of 5 μm was obtained. An adhesive tape having a removable adhesive layer was prepared. In the same manner as in Example 1, a sample for gel content measurement was prepared, and the gel content of the removable adhesive was measured using this sample.
[0032]
For each of the pressure-sensitive adhesive tapes having the peelable pressure-sensitive adhesive layers prepared in Examples 1 to 3 and Comparative Examples 1 to 3, the peel force after initial storage and after storage over time due to accelerated heating was determined in the following manner. Inspection, peeling workability after storage over time, and peeling of terminals were examined. The results are shown in Table 1 (Examples 1 to 3) and Table 2 (Comparative Examples 1 to 3) described below together with the gel content of the removable adhesive measured in each of Examples and Comparative Examples.
[0033]
<Peeling force>
Each adhesive tape was cut to prepare a test piece having a size of 20 mm × 100 mm, and the test piece was reciprocated by a 2 kg roller once on a stainless plate and an acrylic resin plate as adherends. After leaving for 20 minutes, the 180 ° peeling force was measured under the conditions of 23 ° C. and 65% RH at a peeling speed of 0.3 m / min and 30 m / min. The initial peel force shown in the column.
[0034]
Further, the test pieces pressed in the same manner as above were stored in an atmosphere at 50 ° C. for 2 days and 7 days, and then the 180 ° peeling force was measured in the same manner as above. These measured values were taken as the peeling force after storage over time due to accelerated heating shown in the columns "B" (after storage for 2 days) and "C" (after storage for 7 days) in the table.
[0035]
<Peeling workability>
In the same manner as in the measurement of the peeling force, the test piece pressed on the adherend was stored in an atmosphere at 50 ° C. for 7 days, and then was peeled by hand at a practical peeling speed of 30 m / min. Then, the quality of the peelability at that time was evaluated based on the following criteria.
…: Easy peeling with light force. △: Peelable, but peeling workability is very poor because strong force is required. 基材: Breakage of base material occurs during peeling and peeling is impossible. [0036]
<Terminal peeling>
As in the case of the measurement of the peeling force, the test piece pressed to the adherend was stored in an atmosphere at 50 ° C. for 7 days, and then the occurrence of floating from the end was visually observed. The results were evaluated according to the following criteria.
…: No floating is observed. △: floating is partially observed from the end. ×: streaky floating or floating is largely observed from the end.
[Table 1]
[Table 2]
From the results in Tables 1 and 2 above, the pressure-sensitive adhesive tapes having the removable pressure-sensitive adhesive layers of Examples 1 to 3 of the present invention were compared with the pressure-sensitive adhesive tapes of Comparative Examples 1 to 3, Peeling at a practical peeling speed of 30 m / min is light, the rise in adhesive strength with time is small, and the peeling workability is excellent. It can be seen that it has very suitable performance for use.
Claims (3)
ａ）一般式（１）：ＣＨ２ ＝Ｃ（Ｒ１ ）ＣＯＯＲ２ （式中、Ｒ１ は水素またはメチル基、Ｒ２ は炭素数２〜１４のアルキル基である）で表されるアクリル系単量体５０〜９４重量％
または両者が結合しこれとＮ原子とで複素環を構成する有機基である）で表されるＮ，Ｎ−ジ置換（メタ）アクリルアミド３５〜５重量％
ｃ）カルボキシル基含有単量体またはその無水物１０〜１重量％
ｄ）上記のａ〜ｃ成分と共重合可能な単量体２０〜０重量％
からなる単量体混合物の共重合体を主成分とし、ゲル分が７０％以上であることを特徴とする再剥離用粘着剤。The following components a to c or components d and d:
a) Acrylic compound represented by the general formula (1): CH 2 ＣC (R 1 ) COOR 2 (wherein R 1 is hydrogen or a methyl group, and R 2 is an alkyl group having 2 to 14 carbon atoms) 50-94% by weight of monomer
Or an N, N-disubstituted (meth) acrylamide represented by the following formula:
c) 10 to 1% by weight of a carboxyl group-containing monomer or an anhydride thereof
d) 20 to 0% by weight of a monomer copolymerizable with the above components a to c
An adhesive for re-peeling, comprising a copolymer of a monomer mixture comprising as a main component and having a gel content of 70% or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31267494A JP3549168B2 (en) | 1994-11-21 | 1994-11-21 | Removable adhesive and its adhesive sheets |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31267494A JP3549168B2 (en) | 1994-11-21 | 1994-11-21 | Removable adhesive and its adhesive sheets |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08143843A JPH08143843A (en) | 1996-06-04 |
| JP3549168B2 true JP3549168B2 (en) | 2004-08-04 |
Family
ID=18032061
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31267494A Expired - Lifetime JP3549168B2 (en) | 1994-11-21 | 1994-11-21 | Removable adhesive and its adhesive sheets |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3549168B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1106436C (en) * | 1995-02-16 | 2003-04-23 | 美国3M公司 | Articles incorporating pressure-sensitive adhesives having improved adhesion ot plasticized polyvinyl chloride |
| JP3549173B2 (en) * | 1996-05-23 | 2004-08-04 | 日東電工株式会社 | Adhesives for wafer processing and their adhesive sheets |
| JP4495813B2 (en) * | 1999-12-24 | 2010-07-07 | 日東電工株式会社 | Low-fouling adhesive sheets and resist removal methods |
| US6441114B1 (en) | 1999-06-11 | 2002-08-27 | 3M Innovative Properties Company | Adhesives for use on fluorine-containing or polycarbonate surfaces |
| JP4503935B2 (en) * | 2003-03-17 | 2010-07-14 | 日本合成化学工業株式会社 | Re-peelable water-based adhesive composition |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63118383A (en) * | 1986-11-07 | 1988-05-23 | Nitto Electric Ind Co Ltd | Pressure-sensitive adhesive |
| JP2810540B2 (en) * | 1990-11-30 | 1998-10-15 | 日東電工株式会社 | Pressure-sensitive adhesive composition for vibration damping material |
| JP3154764B2 (en) * | 1991-09-25 | 2001-04-09 | 日東電工株式会社 | Pressure-sensitive adhesive for masking and its adhesive film |
| JP3481307B2 (en) * | 1994-07-05 | 2003-12-22 | 古河電気工業株式会社 | Adhesive tape for semiconductor wafer surface protection |
| JPH08109356A (en) * | 1994-10-07 | 1996-04-30 | Sekisui Chem Co Ltd | Acrylic tacky tape |
| JP3549173B2 (en) * | 1996-05-23 | 2004-08-04 | 日東電工株式会社 | Adhesives for wafer processing and their adhesive sheets |
-
1994
- 1994-11-21 JP JP31267494A patent/JP3549168B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| JPH08143843A (en) | 1996-06-04 |
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