JP4044627B2 - Adhesive sheets - Google Patents

Description

（Ｒは炭素数２〜２０の直鎖状または分枝状の炭化水素基である）
で表わされる繰り返し単位を有するジオ―ルで、数平均分子量としては、４００以上、好ましくは９００以上（通常１万まで）であるのがよい。分子量が低すぎると、粘着特性のバランスがとりにくくなる。
【００１０】
このようなポリカ―ボネ―トジオ―ルには、ポリヘキサメチレンカ―ボネ―トジオ―ル、ポリ（３−メチルペンテンカ―ボネ―ト）ジオ―ル、ポリプロピレンカ―ボネ―トジオ―ル、それらの混合物、またはそれらの共重合物などがある。市販品としては、ダイセル化学工業（株）製の「ＰＬＡＣＣＥＬ ＣＤ２０５ＰＬ」、「同ＣＤ２０８ＰＬ」、「同ＣＤ２１０ＰＬ」、「同ＣＤ２２０ＰＬ」、「同ＣＤ２０５」、「同ＣＤ２０８」、「同ＣＤ２１０」、「同ＣＤ２２０」、「同ＣＤ２０５ＨＬ」、「同ＣＤ２０８ＨＬ」、「同ＣＤ２１０ＨＬ」、「同ＣＤ２２０ＨＬ」などを挙げることができる。
【００１１】
ジオ―ル成分としては、必要により、エチレングリコ―ル、プロピレングリコ―ル、ブタンジオ―ル、ヘキサンジオ―ル、オクタンジオ―ル、デカンジオ―ル、オクタデカンジオ―ルなどの直鎖状のジオ―ルや、各種分枝状のジオ―ルなどの成分を、適宜混合使用してもよい。また、ポリマ―を高分子量化するために、３官能以上のポリオ―ル成分を少量添加してもよい。
【００１２】
ジカルボン酸成分は、炭素数が２〜２０の脂肪族または脂環族の炭化水素基を分子骨格としたもので、上記の炭化水素基は直鎖状のものでも分枝状のものでもよい。具体的には、コハク酸、メチルコハク酸、アジピン酸、ピメリツク酸、アゼライン酸、セバシン酸、１，１２−ドデカン二酸、１，１４−テトラデカン二酸、テトラヒドロフタル酸、エンドメチレンテトラヒドロフタル酸、これらの酸無水物や低級アルキルエステルなどが挙げられる。
【００１３】
ポリエステルは、上記のジオ―ル成分と上記のジカルボン酸成分とを、常法にしたがい、無触媒または適宜の触媒などを用いて、エステル化反応させることにより、得ることができる。エステル化反応に際して、ジオ―ル成分とジカルボン酸成分とは、当モル反応とするのが望ましいが、エステル化反応を促進するために、どららかを過剰に用いて反応させてもよい。
【００１４】
本発明においては、このようなポリエステルからなるポリカ―ボネ―ト構造を持つポリマ―を特定のレベルに架橋して、実質的にタツクを示さない（室温で非粘着ないし微粘着である）が、良好な自着性を有する、また再剥離性にもすぐれた粘着剤組成物とする。架橋の度合いは、溶剤不溶分が６６〜９５重量％、とくに好ましくは６６〜９０重量％となる程度であるのがよい。溶剤不溶分が６６重量％未満となると、十分な再剥離性が得られず、また９５重量％を超えると、自着力が低くなり、いずれも好ましくない。
【００１５】
架橋方法は任意であり、たとえば、ポリマ―に含まれる水酸基および／またはカルボキシル基と反応しうる官能基を有する化合物を添加して反応させる、いわゆる架橋剤を用いる方法が挙げられる。このような架橋剤としては、ポリイソシアネ―ト化合物、エポキシ化合物、アジリジン化合物、金属キレ―ト化合物、金属アルコキシド化合物などがあり、これらの中でも、ポリイソシアネ―ト化合物がとくに好ましく用いられる。
【００１６】
このポリイソシアネ―ト化合物としては、エチレンジイソシアネ―ト、ブチレンジイソシアネ―ト、ヘキサメチレンジイソシアネ―トなどの低級脂肪族ポリイソシアネ―ト類、シクロペンチレンジイソシアネ―ト、シクロヘキシレンジイソシアネ―ト、イソホロンジイソシアネ―トなどの脂環族ポリイソシアネ―ト類、２，４−トリレンジイソシアネ―ト、ジフエニルメタンジイソシアネ―ト、キシリレンジイソシアネ―トなどの芳香族ポリイソシアネ―ト類などが挙げられる。また、トリメチロ―ルプロパンのトリレンジイソシアネ―ト付加物〔日本ポリウレタン（株）製の「コロネ―トＬ」〕、トリメチロ―ルプロパンのヘキサメチレンジイソシアネ―ト付加物〔日本ポリウレタン（株）製の「コロネ―トＨＬ」〕などを使用することもできる。
【００１７】
これらの架橋剤は、その１種を単独でまたは２種以上の混合系で使用できる。使用量としては、架橋するべきポリマ―とのバランスにより適宜選択される。一般には、ポリマ―１００重量部に対して、上記の架橋剤が２〜１０重量部程度となる割合とするのがよく、このような割合で用いることにより、溶剤不溶分が前記範囲内の粘着剤組成物を得ることができる。
【００１８】
他の架橋方法として、実質的な架橋剤として多官能モノマ―を添加し、電子線などで架橋させる方法をとつてもよい。この多官能モノマ―としては、ポリエチレングリコ―ルジ（メタ）アクリレ―ト、ペンタエリスリト―ルトリ（メタ）アクリレ―ト、テトラメチロ―ルメタンテトラ（メタ）アクリレ―ト、トリメチロ―ルプロパントリ（メタ）アクリレ―トなどが挙げられる。
【００１９】
これら多官能モノマ―の使用量としては、架橋するべきポリマ―とのバランスにより、さらには粘着剤組成物としての使用目的によつて適宜選択される。一般には、ポリマ―１００重量部に対し、多官能モノマ―が３重量部以上（通常１０重量部程度まで）の割合とするのがよく、このような割合で用いることにより、溶剤不溶分が前記範囲内の粘着剤組成物を得ることができる。
【００２０】
本発明の粘着剤組成物は、上記のポリマ―を上記のように架橋処理してなり、自着力が１００ｇ／２０mm幅以上、好ましくは１５０ｇ／２０mm幅以上、より好ましくは２００ｇ／２０mm幅以上（通常１，５００ｇ／２０mm幅まで）で、再剥離力が２，０００ｇ／２０mm幅以下、好ましくは１，８００ｇ／２０mm幅以下、より好ましくは１，５００ｇ／２０mm幅以下（通常１００ｇ／２０mm幅まで）となる、自着力を有しかつ再剥離可能な性質を有するものである。
【００２１】
自着力が１００ｇ／２０mm幅未満となると、物品の結束または接着の信頼性に劣り、また、再剥離力が２，０００ｇ／２０mm幅を超えると、再剥離が困難となる。なお、本明細書にいう「自着力」とは、後記の実施例に示すように、粘着面同士を貼り付けたときの初期の剥離力を示し、一方「再剥離力」とは、１日放置後の上記剥離力（自着力）を示すものである。
すなわち、「自着力」とは、幅２０ mm 、長さ１５０ mm の粘着テ―プを、その中央部で粘着面同士を２ Kg ロ―ラ―で貼り合わせ、雰囲気温度２３℃、貼り付け２０分後、剥離速度３００ mm ／分の条件で測定される剥離力を意味する。
また、「再剥離力」とは、雰囲気温度２３℃にて、幅２０ mm 、長さ１５０ mm の粘着テ―プを、その中央部で粘着面同士を２ Kg ロ―ラ―で貼り合わせ、同温度で２４時間保存後、剥離速度３００ mm ／分の条件で測定される剥離力を意味する。
【００２２】
本発明の粘着剤組成物には、必要により、従来公知の各種の粘着付与剤を添加することができる。また、無機または有機の充填剤、金属粉、顔料などの粉体、粒子状物、箔状物、老化防止剤、可塑剤などの従来公知の各種の添加剤を、任意に含ませることができる。
【００２３】
本発明の粘着シ―ト類は、基材の片面または両面に上記の粘着剤組成物を塗着ないし転写して、シ―ト状やテ―プ状などの形態としたものである。ここで、基材としては、ポリエステルフイルムなどのプラスチツクフイルムのほか、紙、不織布、織布などの多孔質材料、金属箔など従来公知のものが任意に用いられる。これら基材の種類や厚さおよび粘着剤組成物の厚さなどは、使用目的に応じて、適宜設定することができる。また、この基材は、粘着シ―ト類の使用に際して剥離される剥離性基材であつてもよく、この場合、基材自体が剥離性を有するものでも、基材表面に剥離処理を施したものであつてもよい。
【００２４】
【実施例】
つぎに、本発明を実施例によりさらに詳細に説明するが、本発明の範囲は以下の実施例によりなんら制限を受けるものではない。また、以下において、部とあるのは重量部を意味するものとする。
【００２５】
実施例１
四つ口セパラブルフラスコに攪拌機、温度計および水分離管を付し、ポリカ―ボネ―トジオ―ル〔ダイセル化学工業（株）製の「ＰＬＡＣＣＥＬ ＣＤ２１０ＰＬ」、水酸基価：１１５．０ＫＯＨmg／ｇ〕２００．０ｇ（水酸基：０．４１当量）、無水コハク酸２０．５１ｇ（酸基：０．４１当量）、触媒としてのジブチルチンオキサイド（以下、ＤＢＴＯという）１０２mgを仕込み、反応水排出溶剤としての少量のトルエンの存在下、攪拌を開始しながら１８０℃まで昇温し、この温度で保持した。しばらくすると水の流出分離が認められ、反応が進行し始めた。約３０時間反応を続けて、重量平均分子量６５，０００となるポリエステルを得た。
【００２６】
このポリエステルをトルエンで固形分濃度４０重量％に希釈した。このポリエステル１００部（固形分）に対し、架橋剤としてトリメチロ―ルプロパンのヘキサメチレンジイソシアネ―ト付加物〔日本ポリウレタン（株）製の「コロネ―トＨＬ」〕３部（固形分）を添加し、粘着剤溶液とした。この粘着剤溶液を、アプリケ―タ―により、厚さが３８μｍのポリエチレンテレフタレ―トフイルム（以下、ＰＥＴフイルムという）上に塗布し、１３０℃で５分間乾燥して、厚さが３０μｍの粘着剤層を形成した。さらに、アフタ―キユア―として、５０℃の雰囲気中で２日間のエ―ジングを行い、粘着テ―プを作製した。
【００２７】
実施例２
四つ口セパラブルフラスコに攪拌機、温度計および水分離管を付し、ポリカ―ボネ―トジオ―ル〔ダイセル化学（株）製の「ＰＬＡＣＣＥＬ ＣＤ２１０ＰＬ」、水酸基価：１１５．０ＫＯＨmg／ｇ〕２５０．０ｇ（水酸基：０．５１２当量）、アジピン酸３７．４４ｇ（酸基：０．５１２当量）、触媒としてのＤＢＴＯを１２７mg仕込み、反応水排出溶剤としての少量のトルエンの存在下、攪拌を開始しながら１８０℃まで昇温し、この温度で保持した。しばらくすると水の流出分離が認められ、反応が進行し始めた。約３０時間反応を続けて、重量平均分子量７２，０００となるポリエステルを得た。
【００２８】
このポリエステルをトルエンで固形分濃度４０重量％に希釈した。このポリエステル１００部（固形分）に対し、架橋剤としてトリメチロ―ルプロパンのヘキサメチレンジイソシアネ―ト付加物〔日本ポリウレタン（株）製の「コロネ―トＨＬ」〕３部（固形分）を添加し、粘着剤溶液とした。これを、アプリケ―タ―により、厚さが３８μｍのＰＥＴフイルム上に塗布し、１３０℃で５分間乾燥して、厚さが３０μｍの粘着剤層を形成した。さらに、アフタ―キユア―として、５０℃の雰囲気中で２日間のエ―ジングを行い、粘着テ―プを作製した。
【００２９】
実施例３
四つ口セパラブルフラスコに攪拌機、温度計および水分離管を付し、ポリカ―ボネ―トジオ―ル〔ダイセル化学工業（株）製の「ＰＬＡＣＣＥＬ ＣＤ２２０ＰＬ」、水酸基価：５６．１ＫＯＨmg／ｇ〕２５０．０ｇ（水酸基：０．２５当量）、セバシン酸２５．２８ｇ（酸基：０．２５当量）、触媒としてのＤＢＴＯを６２mg仕込み、反応水排出溶剤としての少量のキシレンの存在下、攪拌を開始しながら１８０℃まで昇温し、この温度で保持した。しばらくすると水の流出分離が認められ、反応が進行し始めた。約２０時間反応を続けて、重量平均分子量５５，０００となるポリエステルを得た。
【００３０】
このポリエステルをトルエンで固形分濃度５０重量％に希釈した。このポリエステル１００部（固形分）に対し、架橋剤としてヘキサメチレンジイソシアネ―ト３量体（イソシアヌレ―ト）〔日本ポリウレタン（株）製の「コロネ―トＨＸ」〕３部（固形分）を添加し、粘着剤溶液とした。これを、アプリケ―タ―により、厚さが３８μｍのＰＥＴフイルム上に塗布し、１３０℃で５分間乾燥して、厚さが３０μｍの粘着剤層を形成した。さらに、アフタ―キユア―として、５０℃の雰囲気中で２日間のエ―ジングを行い、粘着テ―プを作製した。
【００３１】
実施例４
実施例３で得たポリエステル１００部（固形分）に対し、実質的な架橋剤としてトリメチロ―ルプロパントリアクリレ―ト５部を添加し、粘着剤溶液とした。この粘着剤溶液を、アプリケ―タ―により、厚さが３８μｍのＰＥＴフイルム上に塗布し、１００℃で５分間乾燥して、厚さが３０μｍの粘着剤層を形成した。さらに、電子線を５Ｍａｒｄ照射し、粘着テ―プを作製した。
【００３２】
比較例１
実施例３で得たポリエステル１００部（固形分）に、架橋剤としてジフエニルメタンジイソシアネ―ト〔日本ポリウレタン（株）製の「ミリオネ―トＭＴ」〕２部（固形分）を添加し、粘着剤溶液とした。この粘着剤溶液を、アプリケ―タ―により、厚さが３８μｍのＰＥＴフイルム上に塗布し、１３０℃で５分間乾燥して、厚さが３０μｍの粘着剤層を形成した。さらに、アフタ―キユア―として、５０℃の雰囲気中で２日間のエ―ジングを行い、粘着テ―プを作製した。
【００３３】
比較例２
スチレン−イソプレン−スチレンブロツクポリマ―（シエル化学社製の「カリフレツクスＴＲ１１０７」）１００部、石油系樹脂５０部、フエノ―ル系老化防止剤１部を、トルエン１５０部に溶解し、粘着剤溶液とした。これを、アプリケ―タ―により、厚さが３８μｍのＰＥＴフイルム上に塗布し、１００℃で３分間乾燥して、厚さが３０μｍの粘着剤層を形成し、粘着テ―プを作製した。
【００３４】
上記の実施例１〜４および比較例１，２の各粘着テ―プについて、以下の要領により、溶剤不溶分、自着力および再剥離性の測定を行つた。また、タツクフリ―（タツクの有無）の評価も行つた。これらの試験結果は、後記の表１に示されるとおりであつた。
【００３５】
＜溶剤不溶分の測定＞
粘着剤を約０．１ｇサンプリングして精秤し、約５０ｍｌのトルエン中に室温で５日間浸漬したのち、溶剤不溶分を取り出し、１３０℃中で約１時間乾燥し、秤量した。溶剤不溶分〔Ｘ〕（重量％）を、下記の式で算出した。

【００３６】
＜自着力の測定＞
幅２０mm、長さ１５０mmの粘着テ―プを、その中央部で粘着面同士を２Kgロ―ラ―で貼り合わせ、雰囲気温度２３℃、貼り付け２０分後、剥離速度３００mm／分の条件で、剥離力を測定した。
【００３７】
＜再剥離性の測定＞
雰囲気温度２３℃にて、幅２０mm、長さ１５０mmの粘着テ―プを、その中央部で粘着面同士を２Kgロ―ラ―で貼り合わせ、同温度で２４時間保存後、剥離速度３００mm／分の条件で、剥離力を測定した。
【００３８】
＜タツクフリ―の評価＞
粘着テ―プの粘着面に指で触れ、タツクがないと感じられる場合を○、タツクがあると感じられる場合を×、と評価した。
【００３９】

【００４０】
上記の表１から明らかなように、本発明の粘着剤組成物を用いた実施例１〜４の粘着テ―プは、いずれも、タツクフリ―でありながら、良好な自着力を有しているとともに、再剥離性にもすぐれている。これに対し、比較例１の粘着テ―プは、自着力は大きいが再剥離性に劣つており、また、比較例２の粘着テ―プは、タツクを有しているとともに、再剥離性にも劣つている。
【００４１】
【発明の効果】
以上のように、本発明においては、ポリカ―ボネ―ト構造を持つ特定のポリマ―を主成分として用い、これを特定のレベルに架橋することにより、実質的にタツクを示さないが、すぐれた自着力を有し、かつ再剥離性にもすぐれた粘着剤組成物とその粘着シ―ト類を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-sensitive adhesive composition that is non-adhesive or slightly adhesive (tack-free) at room temperature, has self-adhesive properties, and can be re-peeled. The present invention relates to an adhesive sheet having a tape-like form.
[0002]
[Prior art]
Conventionally, as a self-adhesive pressure-sensitive adhesive for bundling fresh vegetables, fresh flowers, and the like, natural rubber, synthetic rubber, etc. are blended with tackifiers, softeners, etc. Publications such as Sho 54-96539 and 56-26968).
[0003]
[Problems to be solved by the invention]
However, since these pressure-sensitive adhesives have tack (adhesiveness), there is a problem that they adhere to fingers, articles, etc. before and after binding. Further, since it is difficult to peel again after self-attachment, it is necessary to break the adhesive tape in order to release the binding, and there is a risk of damaging the articles bound at that time.
[0004]
In view of the above circumstances, the present invention is a pressure-sensitive adhesive composition that exhibits substantially no tack but has self-adhesive properties and can be re-peeled. It is an object to provide adhesive sheets in the form of the above.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have made a polymer having a specific polycarbonate structure as a main component and substantially crosslink it to a specific level, thereby substantially It has been found that a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet that do not exhibit tack (non-adhesive or slightly adhesive at room temperature), have excellent self-adhesive properties, and can be removed again are obtained. The present invention has been completed.
[0006]
That is, the present invention provides the following formula on one side or both sides of the substrate :
-(O-R-O-C) n-
‖
O
(R is a linear or branched hydrocarbon group having 2 to 20 carbon atoms)
As a polymer having a polycarbonate structure having a repeating unit represented by the formula (1), a diol component essentially comprising a polycarbonate diol having a repeating unit represented by the above formula, and a carbon number of 2 A pressure-sensitive adhesive composition composed mainly of a polyester having a weight average molecular weight of 10,000 or more, synthesized from a dicarboxylic acid component essentially comprising a dicarboxylic acid having a molecular skeleton of an aliphatic or alicyclic hydrocarbon group of -20 The product has a layer formed by crosslinking treatment, the solvent-insoluble content of the polymer in this layer is 66 to 95% by weight, the self-adhesion force is 100 g / 20 mm width or more, and the re-peeling force is 2,000 g / 20 mm width or less. The present invention relates to a pressure-sensitive adhesive sheet .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, as the polymer having a polycarbonate structure having a repeating unit represented by the above formula, a polyester synthesized from a polycarbonate diol or a derivative thereof and a dicarboxylic acid or a derivative thereof, Polyesters synthesized from polycarbonate dicarboxylic acids or their derivatives and diols or derivatives thereof, polyurethanes synthesized from polycarbonate diols or their derivatives and diisocyanates, etc. Of these, polyesters synthesized from polycarbonate diols or their derivatives and dicarboxylic acids or their derivatives are particularly preferred.
[0008]
This polyester is composed of a diol component essentially comprising a polycarbonate diol or its derivative, and a dicarboxylic acid having a molecular skeleton of an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms or a carboxylic acid thereof. A compound having a weight average molecular weight of 10,000 or more, preferably 30,000 or more, and more preferably 50,000 or more (usually up to 300,000) synthesized from a dicarboxylic acid component essentially containing a derivative. When the weight average molecular weight of this polyester is less than 10,000, the cohesive force becomes insufficient.
[0009]
The polycarbonate diol used here has the following formula:

(R is a linear or branched hydrocarbon group having 2 to 20 carbon atoms)
The number average molecular weight is preferably 400 or more, preferably 900 or more (usually up to 10,000). If the molecular weight is too low, it becomes difficult to balance the adhesive properties.
[0010]
Examples of such polycarbonate diols include polyhexamethylene carbonate diol, poly (3-methylpentene carbonate) diol, polypropylene carbonate diol, Or a copolymer thereof. Commercially available products include “PLACCEL CD205PL”, “CD208PL”, “CD210PL”, “CD220PL”, “CD205”, “CD208”, “CD210”, “CD210” manufactured by Daicel Chemical Industries, Ltd. CD220 "," CD205HL "," CD208HL "," CD210HL "," CD220HL ", and the like.
[0011]
As the diol component, linear diols such as ethylene glycol, propylene glycol, butane diol, hexane diol, octane diol, decane diol, octadecane diol, etc. In addition, components such as various branched diols may be appropriately mixed and used. In order to increase the molecular weight of the polymer, a small amount of a tri- or higher functional polyol component may be added.
[0012]
The dicarboxylic acid component has an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms as a molecular skeleton, and the hydrocarbon group may be linear or branched. Specifically, succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, these And acid anhydrides and lower alkyl esters.
[0013]
The polyester can be obtained by subjecting the above diol component and the above dicarboxylic acid component to an esterification reaction using a non-catalyst or an appropriate catalyst according to a conventional method. In the esterification reaction, the diol component and the dicarboxylic acid component are preferably equimolar reaction, but some may be used in an excessive amount to promote the esterification reaction.
[0014]
In the present invention, a polymer having a polycarbonate structure composed of such a polyester is crosslinked to a specific level and does not substantially exhibit a tack (non-adhesive or slightly adhesive at room temperature). The pressure-sensitive adhesive composition has good self-adhesiveness and excellent removability. The degree of crosslinking is such that the solvent-insoluble content is 66 to 95% by weight, particularly preferably 66 to 90% by weight. When the solvent-insoluble content is less than 66 % by weight, sufficient removability cannot be obtained.
[0015]
The crosslinking method is arbitrary, and examples thereof include a method using a so-called crosslinking agent in which a compound having a functional group capable of reacting with a hydroxyl group and / or a carboxyl group contained in the polymer is added and reacted. Examples of such cross-linking agents include polyisocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, metal alkoxide compounds, and among these, polyisocyanate compounds are particularly preferably used.
[0016]
The polyisocyanate compound includes lower aliphatic polyisocyanates such as ethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, cyclopentylene diisocyanate, cyclohexylene diester. Fragrances such as isocyanates, cycloaliphatic polyisocyanates such as isophorone diisocyanate, 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate Family polyisocyanates. Also, tolylene diisocyanate adduct of trimethylolpropane ("Colonate L" manufactured by Nippon Polyurethane Co., Ltd.), hexamethylene diisocyanate adduct of trimethylolpropane [manufactured by Nippon Polyurethane Co. "Colonate HL"] can also be used.
[0017]
These crosslinking agents can be used alone or in a mixed system of two or more. The amount used is appropriately selected according to the balance with the polymer to be crosslinked. In general, the amount of the above crosslinking agent is preferably about 2 to 10 parts by weight with respect to 100 parts by weight of the polymer. By using such a ratio, the insoluble content of the solvent is within the above range. An agent composition can be obtained.
[0018]
As another crosslinking method, a method of adding a polyfunctional monomer as a substantial crosslinking agent and crosslinking with an electron beam or the like may be used. These polyfunctional monomers include polyethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, tetramethylol methanetetra (meth) acrylate, trimethylolpropane tri (meth) acrylate. Etc.
[0019]
The amount of these polyfunctional monomers to be used is appropriately selected according to the balance with the polymer to be crosslinked and further according to the purpose of use as the pressure-sensitive adhesive composition. In general, the polyfunctional monomer should be in a proportion of 3 parts by weight or more (usually up to about 10 parts by weight) with respect to 100 parts by weight of the polymer. A pressure-sensitive adhesive composition within the range can be obtained.
[0020]
The pressure-sensitive adhesive composition of the present invention is obtained by crosslinking the above-mentioned polymer as described above, and has a self-adhesion strength of 100 g / 20 mm width or more, preferably 150 g / 20 mm width or more, more preferably 200 g / 20 mm width or more ( Usually, up to 1,500 g / 20 mm width) and re-peeling force of 2,000 g / 20 mm width or less, preferably 1,800 g / 20 mm width or less, more preferably 1,500 g / 20 mm width or less (usually up to 100 g / 20 mm width) ) And has a self-adhesive force and a re-peelable property.
[0021]
When the self-adhesion force is less than 100 g / 20 mm width, the reliability of bundling or bonding the articles is poor, and when the re-peeling force exceeds 2,000 g / 20 mm width, re-peeling becomes difficult. As used herein, “self-adhesion” refers to the initial peel force when the adhesive surfaces are attached to each other, while “re-peel force” refers to 1 day. It shows the peeling force (self-adhesion force) after being left.
In other words, “self-adhesive strength” means that an adhesive tape having a width of 20 mm and a length of 150 mm is bonded to each other with a 2 Kg roller at the center, and an adhesive temperature of 23 ° C. is applied. It means the peeling force measured after a minute at a peeling speed of 300 mm / min.
“Re-peeling force” refers to an adhesive tape with a width of 20 mm and a length of 150 mm at an ambient temperature of 23 ° C., and the adhesive surfaces are bonded to each other with a 2 Kg roller at the center . It means the peeling force measured under the condition of peeling speed of 300 mm / min after 24 hours storage at the same temperature .
[0022]
Various conventionally known tackifiers can be added to the pressure-sensitive adhesive composition of the present invention as necessary. Also, various conventionally known additives such as inorganic or organic fillers, powders such as metal powders and pigments, particulates, foils, anti-aging agents, and plasticizers can be optionally included. .
[0023]
The pressure-sensitive adhesive sheet of the present invention is formed by applying or transferring the above-mentioned pressure-sensitive adhesive composition on one side or both sides of a substrate to form a sheet or tape. Here, as a base material, conventionally well-known things, such as plastic materials, such as a polyester film, porous materials, such as paper, a nonwoven fabric, a woven fabric, and metal foil, are used arbitrarily. The kind and thickness of these base materials, the thickness of the pressure-sensitive adhesive composition, and the like can be appropriately set according to the purpose of use. In addition, the base material may be a peelable base material that is peeled off when the adhesive sheet is used. In this case, even if the base material itself has peelability, the base material surface is subjected to a peeling treatment. It may be what you did.
[0024]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, the scope of the present invention is not restrict | limited at all by the following Examples. In the following description, “parts” means parts by weight.
[0025]
Example 1
A four-neck separable flask was equipped with a stirrer, thermometer and water separation tube, and polycarbonate diol ("PLACCEL CD210PL" manufactured by Daicel Chemical Industries, Ltd., hydroxyl value: 115.0 KOHmg / g) 200 0.0 g (hydroxyl group: 0.41 equivalent), succinic anhydride 20.51 g (acid group: 0.41 equivalent), dibutyltin oxide (hereinafter referred to as DBTO) 102 mg as a catalyst, and a small amount as a reaction water discharge solvent In the presence of toluene, the temperature was raised to 180 ° C. while stirring was started, and this temperature was maintained. After a while, water outflow separation was observed, and the reaction started to proceed. The reaction was continued for about 30 hours to obtain a polyester having a weight average molecular weight of 65,000.
[0026]
This polyester was diluted with toluene to a solid concentration of 40% by weight. To 100 parts of this polyester (solid content), 3 parts (solid content) of trimethylolpropane hexamethylene diisocyanate adduct ["Colonate HL" manufactured by Nippon Polyurethane Co., Ltd.] was added as a crosslinking agent. And an adhesive solution was obtained. This pressure-sensitive adhesive solution was applied onto a polyethylene terephthalate film (hereinafter referred to as PET film) having a thickness of 38 μm by an applicator, dried at 130 ° C. for 5 minutes, and a pressure-sensitive adhesive having a thickness of 30 μm. A layer was formed. Further, as an after-car, an adhesive tape was prepared by aging for 2 days in an atmosphere at 50 ° C.
[0027]
Example 2
A four-necked separable flask was equipped with a stirrer, thermometer and water separation tube, and polycarbonate diol ("PLACCEL CD210PL" manufactured by Daicel Chemical Industries, hydroxyl value: 115.0 KOHmg / g) 250. 0 g (hydroxyl group: 0.512 equivalent), 37.44 g of adipic acid (acid group: 0.512 equivalent), 127 mg of DBTO as a catalyst were charged, and stirring was started in the presence of a small amount of toluene as a reaction water discharge solvent. The temperature was raised to 180 ° C. and kept at this temperature. After a while, water outflow separation was observed, and the reaction started to proceed. The reaction was continued for about 30 hours to obtain a polyester having a weight average molecular weight of 72,000.
[0028]
This polyester was diluted with toluene to a solid concentration of 40% by weight. To 100 parts of this polyester (solid content), 3 parts (solid content) of trimethylolpropane hexamethylene diisocyanate adduct ["Colonate HL" manufactured by Nippon Polyurethane Co., Ltd.] was added as a crosslinking agent. And an adhesive solution was obtained. This was applied onto a PET film having a thickness of 38 μm by an applicator and dried at 130 ° C. for 5 minutes to form an adhesive layer having a thickness of 30 μm. Further, as an after-car, an adhesive tape was prepared by aging for 2 days in an atmosphere at 50 ° C.
[0029]
Example 3
A four-neck separable flask was equipped with a stirrer, thermometer, and water separation tube, and polycarbonate diol ("PLACCEL CD220PL" manufactured by Daicel Chemical Industries, Ltd., hydroxyl value: 56.1 KOHmg / g) 250 0.0 g (hydroxyl group: 0.25 equivalent), sebacic acid 25.28 g (acid group: 0.25 equivalent), 62 mg of DBTO as a catalyst were charged, and stirring was started in the presence of a small amount of xylene as a reaction water discharge solvent. While raising the temperature to 180 ° C., the temperature was maintained. After a while, water outflow separation was observed, and the reaction started to proceed. The reaction was continued for about 20 hours to obtain a polyester having a weight average molecular weight of 55,000.
[0030]
This polyester was diluted with toluene to a solid concentration of 50% by weight. Hexamethylene diisocyanate trimer (isocyanurate) [“Coronate HX” manufactured by Nippon Polyurethane Co., Ltd.] 3 parts (solid content) as a crosslinking agent for 100 parts (solid content) of this polyester Was added to obtain a pressure-sensitive adhesive solution. This was applied onto a PET film having a thickness of 38 μm by an applicator and dried at 130 ° C. for 5 minutes to form an adhesive layer having a thickness of 30 μm. Further, as an after-car, an adhesive tape was prepared by aging for 2 days in an atmosphere at 50 ° C.
[0031]
Example 4
To 100 parts (solid content) of the polyester obtained in Example 3, 5 parts of trimethylolpropane triacrylate was added as a substantial cross-linking agent to prepare an adhesive solution. This pressure-sensitive adhesive solution was applied onto a PET film having a thickness of 38 μm by an applicator and dried at 100 ° C. for 5 minutes to form a pressure-sensitive adhesive layer having a thickness of 30 μm. Further, an adhesive tape was prepared by irradiating 5 Mard with an electron beam.
[0032]
Comparative Example 1
To 100 parts (solid content) of the polyester obtained in Example 3, 2 parts (solid content) of diphenylmethane diisocyanate [“Millionate MT” manufactured by Nippon Polyurethane Co., Ltd.] was added as a crosslinking agent. An adhesive solution was obtained. This pressure-sensitive adhesive solution was applied onto a PET film having a thickness of 38 μm by an applicator and dried at 130 ° C. for 5 minutes to form a pressure-sensitive adhesive layer having a thickness of 30 μm. Further, as an after-car, an adhesive tape was prepared by aging for 2 days in an atmosphere at 50 ° C.
[0033]
Comparative Example 2
100 parts of styrene-isoprene-styrene block polymer ("Califlex TR1107" manufactured by Ciel Chemical Co., Ltd.), 50 parts of petroleum resin and 1 part of phenolic anti-aging agent are dissolved in 150 parts of toluene, did. This was coated on a PET film having a thickness of 38 μm by an applicator and dried at 100 ° C. for 3 minutes to form a pressure-sensitive adhesive layer having a thickness of 30 μm, thereby preparing a pressure-sensitive adhesive tape.
[0034]
About each adhesive tape of said Examples 1-4 and Comparative Examples 1 and 2, the solvent insoluble content, self-adhesion force, and removability were measured by the following procedures. Also, tack free (presence / absence of tack) was evaluated. These test results were as shown in Table 1 below.
[0035]
<Measurement of solvent insolubles>
About 0.1 g of the pressure-sensitive adhesive was sampled and weighed accurately, and immersed in about 50 ml of toluene at room temperature for 5 days. The solvent-insoluble matter was taken out, dried at 130 ° C. for about 1 hour, and weighed. The solvent insoluble content [X] (% by weight) was calculated by the following formula.

[0036]
<Measurement of self-adhesion>
Adhesive tape with a width of 20mm and a length of 150mm was bonded with a 2Kg roller between the adhesive surfaces at the center. At an ambient temperature of 23 ° C, after 20 minutes of attachment, a peeling rate of 300mm / min. The peel force was measured.
[0037]
<Measurement of removability>
Adhesive tape with a width of 20mm and a length of 150mm at an ambient temperature of 23 ° C, the adhesive surfaces are bonded together with a 2Kg roller at the center, stored at the same temperature for 24 hours, and then peeled off at a rate of 300mm / min. The peel force was measured under the following conditions.
[0038]
<Evaluation of tack free>
When the adhesive surface of the adhesive tape was touched with a finger and it was felt that there was no tack, it was evaluated as ○, and when it was felt that there was tack, it was evaluated as ×.
[0039]

[0040]
As apparent from Table 1 above, the adhesive tapes of Examples 1 to 4 using the adhesive composition of the present invention are all tack-free and have good self-adhesive strength. At the same time, it has excellent removability. On the other hand, the adhesive tape of Comparative Example 1 has a large self-adhesion force but is inferior in removability, and the adhesive tape of Comparative Example 2 has a tack and removability. Also inferior.
[0041]
【The invention's effect】
As described above, in the present invention, a specific polymer having a polycarbonate structure is used as a main component, and this is cross-linked to a specific level, so that it does not substantially exhibit a tack, but is excellent. It is possible to provide a pressure-sensitive adhesive composition having self-adhesive strength and excellent removability and a pressure-sensitive adhesive sheet thereof.

Claims (1)

On one or both sides of the substrate, the following formula:
-(O-R-O-C) n-
‖
O
(R is a linear or branched hydrocarbon group having 2 to 20 carbon atoms)
As a polymer having a polycarbonate structure having a repeating unit represented by the formula (1), a diol component essentially comprising a polycarbonate diol having a repeating unit represented by the above formula, and a carbon number of 2 A pressure-sensitive adhesive composition composed mainly of a polyester having a weight average molecular weight of 10,000 or more, synthesized from a dicarboxylic acid component essentially comprising a dicarboxylic acid having a molecular skeleton of an aliphatic or alicyclic hydrocarbon group of -20 The product has a layer formed by crosslinking treatment, the solvent insoluble content of the polymer in this layer is 66 to 95% by weight, the self-adhesion force is 100 g / 20 mm width or more, and the re-peeling force is 2,000 g / 20 mm width or less. There are pressure-sensitive adhesive sheets .